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RGB to YCbCr colorspace converter. More...
Functions | |
| AFAPI array | rgb2ycbcr (const array &in, const YCCStd standard=AF_YCC_601) |
| C++ Interface for converting RGB to YCbCr. More... | |
| AFAPI af_err | af_rgb2ycbcr (af_array *out, const af_array in, const af_ycc_std standard) |
| C Interface for converting RGB to YCbCr. More... | |
RGB to YCbCr colorspace converter.
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.
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.
Input array to this function should be of real data in the range \([0,1]\).
The following equations are used to convert image from RGB color space to YCbCr color space.
\( Y = 16 + \displaystyle k_r*R + (1 - \displaystyle k_r- \displaystyle k_b)*G + \displaystyle k_b * B \)
\( Cb = 128 + \frac{\displaystyle 1}{\displaystyle 2} * \frac{\displaystyle B - Y\displaystyle }{\displaystyle 1 - \displaystyle k_b} \)
\( Cr = 128 + \frac{\displaystyle 1}{\displaystyle 2} * \frac{\displaystyle R - Y\displaystyle }{\displaystyle 1 - \displaystyle k_r} \)
Output image in YCbCr has following range for their respective channels.
\(Y -> [16, 219]\)
\(Cb-> [16, 240]\)
\(Cr-> [16, 240]\)
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_rgb2ycbcr | ( | af_array * | out, |
| const af_array | in, | ||
| const af_ycc_std | standard | ||
| ) |
C Interface for converting RGB to YCbCr.
| [out] | out | is an array in the YCbCr color space |
| [in] | in | is an array in the RGB 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::rgb2ycbcr | ( | const array & | in, |
| const YCCStd | standard = AF_YCC_601 |
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| ) |
C++ Interface for converting RGB to YCbCr.
| [in] | in | is an array in the RGB 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]