中文说明：读取RGB彩色图像，转换为灰度图像，为下一步进行图像处理做准备，程序中包含读取文件夹下摸个图像的语句，包含多个灰度算法，能够直接出图，
English Description：
Read RGB color image, convert to gray image, prepare for the next step of image processing, the program contains the statement to read an image under the folder, contains multiple gray algorithm, can directly map,