说明：  本程序实现了RGB图像转化为灰度图像，而后对图像进行了二值化，比较适合初学者，因为很多复杂的程序初学者比较难理解，我写的这个程序可以作为入门程序。
(This program realized RGB images to gray image, and then to the binary image.It is suitable for beginners, because many complicated procedure is difficult for beginners, I write this program can be used as introductory programs.)