GammaFwd

Performs gamma-correction of the source image with RGB data.

Syntax

Case 1: Not-in-place operation on integer pixel-order data

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

Supported values for mod:

8u_C3R	16u_C3R
8u_AC4R	16u_AC4R

Case 2: Not-in-place operation on integer planar data

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

Supported values for mod:

8u_P3R

16u_P3R

Case 3: Not-in-place operation on floating-point pixel-order data

IppStatus ippiGammaFwd_<mod>(const Ipp32f* pSrc, int srcStep, Ipp32f* pDst, int dstStep, IppiSize roiSize, Ipp32f vMin, Ipp32f vMax);

Supported values for mod:

32f_C3R

32f_AC4R

Case 4: Not-in-place operation on floating-point planar data

IppStatus ippiGammaFwd_32f_P3R (const Ipp32f* const pSrc[3], int srcStep, Ipp32f* const pDst[3], int dstStep, IppiSize roiSize, Ipp32f vMin, Ipp32f vMax);

Case 5: In-place operation on integer pixel-order data

IppStatus ippiGammaFwd_<mod>(Ipp<datatype>* pSrcDst, int srcDstStep, IppiSize roiSize);

Supported values for mod:

8u_C3IR	16u_C3IR
8u_AC4IR	16u_AC4IR

Case 6: In-place operation on integer planar data

IppStatus ippiGammaFwd_<mod>(Ipp<datatype>* const pSrcDst[3], int srcDstStep, IppiSize roiSize);

Supported values for mod:

8u_IP3R

16u_IP3R

Case 7: In-place operation on floating-point pixel-order data

IppStatus ippiGammaFwd_<mod>(Ipp32f* pSrcDst, int srcDstStep, IppiSize roiSize, Ipp32f vMin, Ipp32f vMax);

Supported values for mod:

32f_C3IR

32f_AC4IR

Case 8: In-place operation on floating-point planar data

IppStatus ippiGammaFwd_32f_IP3R (Ipp32f* const pSrcDst[3], int srcDstStep, IppiSize roiSize, Ipp32f vMin, Ipp32f vMax);

Parameters

pSrc	Pointer to the ROI in the pixel-order source image. Array of pointers to the ROI in each plane of the planar source image.
srcStep	Distance in bytes between starts of consecutive lines in the source image.
pDst	Pointer to the ROI in the pixel-order destination image. Array of pointers to the ROI in each plane of the planar destination image.
dstStep	Distance in bytes between starts of consecutive lines in the destination image.
pSrcDst	Pointer to the source and destination image ROI for the in-place operation.
srcDstStep	Distance in bytes between starts of consecutive lines in the source and destination image for the in-place operation.
roiSize	Size of the source and destination ROI in pixels.
vMin, vMax	Minimum and maximum values of the input floating-point data.

Description

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

This function performs gamma-correction of the source image with RGB data. It uses the following basic equations to convert an RGB image to the gamma-corrected R'G'B' image:

for R,G,B < 0.018

R' = 4.5 * R

G' = 4.5 * G

B' = 4.5 * B

for R,G,B ≥ 0.018

R' = 1.099 * R^0.45 - 0.099

G' = 1.099 * G^0.45 - 0.099

B' = 1.099 * B^0.45 - 0.099

Note that the channel intensity values are normalized to fit in the range of [0..1]. The gamma value is equal to 1/0.45 = 2.22 in conformity with [ITU709] specification.

Return Values

ippStsNoErr	Indicates no error. Any other value indicates an error.
ippStsNullPtrErr	Indicates an error condition if pSrc, pDst, or pSrcDst is NULL.
ippStsSizeErr	Indicates an error condition if roiSize has a field with a zero or negative value.
ippStsGammaRangeErr	Indicates an error condition if the input data bounds are incorrect, that is vMax is less than or equal to vMin.