这种方法一方面将像素的灰度值分散，可以分辨图象中比较细节的内容；另一方面，将图

象的灰度变化控制在一定范围之内，抑制了噪声的产生，较大程度上地保留了原始图象的亮度．-This approach on the one hand spread the pixel gray value, the more details you can identify the contents of the image　the other hand, the image gray scale control in a certain range, suppress noise generation, a greater degree preserved on the original image brightness.