求图像的二值化最佳阈值 利用opencv 实现图像的膨胀，腐蚀，开运算，闭运算，求轮廓操作，并可以从外部文件导入结构算子-Find the best binary image threshold image using opencv achieve dilation, erosion, opening operation and closing operation, find the outline of operation, and can be imported from an extern