YUV is used in the European television system a color coding method (of PAL), the PAL and SECAM analog color television system used in the color space. In modern color television systems, commonly used three-color CCD camera or color camera for taking images, and then the color image signal obtained by the separation, respectively, after correction has been enlarged RGB, and then get through the matrix conversion circuit luminance signal Y and two a color difference signals R-Y (that is, U), B-Y (ie V), finally sending the brightness and color difference signals are encoded using the same channel to send out. This color representation is called the YUV color space representation. The importance of using YUV color space is its luminance signal Y and chrominance signals U, V are separate.Advantages of roleYUV is mainly used to optimize the transmission of color video signals, making it backward compatible with old-fashioned black and white TV. Compared with the RGB video signal transmission, its biggest advantage is that it only takes very little bandwidth (RGB requires three separate simultaneous transmission of video signals). One "Y" indicates brightness (Luminance or Luma), which is gray value; and "U" and "V" that is the color of (Chrominance or Chroma), the role is to describe the image color and saturation, for Specifies the color of the pixel. "Brightness" is the RGB input signal to build, is a specific part of the RGB signal superimposed together. "Chroma" is defined in two aspects of color hue and saturation ─, Cr and Cb were used to represent. Which, Cr reflects the red part of RGB input and RGB signal intensity differences between the values. And Cb reflects the blue part of RGB input and RGB signal intensity differences between the values. The importance of using YUV color space is its luminance signal Y and chrominance signals U, V are separate. If only the Y signal component and not U, V components, then such that the image is black and white gray-scale images. Color TV with YUV space is used to solve the luminance signal Y and color TV black and white TV compatibility issues so black and white TV is also capable of receiving color television signals. For digital video, define the two major from RGB to YUV conversion. Both conversions are based on known ITU-R Recommendation BT.709 specifications. The first conversion is defined in BT.709 earlier for 50-Hz YUV formats. With the ITU-R Recommendation BT.601 relationship specified in the same, ITU-R Recommendation BT.601, also known as its old name of the CCIR 601. This format should be considered for standard definition TV resolution (720 x 576) and lower resolution video YUV format of choice.
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