In the previous round, we compared the current video surveillance field to the chaos of the late Eastern Han Dynasty. The current industry is a mixture of dragons and snakes, and security vendors are mixed. Some manufacturers' descriptions of products can easily lead to confusion. 600 lines, 700 lines, 1000 lines, even 1200 lines, D1, 960H, 720P, 1080P, some friends were dazzled by these concepts. Before deciding on the length of each HD standard, we still need to explain some common parameters in the field of video surveillance.
First of all, we talk about the concept of "line", TVL (TVLine), also known as "TV line." Analog TVs use a line scan, while lines are used to indicate the horizontal resolution of the TV. As shown in the orange circle logo on the test card above, if the number of TV lines can reach 600 lines, we can clearly see the black and white lines in the orange circle in the picture.
Similarly, the line number is also used to represent the resolution of the analog camera in the horizontal direction. However, at present, the identification methods of the number of camera lines by various manufacturers are inconsistent, and they are identified according to the maximum number of lines marked by the processing chip, and are identified according to the number of pixel points of the image sensor, and also according to the number of lines obtained by the test. Personally feel that the actual number of lines obtained by the test is more reliable, no matter what the number of lines of the camera's nominal number, the actual measurement will know how the resolution of the camera is.
As shown in the test card above, let the test card fill the entire shooting screen of the camera. Where black and white lines can be clearly distinguished, it represents the number of lines that the camera can reach. Most of the analog cameras have 500 lines, and some of them do better to 600 to 700 lines.
First of all, we talk about the concept of "line", TVL (TVLine), also known as "TV line." Analog TVs use a line scan, while lines are used to indicate the horizontal resolution of the TV. As shown in the orange circle logo on the test card above, if the number of TV lines can reach 600 lines, we can clearly see the black and white lines in the orange circle in the picture.
Similarly, the line number is also used to represent the resolution of the analog camera in the horizontal direction. However, at present, the identification methods of the number of camera lines by various manufacturers are inconsistent, and they are identified according to the maximum number of lines marked by the processing chip, and are identified according to the number of pixel points of the image sensor, and also according to the number of lines obtained by the test. Personally feel that the actual number of lines obtained by the test is more reliable, no matter what the number of lines of the camera's nominal number, the actual measurement will know how the resolution of the camera is.
As shown in the test card above, let the test card fill the entire shooting screen of the camera. Where black and white lines can be clearly distinguished, it represents the number of lines that the camera can reach. Most of the analog cameras have 500 lines, and some of them do better to 600 to 700 lines.
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