说明：  直方图均衡，图像去雾处理，是把原始图像的灰度直方图从比较集中的某个灰度区间变成在全部灰度范围内的均匀分布。直方图均衡化就是对图像进行非线性拉伸，重新分配图像像素值，使一定灰度范围内的像素数量大致相同。
(Histogram equalization, image processing to the fog, is the original image histogram to a gray scale from the more concentrated into the full range of uniform distribution within the gray area. Histogram equalization is that the image is non-linear stretch, re-distribution of the image pixel values, so that a certain number of pixels within the gray area roughly the same.)