ColorToGray

Converts an RGB image to gray scale using custom transform coefficients.

Syntax

IppStatus ippiColorToGray_<mod>(const Ipp<datatype>* pSrc, int srcStep, Ipp<datatype>* pDst, int dstStep, IppiSize roiSize, const Ipp32f coeffs[3]);

Supported values for mod:

8u_C3C1R	16u_C3C1R	16s_C3C1R	32f_C3C1R	64f_C3C1R
8u_AC4C1R	16u_AC4C1R	16s_AC4C1R	32f_AC4C1R	64f_AC4C1R

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.
coeffs	Transform coefficients.

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

This function uses the following equation to convert an RGB image to gray scale:

Y = coeffs[0] * R + coeffs[1] * G + coeffs[2] * B,

where the coeffs array contains user-defined transform coefficients which must be non-negative and satisfy the condition

coeffs[0] + coeffs[1] + coeffs[2] ≤ 1.

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.