说明：  程序可以选择输出二值图像。二值图像可以通过对每个梯度点取阈值得到，其中阈值T为输入参数。并且要求结合3*3掩模的平滑运算和本实验上面的原算，并对图像进行处理，分割出图像中间的大血管区域，并将结果用二值图表示。在实验中需要对平滑运算方法和阈值T进行反复调整。
(Program can choose the output binary image. Binary image can be taken for each gradient point to the threshold should be, in which the threshold T for the input parameters. And requirements with 3* 3 mask and the smooth operation of the experiment above the original balance, and image processing, image segmentation of the middle region of the great vessels, and the results expressed by binary image. In the experiment the need for smooth computing methods and repeated T threshold adjustment.)