首先读入图像，转化成hsi彩色空间，然后只对亮度I分量作直方图均衡化，最后合成三个分量返回到RGB图，但是这种方法容易使颜色失真，失去了部分图像细节。-First read in the image, into the hsi color space, and then only on the brightness I component for histogram equalization, the final synthesis of the three components of retu