RGBToYCC

Converts an RGB image to the YCC color model.

Syntax

IppStatus ippiRGBToYCC_<mod>(const Ipp<datatype>* pSrc, int srcStep, Ipp<datatype>* pDst, int dstStep, IppiSize roiSize);

Supported values for mod:

8u_C3R	16u_C3R	16s_C3R	32f_C3R
8u_AC4R	16u_AC4R	16s_AC4R	32f_AC4R

Parameters

pSrc	Pointer to the source image ROI.
srcStep	Distance in bytes between starts of consecutive lines in the source image.
pDst	Pointer to the destination image ROI.
dstStep	Distance in bytes between starts of consecutive lines in the destination image.
roiSize	Size of the source and destination ROI in pixels.

Description

The function ippiRGBToYCC is declared in the ippcc.h file. It operates with ROI (see Regions of Interest in Intel IPP).

This function converts the gamma-corrected R'B'G' image pSrc to the PhotoY'C'C' image pDst according to the following basic equations:

Y' = 0.299*R' + 0.587*G' + 0.114*B'

C1' = -0.299*R' - 0.587*G' + 0.886*B' = B'- Y

C2' = 0.701*R' - 0.587*G' - 0.114*B' = R'- Y

The equations above are given on the assumption that R',G', and B' values are normalized to the range [0..1]. In case of the floating-point data type, the input R'G'B' values must already be in the range [0..1]. For integer data types, normalization is done by the conversion function internally.

The computed Y', C1', C2' values are then quantized and converted to fit in the range [0..1] as follows:

Y' = 1. / 1.402 * Y'

C1' = 111.4 / 255. * C1' + 156. / 255.

C2' = 135.64 /255. * C2' + 137. / 255.

In case of integer function flavors, these values are then scaled to the full range of the destination data type (see Table “Image Data Types and Ranges”).

Return Values

ippStsNoErr	Indicates no error. Any other value indicates an error.
ippStsNullPtrErr	Indicates an error condition if pSrc or pDst is NULL.
ippStsSizeErr	Indicates an error condition if roiSize has a field with a zero or negative value.