RGBToHLS
Converts an RGB image to the HLS color model.
Syntax
IppStatus ippiRGBToHLS_<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 |
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
R'B'G'
image pSrc
to the HLS
image pDst
. For function flavors operating on the floating point data, source RGB values must be in the range [0..1].The conversion algorithm from
RGB
to HLS
can be represented in pseudocode as follows:// Lightness: M1 = max(R,G,B); M2 = min(R,G,B); L = (M1+M2)/2 // Saturation: if M1 = M2 then // achromatics case S = 0 H = 0 else // chromatics case if L <= 0.5 then S = (M1-M2) / (M1+M2) else S = (M1-M2) / (2-M1-M2) // Hue: Cr = (M1-R) / (M1-M2) Cg = (M1-G) / (M1-M2) Cb = (M1-B) / (M1-M2) if R = M1 then H = Cb - Cg //change R=M2 to R=M1 if G = M1 then H = 2 + Cr - Cb //change G=M2 to G=M1 if B = M1 then H = 4 + Cg - Cr //change B=M2 to B=M1 H = 60*H if H < 0 then H = H + 360
For floating point function flavors, the computed
H, L, S
values are scaled to the range [0..1]. In case of integer function flavors, these values are scaled to the full range of the destination data type (Table “Image Data Types and Ranges”
).Return Values
- ippStsNoErr
- Indicates no error. Any other value indicates an error.
- ippStsNullPtrErr
- Indicates an error condition ifpSrcorpDstisNULL.
- ippStsSizeErr
- Indicates an error condition ifroiSizehas a field with a zero or negative value.