对输入原始图像求取梯度图像，对梯度图像做前景标记，即在输入图像的每一个目标中心做一个Marker（可手动选取，也可用阈值法得到），在梯度图像上用该Marker作局部极小值的标记，再进行水域变换，即可得到基于标记点的水域分割结果-Input original image to strike a gradient image of the gradient image make prospects mark that each center of the target input image to make a Marker (can be manually selected, can also be used to obtain threshold method), the gradient image as a local with the Marker pole mark lower value, and then convert the waters, the waters can be obtained based on marker segmentation results