This code introduces many computer vision techniques. It explains how to create an image, load an image, show a picture, dim an image, add a constant an wrap, add a constant and saturate, subtract a constant and wrap, subtract a constant and saturate

不用封装好的函数，自己编写函数实现直方图均衡。对图像进行平滑处理。(Do not wrap functions, write their own functions to achieve histogram equalization.The image is processed smoothly.)