其实说白了就是灰度的一个跳变。因此我们只要设定一个阀值，把电脑上的图片中的像素的色彩转化为灰度，再把相邻的两个像素的灰度去比较，当灰度变化超过一定的量的时候，我们就判断它是轮廓。-In fact, it means a grayscale transition. So long as we set a threshold, the computer image pixel color into gray, then gray pixels adjacent to compare the two, when the gray scale than a certain amount of time, we to determine whether it is profile.