Convert from RGB to LUV
MT, SSE2
| FwStatus | fwiRGBToLUV_8u_C3R | ( | const Fw8u * pSrc, int srcStep, Fw8u * pDst, int dstStep, FwiSize roiSize ); | |
| FwStatus | fwiRGBToLUV_8u_AC4R | ( | const Fw8u * pSrc, int srcStep, Fw8u * pDst, int dstStep, FwiSize roiSize ); | |
| FwStatus | fwiRGBToLUV_16u_C3R | ( | const Fw16u * pSrc, int srcStep, Fw16u * pDst, int dstStep, FwiSize roiSize ); | |
| FwStatus | fwiRGBToLUV_16u_AC4R | ( | const Fw16u * pSrc, int srcStep, Fw16u * pDst, int dstStep, FwiSize roiSize ); | |
| FwStatus | fwiRGBToLUV_16s_C3R | ( | const Fw16s * pSrc, int srcStep, Fw16s * pDst, int dstStep, FwiSize roiSize ); | |
| FwStatus | fwiRGBToLUV_16s_AC4R | ( | const Fw16s * pSrc, int srcStep, Fw16s * pDst, int dstStep, FwiSize roiSize ); | |
| FwStatus | fwiRGBToLUV_32f_C3R | ( | const Fw32f * pSrc, int srcStep, Fw32f * pDst, int dstStep, FwiSize roiSize ); | |
| FwStatus | fwiRGBToLUV_32f_AC4R | ( | const Fw32f * pSrc, int srcStep, Fw32f * pDst, int dstStep, FwiSize roiSize ); |
| 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). |
These functions step through an ROI in a source buffer, convert the source data from the RGB color model to the LUV color space, and write the converted data to a destination buffer.
A gamma-corrected RGB image (pSrc) declared in the ROI is converted to a CIE LUV image (pDst) in two steps.
1. Convert( ) RGBToXYZ( ) using the following formulas. X = 0.412453*R + 0.35758 *G + 0.180423*B Y = 0.212671*R + 0.71516 *G + 0.072169*B Z = 0.019334*R + 0.119193*G + 0.950227*B The formulas assume that R, G, and B values are normalized to [0 to 1] for integer data types. For floating point data types, the data must already be in the range [0 to 1]. For integer data types, the converted image data is saturated to [0 to 1] and scaled to the data type range. For floating point data type, data is saturated to [0 to 1]. 2. Convert( ) XYZ to LUV as follows. D65 white point: CIE chromaticity coordinates: xn = 0.312713 yn = 0.329016 CIE luminance: Yn = 1.0 un = 4*xn / (-2*xn + 12*yn + 3) vn = 9*yn / (-2*xn + 12*yn + 3) u = 4*X / (X + 15*Y + 3*Z) v = 9*Y / (X + 15*Y + 3*Z) L = 116 * (Y/Yn)^(1/3) - 16 U = 13*L*(u-un) V = 13*L*(v-vn) Computed L component values are in the range [0 to 100]. Computed U component values are in the range [-124 to 220]. Computed V component values are in the range [-140 to 116]. The formulas assume that R, G, and B values are normalized to [0 to1] for integer data types. For floating point data types, the data must already be in the range [0 to 1]. For integer data types, the converted image data is saturated to [0 to 1] and scaled to the data type range. Scaling is performed as follows. 8U data type: L = L * FW_MAX_8U / 100 U = (U + 134) * FW_MAX_8U / 354 V = (V + 140) * FW_MAX_8U / 256 16U data type: L = L * FW_MAX_16U / 100 U = (U + 134) * FW_MAX_16U / 354 V = (V + 140) * FW_MAX_16U / 256 16S data type: L = L * FW_MAX_16U / 100 + FW_MIN_16S U = (U + 134) * FW_MAX_16U / 354 + FW_MIN_16S V = (V + 140) * FW_MAX_16U / 256 + FW_MIN_16S 32F data type: No conversion is applied, so the components remain in their ranges.