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YCbCr to RGB colorspace converter. More...
Functions | |
| AFAPI array | ycbcr2rgb (const array &in, const YCCStd standard=AF_YCC_601) |
| C++ Interface for converting YCbCr to RGB. More... | |
| AFAPI af_err | af_ycbcr2rgb (af_array *out, const af_array in, const af_ycc_std standard) |
| C Interface for converting YCbCr to RGB. More... | |
YCbCr to RGB colorspace converter.
YCbCr is a family of color spaces used as a part of the color image pipeline in video and digital photography systems where Y is luma component and Cb & Cr are the blue-difference and red-difference chroma components.
RGB (Red, Green, Blue) is the most common format used in computer imaging. RGB stores individual values for red, green and blue, and hence the 3 values per pixel. A combination of these three values produces the gamut of unique colors.
Input array to this function should be of real data with the following range in their respective channels.
\(Y -> [16, 219]\)
\(Cb-> [16, 240]\)
\(Cr-> [16, 240]\)
The following equations are used to convert image from RGB color space to YCbCr color space.
\( R = \frac{\displaystyle Y - \displaystyle 16}{\displaystyle 219} + \frac{\displaystyle C_r - \displaystyle 128}{\displaystyle 112} * (\displaystyle 1 - \displaystyle k_r) \)
\( G = \frac{\displaystyle Y - \displaystyle 16}{\displaystyle 219} - \frac{\displaystyle C_r - \displaystyle 128}{\displaystyle 112} * (\displaystyle 1 - \displaystyle k_r) * \frac{\displaystyle k_r}{\displaystyle 1 - \displaystyle k_b - \displaystyle k_r} - \frac{\displaystyle C_b - \displaystyle 128}{\displaystyle 112} * (\displaystyle 1 - \displaystyle k_b) * \frac{\displaystyle k_b}{\displaystyle 1 - \displaystyle k_b - \displaystyle k_r}\)
\( B = \frac{\displaystyle Y - \displaystyle 16}{\displaystyle 219} + \frac{\displaystyle C_b - \displaystyle 128}{\displaystyle 112} * (\displaystyle 1 - \displaystyle k_b) \)
Output image in RGB will have values in range \([0, 1]\).
Based on the ITU-R BT.xyz[w] standard used, different values of \(k_b\) and \(k_r\) are used to do the color space conversion. You can change these values by passing the af_ycc_std enum value.
| AFAPI af_err af_ycbcr2rgb | ( | af_array * | out, |
| const af_array | in, | ||
| const af_ycc_std | standard | ||
| ) |
C Interface for converting YCbCr to RGB.
| [out] | out | is an array in the RGB color space |
| [in] | in | is an array in the YCbCr color space |
| [in] | standard | specifies the ITU-R BT "xyz" standard which determines the Kb, Kr values used in colorspace conversion equation |
in must be three dimensional and values should lie in the range [0,1] | AFAPI array af::ycbcr2rgb | ( | const array & | in, |
| const YCCStd | standard = AF_YCC_601 |
||
| ) |
C++ Interface for converting YCbCr to RGB.
| [in] | in | is an array in the YCbCr colorspace |
| [in] | standard | specifies the ITU-R BT "xyz" standard which determines the Kb, Kr values used in colorspace conversion equation |
in must be three dimensional and values should lie in the range [0,1]