NVIDIA 2D Image And Signal Performance Primitives (NPP)  Version 11.1.0.*
 All Data Structures Functions Variables Typedefs Enumerations Enumerator Groups Pages
Functions
RGBToHSV
Color Model Conversion

RGB to HSV color conversion. More...

Functions

NppStatus  nppiRGBToHSV_8u_C3R_Ctx (const Npp8u *pSrc, int nSrcStep, Npp8u *pDst, int nDstStep, NppiSize oSizeROI, NppStreamContext nppStreamCtx)
  3 channel 8-bit unsigned packed RGB to 3 channel 8-bit unsigned packed HSV color conversion. More...
 
NppStatus  nppiRGBToHSV_8u_C3R (const Npp8u *pSrc, int nSrcStep, Npp8u *pDst, int nDstStep, NppiSize oSizeROI)
 
NppStatus  nppiRGBToHSV_8u_AC4R_Ctx (const Npp8u *pSrc, int nSrcStep, Npp8u *pDst, int nDstStep, NppiSize oSizeROI, NppStreamContext nppStreamCtx)
  4 channel 8-bit unsigned packed RGB with alpha to 4 channel 8-bit unsigned packed HSV with alpha color conversion. More...
 
NppStatus  nppiRGBToHSV_8u_AC4R (const Npp8u *pSrc, int nSrcStep, Npp8u *pDst, int nDstStep, NppiSize oSizeROI)
 

Detailed Description

RGB to HSV color conversion.

This is how NPP converts gamma corrected RGB or BGR to HSV. This code uses the fmaxf() and fminf() 32 bit floating point math functions.

* Npp32f nNormalizedR = (Npp32f)R * 0.003921569F; // / 255.0F
* Npp32f nNormalizedG = (Npp32f)G * 0.003921569F;
* Npp32f nNormalizedB = (Npp32f)B * 0.003921569F;
* Npp32f nS;
* Npp32f nH;
* // Value
* Npp32f nV = fmaxf(nNormalizedR, nNormalizedG);
* nV = fmaxf(nV, nNormalizedB);
* // Saturation
* Npp32f nTemp = fminf(nNormalizedR, nNormalizedG);
* nTemp = fminf(nTemp, nNormalizedB);
* Npp32f nDivisor = nV - nTemp;
* if (nV == 0.0F) // achromatics case
* {
* nS = 0.0F;
* nH = 0.0F;
* }
* else // chromatics case
* nS = nDivisor / nV;
* // Hue:
* Npp32f nCr = (nV - nNormalizedR) / nDivisor;
* Npp32f nCg = (nV - nNormalizedG) / nDivisor;
* Npp32f nCb = (nV - nNormalizedB) / nDivisor;
* if (nNormalizedR == nV)
* nH = nCb - nCg;
* else if (nNormalizedG == nV)
* nH = 2.0F + nCr - nCb;
* else if (nNormalizedB == nV)
* nH = 4.0F + nCg - nCr;
* nH = nH * 0.166667F; // / 6.0F
* if (nH < 0.0F)
* nH = nH + 1.0F;
* H = (Npp8u)(nH * 255.0F);
* S = (Npp8u)(nS * 255.0F);
* V = (Npp8u)(nV * 255.0F);
*

Function Documentation

NppStatus nppiRGBToHSV_8u_AC4R ( const Npp8u *  pSrc,
int  nSrcStep,
Npp8u *  pDst,
int  nDstStep,
NppiSize  oSizeROI 
)
NppStatus nppiRGBToHSV_8u_AC4R_Ctx ( const Npp8u *  pSrc,
int  nSrcStep,
Npp8u *  pDst,
int  nDstStep,
NppiSize  oSizeROI,
NppStreamContext  nppStreamCtx 
)

4 channel 8-bit unsigned packed RGB with alpha to 4 channel 8-bit unsigned packed HSV with alpha color conversion.

Parameters
pSrc Source-Image Pointer.
nSrcStep Source-Image Line Step.
pDst Destination-Image Pointer.
nDstStep Destination-Image Line Step.
oSizeROI Region-of-Interest (ROI).
nppStreamCtx Application Managed Stream Context.
Returns
Image Data Related Error Codes, ROI Related Error Codes
NppStatus nppiRGBToHSV_8u_C3R ( const Npp8u *  pSrc,
int  nSrcStep,
Npp8u *  pDst,
int  nDstStep,
NppiSize  oSizeROI 
)
NppStatus nppiRGBToHSV_8u_C3R_Ctx ( const Npp8u *  pSrc,
int  nSrcStep,
Npp8u *  pDst,
int  nDstStep,
NppiSize  oSizeROI,
NppStreamContext  nppStreamCtx 
)

3 channel 8-bit unsigned packed RGB to 3 channel 8-bit unsigned packed HSV color conversion.

Parameters
pSrc Source-Image Pointer.
nSrcStep Source-Image Line Step.
pDst Destination-Image Pointer.
nDstStep Destination-Image Line Step.
oSizeROI Region-of-Interest (ROI).
nppStreamCtx Application Managed Stream Context.
Returns
Image Data Related Error Codes, ROI Related Error Codes