Television lines
Encyclopedia
Television lines is a specification of an analog camera's or monitors's horizontal resolution power. It is alternatively known as Lines of Horizontal
Resolution (LoHR), aka lines of resolution
. The TVL is one of the most important resolution measures in a video system. The TVL can be measured with the standard EIA-1956 resolution chart.TVL also makes a variation on horizontal angle of display from a video camera, i.e. The more the TV Lines depending on the size of lens, the smaller/narrower the angle of coverage but better picture quality.
TVL is defined as the maximum number of alternating light and dark vertical lines that can be resolved per picture height. A resolution of 400 TVL means that 200 distinct dark vertical lines and 200 distinct white vertical lines can be counted over a horizontal span equal to the height of the picture. For example, on 4 x 3 inch monitor with 400 TVL, 200 vertical dark lines can be counted over 3 inch width on monitor (Note that the 3 inch of monitor height is used rather than the 4 inch of whole monitor width).
TVL is an inherent quality of a camera or monitor and should not be confused with the horizontal scanning lines of broadcast television systems, which e.g. for a PAL
system are 625 lines, and for the NTSC
system 525 lines.
TVL also makes a variation on an angle of display from a video camera, i.e. The more the TV Lines depending on the size of lens the smaller the angle of coverage but better picture quality.
Resolution (LoHR), aka lines of resolution
Lines of resolution
Lines of resolution is a measure of horizontal resolution in a video system, as measured by the number of vertical black lines that can be resolved on a white background. The term was invented in the early days of television. Since analog transmission of video is scan line-based, the same number of...
. The TVL is one of the most important resolution measures in a video system. The TVL can be measured with the standard EIA-1956 resolution chart.TVL also makes a variation on horizontal angle of display from a video camera, i.e. The more the TV Lines depending on the size of lens, the smaller/narrower the angle of coverage but better picture quality.
TVL is defined as the maximum number of alternating light and dark vertical lines that can be resolved per picture height. A resolution of 400 TVL means that 200 distinct dark vertical lines and 200 distinct white vertical lines can be counted over a horizontal span equal to the height of the picture. For example, on 4 x 3 inch monitor with 400 TVL, 200 vertical dark lines can be counted over 3 inch width on monitor (Note that the 3 inch of monitor height is used rather than the 4 inch of whole monitor width).
TVL is an inherent quality of a camera or monitor and should not be confused with the horizontal scanning lines of broadcast television systems, which e.g. for a PAL
PAL
PAL, short for Phase Alternating Line, is an analogue television colour encoding system used in broadcast television systems in many countries. Other common analogue television systems are NTSC and SECAM. This page primarily discusses the PAL colour encoding system...
system are 625 lines, and for the NTSC
NTSC
NTSC, named for the National Television System Committee, is the analog television system that is used in most of North America, most of South America , Burma, South Korea, Taiwan, Japan, the Philippines, and some Pacific island nations and territories .Most countries using the NTSC standard, as...
system 525 lines.
TVL also makes a variation on an angle of display from a video camera, i.e. The more the TV Lines depending on the size of lens the smaller the angle of coverage but better picture quality.