直方图均衡化的基本思想是把原始图的直方图变换为均匀分布的形式，这样就增加了象素灰度值的动态范围从而可达到增强图像整体对比度的效果-The basic idea of histogram equalization is the histogram transform the original graph form for the uniform distribution, so the pixel gray value of the dynamic range is increased so as to enhance the global contrast of image effects