opencv 色彩空间的转换，包括将rgb转成XYZ格式，YCrCb格式，HSV格式及Lab格式-opencv color space conversion, including rgb convert XYZ format, YCrCb format, HSV and Lab format format

以OPENCV做的各種色彩轉換空間，有 RGB to gray, RGB to HSV, RGB to Lab, RGB to Luv, RGB to Ycbcr -To do a variety of color conversion OPENCV Space, RGB to gray, RGB to HSV, RGB to Lab, RGB to Luv, RGB to Ycbcr