已知图象4点坐标和转换后图像相对应4点坐标， 利用openCV求出homograghy 3x3 矩阵， 然后输出变换后图像,There is an input image called "warpin". The goal is to warp this image so that the tiles are approximately square, that is the camera is rotated to look down, which produces an image call

Smooth function is used a matrix with a 3X3 Gaussian filter kernel.

均值滤波器，可以改变filter的大小。例如：3X3,5X5,7X7 -Mean filter, you can change the size of the filter. For example: 3X3, 5X5, 7X7