图像的边缘检测的原理是检测出图像中所有灰度值变化较大的点，而且这些点连接起来就构成了若干线条，这些线条就可以称为图像的边缘。(The principle of edge detection of an image is to detect all the changes in the gray value of the image, and these points are connected to form a number of lines, these lines can be calle