Conclusion: The mixed color turned to red when the huedifference is over 0.6.
结论：①背景色彩度差大于0.6时，试件和背景混和色明度减小，色相趋向红色；
2
According to huedifference between shaded and non-shaded regions, possible shaded regions were extracted by HSV color model at first.
根据阴影与非阴影区域间存在色调差异，利用HSV彩色模型，提取可能阴影区域。
3
When the huedifference increased, the magnitude of color shift in test target decreased, but the deflection Angle of color shift vector from constant hue line increased.