---计算颜色近似度---
RGB模式:
r1,g1,b1-输入端RGB值
r2,g2,b2-色彩标准中各颜色的RGB值
wr,wg,wb-加权值:wr范围[2.5-3],wg范围[3.5-4],wb范围[1.5-2]
CAM02_UCS模式:
This converts an sRGB value (represented as integers between 0-255) to CAM02-UCS J’a’b’ coordinates. This requires passing through 4 intermediate colorspaces