计算如下图像bread.jpg的直方图，并将图像进行均衡化，比较均衡化前后的图像及直方图。



直方图是统计在每一个灰度级上像素的个数，直方图均衡化是通过点运算使一幅输入图像转换为在每一灰度级上都有相同的象素点数的输出图像（即输出的直方图是平的）。公式如下：

连续情况：

　　　　　　　　

离散的情况：



其中 表示输入图像的直方图， 表示灰度等级， 表示输入图像的面积。

-Calculated as follows bread.jpg image histogram, and a balanced image, and compare images before and after equalization and histogram. Histogram is a statistical gray level in each of the number of pixels, histogram equalization is to make a point of computing the input image is converted to gray level in each pixel have the same points of the output image (ie output histogram is flat). Formula is as follows: continuous case: discrete case: which states that the histogram of the input image, said gray levels, said the size of the input image.