列举了四种方法扫描图像，分别是利用指针；迭代器；at操作符；和OpenCV自带的LUT方法。比较他们的用时。(how to scan images.copare the cosuming time.)

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，此节点主要是用迭代器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 the pixel iterator some of the methods.)