Television Lines or TV Lines. A horizontal measurement of how fine a detail from a scene can be resolved on a display. Expressed as a number, eg. 380TVL, it relates to an equivalent number of equally spaced black and white vertical lines across the viewing screen.
For example, if a camera was pointing at railings in a park and there were 420 railings across the width of the image, you would need a 420TVL camera to be able to count all the vertical railings.
TVL is commonly confused with the number of Video Lines on a screen, ie 625 for PAL (and the other HD formats 720, 1080i etc.)
Lenses, cameras, recorders and monitors have a TVL ratings and should be considered as a total system.
VL – Video lines. The number of horizontal scan lines in an images.
Analog surveillance video resolution is measured in terms of broadcast TV lines as viewed on a monitor screen. Video quality is charted with converging lines of higher and higher density. The TVL resolution number is the line density where the camera is no longer able to reproduce individual lines. The higher this number is, the better the picture.
The digital recording resolution can be expressed in effective pixel dimensions.
Typical pixel dimensions:
||510 x 492
||768 x 494
||811 x 508
||976 x 582