First of all, the original resolution of traditional analog cameras is not high, and it is affected by video impairments such as repeated A/D conversion, electromagnetic transmission interference, interlace scanning, and composite video deinterlacing of D1 pictures. It is not clear, so whether it is D1 or 4CIF is just a theoretical value, in practice, the resolution is completely not reach the theoretical value level. The digital camera adopts digital signal transmission. It converts the optical signal into a digital signal, and then compresses and processes the image by the DSP. Finally, the digital compressed video is output through the network. The digital camera is resistant to electromagnetic interference, progressive scan, and picture resolution. Rates have advantages that traditional analog cameras cannot match.
Second, the traditional analog color camera captures vertical resolution, 625 lines under the PAL standard, 575 lines after blanking, up to 540 lines is currently the limit, and digital HD cameras can reach at least 800 lines, and from the resolution From the above point of view, the highest resolution of a traditional
Analog Camera can reach about D1 or 4CIF, which is approximately (400,000 pixels). However, digital cameras do not have this limitation and can reach megapixels or even tens of millions of pixels. Pixels and sharpness are simply not the same thing.
Thirdly, the digital image scanning mode adopted by the digital HD camera is progressive scanning. Each frame of the image is sequentially scanned by one electron beam and one line after another. The scanning mode of the conventional analog camera uses interlaced scanning, and the interlaced scanning line scan frequency is half that of the progressive scanning. Because of its working principle, interlaced scanning has many disadvantages in applications, such as the occurrence of inter-line flicker effects, parallelism, or the appearance of vertical edge sawing and other undesirable effects, and resulting in reduced overall motion picture clarity.
Fourth, the digital HD camera's color can be more realistic than the analog camera. Since the luminance signal and the chroma signal in the analog video signal occupy the same frequency band and are comb-filtered by the video acquisition chip (bright color separation), It is difficult to completely separate the chroma and luminance signals, resulting in variegated spots and color penetration on the screen. However, the digital HD camcorder does not have such troubles. The colors are more realistic, more layered, and the picture saturation is better.
Fifth, analog cameras need control lines, video cables, audio cables, and power cables to be wired in an independent manner. The cabling is very cumbersome and complicated, and the workload is large and the cost of integrated wiring is high. There are many in engineering applications. Limitations.
September 25, 2019
