说明：  灰度直方图均衡，将图像化为0-1区间的像素值的代码，已经过调试，能用。用于二维或三维图像处理。
(Histogram equalization, the image pixel values ​ ​ into the code 0-1 range, it has been testing, can be used. For two-dimensional or three-dimensional image processing.)