1080i VS 1080p The Difference

1080i vs. 1080p: What's the Difference?

Progressive (1080p) video is considered better than interlaced (1080i), but it's not always clear why; here's what's actually happening on your TV screen.

Today's HDTVs can display beautiful, 1,920 X 1,080-pixel video, but the actual quality of what you're viewing depends on the source material. A lot of the time, you're not seeing exactly 1080p. In fact, most TVs today have two modes with similar names: 1080i and 1080p. Both have the same screen resolution, so what's the difference between the two? Here are five things you need to know:

1080i video is "interlaced." 1080i video plays back at 60 frames per second, but that's a bit deceptive, because it's actually broadcast at 30 frames per second. The TV then displays those frames twice, the first pass is 1,920 X 540 for the even scan line field, and the second pass is 1,920 X 540 for the odd scan line field. The process by which this occurs is called interlacing. It contributes to a sense of motion and reduces perceived flicker.

1080p video is called "progressive scan." In this format, 1,920-by-1,080-pixel high-definition movies are progressively drawn line after line, so they're not interlaced. On paper, that may not seem like a huge deal. But in the real world, what you end up seeing looks sharper and more defined than 1080i, particularly during scenes with a lot of fast motion.

Sometimes 1080p is termed "Full HD" or "True HD," to distinguish it from 1080i or 720p video. Blu-ray discs contain 1080p video at 24 Frames Per Second, and then, using a method known as 3:2 pulldown, display it at 30 frames per second on screen.

Data compression can confuse the issue. Sometimes cable companies will deliver a 1080i picture, but then compress the data significantly in order to use up less bandwidth. The result can mean smeared details or pixelated color gradations in certain scenes. It's still technically HD, and still looks better than standard-definition cable, but it's not as good as it could be.

This also happens with 1080p streaming Internet video, but in that case, it's usually dependent on the speed of your data connection. In fact, Blu-ray is currently the only practical format for watching lots of pure 1080p content. Even the latest Apple TV, which supports 1080p streaming, does so in a compressed format that loses a bit of quality (although it still looks quite good).

Both formats look similar on smaller TVs. As a general rule, you need a larger TV to notice the difference between 1080i and 1080p. Depending on your eyesight, you can probably pick up the difference on a 32-inch LCD if you're particular about it. But most consumers don't really see a marked difference until at least a 42-inch screen, if not larger. In fact, many people are perfectly happy with 720p HDTV sets even at higher sizes; we recently named one, the 51" Samsung PN51E490B4F, best Choice for budget large-screen HDTVs.

1080p isn't even the best anymore. Technology never stands still, of course. Five years from now, you'll probably just want Ultra High Definition (aka 4K) video instead. (For a closer look at 4K video, check out What is Ultra HD?) But for now, if you're a videophile who appreciates a sharper picture, 1080p is definitely the way to go—both in HDTV capability and in the source material you're viewing.

CCTV surveillance systems used as a crime fighting and prevention

CCTV surveillance systems play an important role in fighting and preventing local and international crime. These closed circuit television systems were in place in London before the July 7th bombings and this footage is being used to identify suspects and investigate the attacks.

Besides fighting terrorism, CCTV security systems installed in public places or retail markets can deter crime, provide the police with leads, help citizens feel safer, and improve the economy of a crime-stricken area. Most CCTV systems have now gone digital for improved performance, urveillance camera maneuverability, and quicker feedback as compared to analog systems.

Implementing CCTV systems

Law enforcement or security professionals best support CCTV systems. These teams of rofessionals need to monitor the CCTV video evidence on a timely basis and they need to be properly trained in order to interpret suspicious behavior caught on the system. When all of these factors are in place, then the CCTV security system will be effective for keeping citizens and shoppers safe. In the case of some municipalities or businesses not being able to afford all of the necessary components of a CCTV system, many CCTV providers can recommend a scalable approach so that priority security needs may be addressed first. Then, additional surveillance cameras can be purchased in ucceeding years as the budget allows.

Digital CCTV systems and surveillance cameras

A modern digital CCTV security system consists of hardware and software components that collect and transmit vital surveillance camera information over fiber optic lines to control rooms staffed by security professionals and equipped with digital CCTV monitors. An example of the surveillance cameras used for reducing crime in LA's MacArthur Park include CyberDome DayNite 25X cameras equipped with removable infrared cut filters, 25x optical zoom lenses, 12x digital zoom capabilities, and 360-degree PTZ (pan tilt zoom) capabilities. This MacArthur Park system also includes GE Storesafe DVRs (digital video recorders) and GE KTD-405 keypad controllers. DVRs are capable of saving CCTV data to a PC for up to ten weeks of recording and some even feature motion etection technology, which means that the footage is only recorded when motion triggers the DVR system. Digital surveillance cameras range in type from compact, fixed cameras to direction-controlled models that can see in the dark under various lighting conditions. CCTV decision-makers need to know what kind of job each surveillance camera must fulfill. Will it watch the flow of passerbys (fixed cameras) or will it need to monitor a crime-targeted area (dome cameras with PTZ functions)? These video security managers also need to consider weatherproofing their surveillance cameras if the cameras are mounted in an especially hot or cold climate, or if the viewing fields could be obscured by dirt or dust.

What kind of crimes do CCTV systems prevent?

Evidence has shown that CCTV systems mostly deter property crimes and robberies, but not more violent crimes such as rape and aggravated assault. CCTV systems may not catch these crimes because they may occur away from the surveillance cameras in more deserted areas.
Fortunately in most situations, when a CCTV system is in place, criminals generally shy away from these monitored areas fearing prosecution since these recorded images can be used in court. As noted previously, in order for a CCTV system to be effective, the electronic system must be used in conjunction with human know-how and skills and it should be carefully integrated into existing security plans.

CCTV: Looking ahead

In the next few years, digital CCTV systems will evolve into wireless CCTV systems that employ GSM (global system for mobile communication) or 3G (third generation) onnections. These wireless systems are completely portable and can deliver live images to a PC, an Internet phone, or a laptop. The cameras are tiny, but include many of the sophisticated features of full size digital CCTV cameras. CCTV customers are also seeking IP-based solutions with LAN/WAN delivery options despite some lags in the technology's image quality and frame rate. "Make no mistake about it, the future is wireless," says Thomas M. Wade, president of Samsung CCTV. "We'll be pushing crime-related images to police cars in the future. Imagine an abduction or robbery in which the responding units are seeing the video and the suspects as they are rolling to the scene. It's all possible and it is the general direction of the industry."

There is also talk of linking CCTV cameras together to form a worldwide network to prevent terrorism, but this international surveillance system would cost billions of dollars and would require extensive international cooperation.

Visit : http://www.gobeyondsecurity.com/forum/topics/cctv-surveillance-systems-used