In learning video processing, you first need to thoroughly understand the critical infrastructure Summary:
1, the visual system: photoreceptor cells - cones: under the action of light, color tone feelings, there are three types of the peak located (nearby 570nm) red,
Green (near 535nm) and blue (near 445nm) wavelength;
- Rods: low ambient light, only luminance information is extracted;
2, human color perception properties Description: brightness - and energy is proportional; green wavelength of maximum brightness feeling contribution, followed by red, blue minimal;
Chroma - is determined by the wavelength of the light, and is characterized by two attributes hue and saturation;
3, description of two basic gratings parameters: frame rate (Hz) and number of lines, the grating is defined in both time and in the vertical direction sampling rate;
4, RGB2YUV: Y = f (rgb), U = BY, V = RY; currently using more standard transformation equations 601 and 702;
5, another digital color coordinates: YCbCr-- fact YUV telescopic and shifted versions;
6, the chroma sub-sampling format: None subsampling: 4: 4: 4 --- per 2x2 Y-Cb pixel corresponds to four and four of Cr;
Only the horizontal 2: 1 subsampling: 4: 2: 2 --- per 2x2 Y-2 corresponding to the pixels 2 of Cr and Cb;
Only level 4: 1 subsampling: 4: 1: 1 --- per 4x1 Y-pixels corresponding to a one of Cr and Cb; (disadvantages: vertical and horizontal directions cause
Non-uniform resolution, and therefore with 4: 2: 0)
Both horizontal and vertical 2: 1 subsampling: 4: 2: 0 --- per 2x2 Y-pixels corresponding to a one of Cr and Cb;
Note: pay attention to each representation is not the same AxB
7, the video quality evaluation parameters: a.MSE (mean square error); b.PSNR (PSNR), and use more.