显示彩色图像的三个通道的灰色直方图,显示图像的三个通道，

屏蔽两个通道，

显示三个通道分别显示，

显示感兴趣的区域ROI，共5段代码

-Shows three-channel color image gray histogram displays three channels of the image, shielding the two channels, shows three channels are displayed, the display area of ​ ​ interest ROI of 5 sections of the code