中文说明： 该代码实现在指纹图像中快速检测所有奇异点。使用的方法是行走算法，即在指纹方向场上任意选择一个点，沿着该点的启发式方向（设计出来的，为该点方向的函数）可快速走到奇异点的位置。该算法简单易实现。
English Description：
The code to achieve the fast detection of all singular points in the fingerprint image. The method used is to walk the algorithm, that is, in the direction of the fingerprint to choose a point, along the direction of the heuristic (designed as a function of the direction of the point) can quickly go to the location of the singular point. The algorithm is simple and easy to implement.