读取图像与模板相比较。原理是利用横纵坐标投影的差值的方差大小判断图像差异。可以简单的描述出图像的差异大小。-Read image is compared with the template. Principle is to use the difference between the horizontal and vertical coordinates of the variance of the projection image size determines the difference. Can simply describe the size of the difference image.