Krish 算子是基于特定方向的微分来检测边缘。它先辨认像素为可能的边缘元素，再给它赋予预先定义的若干个方向之一-Krish operator based on the specific direction to detect the edge of the differential. It first to identify the edge pixels for a possible element,then it gives a number of pre-defined directi