RGBToHSV

Convert from RGB to HSV

Supported Technologies

MT

Synopsis

FwStatus   fwiRGBToHSV_8u_C3R ( const Fw8u * pSrc, int srcStep, Fw8u * pDst, int dstStep, FwiSize roiSize );
FwStatus   fwiRGBToHSV_8u_AC4R ( const Fw8u * pSrc, int srcStep, Fw8u * pDst, int dstStep, FwiSize roiSize );
FwStatus   fwiRGBToHSV_16u_C3R ( const Fw16u * pSrc, int srcStep, Fw16u * pDst, int dstStep, FwiSize roiSize );
FwStatus   fwiRGBToHSV_16u_AC4R ( const Fw16u * pSrc, int srcStep, Fw16u * pDst, int dstStep, FwiSize roiSize );

Parameters

dstStep   Destination buffer step size (width of the buffer in bytes).
pDst   Pointer to a location in a destination buffer.
pSrc   Pointer to a location in a source buffer.
roiSize   Specifies the height and width of an ROI.
srcStep   Source buffer step size (width of the buffer in bytes).

Description

These functions step through an ROI in a source buffer, convert the source data from the RGB color model to the HSV color space, and write the converted data to a destination buffer.

A gamma-corrected RGB image (pSrc) declared in the ROI is converted to an HSV image (pDst) as follows. 

Value:

V = max(R, G, B)

Saturation:

temp = min = (R, G, B)
if (V == 0)
 achromatics case
 S = 0
else
 chromatics case
 S = (V-temp)/V
Hue:

Cr = (V - R) / (V - temp)
Cg = (V - G) / (V - temp)
Cb = (V - B) / (V - temp)
if (R==V)
 H = Cb - Cg
if (G==V)
 H = 2 + Cr - Cb
if (B==V)
 H = 4 + Cg - Cr
 H = H * 60
if (H < 0)
 H = H + 360

The formulas assume R, G, and B values are in the range [0 to 1].
For integer data types, the computed image data are scaled to the full range of the destination data type.