说明：  Prew it t 边缘算子是一种边缘样板算子。样板算子由理想的边缘子图像构成, 依次用边缘样板去检测图像, 与被检测区域最为相似的样板给出最大值, 用这个最大值作为算子的输出
(Prewitt operator edge is an edge-operator model. Template operator edge sub-image the ideal structure, followed by edge template to detect an image area to be detected most similar model gives maximum as the operator with the maximum output)