基于MFC对话框的图片打开和获取指定点像素值,调用opencv函数-Open access to the specified point and the pixel values ​ ​ of the image-based MFC dialog, call the opencv function

编程环境：VS+OPENCV ，对于初学者学习基于opencv的图像处理非常有帮助，此节点主要是用at访问像素点的一些方法。(Programming environment: VS + OPENCV, for beginners to learn based on opencv image processing is very helpful, this node is mainly used to access some of the pixels point method.)