中文说明：Frangi 用粗麻布矩阵的血管分割方法。此函数 FRANGIFILTER2D 将使用到粗麻布的特征向量计算船只，根据图像区域概率翻的一番对 Frangi 所描述的方法。
English Description：
A method proposed by frangi for vessel segmentation using hessian matrix.This function FRANGIFILTER2D uses the eigenvectors of the Hessian tocompute the likeliness of an image region to vessels, according to the method described by Frangi.