Image Color Conversion

Intel® IPP implements image processing functions that perform different types of image color conversion. The Intel IPP software supports the following image color conversions:

Color models conversion
Conversion from color to gray scale and vice versa
Different types of format conversion:
from pixel-order to planar format and vice versa changing number of channels or planes changing sampling format altering order of samples or planes
Gamma correction
Reduction from high bit resolution color to low bit resolution color
Intensity transformation using lookup tables
Color twist
Color keying

All Intel IPP color conversion functions perform point operations on pixels of the source image. For a given destination pixel, the resultant channel values are computed using channel values of the corresponding source pixel only, and not involving any neighborhood pixels. Thus, the rectangular region of interest (ROI, see Regions of Interest in Intel IPP) used in function operations may extend to the size of the whole image.

Table Color Conversion Functions lists the Intel IPP color space conversion functions.

Color Conversion Functions
Function Base Name	Description
Color Model Conversion
RGBToYUV, YUVToRGB	Convert RGB image to and from YUV color model.
RGBToYUV422, YUV422ToRGB	Convert RGB image to and from 4:2:2 YUV image.
RGB565ToYUV422	Converts a 16-bit RGB image to the 4:2:2 YUV image
RGBToYUV420, YUV420ToRGB	Convert RGB images to and from 4:0:0 YUV image.
BGRToYUV420	Converts a BGR image to the 4:2:0 YUV image.
YUV420ToBGR	Converts a 4:2:0 YUV image to BGR image.
RGB565ToYUV420	Converts a 16-bit RGB image to the 4:2:0 YUV image
YUV420ToRGB565, YUV420ToRGB555, YUV420ToRGB444	Convert a 4:2:0 YUV image to the 16-bit RGB image.
YUV420ToRGB565Dither, YUV420ToRGB555Dither, YUV420ToRGB444Dither	Convert a 4:2:0 YUV image to the 16-bit RGB image with dithering.
BGR565ToYUV420, BGR555ToYUV420	Convert a 16-bit BGR image to the 4:2:0 YUV image.
YUV420ToBGR565, YUV420ToBGR555, YUV420ToBGR444	Convert a 4:2:0 YUV image to the 16-bit BGR image.
YUV420ToBGR565Dither, YUV420ToBGR555Dither, YUV420ToBGR444Dither	Convert a 4:2:0 YUV image to the 16-bit BGR image with dithering.
RGBToYCbCr	Converts RGB images to the YCbCr color model.
YCbCrToRGB	Converts RGB images from the YCbCr color model.
YCbCrToBGR	Converts a YCbCr image to the BGR color model.
YCbCrToBGR_709CSC	Converts a YCbCr image to the BGR image for ITU-R BT.709 signal.
YCbCrToRGB565, YCbCrToRGB555, YCbCrToRGB444	Convert a YCbCr image to the 16-bit per pixel RGB image.
YCbCrToRGB565Dither, YCbCrToRGB555Dither, YCbCrToRGB444Dither	Convert a YCbCr image to the 16-bit per pixel RGB image with dithering.
YCbCrToBGR565, YCbCrToBGR555, YCbCrToBGR444	Convert a YCbCr image to the 16-bit per pixel BGR image.
YCbCrToBGR565Dither, YCbCrToBGR555Dither, YCbCrToBGR444Dither	Convert a YCbCr image to the 16-bit per pixel BGR image with dithering.
RGBToYCbCr422	Converts an RGB image to a 4:2:2 YCbCr image.
YCbCr422ToRGB	Converts an RGB image to from a 4:2:2 YCbCr image.
RGBToYCrCb422	Converts an RGB image to a 4:2:2 YCrCb image.
YCrCb422ToRGB	Converts an RGB image from a 4:2:2 YCrCb image.
BGRToYCbCr422	Converts a 24-bit per pixel BGR image to a 16-bit per pixel YCbCr image.
YCbCr422ToBGR	Converts a 16-bit per pixel YCbCr image to a 24-bit per pixel BGR image.
BGR565ToYCbCr422, BGR555ToYCbCr422	Convert a 16-bit per pixel BGR image to a 16-bit per pixel YCbCr image.
RGBToCbYCr422, RGBToCbYCr422Gamma	Convert RGB images to and from a 4:2:2 CbYCr image.
CbYCr422ToRGB	Converts 16-bit per pixel CbYCr image to 24-bit per pixel RGB image.
BGRToCbYCr422	Converts a 32-bit per pixel BGR image to a 16-bit per pixel CbYCr image.
BGRToCbYCr422_709HDTV	Converts a BGR image to a 16-bit per pixel CbYCr image for an ITU-R BT.709 HDTV signal.
CbYCr422ToBGR	Converts a 16-bit per pixel CbYCr image to a four channel BGR image.
CbYCr422ToBGR_709HDTV	Converts a 16-bit per pixel CbYCr image to a BGR image for an ITU-R BT.709 HDTV signal.
YCbCr422ToRGB565, YCbCr422ToRGB555, YCbCr422ToRGB444	Convert a 16-bit per pixel YCbCr image that has 4:2:2 sampling format to a 16-bit per pixel RGB image.
YCbCr422ToRGB565Dither, YCbCr422ToRGB555Dither, YCbCr422ToRGB444Dither	Convert a 16-bit per pixel YCbCr image that has 4:2:2 sampling format to a 16-bit per pixel RGB image with dithering.
YCbCr422ToBGR565, YCbCr422ToBGR555, YCbCr422ToBGR444	Convert a 16-bit per pixel YCbCr image that has 4:2:2 sampling format to a 16-bit per pixel BGR image.
YCbCr422ToBGR565Dither, YCbCr422ToBGR555Dither, YCbCr422ToBGR444Dither	Convert a 16-bit per pixel YCbCr image that has 4:2:2 sampling format to a 16-bit per pixel BGR image with dithering.
RGBToYCbCr420	Converts RGB images to a YCbCr color model with 4:2:0 sampling format.
YCbCr420ToRGB	Converts RGB images from a YCbCr color model with 4:2:0 sampling format.
YCbCr420ToRGB565, YCbCr420ToRGB555, YCbCr420ToRGB444	Convert a YCbCr image that has 4:2:0 sampling format to a 16-bit per pixel RGB image.
YCbCr420ToRGB565Dither, YCbCr420ToRGB555Dither, YCbCr420ToRGB444Dither	Convert a YCbCr image that has 4:2:0 sampling format to a 16-bit per pixel RGB image with dithering.
RGBToYCrCb420	Converts an RGB image to a YCrCb image with the 4:2:0 sampling.
YCrCb420ToRGB	Converts a YCrCb image with the 4:2:0 sampling to an RGB image.
BGRToYCbCr420	Converts a BGR image to a YCbCr image with 4:2:0 sampling format.
BGRToYCbCr420_709CSC	Converts a BGR image to a YCbCr image with 4:2:0 sampling for an ITU-R BT.709 CSC signal.
BGRToYCbCr420_709HDTV	Converts a BGR image to a YCbCr image with 4:2:0 sampling for an ITU-R BT.709 HDTV signal.
BGRToYCrCb420_709CSC	Converts a BGR image to a YCrCb image with 4:2:0 sampling for an ITU-R BT.709 signal.
YCbCr420ToBGR	Converts a YCbCr image with 4:2:0 sampling format to the RGB color model.
YCbCr420ToBGR_709CSC	Converts a YCbCr image with 4:2:0 sampling to a BGR image for an ITU-R BT.709 CSC signal.
YCbCr420ToBGR_709HDTV	Converts a YCbCr image with 4:2:0 sampling to a BGR image for an ITU-R BT.709 HDTV signal.
BGR565ToYCbCr420, BGR555ToYCbCr420	Convert a 16-bit per pixel BGR image to a YCbCr image that has 4:2:0 sampling format.
YCbCr420ToBGR565, YCbCr420ToBGR555, YCbCr420ToBGR444	Convert a YCbCr image with 4:2:0 sampling format to a 16-bit per pixel BGR image.
YCbCr420ToBGR565Dither, YCbCr420ToBGR555Dither, YCbCr420ToBGR444Dither	Convert a YCbCr image with 4:2:0 sampling format to a 16-bit per pixel BGR image with dithering.
BGRToYCrCb420	Converts a BGR image to a YCrCb image with 4:2:0 sampling format.
BGR565ToYCrCb420, BGR555ToYCrCb420	Convert a 16-bit per pixel BGR image to a YCrCb image with the 4:2:0 sampling format.
BGRToYCbCr411	Converts a BGR image to a YCbCr planar image that has the 4:1:1 sampling format.
YCbCr411ToBGR	Converts a YCbCr image with the 4:1:1 sampling format to the RGB color model.
BGR565ToYCbCr411, BGR555ToYCbCr411	Convert a 16-bit per pixel BGR image to a YCbCr image that has the 4:1:1 sampling format.
YCbCr411ToBGR565, YCbCr411ToBGR555	Convert a YCbCr image that has the 4:1:1 sampling format to a 16-bit per pixel BGR image.
RGBToXYZ, XYZToRGB	Convert RGB images to and from the XYZ color model
RGBToLUV, LUVToRGB	Convert RGB images to and from the CIE LUV color model.
BGRToLab, LabToBGR	Convert BGR images to and from the CIE Lab color model.
RGBToYCC, YCCToRGB	Convert RGB images to and from the YCC color model.
RGBToHLS, HLSToRGB	Convert RGB images to and from the HLS color model.
BGRToHLS	Converts BGR images to the HLS color model.
HLSToBGR	Converts HLS images to the BGR color model.
RGBToHSV, HSVToRGB	Convert RGB images to and from the HSV color model.
RGBToYCoCg, YCoCgToRGB	Convert RGB images to and from the YCoCg color model.
BGRToYCoCg	Converts a 24-bit BGR image to the YCoCg color model.
SBGRToYCoCg	Converts a 48-bit BGR image to the YCoCg color model.
YCoCgToBGR	Converts a YCoCg image to the 24-bit BGR image.
YCoCgToSBGR	Converts a YCoCg image to the 48-bit BGR image.
BGRToYCoCg_Rev	Converts a 24-bit BGR image to the YCoCg-R color model.
SBGRToYCoCg_Rev	Converts a 48-bit BGR image to the YCoCg-R color model.
YCoCgToBGR_Rev	Converts a YCoCg-R image to the 24-bit BGR image.
YCoCgToSBGR_Rev	Converts a YCoCg-R image to the 48-bit BGR image.
Color - Gray Scale Conversion
RGBToGray	Converts an RGB image to gray scale using fixed transform coefficients.
ColorToGray	Converts an RGB image to gray scale using custom transform coefficients.
CFAToRGB	Restores an RGB image from a gray-scale CFA image
DemosaicAHD	Restores an RGB image from a gray-scale CFA image using the AHD algorithm.
Format Conversion
RGBToRGB565, BGRToBGR565	Convert a 24-bit per pixel image to a 16-bit image.
RGB565ToRGB, BGR565ToBGR	Convert a 16-bit per pixel image to a 24-bit image.
YCbCr422	Converts a 4:2:2 YCbCr image.
YCbCr422ToYCrCb422	Converts a 4:2:2 YCbCr image to a 4:2:2 YCrCb image.
YCbCr422ToCbYCr422	Converts a 4:2:2 YCbCr image to a 4:2:2 CbYCr image.
YCbCr422ToYCbCr420	Converts a 4:2:2 YCbCr image to a 4:2:0 YCbCr image.
YCbCr422To420_Interlace	Converts an interlaced YCbCr image from the 4:2:2 sampling format to the 4:2:0 format.
YCbCr422ToYCrCb420	Converts a 4:2:2 YCbCr image to a 4:2:0 YCrCb image.
YCbCr422ToYCbCr411	Converts a 4:2:2 YCbCr image to a 4:1:1 YCbCr image.
YCrCb422ToYCbCr422	Converts a 4:2:2 YCrCb image to a 4:2:2 YCbCr image.
YCrCb422ToYCbCr420	Converts a 4:2:2 YCrCb image to a 4:2:0 YCbCr image.
YCrCb422ToYCbCr411	Converts a 4:2:2 YCrCb image to a 4:1:1 YCbCr image.
CbYCr422ToYCbCr422	Converts a 4:2:2 CbYCr image to a 4:2:2 YCbCr image.
CbYCr422ToYCbCr420	Converts a 4:2:2 CbYCr image to a 4:2:0 YCbCr image.
CbYCr422ToYCbCr420_Interlace	Converts an interlaced 4:2:2 CbYCr image to a 4:2:0 YCbCr image.
CbYCr422ToYCrCb420	Converts a 4:2:2 CbYCr image to a 4:2:0 YCrCb image.
CbYCr422ToYCbCr411	Converts a 4:2:2 CbYCr image to a 4:1:1 YCbCr image.
YCbCr420	Converts a 4:2:0 YCbCr image.
YCbCr420ToYCbCr422	Converts a 4:2:0 YCbCr image to a 4:2:2 YCbCr image.
YCbCr420ToYCbCr422_Filter	Converts a 4:2:0 YCbCr image to a 4:2:2 YCbCr image with additional filtering.
YCbCr420To422_Interlace	Converts an interlaced 4:2:0 YCbCr image to a 4:2:2 YCbCr image.
YCbCr420ToCbYCr422	Converts a 4:2:0 YCbCr image to a 4:2:2 CbYCr image.
YCbCr420ToCbYCr422_Interlace	Converts an interlaced 4:2:0 YCbCr image to a 4:2:2 CbYCr image.
YCbCr420ToYCrCb420	Converts a 4:2:0 YCbCr image to a 4:2:0 YCrCb image.
YCbCr420ToYCrCb420_Filter	Converts a 4:2:0 YCbCr image to a 4:2:0 YCrCb image with deinterlace filtering.
YCbCr420ToYCbCr411	Converts a 4:2:0 YCbCr image to a 4:1:1 YCbCr image.
YCrCb420ToYCbCr422	Converts a 4:2:0 YCrCb image to a 4:2:2 YCbCr image.
YCrCb420ToYCbCr422_Filter	Converts a 4:2:0 YCrCb image to a 4:2:2 YCbCr image with additional filtering.
YCrCb420ToCbYCr422	Converts a 4:2:0 YCrCb image to a 4:2:2 CbYCr image.
YCrCb420ToYCbCr420	Converts a 4:2:0 YCrCb image to a 4:2:0 YCbCr image.
YCrCb420ToYCbCr411	Converts a 4:2:0 YCrCb image to a 4:1:1 YCbCr image.
YCbCr411	Converts a 4:1:1 YCbCr image.
YCbCr411ToYCbCr422	Converts a 4:1:1 YCbCr image to a 4:2:2 YCbCr image.
YCbCr411ToYCrCb422	Converts a 4:1:1 YCbCr image to a 4:2:2 YCrCb image.
YCbCr411ToYCbCr420	Converts a 4:1:1 YCbCr image to a 4:2:0 YCbCr image.
YCbCr411ToYCrCb420	Converts a 4:1:1 YCbCr image to a 4:2:0 YCrCb image.
Color Twist
ColorTwist	Applies a color-twist matrix to an image with integer pixel values.
ColorTwist32f	Applies a color-twist matrix to an image with floating-point pixel values.
Color Keying
CompColorKey	Performs color keying of two images.
AlphaCompColorKey	Performs color keying and alpha composition of two images.
Gamma Correction
GammaFwd	Performs gamma-correction of the source RGB image.
GammaInv	Converts a gamma-corrected R'G'B' image back to the original RGB image.
Intensity Transformation
ReduceBits	Reduces the bit resolution of an image.
LUT	Maps an image by applying intensity transformation.
LUT_Linear	Maps an image by applying intensity transformation with linear interpolation.
LUT_Cubic	Maps an image by applying intensity transformation with cubic interpolation.
LUTPalette, LUTPaletteSwap	Map an image by applying intensity transformation in accordance with a palette table.
ToneMapLinear, ToneMapMean	Map an HDRI image to an LDRI image.

See the topics listed below for introductory material that discusses color space models essential for understanding of the Intel IPP color conversion functions.

For more information about color spaces and color conversion techniques, see [Jack01], [Rogers85], and [Foley90].