One of the most confusing and difficult topics in the CCTV world is
resolution. Most of us have digital cameras or video camcorders and have heard
the term megapixel used as the most common comparison in resolution between
various makes and models. We are also aware that a larger number means better
picture quality, but many people do not know why. In the CCTV security camera
world, though, most cameras are still analog and their resolution is measured
differently from what we are used to.
When measuring analog resolution, a TV line does not have a defined number
of individual pixels. Instead, the term “TV lines” refers to the number of
discernable horizontal or vertical lines on the screen. Analog security cameras
are measured in Analog TV Lines, and most of them have between 420 and 580. The
higher number of TV Lines, the more information captured. These types of
cameras connect to a security DVR or CCTV VCR via coaxial video cable.
Zoomed too far into a picture from a website and seen the image go from
clear to a bunch of colored squares – each one of those squares is an
individual pixel. A megapixel (MP) is 1 million pixels, and is a specific
measurement for digital resolution that encompasses the area of the output
video.
Example: If a camera outputs a signal that is 1280×1024 pixels, it is shooting at a megapixel resolution of 1280 x 1024 = 1,310,720 pixels = 1.3 Megapixels (MP).
The most common type of digital security cameras are IP Cameras. These,
like your digital camera at home, use strictly digital resolution. They utilize
a network connection to either act as a standalone device or connect to a
network-based DVR (Digital Video Recorder) or NVR (Network Video Recorder). IP
Cameras have fixed resolutions and are now approaching, and in several cases
exceeding, 1 megapixel in resolution, on average. Many of these cameras also
support POE (Power Over Ethernet), which allows them to be powered by the
Ethernet cable used for network connectivity, and PTZ (Pan Tilt Zoom), allowing
for remote control of the pan, tilt and zoom features, if applicable.
I hope this helped everyone distinguish the differences between Analog (TV
Line) and Digital (Pixel) Resolution. We would love to know what you think of
our articles, and if you have any further questions, don’t hesitate to leave a
comment!