Video Resolution–TV Lines vs Pixels–Analog vs Digital
In the CCTV or Video Surveillance world, it is important to understand what we are really talking about when we refer to resolution. We probably all have a digital camera or camcorder and have heard the term megapixel used as the most common comparison in resolution between various makes and models. We are probably also aware that a larger number means better picture quality than a smaller number, but we may not understand why. Most cameras are still analog in the CCTV security camera world, and their resolution is measured differently from what we are used to in this digital revolution.
When measuring analog resolution, a Television Line (TVL) doesn’t have a defined number of 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 TV Lines, and most of them have between 420 and 600 TV Lines. The higher number of TV Lines, the more information captured. Most of today’s cameras connect to a DVR via coaxial video cable.
The smallest element of a digital image is called a pixel. Most of us enlarged a picture from a website large enough to see the image go from clear to a bunch of grainy colored squares. Each one of these 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.
For instance, if a digital or megapixel camera outputs a signal that is 1280×1024 pixels, it is recording at a megapixel resolution of 1280 x 1024 = 1,310,720 pixels = 1.3 Megapixels (MP).
We 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!