中文说明：蛇形算法，用于提取物体的轮廓，对于一般的图形（只要边缘的角度不大于90度）识别率还是很高的。
English Description：
Snake-like algorithm, used to extract the outline of objects, for the average graphics (as long as the edge of the angle of not more than 90 degrees) or very high recognition rate.