Visible to Intel only — GUID: GUID-6E464F03-5132-4EE1-BA4E-04FD5B6E5E81
Visible to Intel only — GUID: GUID-6E464F03-5132-4EE1-BA4E-04FD5B6E5E81
RGBToLUV, BGRToLUV
Converts an RGB or BGR image to the LUV color model.
Syntax
Case 1: RGB to LUV
IppStatus ippiRGBToLUV_<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 |
Case 2: BGR to LUV
IppStatus ippiBGRToLUV_<mod>(const Ipp<datatype>* pSrc, int srcStep, Ipp<datatype>* pDst, int dstStep, IppiSize roiSize);
Supported values for mod:
8u_C3R | 32f_C3R |
Include Files
ippcc.h
Domain Dependencies
Headers: ippcore.h, ippvm.h, ipps.h, ippi.h
Libraries: ippcore.lib, ippvm.lib, ipps.lib, ippi.lib
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
This function operates with ROI (see Regions of Interest in Intel IPP).
This function converts the RGB or BGR image pSrc to the CIE LUV CIE LUV image pDstin two steps. First, the conversion is done into CIE XYZ format, using equations defined for the ippiRGBToXYZ function. After that, conversion to LUV image is performed in accordance with the following equations:
L = 116. * (Y/Yn)1/3. - 16.
U = 13. * L * (u - un)
V = 13. * L * (v - vn)
where
u = 4.*X / (X + 15.*Y + 3.*Z)
v = 9.*Y / (X + 15.*Y + 3.*Z)
un = 0.197839
vn = 0.468342
The computed values of the L component are in the range [0..100], U component in the range [-134..220], and V component in the range [-140..122].
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 RGB values must already be in the range [0..1]. For integer data types, normalization is done by the conversion function internally.
In case of 8u data type, the computed L, U, and V values are quantized and converted to fit in the range [0..IPP_MAX_8U] as follows:
L = L * IPP_MAX_8U / 100.
U = (U + 134.) * IPP_MAX_8U / 354.
V = (V + 140.) * IPP_MAX_8U / 262.
In case of 16u data type, the computed L, U, and V values are quantized and converted to fit in the range [0..IPP_MAX_16U] as follows:
L = L * IPP_MAX_16U / 100.
U = (U + 134.) * IPP_MAX_16U / 354.
V = (V + 140.) * IPP_MAX_16U / 262.
In case of 16s data type, the computed L,U, and V values are quantized and converted to fit in the range [IPP_MIN_16S..IPP_MAX_16S] as follows:
L = L * IPP_MAX_16U / 100. + IPP_MIN_16S
U = (U + 134.) * IPP_MAX_16U / 354. + IPP_MIN_16S
V = (V + 140.) * IPP_MAX_16U / 262. + IPP_MIN_16S
For 32f data type, no further conversion is done and L, U, and V components remain in the ranges [0..100], [-134..220], and [-140..122], respectively.
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. |