说明：  DoG(Difference of Gaussian)滤波算子，主要用于边缘特征提取，用于模式识别中的分割预处理。其主要参数为两个高斯函数的方差，针对方差设计可以对不同的图像特征情况下有不同的表现。
(DoG (Difference of Gaussian) filtering operator, the edge feature extraction is mainly used for pattern recognition of the partition pretreatment. The main parameters for the two Gaussian function of variance, the variance for design characteristics of the different images have different circumstances performance.)