NekoCWD/libcamera
NekoCWD/libcamera
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages 7 Wiki Activity Actions

ipa: libipa: colour: Use Vector and Matrix for linear algebra

Browse source 
Replace the manual vector and matrix calculations with usage of the
Vector and Matrix classes. This simplifies the code and improves
readability.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Milan Zamazal <mzamazal@redhat.com>
This commit is contained in:
Laurent Pinchart 2024-11-18 21:07:01 +02:00
parent 29892f1c56
commit 16c15c428d
1 changed files with 17 additions and 9 deletions
Download patch file Download diff file Expand all files Collapse all files

26
src/ipa/libipa/colours.cpp
View file

@ -31,7 +31,11 @@ namespace ipa {
*/ */
double rec601LuminanceFromRGB(const RGB<double> &rgb) double rec601LuminanceFromRGB(const RGB<double> &rgb)
{ {
return (rgb.r() * .299) + (rgb.g() * .587) + (rgb.b() * .114); static const Vector<double, 3> rgb2y{{
0.299, 0.587, 0.114
}};
return rgb.dot(rgb2y);
} }
/** /**
@ -54,17 +58,21 @@ double rec601LuminanceFromRGB(const RGB<double> &rgb)
*/ */
uint32_t estimateCCT(const RGB<double> &rgb) uint32_t estimateCCT(const RGB<double> &rgb)
{ {
/* Convert the RGB values to CIE tristimulus values (XYZ) */ /*
double X = (-0.14282) * rgb.r() + (1.54924) * rgb.g() + (-0.95641) * rgb.b(); * Convert the RGB values to CIE tristimulus values (XYZ) and divide by
double Y = (-0.32466) * rgb.r() + (1.57837) * rgb.g() + (-0.73191) * rgb.b(); * the sum of X, Y and Z to calculate the CIE xy chromaticity.
double Z = (-0.68202) * rgb.r() + (0.77073) * rgb.g() + (0.56332) * rgb.b(); */
static const Matrix<double, 3, 3> rgb2xyz({
-0.14282, 1.54924, -0.95641,
-0.32466, 1.57837, -0.73191,
-0.68202, 0.77073, 0.56332
});
/* Calculate the normalized chromaticity values */ Vector<double, 3> xyz = rgb2xyz * rgb;
double x = X / (X + Y + Z); xyz /= xyz.sum();
double y = Y / (X + Y + Z);
/* Calculate CCT */ /* Calculate CCT */
double n = (x - 0.3320) / (0.1858 - y); double n = (xyz.x() - 0.3320) / (0.1858 - xyz.y());
return 449 * n * n * n + 3525 * n * n + 6823.3 * n + 5520.33; return 449 * n * n * n + 3525 * n * n + 6823.3 * n + 5520.33;
} }