What Is a Scan Line?

The picture sharpness of a TV is in the unit of horizontal sharpness. In layman's terms, we can divide the picture on the TV horizontally into many, many scanning lines. The finer the division, the clearer these pictures, and the greater the number of horizontal lines. The unit of resolution is "TVLine", also called line.

D1 is 480i format, and NTSC

In the above standards, "i" means interlaced and "P" means progressive. The HDTV standard is a high-quality video signal standard, including 1080i, 720p, and 1080p, that is, D3, D4, and D5 belong to the HDTV standard, but currently supporting 480p is also probably called HDTV support. It is important to note that for TV processing capabilities (such as

Interlaced scanning

In fact, the scanning method used by the television is "inter-strip interlance" or interlaced scanning. This method first scans odd scanning lines such as 1, 3, 5, 7, ... to form the first field. , And then scan 2, 4, 6, 8 ... and so on. The even number of scanning lines constitutes the second field, and the two fields form a frame, as shown in the figure below. For the NTSC television system, 30 frames (60 fields) can be generated per second. Equivalently, it is equivalent to a portrait of 60 per second, which can reduce the flicker phenomenon of the screen and save half of the frequency.

The computer screen is non-interlaced, so it uses a higher scanning frequency.

Progressive

Screens that are scanned in a progressive manner (such as LCD TVs) are scanned in sequence using 1, 2, 3, 4, 5, ..., 486. Fields are not used for scanning. , But progressive scanning is directly taken as a frame (Frame), so it is called sequential scanning or non-interlaced scanning, and because each scan line is twice the interlaced scanning, it is also called ' Octave sweep '"P".