修改了冈萨雷斯《数字图像处理》中的区域生长法。本函数中含有三种选择种子点的方法：分别依据灰度值，种子点位置，交互式选择单个种子点。-Modified the region growing method described in　"Digital Image Processing" . This function contains three options for the method of seed points: based on gray value, the location of the seed points, interactive selection of a single seed point.