Does anyone know what is "L" means in conversion code LbgrtoLab? I searched in web and cannot find any description on this conversion code, currently I tried to use both BgrtoLab / LbgrtoLab, I found that values are different in A and B channels with using same image source. Seems that LBgr can get a better result.
Currently I am using OpenCvSharp 2.4.10.
Even though the meaning of this colour conversion code doesn't appear to be documented, there's no need to despair -- OpenCV is an open source library, so let's consult the source code.
case COLOR_BGR2Lab: case COLOR_RGB2Lab: case COLOR_LBGR2Lab: case COLOR_LRGB2Lab:
case COLOR_BGR2Luv: case COLOR_RGB2Luv: case COLOR_LBGR2Luv: case COLOR_LRGB2Luv:
// ....
bool srgb = code == COLOR_BGR2Lab || code == COLOR_RGB2Lab
|| code == COLOR_RGB2Luv || code == COLOR_BGR2Luv;
// ....
if (srgb && usRGBGammaTab.empty())
Mat(1, 256, CV_16UC1, sRGBGammaTab_b).copyTo(usRGBGammaTab);
else if (ulinearGammaTab.empty())
Mat(1, 256, CV_16UC1, linearGammaTab_b).copyTo(ulinearGammaTab);
// ....
This suggests that the prefix L is meant to distinguish between non-linear (sRGB) and linear RGB colour spaces. More details about what this means can be found in this answer.
