Camera Resolution and TV Lines (TVL)
Resolution can be defined as the fineness of detail that can be distinguished in an image. In CCTV cameras, resolution is measured in TV Lines (TVL). A higher number of TVL means that a camera will be able to render images with more detail. However, TVL is not the sole factor that determines the quality of the final output. For example, the resolution does not affect the color reproduction of the camera. The monitoring device and the video processing of the DVR also impact the final output. Below is a comparison of different TVL resolutions.
NOTE: Resolution is not affected by the lens size of the camera. The images above are taken by cameras with different image sensors and size lenses.
What are TV Lines?
TV Lines are a measure of horizontal resolution. The human eye cannot detect the number of TV Lines that a camera can produce. This must be measured using a specialized chart like the one shown below.
Source: Bosch, 2010
Specifically, TV Lines are measured in the following way: first, take a portion of the image's width equal to the size of the image's height. Then, count the number of vertical lines displayed.
Last Updated: 3/30/2012