2B+D
ISDN’s basic service is called Basic Rate Interface or BRI. BRI is made of two 64-kbps B channels and one 16-kbps D channel (2B+D).10BASE-T
The number refers to the theoretical maximum transmission speed in megabits per second (Mbit/s). The BASE is short for baseband, meaning that there is no frequency-division multiplexing (FDM) or other frequency shifting modulation in use. Each signal has full control of wire, on a single frequency. The T designates twisted pair cable, where the pair of wires for each signal is twisted together to reduce radio frequency interference and crosstalk between pairs.
20mA Current loop
A type of serial communication in which the presence or absence of an electrical signal indicates the state of the bit being transmitted.1/3" CCD chip
CCD(charge coupled device) consists of several hundred thousand individual picture elements (pixels) on a tiny 1/2", 1/3", or 1/4" chip. Each pixel responds to light falling on it by storing a tiny charge of electricity. The 1/3" CCD chip is the most widely used sensor format these days; its size is 5.5mm (diagonal), 4.4mm (horizontal) and 3.3mm (vertical). The 1/4" sensor format, recently being used in color cameras, is 4mm (diagonal), 3.2mm (horizontal) and 2.4mm (vertical).
2:1 INTERLACE
The precise combination of two fields of 312 1/2 lines to create a single frame of 625 lines. (CCIR).
3G Mobile CCTV
3G Broadband can provide remote Mobile CCTV access to IP camera systems in locations where fixed line access is not available - ideal for mobile rapid deployment CCTV systems. A combination of HSDPA or HSUPA 3G Broadband and an advanced codec like H.264 can provide high quality images at reasonable frame rates. We can organise static IP 3G connection and supply an embedded 3G router suitable for your Mobile CCTV application.
3G Router
3G Router has various connectivity options for your 3G Broadband connection. Most 3G providers will ship a USB modem or 3G card with your tariff, but in some cases you may want to buy a separate 3G WiFi Router to share your 3G connection through a local WiFi access point. You will need to purchase a 3G Wireless Router like the Billion BiPAC 7402GXL, or the BiPAC 7300GX, depending on which type of 3G device you have.
The Billion BiPAC 7402GXL is ideal for anyone who wants to share a 3G modem dongle. Plug a compatible dongle in to the built-in USB port and share it via 802.11b/g WiFi, just like standard ADSL broadband WiFi router. The 7402GXL supports most of the modems available from Vodafone.The good news is our Mobile Broadband routers are not locked to a specific network, so you can change your 3G provider in the future safe in the knowledge that your investment in hardware has not been wasted.
Our 3G Router comparison has three sections below covering 3G routers for home users, SME business users and HSDPA 3G Routers designed for industrial applications.
Here are some of the advantages a 3G solution provide:
* No telephone line required for installation - no need to liaise with engineers for the telephone line installation
* Quicker lead time of 4 to 5 days compared to telephone line and ADSL installation of approx 10 days
* 3G solutions are mobile and easily re-deployed if you need to monitor equipment for short periods of time
* A telephone line plus ADSL subscription with static IP.
960H Technology:
960H
is the new analog technology allows cameras and DVRs to capture up to 700TVL,
the highest TVL available to date. 960H represents the number of horizontal
pixels in the CCD image sensor. 960H is the highest resolution available for
analog CCTV and provides a 30% increase in resolution in comparison to D1. The
greater the resolution, the higher the definition of the video image. 960H
enables the CCTV camera to obtain high resolutions of up to 700 TVL. A 960H DVR
must complement the 960H camera to realize the high resolution video.
With
previous D1 DVRs, although you may have a 650TVL analog camera, you can only
record at D1 resolution which can clearly discern only up to 540TVL. With the
new 960H DVR, not only can it capture high-resolution 700TVL cameras, but it
can also enhance the recording quality of the existing cameras as its full
resolution of up to 700TVL will be realized.
Some of the key points of 960H Technology
- an increase in the number of pixels of nearly 30% resulting in significantly enhanced picture detail
- 700TVL highest resolution currently available in Analog
- Backward compatible with D1 cameras and DVRs
- Easily replaces existing analog installations
- Cost increase is minimal (5% to 10%)
ActiveX
ActiveX is Microsoft software component technology, mainly used by Microsoft Windows. They facilitate sharing of information between differing applications. Digital video recorders utilize ActiveX to remotely view security cameras online.
Activity Detection
Mutliplexers use this feature, which is a video motion detection technique, to give relay closure for alarms and to improve the update times of video cameras.
Analogue Signal
In video, the representation of a camera scene by varying voltages in the video signal, the voltage being directly proportional to the light level.
Anti-Aliasing
In digital signal processing, anti-aliasing is the technique of minimizing aliasing (jagged or blocky patterns) when representing a high-resolution signal at a lower resolution.
AGC
Automatic Gain Control: The electronics that regulate the gain or amplification of the video signal.
Aperture
The size of the opening in the iris, which controls the amount of light that reaches the CCD Sensor. The larger the F-Stop numbers, the less light reaches the sensor.
Attenuation
A term that refers to signal loss in a transmission system or light loss through a lens system.
ARP
Address Resolution Protocol: A protocol for mapping MAC and IP addresses. For example, in IP Version 4, the most common level of IP in use today, an address is 32 bits long. In an Ethernet local area network, however, addresses for attached devices are 48 bits long. (The physical machine address is also known as a Media Access Control or MAC address.) A table, usually called the ARP cache, is used to maintain a correlation between each MAC address and its corresponding IP address. ARP provides the protocol rules for making this correlation and providing address conversion in both directions. Here is how ARP works:
When an incoming packet destined for a host machine arrives at a LAN gateway, the gateway requests the ARP program to find a physical host (or MAC address) that matches the packet IP address. If a positive match is found within the ARP cache, the packet data is formatted to the appropriate packet length and sent to the machine with the matching address. If a matching entry is not found for the IP address, ARP then broadcasts an IP address query to all machines on the LAN. The machine recognizing this IP address sends a reply to confirming it as its own. ARP updates the ARP cache for future reference and then sends the packet to the MAC address that replied.
Auto Black
A technique of boosting the video signal level to produce a full amplitude video signal, even when the scene contrast is less than full range (glare, fog, mist, etc.). The darkest part of the signal is set to black and the lightest part to white, thus increasing the contrast.
Auto Dome
Fully integrated, high speed, pan/tilt/zoom camera built into a protective dome housing allowing full and continuous 360 degrees coverage of the scene.
Auto Focus
The lens continuously adjusts to the correct focus automatically lock on to a moving target or person and follow its movement. The tracking processing and control are all handled by the internal electronics in the camera.
Auto Iris
A lens with a mechanical iris which is controlled by a motor or other electrical device and responds to the changing video levels produced by a camera.The iris will be driven more open as the light hitting the image device becomes less and less and visa versa with an increase in light. The lens automatically adjusts the amount of light reaching the imager.
Auto Pan
The camera pans continuously between right and left limit settings.
Auto Homing
An automatic sequential video switcher which has manual switches or buttons which allow a single camera to be displayed on screen without sequential switching.
AutoPlayback
This function records the sequence of movements of the camera's PTZ for later playback allowing a set pattern to be repeated automatically. This function is often called Guard Tour.
Auto White Balance (AWB)
Automatically adjusts a color camera's color to maintain white areas.
Auto Balance
A system for detecting errors in color balance in white and black areas of the picture and automatically adjusting the white and black levels of both the red and blue signals as needed for correction.
Aspect Ratio
The ratio of the vertical to the horizontal image size; 3:4 is the NTSC standard. Differing mediums such as television, HDTV (16 X 9 ), and film, use different aspect ratios. Within computer graphics, it refers to the shape of an individual pixel in a digital image.Example: A 15” monitor (measured diagonally) is 12” wide and 9” tall. The width is four increments of 3” and the height is 3 increments of 3” therefore the ratio is 4 to 3
Antenna
An antenna (or aerial) is an electrical device which converts electric currents into radio waves, and vice versa. It is usually used with a radio transmitter or radio receiver. In transmission, a radio transmitter applies an oscillating radio frequency electric current to the antenna's terminals, and the antenna radiates the energy from the current as electromagnetic waves (radio waves). In reception, an antenna intercepts some of the power of an electromagnetic wave in order to produce a tiny voltage at its terminals, that is applied to a receiver to be amplified. An antenna can be used for both transmitting and receiving.
AVC (Advanced Video Coding)
Both the ITU and MPEG groups have agreed upon AVC as the current video compression standard. ITU calls it H.264, the MPEG group refers to it as MPEG-4, and the public calls it AVC.
APNR
Automatic Number Plate Recognition (ANPR) is probably the next growth product to take off in the world in fact, it is already beginning to be the biggest potential earner for installation companies. On the other hand ANPR technology is completely within the scope of knowledge of CCTV companies, although there are a few new terms and technologies to come to grips with.The camera must be sensitive to the infrared part of the spectrum, to at least 850 nanometres. Then it must be fitted with a filter to restrict the visible part of the spectrum. The lens would have a manual iris set fully open and the shutter speed set to 1/1000th second. Finally an infrared source must be fitted adjacent to the camera.
ALC (Automatic Light Control)
Allows the auto-iris circuitry to either take bright spots more into consideration (peak), bringing out detail in bright areas, or less into consideration (average) bringing out detail in shadows. Select this mode when an auto-iris lens is used.
Analog Video Resolutions
Video surveillance solutions use a set of standard resolutions. National Television System Committee (NTSC) and Phase Alternating Line (PAL) are the two prevalent analog video standards. PAL is used mostly in Europe, China, and Australia and specifies 625 lines per-frame with a 50-Hz refresh rate. NTSC is used mostly in the United States, Canada, and portions of South America and specifies 525 lines per-frame with a 59.94-Hz refresh rate.
These video standards are displayed in interlaced mode, which means that only half of the lines are refreshed in each cycle. Therefore, the refresh rate of PAL translates into 25 complete frames per second and NTSC translates into 30 (29.97) frames per second. Table shows resolutions for common video formats
Table of Analog Video Resolutions (in pixels)
Format NTSC-Based PAL-Based
QCIF 176 × 120 176 × 144
CIF 352 × 240 352 × 288
2CIF 704 x 240 704 x 288
4CIF 704 × 480 704 × 576
D1 720 × 480 720 × 576
Linear dimensions of 4CIF are twice as big as CIF. As a result, the screen area for 4CIF is four times that of CIF with higher bandwidth and storage requirements. The 4CIF and D1 resolutions are almost identical and sometimes the terms are used interchangeably.
AutoScaling
As the camera zooms in to increase the size of objects on the monitor screen, the pan and tilt speeds are reduced so that the relative speed on the screen remains constant for similar joystick control positions.
Base StationA base station is a radio receiver/transmitter that serves as the hub of the local wireless network and may also be the gateway between a wired or fibre network and the wireless network.
Backhaul
In a structured telecommunications network the backhaul portion of the network comprises the intermediate links between the core network (backbone), of the network and the small subnetworks at the edge of the entire network.
Bullet Security Cameras
Bullet Security Cameras are small Video Cameras that are shaped like a rifle bullet. These cameras are typically the width of a cigar, but they are shorter. Infrared Bullet Cameras are larger in diameter than standard bullet cameras. Bullet Cameras easily mount on ceilings or walls. The main advantage of Bullet Cameras is their low cost and small size. Although they have a low cost and are very small, they still provide excellent Picture Quality and Video Recording.
Infrared Bullet Security Cameras are for Day and Night applications. If you need night surveillance, an excellent camera to consider is the Infrared Bullet Camera, which can see up to 100 feet in complete darkness. Bullet Security Cameras are ideal for both indoor and outdoor installations and all of our Bullet Cameras include a Mounting Bracket and a Power Supply.
Balun
Short for Balance/Unbalanced. A device that converts a balanced video signal (e.g. as used on twisted pair) line to an unbalanced signal (e.g. as used on coax). In a balanced line both wires are electrically equal. In an unbalanced line one wire has different electrical properties than the other. CCTV video baluns, also known as UTP baluns, allow traditional coax cable to be replaced by category 5 and other forms of twisted pair wire in CCTV video camera & surveillance installations. Video baluns allow installers to use more cost effective structured cabling techniques to wire security cameras. By using video baluns, UTP wire such as cat-5 can be run over longer distances easier than coax cable and for less money. Active balun transceivers enable UTP wires for cameras to be run distances up to 3,000 feet.
Backlash
Backlash (measured in degrees) is when a camera’s Pan Tilt head cannot stop instantaneously, and is usually caused by excessive looseness in gears, pulleys, or other parts.Pre set PTZ surveillance cameras are rendered ineffectual by Backlash.
Baud
Unit of measure for the speed of data transmission. For example, if a modem is rated at 9600 baud it is capable of transmitting data at a rate of 9600 bits per second.
Bandwidth
The capacity of the transmission medium stated in bits per second or as a frequency. Or, the amount of data that can be transmitted in a fixed amount of time. For digital devices, the bandwidth is usually expressed in bits per second (bps) or bytes per second. For analog devices, the bandwidth is expressed in cycles per second, or Hertz (Hz). Example: A bandwidth of 800 Mhz (Megahertz) would be 800 Mhz wide starting from any point (100 Mhz) and ending 800 Mhz above (900 Mhz). Specific to television technology bandwidth can be related to system resolution or lines of resolution. Where 1 Mhz of bandwidth is equal to 100 lines of resolution.
Brightness
The attribute of visual perception in accordance with which an area appears to emit more or less light (Luminance is the recommended name for the photo-electric quantity which has also been called brightness).
Back Light Compensation (BLC)
Electronically compensates for high background lighting to give detail which would normally be silhouetted. So Cameras with this feature will automatically bring more detail to darker areas of an image when bright lights (usually shining from behind) obscure it.
Blooming
This refers to the defocusing and glow present around the bright areas of a picture when the brightness is increased. Some video cameras feature blooming suppression abilities to avoid this.
Bitmap
Bitmap defines a display space and the color for each pixel or "bit" in the display space. GIF and a JPEG are examples of graphic image file types that contain bit maps. A bit map does not need to contain a bit of color-coded information for each pixel on every row. It only needs to contain information indicating a new color as the display scans along a row. Thus, an image with much solid color will tend to require a small bit map. Because a bit map uses a fixed ‘raster’ method for specifying an image, a user cannot immediately rescale the image without losing definition. Conversely, a vector graphic image is designed to be quickly rescaled. When an artist is satisfied with an image, it is typically created using vector graphics and then converted to (or saved as) a raster graphic file, or bit map.
Burned-In-Image
Also called burn. An image which persists in a fixed position in the output signal of a camera tube after the camera has been turned to a different scene or, on a monitor screen.
Binning
The sensitivity of a CMOS sensor or CCD sensor depends, amongst other factors, on the pixels' size. The larger it is, the lighter it is able to "capture". From another point of view, smaller pixels are more suitable.
Some CMOS cameras and CCD cameras allow the adjustment of the size of their pixels by software. This method is based on the merging of pixels directly on the chip - called binning. The resolution of the CCD or CMOS sensor decreases accordingly.
Usually, the binning process merges 2x2 or 4x4 pixels. Thus, theoretically the sensitivity increases by 4 and 16 respectively, while the resolution decreases by the same factor. In practice, however, the sensitivity increases 3 to 10 times.
In the case of color cameras, binning does not always lead to satisfying results. Depending on the object's position and color there may be more or fewer jagged edges in the image.
BNC
Bayonet Neil-Concelman or British Naval Connector. A connector widely used in the CCTV industry, usually for coaxial cable. Easy to install and reliable with little video signal loss. Pictures of BNC Connectors
Bridging
A term used to describe a type of automatic sequential switcher which has the ability to send a signal to two monitors (dual output) one continually sequencing and the second one able to display any one of the camera inputs on the “bridged” monitor. There are two methods of bridging a second monitor. The first is passive where the video signal is “T”ed off the incoming line and sent to the second monitor, in this case the “bridged” monitor must be unterminated. The second method is active where the video signal is regenerated by a distribution amplifier in the switcher and sent to the “bridged” monitor in which case the monitor must be terminated. The bridging switchers are not always marked as being active or passive so attention must be given to the video signal on the “bridged” monitor to be sure if the termination must be set to on or off.
Bit/s
Bits per second, the actual data rate.
BOOTP
BOOTP (Bootstrap Protocol) is a protocol that lets a network user be automatically configured (receive an IP address) and have an operating system booted or initiated without user involvement. The BOOTP server, managed by a network administrator, automatically assigns the IP address from a pool of addresses for a certain duration of time. BOOTP is the basis for a more advanced network manager protocol, the Dynamic Host Configuration Protocol (DHCP).
Camera Resolution
The industry of CCD video camera sensor uses pixels (picture elements) as its quality parameter. Medium resolution of B/W camera in EIA system is 510 horizontal pixels by 492 vertical pixels and is equivalent to 380 TV lines. High resolution is 768(H) x 492(V) pixels and equivalent to 570 TV lines. Color camera's medium resolution means 330TV lines and high resolution needs more than 460 TV lines.
CCTV Installation
A CCTV system or associated group of systems, together with all necessary hardware,
auxiliary lighting, etc.
Category 5 (CAT 5)
Twisted pair wire with data rate to 100Mbps (1000 Mbps with 4 pair). No longer supported replaced by CAT 5E (1000 Mbps).
C-Mount
An industry standard for lens mounting. The flange back (distance from the surface where the lens comes in contact with the camera to the focal point) of C-Mount lens is 17.526mm (0.69 inch). This is the only difference between the C-Mount lens and CS-Mount lens. C-Mount lens, as well as CS-Mount, is 1 inch diameter with 32 TPI (threads per inch). A C-Ring (5mm spacer ring) is required when a C-Mount lens is to be mounted to a CS-Mount camera unless the camera has built-in Flange-back Adjusting Ring.
CS-Mount Lens
The flange back of CS-Mount lens is 12.5mm(0.492 inch). This is 5mm shorter than the C-Mount lens and you need a 5mm spacer ring (or, C-ring) when you mount a C-Mount lens to a CS-Mount camera. (So, CS-Mount camera is always compatible with C- or CS-Mount lens. But, C-Mount camera is not compatible with CS-Mount lens. Most professional cameras are CS-Mount cameras and include a C-ring.)
CCIR
International Radio Consultative Committee; has made the technical recommendation for the European 625 line standard for video signals.
CCTMA
Closed Circuit Television Manufacturers Association.
Cameo
A small part of a monitor’s viewing area (1/16th the screen area) is called a cameo. Multiplexers create multiple analog signals from security cameras and then combine them into multiple cameos on the screen, which enables simultaneous viewing of up to sixteen different camera pictures.
Candela
A candela is a measurement of luminous intensity and is a replacement to the candle.
CCTV
Closed Circuit Television. It does not broadcast TV signals but transmits them over a closed circuit through electrically conducting cable or wireless transmitter and receiver.
Covert Camera
Covert Cameras, in essence, are a means of offering surveillance of an undetected or more discreet nature. Suitable for use in a broad range of internal applications these miniature Cameras have been designed and developed to provide monitoring tools that are disguised in the form of everyday commercial and domestic objects.Covert cameras tend to be used where there is a requirement to achieve particular objectives.
Covert surveillance
where there is a requirement to monitor activities in a particular location, completely undetected, e.g. in areas of high security like jewellers and banks. They are also useful for back-up surveillance in installations where the primary CCTV equipment is of a more traditional nature, i.e. standard cameras. In this case Covert. Cameras can operate as a back-up where primary cameras are disabled by an intruder.
Crosstalk
In a multiplex signal, video, audio, or data channels with adjacent signal frequencies can create interference. This interference produces a noise known as crosstalk.
CCTV Camera
A part of the CCTV system that captures the video pictures.
Camera Housing
An environmental protective enclosure for a cctv camera. Can include a heater for winter and blower for summer.
CBR
Constant bitrate (CBR) is a term used in telecommunications, relating to the quality of service. Compare with variable bit rate VBR.
When referring to codecs, constant bit rate encoding means that the rate at which a codec's output data should be consumed is constant. CBR is useful for streaming multimedia content on limited capacity channels since it is the maximum bit rate that matters, not the average, so CBR would be used to take advantage of all of the capacity. CBR would not be the optimal choice for storage as it would not allocate enough data for complex sections (resulting in degraded quality) while wasting data on simple sections.
Most coding schemes such as Huffman coding or run-length encoding produce variable-length codes, making perfect CBR difficult to achieve. This is partly solved by varying the quantization (quality), and fully solved by the use of padding. (However, CBR is implied in a simple scheme like reducing all 16-bit audio samples to 8-bits.)
CIF (Common Intermediate Format)
The default frame resolution of 352x288 for DVR systems is known as the CIF.
Color Purity
The degree to which a color is free of white or any other color. In reference to the operation of a tri-color picture tube it refers to the production of pure red, green or blue illumination of the phosphor dot face plate.
CCTV Monitor
A part of the CCTV system that receives the video pictures from a CCTV camera and displays them.
Cable Category
Application and bandwidth rating system for UTP cabling. Categories 1 through 7 are based on EIA/TIA-568-B standards. Category is typically abbreviated CAT. UTP Category 5, 5e, 6, and 7 are used for Ethernet data cabling applications. Ethernet wiring distances are limited to a maximum of 100m (328ft.) when using UTP wiring.
Coaxial Cable
A cable that can carry a wide range of frequencies with very low signal loss. It consists of a metallic shield with a single wire placed along the center of a shield and isolated from the shield by an insulator.
Cable Joints
Every joint in a cable produces a small change in the impedance at that point. The mechanical layouts of the conductors change where it is joined. This cannot be avoided. However, the changes in impedance should be minimised by using the correct connectors. When in line joints are being made, ensure the mechanical layout of the joint follows the cable layout as closely as possible. The number of joints in a cable should be minimised, as each joint is a potential source of problems and will produce some reflections in the cable.
CCD
Charged Coupled Device: A type of solid state image sensor used in CCTV cameras. The sensor converts light energy into electrical signals. Its size is measured diagonally and can be 1/4", 1/3", 1/2" or 2/3". CCD stands for Charge Coupled Device, which is the new age imaging device, replacing the old image tube.
Commissioning
The completion of installation and final testing of a system prior to its handover. The installing/commissioning company should have and use a commissioning checklist
detailing the checks to be carried out when a system is commissioned prior to handover to the customer. The system should be thoroughly checked electrically, mechanically and visually to ensure that it conforms fully to this Code of Practice and the customer’s system specification before being handed over to the customer. Installation work should be executed with an appropriate degree of skill and workmanship. In larger systems, inspection should be carried out at frequent intervals during the installation of the system. Where practicable, commissioning and inspection should be carried out by company personnel other than those who installed the equipment. Commissioning engineers should carry out the procedures detailed on the organisation’s commissioning checklist.
CATV
Cable Access Television.
CONTRAST RANGE
The ratio between the whitest and blackest portions of television image.
Cable ties: Where cable ties are used, they shall not be over-tightened because of the possible damage to the performance of coaxial cables.
CCTV Surveillance Vehicles
CCTV Surveillance vehicles are amongst the most versatile and cost-effective solutions to a vast range of surveillance problems and yet their use to date has been restricted in the main to Police Authorities.
The focus on tackling Crime and Disorder issues and the increased enforcement roles of Local Authorities created by deregulation of traffic and environmental offences creates differing surveillance issues for the newly empowered enforcement agencies. A CCTV Surveillance vehicle can be equipped with a range of cameras and recording equipment, which produces evidential quality images comparable with those produced by a central control room and fixed installations. The specification and range of equipment depends on the end users surveillance issues but can include a mix of fixed & PTZ cameras, digital or analogue recording, ANPR systems with on site editing & playback facilities.
Units are usually designed with a combination of power supplies that cater for silent, covert surveillance with up to 24-hour capacity or continuous surveillance utilising the vehicle's power sources. Surveillance vehicles can be deployed to monitor incidents in static locations or on the move, up to 70 mph. Particular attention is given to the safety and comfort of operators who are often exposed to potentially volatile surveillance situations.
CCTV Surveillance Vehicle Uses
1. Anti Social Behaviour.
2. Crime Prevention & Prosecution.
3. Traffic Enforcement i. Bus Lane Enforcement ii. Enforcement of On Street Parking Offences iii. Environmental Enforcement iv. Emergency Planning etc
Customer
A person or organisation utilising any or all of the services of a company for the design,installation and/or maintenance of a Closed Circuit Television System.
Client/Server
Client/server describes the relationship between two computer programs in which one program, the client, makes a service request from another program, the server, which fulfills the request. Although programs within a single computer can use the client/server concept, it is a more relevant in a network. In a network, the client/server model provides a convenient way to interconnect programs that are distributed efficiently across different locations. Computer transactions using the client/server model are very common.
For example, to check your bank account from your computer, a client program in your computer will need to forward your enquiry to a server at the bank. The bank’s server program responds by forwarding that query – via it’s own client program – to a database running on another server at yet another bank. Your balance information is returned to the requesting data client at your bank, that in turn serves it back to the client in your personal computer. Your huge bank balance is subsequently displayed on the screen.
The client/server model is one of the founding concepts of network computing. Most business applications written today use the client/server model—as does the Internet's main program, TCP/IP. In marketing, the term has been used to distinguish distributed computing by smaller dispersed computers from the 'monolithic‘ centralized computing of mainframe computers. But this distinction has largely disappeared as mainframes and their applications have also turned to the client/server model and become part of network computing.
In the usual client/server model, one server, sometimes called a daemon, is activated and awaits client requests. Typically, multiple client programs share the services of a common server program. Both client programs and server programs are often part of a larger program or application. Relative to the Internet, your Web browser is a client program that requests services (the sending of Web pages or files) from a Web server (which technically is called a Hypertext Transport Protocol or HTTP server) in another computer somewhere on the Internet. Similarly, your computer with TCP/IP installed allows you to make client requests for files from File Transfer Protocol (FTP) servers in other computers on the Internet.
Other program relationship models included master/slave, with one program being in charge of all other programs, and peer-to-peer, with either of two programs able to initiate a transaction.
Composite Video Signal
An electrical signal conveying all of the elements of the image such as synchronisation pulse, luminance (monochrome intensity) and if it is a colour signal, chrominance (the colour component).
Conduit: when metal or plastic conduit is used suitable bushes or grommets should be fixed to each end to prevent damage to the cable. Where metal conduit is cut any protective medium, such as galvanise shall be repaired. When conduit is used to carry the, cable it must terminate as close as possible to the unit to be connected.
CCD Format
Indicates the size of the camera sensor used. In general, the larger the sensor, the more sensitive the camera and the better the image quality. The format is quoted in inches, for example 1/4 or 1/3 inch.
CE
CE stands for Conformité Européenne, a French term that can be literally translated into English as European Conformity. The foreword to CE Marking, The New European Legislation for Products, by Kluwer Business Information.
The CE Marking offers great advantages to trade and industry in the United States. The new European legislation has created a uniform market within Europe. Up to now, American manufacturers and exporters have had to deal with various sets of national legislation within Europe. Thanks to the introduction of CE Marking, the trade constraints between Member States of the European Economic Area (EEA) have disappeared. The CE Marking forms, as it were, the "trade passport" for products within the EEA.
The CE testing is primarily EMC and safety related, with the protection of the public and consumers being a primary concern. A further goal is the harmonization of related national regulations, the reduction of regulatory barriers between European countries, and the facilitation of the movement of goods between them.
CHAP
CHAP (Challenge-Handshake Authentication Protocol) is a more secure procedure for connecting to a system than the Password Authentication Procedure (PAP). Here's how CHAP works:
Once the link is established, the server sends a challenge message to the connection requestor. The requestor responds with a value obtained by using a one-way hash function. The server checks the response by comparing it with its own calculation of the expected hash value. If the values match, the authentication is acknowledged; otherwise, the connection is usually terminated. At any time, the server can request the connected party to send a new challenge message. Because CHAP identifiers are changed frequently and because the server can request authentication at any time, CHAP provides greater security than PAP. RFC1334 defines both CHAP and PAP.
CSA approval
Every electrical device or component must be certified by the Canadian Standards Association (or recognized equivalent) before it can be sold in Canada. Implicit in this is that all wiring must be done with CSA-approved materials.They perform esting similar to the UL (a bit more stringent), except that CSA (or recognized equivalent) approval is required by law. Again, like the UL, if a fire was caused by non-CSA-approved equipment, your insurance company may not have to pay the claim.
COFDM (Coded Orthogonal frequency-division multiplexing)
COFDM is a frequency-division multiplexing (FDM) scheme used as a digital multi-carrier modulation method. A large number of closely-spaced orthogonal sub-carriers are used to carry data. The data is divided into several parallel data streams or channels, one for each sub-carrier. Each sub-carrier is modulated with a conventional modulation scheme (such as quadrature amplitude modulation or phase-shift keying) at a low symbol rate, maintaining total data rates similar to conventional single-carrier modulation schemes in the same bandwidth.
D1
D1 is a resolution of 720x486 (NTSC) or 720x576 (PAL), and was one of Sony’s first digitized videotape formats.
Digital Video Resolutions
User expectations for resolution of video surveillance feeds are increasing partially due to the introduction and adoption of high-definition television (HDTV) for broadcast television. A 4CIF resolution, which is commonly deployed in video surveillance, is a 4/10th megapixel resolution. The HDTV formats are megapixel or higher. Table lists the typical resolutions available in the industry.
Size/ Format Pixels
QQVGA 160x120
QVGA 320x240
VGA 640x480
HDTV 1280x720
1M 1280x960
1M 1280x1024
2M 1600x1200
HDTV 1920x1080
3M 2048x1536
Depth Of Field
A specific “window” of distance in which objects remain in focus. Example – a camera’s field of view will present a picture encompassing a distance of 200 feet from the camera; objects in the picture are in focus at a distance of 10 feet to 90 feet within the picture. The window or depth of field is 80 feet for this example. The depth of field will change in relation to the change in F-stop where the depth of field increase as the F-stop increases (F-numbers get larger).
Depth Of Focus
The range of sensor-to-lens distance for which the image formed by the lens is clearly focused.
DAS
Direct attached storage is the term used to describe a storage device that is directly attached to a host system. The simplest example of DAS is the internal hard drive of a server computer,though storage devices housed in an external box come under this banner as well. DAS is still,by far,the most common method of storing data for computer systems. Over the years,though, new technologies have emerged which work, if you'll excuse the pun, out of the box.
Dome Cameras
Dome Security Cameras are named for their dome like shape. Dome Cameras are commonly used in surveillance systems inside of Casinos, Retail Stores, and Restaurants. This is because dome cameras are more fashionable and blend in very well to their surroundings. Because of their dome shape, it is difficult for someone to tell which direction the lens of the camera is pointing. When shopping for a dome camera, you should consider if you need night vision, in which case you should look at an infrared dome camera. If the area that you are installing your camera is susceptible to vandalism or tampering, you should consider installing an armor dome camera. A varifocal dome camera gives you the flexibility to adjust the focal distance of the camera lens to exactly where you need it. We also offer outdoor surveillance cameras that have armor domes to deter vandalism. CCTV Camera Pros offers combinations of all of the above mentioned types of Dome Cameras.
Digital Watermark
Digital watermark technology embeds the device information onto
the recorded video. Digital watermarks may be used to verify the
authenticity or integrity of the video or to show the identity of its owners.
DISTORTION
The deviation of the received signal waveform from that of the original transmitted waveform.
DIGITAL SIGNAL PROCESSING
An algorithm within the camera that digitizes data (the image). Examples include automatic compensate for backlight interference, color balance variations and corrections related to aging of electrical components or lighting. Functions such as electronic pan and zoom, image annotation, compression of the video for network transmission, feature extraction and motion compensation can be easily and inexpensively added to the camera feature set.
DivX
DivXNetworks created DivX, a MPEG-4 digital video technology. Among its benefits is compression technology, which allows DivX equipped network cameras to store a month of video on a 20’gigabyte hard drive.
DISTRIBUTION AMPLIFIER
A device that provides several isolated outputs from one looping or bridging input, and has a sufficiently high input impedance and input-to-output isolation to prevent loading of the input source.
DSL (Digital Subscriber Line)
DSL is a digital telecommunications protocol that allows existing copper phone lines to be used for high-speed transfer of data between home and business end-users. xDSL refers to the various types of Digital Subscriber Lines which include: ADSL (Asymmetric DSL), SDSL (Single-line DSL), HDSL (High-data-rate DSL) and VDSL (Very-high-data-rate DSL). In theory, ADSL (the most common of these types), allows for download speeds of up to 9 Mbps and upload speeds of up to 640 Kbps. In reality, commercial performance is normally up to 1.544 Mbps download and 128 Kbps upload.
Dynamic IP address
This is the rotation of IP addresses such that every time a user logs onto the Internet, their IP address changes. This is done for Internet security purposes, either by the user or by their ISP. This process can interfere with the use of networked devices such as Network IP Cameras because they normally require a static IP address to function properly.
Dwell
The length of time a picture from a single camera stays on the screen. Usually associated with automatic sequential switchers.
Defog
By modeling the imaging features of smoke, dust, fog, etc., defog
technology effectively restores details and color to obtain accurate and
natural video. Defog technology helps maintain clarity in images captured in
poor weather conditions such as rain, smog, or fog.
Day/Night (IR sensitive)
A camera that has normal color operation in situations where there is sufficient illumination (day conditions), but where the sensitivity can be increased when there is little light available (night conditions). This is achieved by removing the infrared cut filter required for good color rendition. The sensitivity can be further enhanced by integrating a number of frames to improve the signal-to-noise ratio of the camera.
DHCP
Dynamic Host Configuration Protocol: In simple terms, DHCP determines if your IP is static or dynamic and the length of time an IP address is assigned.
Dynamic Host Configuration Protocol is controlled by a DHCP server. Your router can be a DHCP server...and if you're on a home network, it most likely serves this purpose.
I know this might be confusing because the word dynamic is in the term, but just because you have DHCP enabled on your computer doesn't mean you can't be assigned a static IP. DHCP enabled on your computer simply means you're letting a DHCP server assign its IP. Having it enabled DOES NOT mean it's a DHCP server.
A true DHCP server (not your Linksys router) gives the LAN Admin a ton of control with IP assigning.Under the General Setup or LAN Setup tab in your router, you'll see a settings option for DHCP. You can control how many IPs are assigned or to enable /disable the DHCP server portion of the router. If you disable it, you'll have to statically assign IPs to each computer, or have a DHCP server or your network. This goes for wired and wireless. Any connection on your network has an IP address.
DNS
Domain Name System: A service that stores domain names and translates them into Internet Protocol (IP) addresses.It is much easier for us to remember a word than a series of numbers. The same is true for email addresses.
For example, it is much easier for you to remember a web address name such as arindamcctvaccesscontrol.blogspot.com than it is to remember 122.168.1.1 or in the case of email it is much easier to remember cctv.accesscontrol@somedomain.com than cctv.accesscontrol@122.168.1.1
DVR
Digital Video Recorder; records video pictures digitally on a hard disk drive (HDD). This HDD, usually built-in, has capacity of 250 GB, 320 GB or 1.5TB to store the records. You can program the picture resolution and recording speed (how many frames per second) according to the application; real-time or time lapse recording also available. Overwriting the oldest pictures is programmable.
Event alarm recording which records only when a movement is captured within the image frame is easier to program and more reliable than the Time Lapse VCR's alarm recording function. You just assign dots over the screen where you want to detect the movement. As DVR records digitally, the image quality remains the same regardless of how many times the images are stored or rerecorded. And, you can select images quickly by using time/date or alarm search, or just browsing through.
Decibel (dB)
Cable and amplifier performance are usually defined as a certain loss or gain of signal expressed in Decibels (dB). The dB is not a unit of measure but is a way of defining a ratio between two signals. The dB was originally developed to simplify the calculation of the performance of telephone networks, where there were many amplifiers and lengths of cable on a network.
The calculations become extremely difficult, and often produce very large figures using ordinary ratios, when many of them have to be multiplied and divided to work out the signal levels of the network. However these calculations become relatively simple if the ratios are converted to the logarithm of the ratio, which can then be just added and subtracted. This therefore, is the reason for using the decibel, which in simple terms is:
10 x log (ratio)
This dB (power dB) is often used to measure power relative to a fixed level. It is not a measure in its own right. If the impedance at which the measurements are made is constant, the dB becomes 20 x log (ratio). This is the dB (voltage dB) which is normally used to define cable loss or amplifier gain in the CCTV industry.
The advantage of using this method becomes obvious when working out the performance of a network containing more than one or two items. Many people who do not use dBs all the time have problems relating them to real ratios. The key figures to remember are:
If the ratio is 2:1, then 20 x log 2= 20 x .310 = 6.021, e.g. 6dB.
If the ratio is 10:1, then 20 x log 10= 20 x 1 =20, e.g. 20 dB.
If the ratio is 20:1, then 20 x log 20= 20 x 1.3=26, e.g. 26 dB.
Similarly a ratio of 100:1 is equal to 40 dB.
Therefore, put in reverse, some common ratios are:
6 dB is a loss or gain of 2:1
20 dB is a loss or gain of 10:1
26 dB is a loss or gain of 20:1
40 dB is a loss or gain of 100:1
DFS (Dynamic Frequency Selection)In radio resource management of a wireless network, channel allocation schemes are required to allocate bandwidth and communication channels to base stations, access points and terminal equipment. The aim is to achieve maximum system spectral efficiency by means of frequency reuse, but still assure a certain grade of service by avoiding co-channel interference and adjacent channel interference among nearby cells or networks that share the bandwidth. Dynamic Frequency Selection (DFS) is one such approach and may be applied in wireless networks with several adjacent non-centrally controlled access-points. The access-points automatically select a frequency channel with low interference level.
Earth Currents
When installing TV cameras or other equipment on large sites, the potential of the earth connection provided for the equipment can vary by quite large voltages (up to 50 Volts). This can produce high currents in cables connected between different points on the site and will produce interference on the video signal.
Most video equalising amplifiers have differential inputs that can reject a certain amount of interference due to earth potential variations (up to 10 Volts). However, it is good practice, and a safe precaution, to break the earth connection using a video transformer or opto-coupled equalising amplifier on long cables. It is not safe or legal to remove earth connections from equipment and rely on the earth provided by the video cable.
ELC (Electronic Light Control)
Compensates for moderate light changes in indoor applications without the use of auto iris lenses. Select this mode when a fixed iris lens or manual iris lens is used.
Electronic Shutter
Electronic Shutter, one of the major features of CCD camera, is not really a moving shutter, but a clever piece of signal processing. Under low light conditions, the CCD is allowed to gather signal at the electronic shutter speed of full 1/60th of a second. Under brighter lighting conditions, the video processing chip automatically responds by reading the CCD and then immediately "early purging" it, resulting in precise control over the video level. Even at a shutter speed of 1/100,000th of a second, the CCD camera is still delivering 60 images per second, but each image is gathered over a much shorter period of time. It doesn't end with the CCD...the image is constantly monitored and optimized by advanced on board signal processing circuitry. The end result is a fantastic picture, with no fiddling, no adjustments, and best of all, unbelievable reliability.
Ethernet
The most commonly used local area network (LAN) access method. Ethernet complies with the IEEE 802.3 standard. The Ethernet standard supports 10 Mbps, 100 Mbps, 1000 Mbps, and 10 GB (Gigabit) data transmission rates.
External Synchronization
A means for ensuring that all equipment in a CCTV system is synchronised to one source.
Equalizer
An electronic circuit that introduces compensation for frequency discriminative effects of elements within the television system, particularly long coaxial transmission systems.
E-mail notification
This is a feature of certain motion detecting Network IP Cameras. When activity is detected, they can email authorized users images or video. Griffid is one example of camera management software that accomplishes this.
Embedded operating system
Cameras with this can also operate as computers. With an OS like Linux installed, they can perform other tasks such as sending images to a web site via FTP, email notification, and being simultaneously accessible by multiple users.
ETRAX
The ETRAX ( Ethernet Token Ring AXIS) chip is the cornerstone of Axis technology and the 'brain' in nearly all Axis products. A multipurpose Linux chip with integrated Ethernet networking and extremely flexible I/O options.
Environmental Housings
Equipment enclosures and associated accessories, such as heaters, washers and wipers, to meet specified environmental conditions. Usually given an IP rating.
Extruded aluminum
This type of aluminum is used to construct housings for CCTV (closed circuit television) applications and provides the added benefits of increased strength, durability and resistance to harsher environmental conditions as compared to plastics.
EIS
In conditions with slight vibrations (e.g., an electrical pole in
strong winds), videos will appear fuzzy due to the vibration. EIS (Electronic
Image Stabilization) can help reduce the effects of vibration in a video.
Fiber Optic Transmission
Refers to the transmission of video and data via optical fibers. Optical fibers are thin glass strands that are designed for light wave transmission. Video and data are digitized and transformed into a series of light pulses. There are two primary types of optical fiber; singlemode and multimode. Singlemode fiber is used when large distances must be spanned, typically greater than 2 Km/1.2 miles. Multimode is typically used to span smaller distances such as the inside of buildings or on small campuses
FlexiDome
Fixed compact cameras in surveillance domes with economical, indoor models and high-performance, vandal resistant styles.
Flange-back Adjusting Ring
Some models of CCTV cameras have built-in Flange-back Adjusting Ring, which adjusts the back-focal distance or picture focus. A C-Ring (5mm spacer ring) is not required when a C-Mount lens is to be mounted to a camera that has built-in Flange-back Adjusting Ring.
FTP (File Transfer Protocol)
FTP (File Transfer Protocol), a standard protocol, is the simplest way to exchange files between computers on the Internet. Like the Hypertext Transfer Protocol (HTTP), which transfers displayable Web pages and related files, and the Simple Mail Transfer Protocol (SMTP), which transfers e-mail, FTP is an application protocol that uses the Internet's TCP/IP protocols. FTP is commonly used to transfer Web page files from their computer of origin to a publicly accessible computer server for everyone on the Internet. FTP is also commonly used to download programs and other files to your computer from other servers.
As a user, you can use FTP with a simple command line interface (for example, from the Windows MS-DOS Prompt window) or with a commercial program that offers a graphical user interface. Your Web browser can also make FTP requests to download programs you select from a Web page. Using FTP, you can also update (delete, rename, move, and copy) files at a server. You need to log on to an FTP server. However, publicly available files are easily accessed using anonymous FTP.FTP is usually provided as part of a suite of programs that come with TCP/IP.
FPS
Frames per second describes the number of full video framesrealtime video consists of 30 frames / sec. for NTSC format and 25 frames / sec. for PAL format. Be sure not to confuse frames per second with "fields per second" or "images per second". A complete frame of video is compiled of two separate images (or fields), so the number of fields in one second is always twice the number of frames per second.
FRAME
In video it is one still picture with a duration or dwell time of 1/30th of a second made up of 525 horizontal lines. A frame is made from two fields each having 262 &Mac189; horizontal lines which are interlaced. The video frame is similar to one still picture of a motion picture film.
FRAME TRANSFER
A CCD imager where an entire matrix of pixels is read into storage before being output from the camera. Differs from Interline Transfer where lines of pixels are output.
Floodlights
All floodlights are enclosed for protection against weather corrosion and may be equipped with a 'Passive Infrared' switching facility to switch the unit on automatically whenever someone enters the designated area.
F-Number
The standard measure of the lens aperture, which is the iris diameter, divided by the focal length of the lens. The lower the maximum aperture, the more light that passes through the lens.
F-Stop
“Light Factor (f)”. The ability of a camera lens to pass light. A value used to indicate the speed of a lens where the smaller the number the better the lens “a fast lens”, the normal f stop in CCTV lenses is f/1.4 or f/1.2. Each increase in f-stop decreases the amount of light passed through the lens by 50%. The normal f-stops are: f/1.0 – f/1.4 – f.
Focal Length
Focal Length(FL) is the distance from the center of a lens to the focal point (CCD sensor chip). FL, as well as the CCD chip's format, is the major factor to determine the angle of view of a lens. For example, a 6.0mm FL lens on 1/3" sensor format has 56.8 degree of diagonal angle of view and a 5.0mm FL lens on 1/3" sensor format has 66.9 degree. But, the same 6.0mm FL lens can see 75.5 degree on 1/2" sensor format. The angle of view also varies a little depending on the manufacturer of the lens.
For 1/3" CCD chip camera, the following formula is a simple way to determine the focal length of a lens needed.
(Distance to subject / Width of subject) x 4.5mm = Focal Length.
For example, if you want to watch a subject of 5.5ft width at 10ft distance with a 1/3" CCD camera, you will need a 8.0mm FL lens. That is, 10ft / 5.5ft x 4.5mm = 8.18mm. A 8.0mm FL lens mounted on 1/3" CCD camera will cover the subject you want to watch.
Fixed Focal Length Lens
A lens with a pre-determined fixed focal length, normally having a focus control and iris adjustment.
Field Of View.
The width and height or area desired to be covered by one camera. This area is determined by the focal length of the lens on the camera and the distance the camera is mounted from the scene.
Focus Control
A means for adjustment of a lens to allow objects at various distances from a camera lens to be sharply focussed on the imaging device.
Focus Shift
Focus Shift is the condition that occurs when images that are sharp and in focus under artificial lighting (such as external cameras illuminated with IR lighting at night) are out of focus (appear soft or blurred) in daylight conditions and vice versa. The problem is caused by the nature of light. Different types of light have different wavelengths which means that an image viewed in different light conditions will appear slightly differently. Unless the lens is adjusted for different light conditions, it is impossible for a standard lens to produce a sharply focused image in all types of light.
To overcome this lenses either have to be adjusted manually for day and night time performance (impractical) or, if the camera is fitted with a remote controlled motor zoom lens, the picture may easily be brought back into focus (not possible with static lenses, of course, or on an unmanned site). A third option is to use the more expensive IR corrected lenses.
Foot Candle (Ft-Cd)
A measure of light intensity. A unit of illuminance on a surface that is everywhere one foot from a uniform point source of light of one candle and equal to one lumen per square foot.
Fresnel Zone
If unobstructed, radio waves will travel in a straight line from the transmitter to the receiver. But if there are obstacles near the path, the radio waves reflecting off those objects may arrive out of phase with the signals that travel directly and reduce the power of the received signal. On the other hand, the reflection can enhance the power of the received signal if the reflection and the direct signals arrive in phase.
In radio communications, a Fresnel zone is one of a number of concentric ellipsoids which define volumes in the radiation pattern created by an antenna.
The cross section of the first (innermost) Fresnel zone is circular. Subsequent Fresnel zones are annular (doughnut-shaped) in cross section, and concentric with the first.
To maximise receiver strength, it is necessary to minimise the effect of the out-of-phase signals by removing obstacles from the radio frequency line of sight (LoS). The strongest signals are on the direct line between transmitter and receiver and always lie in the first Fresnel zone.
Factory default settings
These are the settings that originally applied for a device when it was first delivered from the factory. If it should become necessary to reset a device to its factory default settings, this will, for many devices, completely reset any settings that were changed by the user.
GHz
A multiple unit of Hertz (Hz). GigaHertz, 1x10^9 Hz.
Gamma
Degree of contrast in a video picture between output magnitude and input magnitude. GB Gigabyte. A value of one (1) indicates a linear characteristic. Less than one indicates a curve or less contrast levels represented by a softer looking picture. The standard for a camera is 0.45 and for monitors is 0.55.
Gamma Correction
To provide for a linear transfer characteristic from input to output device.
GPRS
General Packet Radio Service (GPRS) is a packet oriented mobile data service on the 2G and 3G cellular communication system's Global System for Mobile communications (GSM). GPRS was originally standardized by European Telecommunications Standards Institute (ETSI). It is now maintained by the 3rd Generation Partnership Project (3GPP).
GSM
GSM (Global System for Mobile Communications), is a standard developed by the European Telecommunications Standards Institute (ETSI) to describe technologies for second generation (2G) digital cellular networks. Developed as a replacement for first generation (analogue) networks, the GSM standard originally described a digital, circuit switched network optimised for full duplex voice telephony. The standard was expanded over time to include first circuit switched data transport, then packet data transport via GPRS. Packet data transmission speeds were later increased via EDGE. The GSM standard is succeeded by the third generation (3G) UMTS standard developed by the 3GPP. GSM networks will evolve further as they begin to incorporate fourth generation (4G) and LTE advanced standards.
Gray Scale
A pattern of vertical bars with shades of gray starting with white and gradually getting darker gray until ending at black. Most gray scales used in television have 10 steps or bars. The pattern is used to test the ability of a camera to reproduce true white, black and the varying steps of gray in-between.
Geometric Distortion
The warped look of objects in a television picture due to erratic scanning of the electron beam in the picture tube or vidicon tube.A circle may look egg shaped or a straight line look like a curve.
Galvonometric lens
They are sometimes called a galvometric or galvano lens. This type of automatic iris lens is driven by a reference voltage produced by the camera. The lens contains a driving motor to open and close the lens and a damping coil to prevent hunting. In effect the camera contains the iris amplifier and operates the iris motors. These lenses have four connections, +ve drive, -ve drive, +ve damping and -ve damping. The camera specification should be checked to ensure that it contains the circuitry for this type of lens. They are usually less expensive than lenses with a built in amplifier and simpler to install but can only be used with a limited range of cameras. Again for this type of lens many cameras are being produced with screw connectors instead of a socket.
Genlock
A device that adjusts the frequency of internal sync to an external data.
GUI (Graphical User Interface)
Pronounced ‘gooey’, this is the interface between the computer and the matrix switcher. Active areas of the computer screen are programmable, feature menus, icons, are clickable, and able to activate devices such as VCRs and matrix switchers. Essentially, the GUI makes the CCTV system easier to use.
GIF (Graphics Interchange Format)
A GIF (some people say "DJIF" and others say "GIF" with a hard G) is one of the two most common file formats for graphic images on the World Wide Web. The other is the JPEG.
On the Web and elsewhere on the Internet (for example, bulletin board services), GIF has become a de facto standard image format. CompuServe owns the format, and companies commercially developing products exploiting the format need to buy a license. Ordinary Web users and businesses publishing GIF images on their Web sites do not need a license.
Technically, a GIF uses the 2D raster data type, is encoded in binary, and uses LZW compression. There are two versions of the format, 87a and 89a. Version 89a (July, 1989) allows for the possibility of an animated GIF, which is a short sequence of images within a single GIF file. A GIF89a can also be specified for interlaced presentation.
An Internet committee has developed a patent-free replacement for the GIF, the PNG format, and major browsers will soon be supporting it.
Ghost
A shadowy or weak image in the received picture, offset to either the right or to the left of the primary image.
H.264
H.264 is the next-generation video compression technology in the MPEG-4 standard, also known as MPEG-4 Part 10. H.264 can match the best possible MPEG-2 quality at up to half the data rate. Video is compressed using two types of frames:
* I Frame, also known as the Index or Key Frame and contains the whole image
* P Frame, which only contains the information that is different from the previous frame.
MJPEG only uses I Frames, whereas MPEG-4 and H.264 use a combination of both I and P Frames and consequently use considerably less bandwidth them MJPEG. H.264 will require up to 50% less bandwidth than MPEG-4 to transmit the same quality image, therefore it is the chosen compression standard for the highest performance IP cameras. H.264 also delivers excellent video quality across the entire bandwidth spectrum — from 3G to HD and everything in between (from 40 Kbps to upwards of 10 Mbps).
H.265
H.265 (also known as HEVC, short for High Efficiency
Video Coding, developed by the Joint
Collaborative Team on Video Coding (JCT-VC)) is a video compression
standard whose predecessor is H.264/MPEG-4 AVC. H.265 HEVC ensures to deliver
video quality identical to H.264 AVC at only half the bit rate, including
better compression, delicate image and bandwidth saving. It Support up to 8K,
Support up to 300 fps. It is likely to implement Ultra HD, 2K, 4K for Broadcast
and Online (OTT).
Heat Map
The video surveillance heat map records the motion of customer
foot traffic over a period of time and displays temporal density and spatial
statistics in different colors. For instance, in the figure red shows the areas
customers most frequently visited and tended to stay longer, and blue reflects
otherwise. Heat map is ideal for use in locations such as supermarkets, retail
stores, etc., to help businesses identify the most popular merchandise and
where to place products in order to increase sales.
HOMING
A term used to describe a type of automatic sequential switcher which will stop sequencing and remain on a single camera input displayed on the monitor when a switch or button is depressed which is identified with the desired camera to be displayed. This switcher has only one monitor output.
HUNTING
An industry term used to describe a auto-iris lenses inability to stabilize under certain light conditions.
HDD Group
HDD (Hard Disk Drive) Group mode is one of the HDD storage modes
in Hikvision DVRs/NVRs. Multiple HDDs can be managed in groups. Video from
specified channels can be recorded onto a certain HDD group through HDD
settings.
HDD Quota
HDD (Hard Disk Drive) Quota mode is one of the HDD storage modes
in Hikvision DVRs/NVRs. Each camera can be configured with an allocated quota
of HDDs to store recorded files.
Hz (Hertz)
Cycles per second.
HORIZONTAL RESOLUTION
A number used to measure the ability of a camera or monitor to accurately reproduce a picture with many small picture elements. A resolution chart is used when testing a camera. The chart has several circles one large one in the center with lines in a fan shape converging in the center. The lines are marked with resolution numbers which increase as the lines become closer to each other and the center. The maximum resolution displayed on the chart is 800 lines. The more common CCTV cameras are capable of producing from 350 to 500 lines of resolution.
HUE
Corresponds to colors such as red, blue, etcetera.
High definition television (HDTV)
Much more number of lines of resolution and produces better quality image by about 2 to 5 times than standard television. Resolution is defined as number of horizontal pixels x number of vertical pixels, for example 1280 x 720 or 1920 x 1080. Often the number of horizontal pixels is implied from context and is omitted.
The resolution number is appended with i or p; the lower-case i denotes interlaced and the lower-case p progressive. With the interlaced scanning method (when the notation is 1080i), the 1,080 lines of resolution are divided into pairs. The first 540 alternate lines are painted on a frame and then the second 540 lines are painted on a second frame. The progressive scanning method (when the notation is 1080p) simultaneously displays all 1,080 lines on every frame with better quality pictures, requiring greater bandwidth.
The notation can also be appended with scanning rate like 1080i60, 1080p30, or 720p60. The numbers after i or p are scanning rate per second. For commercial naming of a product, the frame rate is often dropped.
HyperSense Technology
Dedicated Micros’ unique HyperSense Technology was introduced
for the first time in the new Dedicted Micros License Plate capture security cameras which are optimized to capture and record vehicle license plates. HyperSense Technology rejects ambient light from any scene leaving only the objects that strongly reflect the IR light emitted by the integrated IR LED array. This makes HyperSense ideal for analytics and License Plate Recogintion applications where retroflective backgrounds on license plates will offer a high contrast between license plate numbers & letters and the plate background.
HTML (Hypertext Markup Language)
HTML is the set of "markup" symbols or codes inserted in a file intended for display in web browser. The markup tells the browser how to display the page's words and images for the user.
HTTP (Hypertext Transfer Protocol)
HTTP is the set of rules for exchanging files (text, graphic images, sound, video, and other multimedia files) on the web. The HTTP protocol runs on top of the TCP/IP suite of protocols.
HTTPS (Hypertext Transfer Protocol over SSL)
HTTPS is a web protocol used by browsers and web servers to encrypt and decrypt user page requests and the pages returned by the server.
The encrypted exchange of information is governed by the use of an HTTPS certificate (issued by a Certificate Authority), which guarantees the authenticity of the server.
IEEE 802.1x
The IEEE 802.1x standard provides a general method for authentication and authorization in IEEE-802 networks. Authentication is carried out via the authenticator, which checks the transmitted authentication information using an authentication server (see RADIUS server) and approves or denies access to the offered services (LAN, VLAN, or WLAN) accordingly.
ISM band
The industrial, scientific and medical (ISM) radio bands are portions of the radio spectrum reserved internationally, originally for the use of radio frequency (RF) for industrial, scientific and medical purposes other than communications. Examples of use include radio-frequency process heating and microwave ovens. The powerful emissions of these devices can create electromagnetic interference and disrupt other radio communication using the same frequency. In general, communications equipment operating in these bands must tolerate any interference generated by other ISM equipment, and users have no regulatory protection from ISM device operation. Despite this, in recent years the fastest-growing uses of these bands have been for short-range, low power communications systems. Cordless phones, Bluetooth devices, and wireless computer networks all use the ISM bands.
Illumination
A video surveillance camera requires a certain amount of lights produced by natural or artificial illumination. B/W cameras work with any type of light sources, but color cameras need lights that contain all the colors in the visible spectrum.
The amount of lights is defined by LUX(Lumens per Square Meter). One LUX is a candle light volume at one meter distance. Followings are some examples of natural lights expressed in LUX.
Full daylight: 10,000 LUX
Very dark day: 100 LUX
Twilight: 10 LUX
Deep twilight: 1 LUX
Full moon: 0.1 LUX
Quarter moon: 0.01LUX
A good B/W camera can see in full moon condition. But, a color camera will need an additional artificial light in full moon.
Image Intensifier
An electronic device which is used to amplify small amounts of light into usable amounts of light to produce a video picture. The device uses very high voltages to accelerate photons in a vacuum tube. The device is placed between a lens mount and an image device such as a vidicon or CCD. The lenses used on cameras with intensifiers must have special attributes with f-stops of up to f/1200.
Image Stabilization
An algorithm that virtually eliminates camera shake in both the vertical and horizontal axes, resulting in exceptional image clarity.
Impedance
Electrical characteristic of a system or component, expressed in ohms. CCTV industry has standardized 75-ohm impedance.It is extremely important that the impedances of the signal source, cable, and load are all equal. Any mismatch in these will produce unpleasant and unacceptable effects in the displayed picture. These effects can include the production of ghost images and ringing on sharp edges, also the loss or increase in a discrete section of the frequency band within the video signal.
The impedance of a cable is primarily determined by its physical construction, the thickness of the conductors and the spacing between them being the most important factors. The materials used as insulators within the cable also affect this characteristic. Although the signal currents are very low, the sizes of the conductors within the cable are very important. The higher frequency components of the video signal travel only in the surface layer of the conductors.
INT
Internal sync mode that sets to internal 2:1 interlace.
INTERLACE
In television theory the method of placing horizontal scan lines in between each other during the period of one frame. The first field lays down 262 & Mac189; horizontal lines and then the second field lays down 262 & Mac189; horizontal lines in between the first set of lines in field number one.
Interlaced Scanning
A scanning process for reducing image flicker in which the distance from center to center of successively scanned lines is two or more times the nominal line width, and in which the adjacent lines belong to different fields.
IR
Infrared light, invisible to the human eye.It usually refers to wavelengths longer than 700 nm. Monochrome (B/W) cameras have extremely high sensitivity in the infrared region of the light spectrum.
Infrared Illumination (IR Illumination)
Electromagnetic radiation (light) with a longer wavelength than is visible to the human eye. IR illumination is prominent at dusk and dawn and in incandescent lamps. IR illuminators come in the form of lamps with the appropriate filters, LEDs, or lasers. CCD sensors are less sensitive to IR than visible light, but IR can significantly increase the total illumination level, leading to a much better image at low light levels.
Infrared camera (IR Camera)
These cameras are well suited for surveillance of low light areas or areas with no light at all. Infrared LEDs surround the lens and shine infrared light, illuminating the scene. They usually have a fixed focal length lens, and present b/w images during low light (though some offer color in the day and b/w at night).
Infrared detector
This is an alarm that uses infrared light to detect nearby movement.
Infrared illuminator
A light source working in the infrared frequency range is called an infrared illuminator.
Infrared radiation
Invisible to the human eye, this electromagnetic radiation has a wavelength of greater than 750 manometers.
IR-corrected lenses
IR-corrected lenses should always be used and not only when using IR-illumination at night time. Many light sources include a part of IR-light, small or light. In connection with monochrome- or day/night cameras IR-corrected lenses will provide a sharper picture because all the light is focused, resulting in a far crisper picture compared to ordinary lenses. Sunlight contains much IR-light, but also many artificial light sources, especially halogen. Also, ordinary incandescent light bulbs include a considerable amount of IR-light. When having illumination with a mixture of visible and infrared light, it is possible to obtain a considerable improvement of the picture reproduction without having to replace the camera - just by replacing the lens. So there are excellent reasons for using IR corrected lenses in all environments.
"It is not possible to modify standard lenses to make them IR-corrected, e.g. just by coating the lens elements - at least not with optimum results. From the early stages of the design phase IR-correction must be considered and included in the design; special glass must be used for the lens elements and special coating of the lens element surfaces is required. Previously, this caused IR-corrected to be fairly expensive, but new efficient production technologies have reduced costs dramatically."
Interline Transfer
A technology of CCD design, where rows of pixels are output from the camera. The sensor’s active pixel area and storage register are both contained within the active image area. This differs from “frame transfer” cameras that move all active pixels to a storage register outside of the active area.
IK code
The European standard EN 62262 - the equivalent of international standard IEC 62262:2002 - relates to IK ratings. This is an international numeric classification for the degrees of protection provided by enclosures for electrical equipment against external mechanical impacts. It provides a means of specifying the capacity of an enclosure to protect its contents from external impacts. The IK Code was originally defined in European Standard BS EN 50102:1995 and amended in 1998. Following its adoption as an international standard (IEC 62262) in 2002, the European standard was renumbered EN 62262.
EN 62262 specifies the way enclosures should be mounted when tests are carried out, the atmospheric conditions that should prevail, the number of impacts (5) and their (even) distribution, and the size, style, material, dimensions etc. of the various types of hammer designed to produce the energy levels required.
IP Rating
The IP rating (or International Protection Rating, sometimes also interpreted as Ingress Protection Rating) consists of the letters established by the International Electro Technical Commission, is used to provide an Ingress Protection rating to a piece of electronic equipment or to an enclosure for electronic equipment. The protection class after EN60529 are indicated by short symbols that consist of the two code letters IP and a code numeral for the amount of the protection.
The two digits represent different forms of environmental influence:
• The first digit represents protection against ingress of solid objects.
• The second digit represents protection against ingress of liquids.
The larger the value of each digit, the greater the protection.
IP 66
IP code (Ingress Protection) that indicates the degree of protection provided by enclosures for electrical equipment. The first number indicates protection of internal equipment against the ingress of solid foreign objects. The second number indicates protection of internal equipment against harmful ingress of water. Higher digits refer to higher levels of protection.
IP Protection of the PANEL-PIP
The PANEL-PIP is available in various housings. Those allow a protection level of up to all around IP65.
IP65
IP 65 means it is totally protected against dust and low pressure of jets of water from all directions- limited ingress permitted
IP Protection of PIP
A PIP in the standard PIP housing is generally IP51 protected. Higher IP protection level with the standard PIP housing (up to IP54) can be reached with good positioning / orientation of the PIP. In other special PIP-housings, like a MIL-housing up to IP67 protection is possible.
IP Address
The address of a device attached to an IP network. Each device on an IP network must use a unique address. Every IP data packet contains a source address (sender) and a destination address (recipient). Each IP address consists of 32-bits that are arranged into four 8-bit octets (x.x.x.x). IP addresses range from 0.0.0.0 to 255.255.255.255. This IP address are 4 kinds Class A, B, C and D.
Class A = 0.0.0.0 to 127.255.255.255
Class B = 128.0.0.0 to 191.255.255.255
Class C = 192.0.0.0 to 223.255.255.255
Class D = 224.0.0.0 to 239.255.255.255 (Multicast)
Class E = 240.0.0.0 to 255.255.255.255 (Reserved)
IPv4
Currently used by most network devices. However,with more and more computers accessing the internet, IPv4 IPs are running out quickly. Just like in a city, addresses have to be created for new neighborhoods but,if your neighborhood gets too large,you will have to come up with an entire new pool of addresses. IPv4 is limited to 4,294,967,296 IPs.
IPv5
This is an experimental protocol for UNIX based systems. In keeping with standard UNIX (a computer Operating System) release conventions, all odd-numbered versions are considered experimental. It was never intended to be used by the general public.
IPv6
The replacement for the aging IPv4. The estimated number of unique IPs for IPv6 is 340,282,366,920,938,463,463,374,607,431,768,211,456 or 2^128.
The old and current standard of IPs was this: 192.168.100.100 the new way can be written different ways but means the same and are all valid:
* 1080:0000:0000:0000:0000:0034:0000:417A
* 1080:0:0:0:0:34:0:417A
* 1080::34:0:417A
IP Camera (or Network Camera)
This signal from an IP camera is delivered over an IP network. The camera digitizes the images, compresses them, and then sends them over the network (if this sounds similar to a webcam, that’s because there is digital webcam technology contained within a network camera). But a typical IP network camera is much more advanced as compared to a consumer web camera which needs to be attached to a computer to operate. IP enabled security cameras usually offer a browser interface so that the user can operate and view the video remotely over the Internet. A DVR system is often comprised of an IP camera and a NVR.
Iris
An adjustable opto-mechanical aperture built into a camera that controls the amount of lights coming through the lens.
Iris Amplifier
These are sometimes referred to as a servo lens. The most common type contains an amplifier and is connected to the video signal of the camera. It also is driven by a 9 volt dc voltage provided from the camera. As was mentioned previously, the voltage of the video signal is proportional to the amount of light on the imaging device. When the light level falls so does the video level. The amplifier is continuously monitoring this voltage to maintain it at 1 volt peak to peak. As the voltage changes so the iris amplifier opens or closes the iris to maintain a constant 1 volt.
The majority of cameras that provide an automatic iris drive include socket on the rear. There are three connections, +9v, 0v, video. Unfortunately there is no current standard for this connector but most cameras are packed with the appropriate plug. This can create problems if one camera is substituted for another make during maintenance or service. It can mean that the service engineer has to change the iris plug on site that is not an easy job. In recognition of this problem many cameras are now being produced with screw terminals on the rear
IPS
Images per Second: a measurement of the rate that pictures are displayed to create a video stream. A rate of 25 IPS (PAL) or 30 IPS (NTSC) is generally considered to be full motion video.
iSCSI
iSCSI, pronounced eye-skuzzy, is a protocol, a standardized way to talk to IP-based storage across an IP network.iSCSI combines the latest and greatest from the storage and communications worlds – SCSI storage (which uses the SCSI protocol) and the IP network (which uses the TCP/IP protocol).iSCSI is simply SCSI over IP. iSCSI stands for IP SCSI.Until the Internet Engineering Task Force (IETF) invented iSCSI back in 2002,the main storage protocol was SCSI (Small Computer Systems Interface). SCSI is still the most widespread method of communicating with RAID.iSCSI is IP network-based, RAID storage can be located anywhere on the high-speed network. This includes being shared storage on the network (Network-Attached Storage) and dedicated storage, independent of the network (Direct-Attached Storage).
Joystick
PTZ controllers utilize this stick as a control device for pan and tilt movement of a PTZ security camera’s pan and tilt head.
JPEG
Joint Photographic Experts Group: The name of the committee that created a standard for encoding still images.
JPEG Surveillance DVR
CCTV Camera Pros is proud to present our JPEG Series Surveillance DVRs. View your security cameras over the internet using these professional surveillance DVRs. All DVRs come standard with the DVR viewer software that allows you to remotely view cameras. See Internet viewing images at the bottom of this page. The 4, 8, and 16 channel DVR all come standard with the following features:
• Remote Internet Viewer Software
• Remote Video Backup Software
• Real Time Live Video Display
• Simultaneously Record, Playback, Ethernet
• Real Time Recording: 120, 240, & 480 Frames per Second Recording (4,8,16CH)
• Dynamic IP support for DSL or Cable Connection
• JPEG Video Recording Provides the Clearest Picture on the Market • Remote Viewing uses MPEG-4 H.264 for Maximum Efficiency
• 250 GB Hard Drive comes pre-installed
• Easy Controls for PTZ Cameras
• Recording Modes: Scheduled, Motion Detection, Alarm
• CD Burner & USB Port for Video Backups
• Network Connection via Ethernet
• VGA Video Output to Standard Computer Monitor
• Server Rack Mounting Hardware
• Wireless Remote Control
kBit/s
Kilobits per second: The actual data rate.
Last Mile Access
The "last mile" or "last kilometer" is the final leg of delivering connectivity from a communications provider to a customer. The phrase is often used by the telecommunications industry. The actual distance of this leg may be considerably more than a mile, especially in rural areas. It is typically seen as an expensive challenge because "fanning out" wires and cables is a considerable physical undertaking. Because the last mile of a network to the user is also the first mile from the user to the world in regards to sending data (such as uploading), the term "first mile" is sometimes used.
To solve the problem of providing enhanced services over the last mile, hybrid technology communications networks are used increasingly. One example is Fixed Wireless Access, where a wireless network is used instead of wires to connect a terminal to the wire or fiber network CCTV system.
Licensed Band
Unlicensed or license-free radio frequencies are those parts of the radio frequency spectrum which can be used without restriction or the need to pay a license fee as long as the equipment is operating within defined rules.
Any person or organization may implement a license free network using appropriately certified radio equipment for private or public purposes.
Some of the most commonly used license free frequencies in theUS
Some of the most commonly used license free frequencies in the
The International System Unit of measurement of the intensity of light. It is equal to the illumination of a surface one meter away from a single candle.
Lens
A lens is a transparent optical device with perfect or approximate axial symmetry which transmits and refracts light, converging or diverging the transmitted light and to form images. A simple lens consists of a single optical element. A compound lens is an array of simple lenses (elements) with a common axis; the use of multiple elements allows more optical aberrations to be corrected than is possible with a single element. Lenses are typically made of glass or transparent plastic.
Lens Formats
The early CCTV lenses were designed for the 1" format tube camera and many of these are still available on the market. The lens screw thread on these cameras is called a C-mount. In recent years' lenses have been developed for the 2/3," 1/2" and now 1/3" format cameras. For this reason great care must be exercised when selecting a lens for a particular camera. Just as there are four sizes of camera so there are four sizes of lenses and they are not compatible in every combination. A lens designed for a larger format camera may be used on a smaller format but not the reverse. In addition the field of view will not be the same on different size cameras. There is now a further complication in that there is a new range of lenses with what is called the CS-mount. In this case a C-mount lens may be used on a CS-mount camera with an adapter ring but a CS-mount lens can not be used on a C-mount camera. The difference between the two types of mount is the back focal length (not the same as the focal length). This is an optical change to the back focal length and is not a mechanical difference to the lens. The screw thread and shoulder length for each type of mount are identical making it impossible to see the difference except that the overall size of the CS-mount lens is smaller. The main problem is that either type of lens can be screwed onto both types of camera without damage. The result is that if the wrong type is used it will be impossible to focus the camera.
Lens Speed
The ability of a lens to transmit light, represented as the ratio of the focal length to the diameter of the lens. A fast lens would be rated
Lens Preset Positioning
Follower Pots are installed on lens that allows feedback to the controller information relevant to zoom and focus positioning allowing the controller to quickly adjust to a preselected scene and arrive in focus at the proper focal length automatically.
License Plate Recognition
CCTV Camera Pros license plate recognition (LPR) system, provides high-resolution video monitoring and recording. Our License Plate Recognition (LPR) system is an effective video surveillance and parking lot monitoring solution. Many parking lots have a high security risk rating. It is difficult for security personnel to monitor isolated areas or levels of large lots. Most lots need an effective digital surveillance systems to provide live monitoring and continuous recording. These video surveillance systems provides protection and reassurance to customers and employees.
The license plate capture system activates the LPR recognition process in two ways. The first is via software video motion detection, which detects vehicles passing through the camera and illumination zone. The second is by input / output activation, which triggers recognition and recording upon I/O activation. The system supports both camera overview and picture-in-picture modes with ease of monitoring.
Line Amplifier
An amplifier for audio or video signals that feeds a transmission line; also called program amplifier.
Line Crossing Detection
Line Crossing detection is one of the behavior
detection features in Hikvision’s Smart Features set. If a person crosses a
pre-defined virtual line, the camera will automatically detect the event and
can trigger alarms or recording if pre-configured to do so.
LoS (Line of Sight)
At higher radio frequencies any obstruction between the transmitting antenna and the receiving antenna will block the signal. Therefore, since the ability to visually see a transmitting antenna roughly corresponds to the ability to receive a radio signal from it, the propagation characteristic of high-frequency radio is called "line-of-sight".
Low-powered microwave transmitters can be significantly affected by foliage, tree branches and leaves. If a direct visual link cannot be established, it is important to take into account the curvature of the Earth when calculating line-of-sight from maps. The presence of objects not in the direct visual line of sight can also interfere with radio transmission. This is caused by diffraction effects and for the best propagation, an area known as the first Fresnel zone should be kept free of obstructions. Objects within the Fresnel zone can disturb line of sight propagation even if they don't block the geometric line between antennas. Reflected radiation from the ground may also act to cancel out the direct signal. This effect can be reduced by raising either or both antennas further from the ground.
MAC
Media Access Control: A quasi-unique identifier attached to most network adapters (NICs). It is a number that acts like a name for a particular network adapter.
Mega-Pixel IP Cameras
Megapixel IP Cameras are suitable in really demanding situations where you need to be able to identify persons or objects in a scene. This could be point-of-sales (POS) monitoring where it is necessary to clearly see every item a customer is purchasing, or situations where you need to be able to identify a face. Casino surveillance and license plate recognition are also applicable. Highly detailed images can be achieved by installing a network camera with a telescopic lens or a lens with zoom capability to allow a closer view of the area of interest. Using a Megapixel IP Camera in all such cases will provide even higher resolution images with more details than a non-megapixel network camera.
Mini-DIN
Multi-wire cable with Mini-DIN connectors at both ends. Usually has 4 inner wires.
MMS (Microsoft Media Services)
MMS is the first streaming protocol created for the Microsoft Windows Media Player.
MAGNIFICATION
A term used with regard to lenses and has evolved to be the same with “power” when describing the size of a zoom lens. A 16 to 160 mm lens is said to be a 10X or ten power zoom lens.It has a magnification of 10. The other standard is a 6X lens like a 12.5-75 mm. The largest mm is divided by the shortest mm to give the power or magnification.
Manual Zoom Lens
A zoom lens is one in which the focal length can be varied manually over a range by means of a knurled ring on the lens body. It has the connotation of 'zooming in' and therefore infers a lens with a longer than normal focal length. The zoom ratio is stated as being for instance 6:1 this means that the longest focal length is six times that of the shortest. The usual way of describing a zoom lens is by the format size, zoom ratio and the shortest and longest focal lengths, i.e. 2/3," 6:1, 12.5mm to 75mm. Again, great care must be taken in establishing both the camera and the lens format. The lens just described would have those focal lengths on a 2/3" camera but a range of 8mm to 48mm on a 1/2" camera. Similarly a lens giving the same performance on a 1/2" camera would be a 1/2," 6:1, 8mm to 48mm.
Motorised Zoom Lens
Manual zoom lenses are not widely used in CCTV systems because the angle of tilt of the camera often needs to be changed as the lens is zoomed in and out. The most common need for a zoom lens is when used with a pan tilt unit. The lens zoom ring is driven by tiny DC motors and controlled from a remote source. With a correctly set up camera lens combination the focus should not change from one limit of zoom to the other.
With the development of ever smaller cameras and longer focal length lenses the method of mounting the camera/lens combination must be taken into account. There are many cases where the lens is considerably larger than the camera and it may be necessary to mount the lens rigidly with the camera supported by it. In other cases it may be necessary to provide rigid supports for both camera and the lens. Always check the relationship between the camera and lens sizes and weights when selecting a housing or mounting. Most manufacturers of housings can provide lens supports as an accessory.
The most frequent reason for the focus changing when zooming is that the mechanical focus of the camera has not been set correctly.
Manual Iris
With this type of lens the iris opening is set manually by rotating a knurled ring on the lens body. Typically it will have a range of settings from the maximum to fully closed although the adjustment will be rather course. This type of lens is only suitable for indoor applications where the light levels remain fairly constant. It can also be used indoors with cameras having electronic shutters making a significant saving in cost. Care must be exercised in using this camera/lens combination in external applications because the camera may not have adequate control over the total light range. Also they do not have a neutral density filter to cope with extremely bright sunlight.
In most indoor situations the overall level of light will vary significantly between summer and winter due to light from windows, skylights, etc. Therefore it is often necessary to adjust the aperture two or three times a year to maintain optimum clarity of the picture.
Multiplexer
a multiplexer allows several camera signals to be recorded onto one videotape. To do this it synchronises the camera signals (lines them up in time) and marks each one with a code, allowing every camera to be replayed independently from tape, regardless of how many cameras are recorded on that tape. In addition, each image is stamped with a time and date caption.
Many multiplexers also provide the ability to view several cameras simultaneously on one or more monitors. These groups of pictures, when displayed on one monitor, are usually called multi-scene pictures. This is particularly useful when there are a large number of cameras across a site.
Matrix Switcher
A matrix switcher is a more complex design enabling the user to switch any video signal to any call-up monitor in a large-scale system. They normally incorporate PTZ control and other features such as preset and alarm inputs and outputs.
MJPEG
Motion JPEG is a digital video encoding standard where each video frame is separately compressed into a JPEG image. When using MJPEG streams, the frame size of each image plays a key role in estimating the storage and transmission requirements. Since each frame is unique and varies according to the image complexity, it is difficult to provide a guide that provides fixed frame sizes. An IP camera that provides images with low complexity will generate smaller frame sizes. Smaller frames will require less bandwidth and storage capacity.
The following formula is used to calculate the bandwidth requirements for MJPEG streams:
MJPEG storage = Average Frame size x Frame rate x duration
Example 1: For an 8-hour archive of a CIF video stream with 50 percent quality and 15 frames per second, the following is the calculation:
4 KB x 15fps x 3600s = 216,000 KB/ hour
= 216MB /hour x 8 hours
= 1.728 GB
Example 2: For a 24-hour archive of a 4CIF video stream with 100 percent quality and 5 frames per second, the following is the calculation:
320 KB x 5fps x 3600s = 5,760,000 KB /hour
= 5,760MB /hour = 5.76GB /hour x 24 hours
= 138.24 GB
MPEG-4
A further development of MPEG-2 designed for transmitting audiovisual data at very low transfer rates (for example over the Internet). A digital video encoding and compression standard that uses interframe encoding to significantly reduce the size of the video stream being transmitted. With interframe coding, a video sequence is made up of keyframes that contain the entire image. In between the keyframes are delta frames, which are encoded with only the incremental differences. This often provides substantial compression because in many motion sequences, only a small percentage of the pixels are actually different from one frame to another.
The following formula is used to calculate the bandwidth requirements for MPEG-4 streams:
MPEG4 storage = Bit rate (kbps) x duration
The target bit rate is configured on the camera and is already expressed in bits per second.
Example 1: For an 8-hour video stream with target bit rate of 768kbps, the following is the calculation:
768kbps / 8 bits/s = 96 KB /second x 3600 s
= 345,600 KB/hour / 1000
= 345.6 MB/hour x 8 hours
= 2.764 GB
Monitors - Surveillance Monitors
CCTV Camera Pros supplies a variety of CCTV monitors. Most of the surveillance DVRs that we supply have VGA (D-SUB) video outputs which allows you to use the less expensive and more readily available VGA surveillance monitors. For surveillance systems that require a CCTV monitor with BNC video inputs, we also carry a variety of screen sizes available in for BNC input monitors.15" 17", 19", 22", 32" cctv monitors
Monitor Resolution
The monitors in NTSC system have 525 vertical scanning lines regardless of their size. The horizontal 700 TV lines of B/W monitors represents medium level and more than 900 TV lines means high resolution in EIA system. The color monitor's horizontal resolution of 300 TV lines means medium quality and that of more than 450 TV lines means high resolution.
To maximize the system's resolution, it is recommended to choose a monitor which has better resolution than that of the camera.
MOD (Minimum Object Distance)
The closest distance a lens will be able to focus upon an object. Wider angle (shorter focal length) lenses generally have a smaller MOD than larger focal length (narrower angle) lenses.
Multimode Fiber
An optical fiber with a larger core (typically 50 or 62.5 microns) than singlemode fiber (see Singlemode Fiber). The core is made of plastic or glass fibers. It is the most commonly used fiber for cabling short distances as used in LANs. The name multimode comes from the fact that light rays travel down multiple reflective paths (modes) within the fiber. This allows light to enter the core at different angles, making it easier to connect to broader light sources such as LEDs (light emitting diodes). Fiber optic interfaces and multimode fiber-based transmission systems are less expensive than those based on singlemode fiber. However, the use of multiple reflective paths (modes) increases modal dispersion (see Modal Dispersion) and shortens the distances that this type of fiber optic transmission system can span.
Multi-Address Mode
Multi-address mode is an NVR (Network Video
Recorder) function on networks with more than one NIC (Network Interface
Controller). Each NIC works independently with separate parameter settings,
which can be assigned with a different IP address in a different network.
Multi-address mode can be used to establish network isolation.
Noise
Undesired signals that corrupt the original video signals and may reduce he image quality.
NAS
A network-attached storage (NAS) device is a server that is dedicated to nothing more than file sharing. NAS does not provide any of the activities that a server in a server-centric system typically provides, such as e-mail, authentication or file management. NAS allows more hard disk storage space to be added to a network that already utilizes servers without shutting them down for maintenance and upgrades. With a NAS device, storage is not an integral part of the server. Instead, in this storage-centric design, the server still handles all of the processing of data but a NAS device delivers the data to the user.A NAS device does not need to be located within the server but can exist anywhere in a LAN and can be made up of multiple networked NAS devices.
Some of the big advantages of NAS include the expandability; need more storage space, add another NAS device and expand the available storage. NAS also bring an extra level of fault tolerance to the network. In a DAS environment, a server going down means that the data that that server holds is no longer available. With NAS, the data is still available on the network and accessible by clients.Fault tolerant measures such as RAID, which we'll discuss later),can be used to make sure that the NAS device does not become a point of failure.
NAT (Network address translation)
When a network device with a private IP address wants to send information via the Internet, it must do so using a router that supports NAT. Using this technique, the router can translate a private IP address into a public IP address without the sending host’s knowledge.
ND FILTER
A filter that attenuates light evenly over the visible light spectrum. It reduces the light entering a lens, thus forcing the iris to open to its maximum.
NTSC
NTSC (National Television Systems Committee) is the standard for analog television transmission in the United States and many other counties worldwide. NTSC was developed in 1953 by the National Television System Committee. Alternatives to NTSC were developed later, including PAL and SECAM. NTSC provides 482 lines of vertical resolution and 16 million colors. NTSC transmits 525 lines, but some lines are used for sync, vertical retrace, and closed captioning. NTSC delivers 29.97 frames per second. NTSC does this by delivering 59.94 interlaced half-frames per second.
Net mask
A mask that explains which part of an IP address is the network address and which part is the host address. It is usually written in dotted decimal notation, for example 255.255.255.192 (see also Subnet Mask).
Net-Fault Tolerance Mode
Net-Fault Tolerance Mode is an NVR (Network Video
Recorder) function on networks with more than one NIC (Network Interface
Controller). All the NICs use the same IP address. If a working NIC breaks
down, others will continue to work and the NVRs’ network connection is not
affected.
Network Bandwidth Usage
Figuer shows a simple scenario with two sites.
Two OM Viewers are displaying video streams from Camera 1 and Camera 2 while one OM Viewer is displaying three video streams: two streams from Camera 1 and one stream from Camera 2. The network bandwidth required to display video streams for Camera 2 in Site A are relatively small for a LAN environment, but the traffic from Camera 1 can be significant for WAN environments since four different 1Mbps streams have to traverse the WAN locations.
NVR
The Network Video Recorder heralds the arrival of the next natural point in the development of recording technology.
It is important to differentiate between DVRs and NVRs, as both are often termed ‘digital’. A DVR digitally compresses analog video feeds and stores them on a hard-drive, the term ‘digital’ referring to the compression and storage technology, not the transmitted video images. The DVR therefore has to be located near the analog feeds. In contrast an NVR stores digital images directly from the IPnetwork.
Therefore the most obvious difference between the DVR and NVR is that whereas the DVR records from analog streams provided from analog cameras the NVR records video streams that have already been encoded at the cameras. Thus you find no video connectors anywhere on a NVR; it’s input and output is IP data comprising compressed and encoded video. This will typically be in MPEG-4 format which has enjoyed widespread adoption in the CCTV industry as the current compression technology of choice, due largely to its efficiency.
N+1 Hot Spare
N+1
hot spare protects the system against NVR (Network Video Recorder) network
failures. When an NVR fails to connect to the network, a hot spare NVR will
take its place to ensure data integrity and reliability. After the failed NVR
is online, the hot spare NVR will send the data back to the working NVR.
Optical Speed
Lens speed, expressed by f-number. Smaller f-number means faster lens. Optical Speed is about how fast a lens collects lights and is defined by the f-number like f/1.2, f/2.0, etc. This speed is determined by the Focal Length (FL) and the Diameter(D) of a lens; f-number = FL/D.
Larger FL, if the Diameter is same, makes higher f-number (like f/4 or f/8) lens that collects less lights to the camera sensor and results a slower lens. Lower f-number (like f/1.2 or f/1.4) lenses pass more lights to the camera sensor. Larger Diameter, if the FL is given, will make a lower f-number lens which can operate in lower light level.
In conclusion, the lower the f-number, the more lights reaching the camera sensor and the better the video picture. The f-numbers are usually marked at the iris rings of lenses.
Operational Requirement (OR)
A preliminary document which establishes the client’s requirements in terms of functionality.
(Note: This is not the system specification, but is intended to assist the designer to arrive at a system specification which meets the client’s requirements).
OEM
This is a designation for companies that manufacture equipment that is then marketed and sold to other companies under their own names(Original equipment manufacture)
Outdoor Housing Cases
Followings are the dimensions of economically developed Outdoor Housing Cases for the CCTV Cameras;
Small size: 80(W) x 70(H) x 260(D) mm
Medium size: 103(W) x 98(H) x 370(D) mm
Large size: 142(W) x 115(H) x 392(D) mm
Professional Cameras should be mounted in medium or large size housing cases and Web Cameras in large size ones. A heater and/or blower can be built into medium or large size housing case. When a heater and/or blower is built-in, the available inside depth length is reduced by about 40 to 50mm. A heater and/or blower is usually required to be powered separately by 110VAC or 24VAC. And, you need an outdoor mounting brackets for the housing cases.
Other special housing cases such as dome camera housings, triangular ceiling or corner mount housings, elevator-cab housings, explosion-proof housings are usually expensive.
Optical Axis
Optical centerline that passes through the center of a lens or mirror, etc.
ONVIF (Open Network Video Interface Forum)
ONVIF is an open industry forum for the development of a global standard for the interface of network video products.
ODBC
Open Database Connectivity (ODBC) is a standard or open application programming interface (API) for accessing a database. By using ODBC statements in a program you can access files in a number of different databases; including, Access, dBase, DB2, Excel, and Text. In addition to the ODBC software, a separate module or driver is needed for each database to be accessed. The main proponent and supplier of ODBC programming support is Microsoft.
ODBC is based on and closely aligned with the Open Group standard Structured Query Language (SQL) Call-Level Interface. It allows programs to use SQL requests that will access databases without having to know the proprietary interfaces to the databases. ODBC handles the SQL request and converts it into a request the individual database system understands.
ODBC was created by the SQL Access Group and first released in September, 1992. Although Microsoft Windows was the first to provide an ODBC product, versions now exist for UNIX, OS/2, and Macintosh platforms as well.
In the newer distributed object architecture called CORBA, the Persistent Object Service (POS) is a superset of both the Call-Level Interface and ODBC. When writing programs in the Java language and using the Java Database Connectivity (JDBC) application program interface, you can use a product that includes a JDBC-ODBC "bridge" program to reach ODBC-accessible databases.
PAL
which is short for Phase Alternating Line, is an analogue television decoding system used in broadcast television systems in MHz for PAL, compared to 3.579545 MHz for NTSC. The SECAM system, on the other hand, uses a frequency modulation scheme on its two line alternate colour subcarriers 4.2500large parts of the world. The basics of PAL and the NTSC system are very similar; a quadrature amplitude modulated subcarrier carrying the chrominance information is added to the luminance video signal to form a composite video baseband signal. The frequency of this subcarrier is 4.43361875 0 and 4.40625 MHz.
The name "Phase Alternating Line" describes the way that the phase of part of the colour information on the video signal is reversed with each line, which automatically corrects phase errors in the transmission of the signal by cancelling them out. Lines where the colour phase is reversed compared to NTSC are often called PAL or phase-alternation lines, which justifies one of the expansions of the acronym, while the other lines are called NTSC lines. Early PAL receivers relied on the imperfections of the human eye to do that cancelling; however this resulted in a comb like effect on larger phase errors. Thus, most receivers now use a chrominance delay line, which stores the received colour information on each line of display; an average of the colour information from the previous line and the current line is then used to drive the picture tube. The effect is that phase errors result in saturation changes, which are less objectionable than the equivalent hue changes of NTSC. A minor drawback is that the vertical colour resolution is poorer than the NTSC system's, but since the human eye also has a colour resolution that is much lower than its brightness resolution, this effect is not visible. In any case, NTSC, PAL and SECAM all have chrominance bandwidth (horizontal colour detail) reduced greatly compared to the luminance signal.
Pan
Camera movement in the horizontal direction.
Pre/post alarm images
The images from immediately before and after an alarm. These images are stored in a buffer for later retrieval.
PEAK-TO-PEAK
The amplitude (voltage difference between the most positive and the most negative excursions (peaks) of an electrical signal. A full video signal measures one volt peak to peak.
PTZ Security Cameras
PTZ Security Cameras allow you control the pan, tilt and zoom operations of the camera lens remotely or through surveillance DVR. PTZ Cameras have the ability to move up, down, right, left, and even zoom.
PVC or metal trunking:
where trunking is used to carry the cable it should terminate as close as possible to the unit to be connected. Where conduit or trunking is used, the manufacturers recommended capacity of the containment shall be observed.
Picture Element (Pixel)
Photo sensor site in an image sensor like CCD chip; converts the input light image to an electronic signal.
P-Iris
P-Iris is an automatic, precise iris control developed by Axis Communications of Sweden and Kowa Company of Japan. It involves a P-Iris lens and specialized software that optimize image quality.
Pinhole Lens
A lens with a relatively small front opening so it can be used in covert application.
Progressive scan
Progressive scan, as opposed to interlaced video, scans the entire picture, line by line every sixteenth of a second. In other words, captured images are not split into separate fields as in interlaced scanning.
Computer monitors do not need interlace to show the picture on the screen, but instead show them progressively, on one line at a time in perfect order i.e. 1, 2, 3, 4, 5, 6, 7 etc., so there is virtually no "flickering" effect. In a surveillance application, this can be critical when viewing detail within a moving image, such as a person running. A high-quality monitor is required to get the best from progressive scan.
Pixel
The smallest addressable unit on a display screen or bitmapped image.
Port
1) On computer and telecommunication devices, a port (noun) is generally a specific place for being physically connected to some other device, usually with a socket and plug of some kind. Typically, a personal computer is provided with one or more serial ports and usually one parallel port. 2) In programming, a port (noun) is a logical connection place and specifically, using the Internet protocol TCP/IP, the way a client program specifies a particular server program on a computer in a network. Higher-level applications that use TCP/IP, such as the Web protocol Hypertext Transfer Protocol, have ports with preassigned numbers. These are known as well-known ports that have been assigned by the Internet Assigned Numbers Authority (IANA). Other application processes are given port numbers dynamically for each connection. When a service (server program) initially is started, it is said to bind to its designated port number. As any client program wants to use that server, it also must request to bind to the designated port number. Port numbers are from 0 to 65535. Ports 0 to 1024 are reserved for use by certain privileged services, which are assigned and controlled by IANA. These are usually used as universal port numbers for servers, though there are exceptions. On Unix-like operating systems, binding to one of these ports requires superuser(root)access. Ports 1,024 through 49,151 (0xBFFF) are the registered ports. These ports are not assigned or controlled by IANA. They can only be registered with IANA to prevent duplication. Ports 49,152 through 65,535 (0xFFFF) are the dynamic (private) ports, which are neither controlled nor registered.These ports can be used by any process. They are also known as the ephemeral ports, from which the UDP software running on the client host randomly chooses in order to define itself. In other words, they are used as temporary ports primarily by clients when communicating to servers. For the HTTP service, port 80 is defined as a default and it does not have to be specified in the Uniform Resource Locator (URL).
Port 21
Port 21 (outbound) Used for FTP traffic. FTP (File Transfer Protocol) is a standard for exchanging files across networks. FTP uses the TCP/IP standards for data transfer, and is sometimes used for downloading events from devices.
Port 25
Port 25 (inbound and outbound): Used for SMTP traffic. SMTP (Simple Mail Transfer Protocol) is a standard for sending e-mail messages between servers. This port should be open since,depending on configuration, some cameras may send images to them surveillance system server via e-mail.
Port 554 (outbound):
Used for streaming MPEG4/H.264 video on many devices.
Port 80(inbound and outbound)
Used for HTTP traffic between the surveillance servers and cameras,Client programs, and the default communication port for the surveillance system's Image Server. HTTP (HyperText Transfer Protocol) is a standard for exchanging files across networks, widely used for formatting and transmission of data on the world wide web.
Any other port numbers you may have selected to use,for example if you have changed the Image Server's port from its default port number (80) to another port number.
PPP
Point-to-Point Protocol. For communications between two computers using a serial interface.
PAP
PAP (Password Authentication Procedure) is a procedure used by PPP servers to validate a connection request. PAP works as follows:
After the link is established, the requestor sends a password and an id to the server. The server either validates the request and sends back an acknowledgement, terminates the connection, or offers the requestor another chance. Passwords are sent without security and the originator can make repeated attempts to gain access. For these reasons, a server that supports CHAP will offer to use that protocol before using PAP. PAP protocol details can be found in RFC 1334.
PPPoE
Point-to-Point Protocol over Ethernet.
PEM (Privacy Enhanced Mail)
An early standard for securing electronic mail. The PEM-format is often used for representing an HTTPS certificate or certificate request.
POE
POE - Power Over Ethernet. Many applications benefit from electrical power sent over ethernet cables. This avoids a separate power cord for things like internet phones and wireless access points. PoE basically "injects" power into an ethernet cable at the source, and "picks" off that power at the destination. The power "injector" and "picker" can be external adaptors or can be "embedded" into the devices themselves. Either way, the destination device is completely powered by the ethernet cable, no extension cord or outlets required. Voila, Power-over-Ethernet.
Ping
Ping is a basic network program used diagnostically to check the status of a network host or device. Ping can be used to see if a particular network address (IP address or host name) is occupied or not, or if the host at that address is responding normally. Ping can be run from e.g. the Windows Command prompt or the command line in Unix.
Proxy Server
In an enterprise that uses the Internet, a proxy server acts as an intermediary between a workstation user and the Internet. This affords the enterprise with security, administrative control, and a caching service.
Any proxy server associated with a gateway server, or part of a gateway server, effectively separates the enterprise network from the outside network and the local firewall. It is the firewall server that protects the enterprise network from outside intrusion.
A proxy server receives requests for Internet services (such as a Web page request) from many users. If it a request passes filtering requirements, the proxy server, assuming it is also a cache server, looks in its local cache of previously downloaded Web pages. If it finds the page, it is returned to the user without forwarding the request to the Internet. If the page is not in the cache, the proxy server, acting as a client on behalf of the user, uses one of its own IP addresses to request the page from another server over the Internet. When the requested page is returned, the proxy server forwards it to the user that originally requested it.
To the user, the proxy server is invisible; all Internet requests and returned responses appear to be returned directly from the addressed Internet server. (Note that in practice the proxy server is not quite invisible, as its IP address has must be specified as a configuration option within the Web browser, or other protocol program.)
The fundamental advantage of a proxy server is that its cache can serve all users. Internet sites that are frequently requested are most likely to be in the proxy's cache. This method of storing Web pages locally invariably improves user response times significantly.
The functions of proxy, firewall, and caching can be included in separate server programs or combined in a single package. Different computers use different server programs. For example, a proxy server may coexist in the same machine with a firewall server, or it may be installed on a separate server and forward requests through the firewall.
Presets
The pre-positioning of pan, tilt and zoom cameras by the use of potentiometers in the moving parts of the camera head. These allow the control equipment to store and move to a set reference point when the controller dictates or when an alarm exists.
Protocol
A special set of rules (in information technology).
Quad
Utilizing digital video, this piece of equipment displays signals from four surveillance cameras on one monitor.
Quad Splitter
Combines up to 4 video inputs into one channel and displays them on one monitor screen split into 4. Usually, it also has built-in switcher which can display the pictures one by one. Some models have BNC jacks for video inputs and others RCA jacks. You may choose one according to your camera's video connection type. But, if the video input jack is different with your camera's connection, you can get a BNC/RCA converter easily at any electronic parts shop like Radio Shack or Best Buy, etc. B/W splitter works with B/W cameras and color splitter with color cameras. A quad splitter is to be connected to a CCTV monitor, TV or VCR.
QCIF
This resolution is one quarter of CIF, with 144 lines and 176 pixels per line.
QoS(Quality of Service)
QoS provides the means to guarantee a certain level of a specified resource to selected traffic on a network. Quality can be defined as e.g. a maintained level of bandwidth, low latency, no packet losses, etc. The QoS in Axis network video products marks the data packets for various types of network traffic originating from the product. This makes it possible for network routers and switches to e.g. reserve a fixed amount of bandwidth for these types of traffic.
Recording CCTV
Most systems now use Digital Video recording direct to hard drive. Long recording periods can be achieved by using the right video compression the following types are used:
1. MPEG4
2. JPEG2000
3. Wavelet
4. MPEG
5. H.265
6. MJPEG
Recording times can be increased with the combination of Video motion detection , selectable frames rates, and the right video compression.
Archived images are normally saved to CDR or DVD complete with watermark to prevent unauthorised tampering of the evidence.
Resolution
The measure of the fine detail that can be seen in an image. For analog systems this is typically measured in Television Lines or TVL. The higher the TVL rating, the higher the resolution.
Resolution-horizontal
The amount of resolvable detail in the horizontal direction in a picture. It is usually expressed as the number of distinct vertical lines, alternately black and white, which can be seen in a distance equal to picture height.
Resolution-horizontal - vertical
The amount of resolvable detail in the vertical direction in a picture. It is usually expressed as the number of distinct horizontal lines, alternately black and white, which can theoretically be seen in a picture.
RF (Radio Frequency)
A frequency at which coherent electromagnetic radiation of energy is useful for communication purposes.Also, the entire range of such frequencies.
RFID
Radio Frequency Identification (RFID) is an automatic identification method, relying on storing and remotely retrieving data using devices called RFID tags or transponders. An RFID tag is an object that can be attached to or incorporated into a product, animal, or person for the purpose of identification using radio waves. Chip-based RFID tags contain silicon chips and antennas. Passive tags require no internal power source, whereas active tags require a power source.
RFID cards are also known as "proximity", "proxy" or "contactless cards" and come in three general varieties: passive, semi-passive (also known as semi-active), or active. ProxiGuard uses passive cards of.
Passive RFID tags have no internal power supply. The minute electrical current induced in the antenna by the incoming radio frequency signal provides just enough power for the CMOS integrated circuit in the tag to power up and transmit a response. ProxiGuard uses EM type of cards with low frequency of 125Khz.
RG Cable (RG59, RG6, & RG11)
One of coaxial cables suitable for video transmission in CCTV system. RG stands for military specs Radio Guide (which is old and meaningless anymore) and the RG numbers are kind of arbitrary. The most common RG designations seen these days are RG-6, RG-8, RG-11, RG-58 and RG-59. RG-58 and RG-8 are 50 ohm coaxes, unsuited for video work. RG-6, RG-59 and RG-11 are all 75 ohm cable types, with RG-59 being the smallest (20 AWG centre conductor), RG-6 in between (18 AWG), and RG-11 being the largest (14 AWG).
RG-59 Siamese CCTV Cable
RG59 Siamese CCTV cable allows installers to run both the video and power to security cameras using a single cable run. RG-59 cable comes in 500 and 1000 foot spools and is available in black or white colors. RG59 is cut by you or your installer to the exact length that you need for each camera run. The RG59 portion of the cable is COAX and is used to run the video to the security camera. The 18 guage pair is used to run the AC or DC power to your cameras.
RG59 Siamese cable is a heavily shielded cable which contains a COAX video and pair of 18 guage 2 conductor power in one jacket. The advantages to using RG59 cable is that its more durable and can be run in long distances without interference. You can also cut each security camera run the exact length that you need. You will need to attach BNC connectors to each end of the RG59 coax part of the cable for the CCTV video transmission. BNC connectors are available in twist on, crimp on, and compression types. 500 foot spools of RG59 are also available. Watch this video to see how to attach a BNC crimp on connector to RG59 cable.
Cable Features:
• Siamese type configuration to run video and power in one cable jacket
• RG-59/U Type coax plus one pair 18 AWG stranded
• (Coax) solid bare copper conductor 20 AWG
• Gas injected polyethylene coaxial core Nom. OD .142 inch (3.61 mm) with an aluminum polyester tape barrier
• Bare copper braid shield 95% coverage
• Unshielded 18 AWG twisted pair employing PVC insulation and PVC fillers
• Overall PVC jacket Nom. OD .232 x .460" (5.89 x 11.68 mm)
• Runs both video and power in one cable
• Video run in RG59 Coax cable
• Works with twist-on, crimp-on, and compression BNC connectors
• Power run through 18 guage pair
• Cable can be cut to exact length
• Heavily shielded to minimize interference
• Can be run up to 1000ft without amplification
• Available in Black or White
Router
A device on the Internet that determines the next network point to which a data should be forwarded.
Reflected Light Level
The amount of light reflected from the scene, measured in lux.
RS
The initials “RS” stand for “Recommended Standard”. There are many standards set by “IEE” “International Electronic Engineers” pertaining to types of signals produced by an electronic circuit. This particular standard deals with a television signal parameter setting certain standards for signal level and timing.
ROI
In
some surveillance scenarios, users pay special attention only to a certain
region instead of the entire image. The region that attracts special attention
is known as the region of interest, or ROI. The ROI encoding method was
developed to provide different compression levels between the ROI and
background information in order to capture clearer key information without
increasing the overall bitrate. The application of ROI encoding technology
helps to conserve bandwidth and optimize the bitrate resource allocation, thus
ensuring the image quality of the region of interest.
RSSI
In telecommunications, Received Signal Strength Indicator (RSSI) is a measurement of the power present in a received radio signal.
RSSI is a generic radio receiver technology metric, which familiar to users of wireless networking of IEEE 802.11 protocol family.
RSSI is a generic radio receiver technology metric, which familiar to users of wireless networking of IEEE 802.11 protocol family.
RS232/RS422/RS485
Recommended standards for serial data transmission. A communication interface for third party control, firmware upgrades, and service purposes for camera and DVR products.
RTP (Real-time Transport Protocol)
The Internet Engineering Task Force (IETF) developed RTPs to specify audio and video signal management. It standardizes the packet formatting for both for easy synchronization and Internet delivery. Streaming media systems and video conferencing systems use RTP, while DVR systems rely on this protocol in the implementation of the remote view feature. Since it doesn’t specify how video surveillance playback is implemented, the data from different RTP based surveillance systems usually cannot interoperate.
RTSP (Real Time Streaming Protocol)
This open standard for Internet streaming of audio and video is popular among DVR makers for remote viewing of live or stored security camera video over the Internet. RTSP controls the transmission of the data stream much the way a television remote controls the television. Like RTP, interoperability problems exist between different DVR systems.
Real time video(RTV)
Any picture having 24 or more frames per second appears continuous, or in real time.
Remote monitoring
This allows an off site user to monitor surveillance camera feeds, so a user can survey a site regardless of their location from it. The transfer of data from camera to user can be either over the Internet or the Ethernet, with IP cameras being suited to the task.
Remote Surveillance DVR
The DVR viewer software that comes with our MPEG4 Series DVRs and JPEG Series DVRs allow an operator to remotely view surveillance over the Internet. Keep an eye on your home or business by remotely viewing security cameras live over the internet. By connecting one of our MPEG4 or JP Series DVRs to a high speed Internet connection, such as cable, and running the DVR viewer software on the Windows desktop or laptop computer that you want to monitor from, you can be setup very quickly.
Repeater Amplifiers
When a video signal has to be transmitted over extremely long or poor quality cables, it is necessary to use a repeater amplifier within the system. The distance along the cable at which it should be installed can be calculated from the cable loss figures. When using repeater amplifiers, an extra allowance of 3dB should be made for the cable loss. It is better to insert a repeater amplifier in a cable run before the video signal deteriorates too much, than to attempt to equalise a very poor quality signal. There is no actual limit to the length of cable and number of repeater amplifiers that can be used. The problem that occurs is that the signal to noise ratio deteriorates with each amplifier.
The practical limit is approximately 4 repeater amplifiers in cascade with a launch and equalising amplifier at the ends of the cable. This configuration can easily operate over cable lengths of 50 Km or more if the correct type of cable is used. This applies equally to coaxial or balanced cables.
RoHS
The definition and aim of the RoHS directive is quite simple. The RoHS directive aims to restrict certain dangerous substances commonly used in electronic and electronic equipment. Any RoHS compliant component is tested for the presence of Lead (Pb), Cadmium (Cd), Mercury (Hg), Hexavalent chromium (Hex-Cr), Polybrominated biphenyls (PBB), and Polybrominated diphenyl ethers (PBDE). For Cadmium and Hexavalent chromium, there must be less than 0.01% of the substance by weight at raw homogeneous materials level. For Lead, PBB, and PBDE, there must be no more than 0.1% of the material, when calculated by weight at raw homogeneous materials. Any RoHS compliant component must have 100 ppm or less of mercury and the mercury must not have been intentionally added to the component. In the EU, some military and medical equipment are exempt from RoHS compliance.
RTOS:
For single - or PC-based DVR is, RTOS (Real Time Operation System) is the best operating system, currently available in the market this type of supplier mainly to South Korea and Japan. Many South Korean manufacturers such as 3 R, Korea Computer Technologies, Kodicom, Artinix feel that single-DVR with high economic efficiency, high stability and Security Controller and the existing high compatibility, and other features, it rolled out the first time, have a single type of DVR. For Japanese manufacturers, will be committed to the development of single-DVR is mainly based on considerations of image clarity, the majority of PC-based DVR image quality are not as single-DVR.
However, the current single-DVR is the greatest challenge facing the networking functions.
RTCP
RTCP ( Real-Time Control Protocol) provides support for real-time conferencing of groups of any size within an intranet. This support includes source identification and support for gateways like audio and video bridges as well as multicast-to-unicast translators.
It offers quality-of-service feedback from receivers to the multicast group as well as support for the synchronization of different media streams.
RAID
RAID (Redundant Array of Independent Disks) is a
storage technology that combines multiple disk drive components into a logical
unit. A RAID setup stores data over multiple hard disk drives to provide enough
redundancy so that data can be recovered if one disk fails. Data is distributed
across the drives in one of several ways called “RAID levels,” depending on
what level of redundancy and performance is required.
Region Entrance
Region Entrance is a behavior analysis function
of Hikvision’s Smart Features set. If someone enters a pre-defined virtual
region, the camera will automatically detect the event and can trigger alarms
or recording if pre-configured.
Saturation (Color)
The vividess of a color. I is directly related to the amplitude of the chrominance signal.
SAN
A Storage Area Network or SAN is a network of storage devices that are connected to each other and to a server, or cluster of servers, which act as an access point to the SAN. In some configurations a SAN is also connected to the network. SAN's use special switches as a mechanism to connect the devices. These switches, which look a lot like a normal Ethernet networking switch, act as the connectivity point for SAN's. Making it possible for devices to communicate with each other on a separate network brings with it many advantages. Consider, for instance, the ability to back up every piece of data on your network without having to 'pollute' the standard network infrastructure with gigabytes of data. This is just one of the advantages of a SAN which is making it a popular choice with companies today, and is a reason why it is forecast to become the data storage technology of choice in the coming years. According to research company IDC, SAN's will account for 70% of all network storage by 2004.
Satellite
A remote point or radio transmitting device.
Smart Tracking
The Smart Tracking function is an innovative technology for PTZ
dome cameras, which can enhance the effectiveness of the video surveillance
system. In surveillance scenes where the occasional presence of people or
vehicles require special attention (e.g., bank vaults, hotel corridors, parking
garages, etc.), smart tracking can be used to detect moving objects and follow
their movements until they’re out of view.
Scanner
A pan unit.
Storage/Surveillance Storage
Surveillance video is almost always stored for later retrieval and review. The average storage duration is between 30 and 90 days. However, a small percentage of organization store video for much shorter (7 days) or for much longer (some for a few years).The two most important drivers for determining storage duration is the cost of storage and the security threats an organization faces.
Three fundamental types of storage may be selected:
•Internal storage uses hard drives built inside of a DVR, NVR or server. Today this is still the most common form of storage. With hard drives of up to 1 TB common today, internal storage can provide total storage of 2TB to 4TB
•Directly Attached storage is when hard drives are located outside of the DVR, NVR or server. Storage appliances such as NAS or SANs are used to manage hard drives. This usually provides greater scalability, flexibility and redundancy.
•Storage Clusters are IP based 'pools' of storage specialized in storing video from large numbers of cameras. Multiple DVRs, NVRs or servers can stream video to these storage clusters. They provide efficient, flexible and scalable storage for very large camera counts.
Shutter
Ability to control the integration (of light) time to the sensor to less than 1/60 second; e.g: stop motion of moving traffic.
Sharpness
This is the control of fine detail within a picture. This feature was originally introduced into color TV sets that used notch filter decoders. This filter took away all high frequency detail in the black and white region of the picture. The sharpness control attempted to put some of that detail back in the picture. Sharpness controls are mostly superfluous in today’s high-end TVs. The only logical requirement for it nowadays is on a VHS machine.
Sensitivity
A measure of the amount of light required to provide a standard video signal. Sensitivity values are stated in lux or foot-candles.
Signal Strength
In the context of radio, signal strength refers to the magnitude of the electric field at a reference point that is a significant distance from the transmitting antenna. It may also be referred to as received signal level or field strength. Typically, it is expressed in voltage per length or signal power received by a reference antenna. High-powered transmissions, such as those used in broadcasting, are expressed in dB-millivolts per metre (dBmV/m)or in decibels above a reference level of one milliwatt (dBm).
Standard Minimum Signal
1000 microvolts at 75 ohms (0dB mV) in RF systems; 0.7 Vp-p non-composite,1Vp-p composite in video systems.
Scene Illumination
The density of light in LUX falling on the area to be viewed. For best results the ratio of the lightest to the darkest areas should not be more than a factor of two.
Scene Change Detection
Scene
change detection is a behavior analysis function of Hikvision’s Smart Features
set. If someone changes the camera’s viewing direction so that the camera
captures a different scene, the camera will automatically detect the event and
can trigger alarms or recording if pre-configured.
SECAM
Sequential Couleur A'Memorie, a color television system used in France, Russia and other countries that do not use either the NTSC or PAL system. It has 625 horizontal scan lines and 25 frames per second.
SDI & SMPTE
SDI (Serial Digital Interface) is a format for transmitting video over cable, being standardized by SMPTE (Society of Motion Picture and Television Engineers). These standards are especially used for transmission of uncompressed, unencrypted digital video signals (optionally including embedded Audio and/or Time Code) within television facilities.
Sequential Switcher
Video Switcher. A device that allows the video signals from multiple cameras to be displayed on a monitor, or recorded on a VCR one at a time in sequence.
S-Video
Transmits luminance and color portions separately, using multiple wires, thus avoiding the color encoding process and its inevitable loss of picture quality.
Smart Playback
Smart Playback is a feature of Hikvision’s Smart
Feature set. Smart Playback provides an easy way to go through less important
information quickly. In Smart Playback mode, the system will analyze the video
containing the motion or VCA (Video Content Analytics) information. The video
with motion or VCA will be played at normal speed while the one without motion
or VCA information will be played at up to 16-times speed. The Smart Playback
rules and areas are configurable.
SSL/TLS
SSL/TLS (Secure Socket Layer/Transport Layer Security) two protocols (SSL is succeeded by TLS) are cryptographic protocols that provide secure communication on a network. SSL is commonly used over HTTP to form HTTPS, as used e.g. on the Internet for electronic financial transactions. SSL uses public key certificates to verify the identity of the server.
SMTP
SMTP (Simple Mail Transfer Protocol) is a TCP/IP protocol used for sending and receiving e-mail. However, since it is limited in its ability to queue messages at the receiving end, is usually used with one of two other protocols, POP3 or IMAP. These other protocols allow the user to save messages in a server mailbox and download them periodically from the server. Users generally use an e-mail application that utilizes SMTP for sending e-mail, with either POP3 or IMAP for receiving their messages from their local server. Most e-mail programs like Eudora allow you to specify both an SMTP server and a POP server. On UNIX-based systems, sendmail is the most widely used SMTP server for e-mail. A commercial package, Sendmail, includes a POP3 server and also comes in a version for Windows NT. SMTP is usually implemented to operate over TCP port 25. The specification details for SMTP are included in RFC 821 of the Internet Engineering Task Force (IETF). Europe is X.400 is a widely used alternative to SMTP.
Subnet
A subnet is an identifiably separate part of an organization's network. Typically, a subnet may represent all the machines at one geographic location, in one building, or on the same local area network (LAN). Having an organization's network divided into subnets allows it to be connected to the Internet with a single shared network address.
Subnet mask
Subnetting is a method that allows one large network to be broken down into several smaller ones. IP addresses are grouped by something called a subnet mask. Every IP address has a corresponding subnet mask. The subnet mask specifies the range of the IP addresses in a group. The subnet mask looks a lot like an IP address. It is made up of four eight-bit numbers separated by periods. These numbers once again range from 0 to 255. A typical subnet mask is 255.255.255.0.
Static IP Address
One that is fixed and never changes. This is in contrast to a dynamic IP address which may change at any time. Most ISP's can offer to assign a single static IP or a block of static IP's for a few extra bucks a month and may require you upgrading to a business account.
Sensor Lens
These lenses include a light sensor similar to that in a photographic camera. This measures the light levels and adjusts the iris aperture accordingly. It requires a 12 volt dc supply that may be obtained from any source. This type of lens is not very common now it was introduced for use on cameras that did not have a video and 12 volt output. The problem was that the light sensor was pre-set and not responsive to the video level therefore the correct level was not always maintained. The vast majority of cameras now provide an automatic lens connection therefore there will only be rare cases where this lens will be required.
SentryScope
SentryScope is a 21 million-pixel ultra high resolution digital surveillance system with a 90° angle of view, it can provide facial identification in a area 90m wide and 60m away from the camera even in playback.
SentryScope uses advanced linescan technology to achieve ultra-high resolution surveillance video footage. Capable of capturing up to 21 million pixels per image, SentryScope can view large areas, while capturing enough data in each image to allow zooming into sub-regions in fine detail. In unmanned and partially-manned operations the ability to identify, suspicious people, item, and / or activity after the event, is critical. SentryScope is now available with upgradable storage capacities allowing the user to record for 30 days+. Not to mention the state of the art SentryChroma giving a fast overlay in full colour.
Sentry-IR
Imagine your high resolution SentryScope images being as crystal clear in low light conditions as they are in broad day light.
Now this is possible! Some of Technology Ltd company are releasing SentryScope with Infra Red cut filter and a 180 degree Ifra red illuminator.
Smear
An unwanted side effect of vertical charge transfer in a CCD chip.It shows as vertical white (or sometimes red) stripes in parts of the image where there are very bright highlights. In some modern chip sets smear is minimized to almost undetectable levels.
Spot Filter
A small insert used in a lens to increase the f-stop range of the lens.
Simplex (Multiplexer)
A multiplexer with 1 frame store that can either time multiplex records or show
multi-screen pictures in live or play back. It cannot record the multiplexer pictures whilst showing multi-screen pictures.
S/N RATIO
Signal to noise ratio, a measurement of the noise level in a signal expressed in dB (decibels). In a video signal values from 45dB to 60dB produce an acceptable picture. Less than 40dB is likely to produce a 'noisy' picture.
SSNR
Samsung Super Noise Reduction(SSNR) is a state of art technology exclusively developed by Samsung Techwin. With this superior technology a camera can provide virtually the same image of what it actually sees by remarkably reducing random and fixed noise under low illumination. in one words SSNR is Clearer & Crisper Image in Low Light.
Switch
A switch is a network device that connects network segments together, and which selects a path for sending a unit of data to its next destination. In general, a switch is a simpler and faster mechanism than a router, which requires knowledge about the network and how to determine the route. Some switches include the router function.
Switcher
A video switcher enables different cameras to be switched to call-up monitors. In a smaller, cost-conscious applications, a manual switcher allows users to select the camera they want to see by pressing the appropriate button. The most popular type of switcher, a sequential switcher, contains circuitry that will switch one camera to another automatically. The operator can set the length of time (dwell time) that a scene remains on the monitor before sequencing automatically to the next camera. This allows operators to keep tabs on numerous cameras with only one monitor, but also creates a drawback know as "switcher dilemma". To illustrate switcher dilemma, imagine a system with eight cameras, each programmed to switch after dwelling on the monitor for 5 seconds. In this scenario, a considerable gap will occur between the time the first image is displayed and the time the eighth image is displayed. The situation worsens when recoding the video for review at a later time. On playback, you may see a door opening on camera 1, then suddenly the video switches to camera 2, followed by camera 3 and so on. By the time camera 1 appears again, the door is closed and you are left wondering who came through the door while camera 2 through 8 were flashing sequentially on the monitor.
Synchronising
The video signal from a TV camera has to provide a variety of information at the monitor for a correct TV picture to be displayed. This information can be divided into: Synchronising pulses that tell the monitor when to start a line and a frame; video information that tells the monitor how bright a particular point in the picture should be; chrominance that tells the monitor what colours a particular part of the picture should be (colour cameras only).
Server
In general, a server is a computer program that provides services to other computer programs in the same or other computers. A computer running a server program is also frequently referred to as a server. In practice, the server may contain any number of server and client programs. A web server is the computer program that supplies the requested HTML pages or files to the client (browser).
Sudden Audio Increase/Decrease Detection
Sudden Audio Increase/Decrease Detection is a
behavior analysis function of Hikvision’s Smart Features set. If there is
sudden audio change, either increase or decrease, the camera will automatically
detect the event and can trigger alarms or recording if pre-configured.
T1 channels
In North America, a digital transmission channel carrying data at a rate of 1.544 Mbps. In Europe, a digital transmission channel carrying data at a rate of 2.048 Mbps.
TEARING
A term used to describe a picture condition in which groups of horizontal lines are displaced in an irregular manner.
TFT
Thin-Film-Transistor. This technology is used mainly for manufacturing flat computer and video screens that are superior to the classic LCD screens. Colour quality, fast response time and resolution are excellent for video.
Test Pattern
A chart especially prepared for checking overall performance of a television system. It contains various combinations of lines and geometric shapes. The camera is focused on the chart, and the pattern is viewed at the monitor for fidelity.
Tracking Dome Camera
Tracking Dome Camera will automatically lock on to a moving target or person and follow its movement. The tracking processing and control are all handled by the internal electronics in the auto tracking camera making it a high performance and reliable unit.
Tilt
Camera movement in the vertical direction.
Transcoded Stream
Hikvision
NVRs support a transcoded stream for remote live views and playback. Under
situations with limited bandwidth, users can use a transcoded stream to lower
the resolution, bitrate, and frame rate of the original bit stream to fulfill
the needs of a low-bandwidth network and offer more solutions for remote
monitoring.
TVL
Television lines (TVL) is a specification of an analog camera's or monitor's horizontal resolution power. It is alternatively known as Lines of Horizontal Resolution (LoHR). The TVL is one of the most important resolution measures in a video system. The TVL can be measured with the standard EIA-1956 resolution chart. TVL is defined as the maximum number of alternating light and dark lines that can be resolved. A resolution of 400 TVL means that 200 distinct dark lines and 200 distinct white lines can be counted over a horizontal span equal to the height of the picture. TVL is an inherent quality of a camera or monitor and should not be confused with the horizontal scanning lines of broadcast television systems, which e.g. for a PAL system are 625 lines, and for the NTSC system 525 lines.
TPC (Transmit Power Control)
A mechanism used within some networking devices in order to prevent too much unwanted interference between different wireless networks (e.g.the owner’s network and the neighbor’s network).
The network devices supporting this feature are IEEE 802.11h Wireless LAN devices in the 5 GHz band compliant to the IEEE 802.11a. The idea of the mechanism is to automatically reduce the used transmission output power when other networks are within range.
The network devices supporting this feature are IEEE 802.11h Wireless LAN devices in the 5 GHz band compliant to the IEEE 802.11a. The idea of the mechanism is to automatically reduce the used transmission output power when other networks are within range.
Time Lapse VCR
A video recorder that can be set to record continuously over long period of time. This can be anything from two hours to 960 hours.
Triple Streams
Triple
streams provide much more flexibility to users by allowing different data
streams to be sent simultaneously. Each stream has independent purposes:
• The first stream with high resolution and
full frame rate can be used for main monitoring.
• The second stream with lower resolution
can be used for mobile monitoring.
• The third stream with high, low, or
dynamic resolution offers more flexible choices.
Telnet
Telnet is a simple method with which to access someone else's computer—assuming they have given you permission. (Such a computer is frequently called a host computer.) At a more technical level, Telnet is a user command and an underlying TCP/IP protocol for accessing remote computers. The Web or HTTP protocol and the FTP protocol allow you to request specific files from remote computers, but do not allow you logon as a user of that computer. With Telnet, you logon as a regular user with whatever privileges you may have been granted for specific applications and data residing on that computer.
A Telnet command request looks like this (the computer name is made-up):
telnet the.libraryat.harvard.edu
The result of this request would be an invitation to logon with a userid and a prompt for a password. If accepted, you may logon just like any other regular user.
Telnet is most likely to be used by program developers, or anyone that has a need to use specific applications that reside on a remote host computer.
Underscan
Decreases raster size in both H and V so that all four edges of the picture are visible on the monitor.
UPS
Uninterruptible(Unintrarupt) Power Supply. These are power supplies used in the majority of high security systems, whose purpose is to back-up the system when the mains power fails. The duration of this depends on the size of the UPS, usually expressed in output VA (or kVA), and the hold up time expected from fully charged batteries. There are two common types, "off line" and "on line". Off line uses a switch to change from mains to battery operation, thus there can be a short break in the output. On Line UPSs are a type where the convertor is always working, hence there is no switch over break at the output.
URL
Previously Universal Resource Locator. The unique address for a file that is accessible on the Internet.Eg: www.arindamcctvaccesscontrol.blogspot.com
UTP
Unshielded Twisted Pair: A variant of twisted pair cabling, UTP cable is not surrounded by any shielding. The wires in a twisted pair cable are twisted around each other to minimize interference from the other twisted pairs in the cable. UTP is the primary wire type for telephone usage and the most commonly used type of networking cable.
UDP
UDP (User Datagram Protocol) is a communications method (protocol) that offers a limited amount of service when messages are exchanged between computers in a network using the Internet Protocol (IP). UDP is an alternative to the Transmission Control Protocol (TCP) and, together with IP, is sometimes referred to as UDP/IP. Like the Transmission Control Protocol, UDP uses the Internet Protocol to actually get a data unit (called a datagram) from one computer to another. Unlike TCP, however, UDP does not provide the service of dividing a message into packets (datagrams) and reassembling it at the other end. Specifically, UDP doesn't provide sequencing of the packets that the data arrives in. This means that the application program that uses UDP must be able to make sure that the entire message has arrived and is in the right order. Network applications that want to save processing time because they have very small data units to exchange (and subsequently very little message reassembling to do) may prefer UDP to TCP. The Trivial File Transfer Protocol (TFTP) uses UDP instead of TCP.
UDP provides two services not provided by the IP layer. It provides port numbers to help distinguish different user requests and, optionally, a checksum capability to verify that the data arrived intact.
In the Open Systems Interconnection (OSI) communication model, UDP, like TCP, is in layer 4, the Transport Layer.
UL / UL listing
The UL stands for "Underwriters Laboratory".Now it is independent and non-profit. It tests electrical components and equipment for potential hazards. When something is UL-listed, that means that the UL has tested the device, and it meets their requirements for safety - ie: fire or shock hazard.It doesn't necessarily mean that the device actually does what it's supposed to, just that it probably won't kill you. The UL does not have power of law in the U.S. -- you are permitted to buy and install non-UL-listed devices. However,insurance policies sometimes have clauses in them that will limit their liability in case of a claim made in response to the failure of a non-UL-listed device. Furthermore, in many situations the NEC will require that a wiring component used for a specific purpose is UL-listed for that purpose. Indirectly, this means that certain parts of your wiring must be UL-listed before an inspector will approve it and/or occupancy permits issued.
VHS
Victor Home System; used by most VCRs as the recording medium.
Variofocal Lens
This type of lens has the capability of varying its focal length in order to zoom in on images. An auto iris feature is required in order to achieve this. Variofocal lenses are contrasted with fixed focal lenses, which are less expensive and often allows more light to pass through them at their set length, enabling better detection in low light circumstances.
Video Equalization/Corrector
A device which can correct for various frequency losses in the transmission of a video signal, the losses typically being due to long distance transmission.
Vertical resolution
The number of horizontal lines resolved in a picture is called the vertical resolution, and is determined by the television scanning method, be it NTSC, PAL, or some other format.
Vibration sensor
A device that activates when it detects vibrations in its detection zone, and then activates a specific surveillance camera is known as a vibration sensor.
Video compression
This technique (often a MPEG format) compresses video into lower bit rates for easier Internet transmission, often along narrower bandwidths. Video or audio is compressed to shrink file size, ensuring acceptable transfer speed. Compressed video can sometimes be of a noticeably lower quality, but still clear enough to be useful.AVC is the successor to MPEG as the new video compression standard.
Video Analytics
Video analytics scan incoming video feeds to (1) optimize storage or (2) to identify threatening/interesting events.
Storage optimization is the most commonly used application of video analytics. In its simplest form, video analytics examines video feeds to identify changes in motion. Based on the presence or absence of motion, the video management system can decide not to store video or store video at a lower frame rate or resolution. Because surveillance video captures long periods of inactivity (like hallways and staircases, buildings when they are closed, etc.), using motion analytics can reduce storage consumption by 60% - 80% relative to continuously recording.
Using video analytics to identify threatening/interesting events is the more 'exciting' form of video analytics. Indeed, generally when industry people talk of video analytics, this is their intended reference. Common examples of this are perimeter violation, abandoned object, people counting and license plate recognition. The goal of these types of video analytics is to pro-actively identify security incidents and to stop them in progress (e.g., perimeter violation spots a thief jumping your fence so that you can stop them in real time, license plate recognition identifies a vehicle belonging to a wanted criminal so you can apprehend him).
These video analytics have been generally viewed as a disappointment. While many observers believe that video analytics will improve, the video analytics market is currently contracting (in response to its issues and the recession)
VQD
VQD (Video Quality Diagnosis) is a feature that
monitors the video for abnormal qualities (i.e., blurred image, abnormal
brightness, and color cast). An alarm will be triggered and linked with
configured response actions.
Video amplifier
This device boosts the strength of a video signal.
Video distribution amplifier
This amplifier is able to boost signal strength and also to create multiple video signal outputs.
Video Motion Detector
A detection technology which can respond to pre-determined changes in the video, and
generate an alarm condition and/or initiate some other function within the system.
Video Line Amplifier /Video Equalization/Corrector
A device providing amplification of the video signal along a transmission line. which can correct for various frequency losses in the transmission of a video signal, the losses typically being due to long distance transmission.
Video server
This enables an analog camera to be converted into an IP camera, able to stream digital video over an office network, phone, or ISDN connection. Therefore, an analog based surveillance system can be upgraded and networked to function as an IP surveillance system.
Video Management System
Video management systems are the hub of video surveillance solutions, accepting video from cameras, storing the video and managing distribution of video to viewers.
There are four fundamental options in video management systems. Most organizations choose one of the four. However, it's possible that companies may have multiple types when they transition between one to another.
Like: DVR, HDVR, NVR & IP Video Surveillance Software.
Video streaming
Streaming video delivers compressed multimedia content over the Internet in a stream of packets. Viewers view the file as it downloads, instead of downloading the entire file first. Streaming video first initializes the transfer, and then buffers it. Bandwidth determines both picture quality and whether or not the viewed video catches up with the downloading content, which causes the video to stop. Real-player is one of the most popular free streaming video players available. Video streaming is commonly used for viewing live feeds from security cameras, with RTSP/RTP being the main streaming technology currently in use.
Video surveillance
This term refers to the use of CCTV and DVR to monitor secure sites, or portions thereof. Video Surveillance systems can start with a few as one camera. For systems using more than 16 cameras, enterprise video surveillance systems are preferable. The many terms defined in this glossary give an idea of the many options available for different security needs and situations. In today’s professional world, Video Surveillance (often referred to as CCTV) is the most cost effective way to achieve loss prevention.
Video Surveillance Network
Increasing demand and advancing technology have brought about the need for video surveillance systems to be integrated into computer networks, commonly known as LAN's (local area networks). CCTV Camera Pros offers a variety of network accessories to accommodate a modern computer network surveillance system. Browse our video surveillance network accessories section to find network switches, PoE (Power over Ethernet) injectors / adapters and CAT-5 cable
The advantages of integrating your video surveillance into a LAN are:
* Remote access and camera views from the internet
* Enable the use of IP cameras
* Allow for PC-based DVR's with enhanced features
* PoE (Power over Ethernet) to reduce cable and costs
VPN
A virtual private network (VPN) is a private data network that makes use of the public telecommunication infrastructure, maintaining privacy through the use of a tunneling protocol and security procedures. In contrast to a system of privately owned or leased lines used by a single organization, VPN uses the public network infrastructure to deliver the same capabilities—at much lower cost by. A virtual private network makes it possible to have the same secure sharing of public resources for data. It is now quite commonplace for phone companies to provide secure shared resources for voice messages. Today, many companies are looking at using a private virtual network for both extranets and wide-area intranets.
Using a virtual private network involves encrypting data before sending it through the public network. It then needs to be decrypted at the receiving end. An additional level of security involves encrypting not only the data, but also the originating and receiving network addresses. Microsoft, 3Com, and several other companies have proposed a standard protocol, the Point-to-Point Tunneling Protocol (PPTP), and Microsoft has built this protocol into its Windows NT server. VPN software such as Microsoft's PPTP support, as well as security software, would usually be installed on a company's firewall server.
VMD
Video Motion Detector. A detection device generating an alarm condition in response to a change in the video signal, usually motion, but it can also be change in light. Very difficult to set up for use externally but can be useful in carefully controlled situations. Modern VMD systems can learn the scene and ignore such things as tree and foliage movement.
VOD
Video On Demand. A service that allows users to view whatever program they want whenever they want it with VCR-like control capability such as pause, fast forward and rewind.
VBR:
Variable bitrate (VBR), or less commonly variable bit rate, is a term used in telecommunications and computing that relates to the bitrate used in sound or video encoding. As opposed to constant bitrate (CBR), VBR files vary the amount of output data per time segment. VBR allows a higher bitrate (and therefore more storage space) to be allocated to the more complex segments of media files while less space is allocated to less complex segments. The average of these rates can be calculated to produce an average bitrate for the file.
MP3, WMA, Vorbis, and AAC audio files can optionally be encoded in VBR. Variable bit rate encoding is also commonly used on MPEG-2 video.
The advantages of VBR are that it produces a better quality-to-space ratio compared to a CBR file of the same size. The bits available are used more flexibly to encode the sound or video data more accurately, with fewer bits used in less demanding passages and more bits used in difficult-to-encode passages.
The disadvantages are that it may take more time to encode, as the process is more complex, and that some hardware might not be compatible with VBR files.
Video Band
The frequency band used to transmit a composite video signal.
Video Motion Detector
A detection technology which can respond to pre-determined changes in the video, and
generate an alarm condition and/or initiate some other function within the system.
Viewing Video
Surveillance video is ultimately viewed by human beings. Most surveillance video is never viewed. Of the video that is viewed, the most common use is for historical investigations. Some surveillance video is viewed live continuously, generally in retail (to spot shoplifters) and in public surveillance (to identify criminal threats).
Four fundamental options exist for viewing video:
• Local Viewing directly from the DVR, NVR or servers is ideal for monitoring small facilities on site.
• Remote PC Viewing is the most common way of viewing surveillance video. In this approach, standard PCs are used to view live and recorded video. Either a proprietary application is installed on the PC or a web browser is used. Most remote PC viewing is done with an installed application as it provides the greatest functionality.
• Mobile Viewing allows security operators in the field to immediately check surveillance video. As responders and roving guards are common in security, mobile viewing has great potential. Though mobile clients have been available for at least 5 years, they have never become mainstream due to implementation challenges with PDAs/phones. Renewed interest and optimism has emerged with the introduction of the Apple iPhone.
• Video Wall Viewing is ideal for large security operation centers that have hundreds or thousands of cameras under their jurisdiction. Video walls provide very large screens so that a group of people can simultaneously watch. This is especially critical when dealing with emergencies.
Videocassette Recorder (VCR)
A device that accepts signals from a video camera/microphone and records video/audio on magnetic tape in a cassette. The VCR can play back recorded video/audio on a television set or CCTV monitor.
Video Switcher
Switcher or Sequential Switcher. Video Switcher is a combiner to combine multiple cameras and to show them on a monitor screen one by one, manually or automatically. When it works on automatic sequential mode, you can program the dwelling time on each camera, usually from 1 second to 30 or 60 seconds. Most video switchers have BNC jacks for video input so that if your cameras have RCA connections, you will need BNC/RCA adapters. This adapter may be provided by the equipment supplier or can be found easily at any electronic parts shop like Radio Shack or Best Buy, etc. Most commercialized video switchers are for 4 channels or 8 channels, which can be connected by up to 4 or 8 cameras. Video Switcher works for both B/W and color cameras and is to be connected to a CCTV monitor, TV or VCR.
Virtual Host
Virtual
Host is an NVR (Network Video Recorder) function that lets users link directly
to an IPC (Internet Protocol Camera)’s configuration Web page through the
Internet Explorer (IE) browser. Virtual Host solves the issue of logging into
an IPC when the IPC is on a different network from the NVR, making the
system more convenient and user-friendly.
Wavelet
A mathematical function useful in digital signal processing and image compression. In the Internet communications, wavelet has been used to compress images to a greater extent than is generally possible with other methods such as JPEG or MPEG.
Weatherproof Housings
Weatherproof housings must be about the most mundane aspect of a CCTV installation. Or so it seems because many engineers simply consider the housing as a protection against the elements. However there are many aspects to consider and many suppliers of housings. It is about the cheapest element of an external system yet price seems to be the main factor in selecting which to use. Important considerations should be:
* Ease of access for pre-assembly in workshop.
* Ease of access during installation.
* Ease of access for future service needs.
* Is the camera mounting plate insulated from the case?
* Can the mechanical focusing screws on the camera be accessed? Some are at the back, some at the side and some on top.
* Can the lens be focused and the peak/average settings adjusted on site?
* Can one man remove the cover and work on the inside?
* If there is a telemetry board fitted can it be accessed without removing the camera?
The most common type of housing is that where the camera is mounted on a flat bed. A rectangular box shaped cover drops down over the complete assembly and is held in place by four spring clips. This is great for assembly in the workshop because everything is nicely accessible. The problem comes when a service engineer at the top of a ladder needs to work on it. Many engineers know that it needs four hands to hold the clips clear and two to remove the cover. Especially if it has been on for some time and the cover is welded to the rubber seal. Once the cover is off everything is exposed to the elements and it is no quick job to replace it.Another design is a box like housing with two latches on each side. When the latches on one side are released, the cover pivots open on the opposite side latches. The cover may be opened in either direction. If all four latches are released, the cover can be completely removed.
Web Camera (or Web Camera Server)
A CCTV Camera with built-in web server computer.
Watermark(Digital Watermarking)
You may need to add identity and ownership information to your video, ensure that viewers know the source. Digital Watermarking allows you to embed text or graphics, for example, a logo, in digital media such as video or images. It is an excellent way to stamp a personalized identification mark such as your company name, date of creation etc. on the visual material.
Web Server
The computer program (housed in a computer) that serves requested HTML pages or files.
Wide angle lens
This lens enables a wide view of the scene, with a magnification ratio less than 1.
White balance
CCD security cameras feature this adjustment to compensate for ambient light color. Since there’s a color difference between standard light bulb light and sunlight, white balance adjusts to ensure a more realistic picture. This feature may be set by manual adjustment, or it may have preset settings for the most common situations.
Wireless
The wireless transmission of video signals can be carried out over both short and long ranges, with 2.4 to 5 GHz devices for short distances and high-power line dedicated site solutions for several miles or more.
Wireless Transmitter and Receiver
When it is difficult to run a cable to transmit video signals of the camera to the monitor, you might want to consider wireless transmission. But, the wireless signals may be attenuated or blocked by heavy metal walls, high voltage power lines, microwave equipment and others.
The wireless system is strictly controlled by the FCC. The commercialized models are usually FCC approved by the manufacturers and you don't need to get a separate FCC approval. But, you can not change or modify the specification of each model without prior approval from the FCC. Each manufacturer has different bandwidths of frequency approved from the FCC and will not be compatible with other manufacturer's models.
Most commercialized wireless systems have 4 or 10 channels; you can not use more than 4 or 10 transmitters in one area due to conflicts of the overlapped channel(s). But you can have as many additional wireless receivers as you want as far as they are within the range.
WINS
WINS (Windows Internet Naming Service), part of the Microsoft Windows NT Server, manages the association of workstation names and locations with Internet Protocol addresses (IP addresses) without the user or an administrator having to be involved in each configuration change. WINS automatically maps computer names with their corresponding IP addresses into a table, ensuring that each name is unique and dissimilar to any existing computer name. When a computer is moved to another geographical location, the subnet part of the IP address is likely to change. Using WINS, the new subnet information will be updated automatically in the WINS table. WINS complements the NT Server's Dynamic Host Configuration Protocol (DHCP), which negotiates dynamic IP addresses for different computers each time they connect to the network. If you are using a computer user on a network connected to a Windows NT Server, you may find WINS mentioned in some of your network-related programs or system messages.
Based on Microsoft's paper, DHCP and WINS have been proposed open standards to the Internet Engineering Task Force (IETF) in Request for Comments 1533, 1534, 1541, and 1542. New features are included in the follow-on to Windows NT, Windows 2000.
Y Signal
A signal transmitted in color television containing brightness information.This signal produces a black and white picture on a standard monochrome receiver. In a color picture it supplies fine detail and brightness information.
Y/C
Occasionally known as s-video, this video signal splits chrominance (c) and luminance (y) onto two separate signal wires for better composite video picture quality.
YIQ (Luminance In-Phase Quadrature)
The color space used in NTSC is called the YIQ.
YUV (Luminance Chrominance)
YUV is the color space used in PAL, and is preferred for video signals. YUV and RGB can be converted back and forth.
Zoom
Changing the effective focal length to allow different fields of view to fill the picture area. Zoom can be optical, where the lens is adjusted, or digital, where a portion of the view selected is magnified electronically.
Zoom lens
A zoom lens has the advantage of offering a variable focal length to view both wide angle to telephoto scenes.
Zoom ratio
The ratio of the starting focal length (wide) to the ending focal length (telephoto) of a zoom lens. A 10X zoom will magnify the image at the wide end by 10 times. Examples of a 10X zoom lenses; 8mm~80mm, 12mm~120mm.
Zero Channel
For
remote access, users are able to combine multiple channel videos into one zero
channel and save transmission bandwidth.
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