基于Sobel算子.该方法将图像划分成预先设定大小的网格，在两个尺度上对图像进行分析，完成图像的边缘检测。首先用Sobel算子求得图像边缘，依据网格内含有边缘像素的数目以及连通情况将不同的网格分别处理。 然后以网格为数据单元，在较大尺度上运用Sobel算子得到图像边缘。最后通过设定数据的优先级和使用形态学的方法合并两次计算边缘的结果。-Based on the Sobel operator. This method is an image divided into pre-set the size of grid, in the two scales of image analysis, image edge detection. First of all, seek to use Sobel edge operator, based on the edge of the grid contains the number of pixels as well as the connectivity will be a different deal with the grid, respectively. And then to the grid for the data unit, in the larger scale use Sobel edge operator. Finally the data by setting the priority and use of morphological methods of calculation of the merger of two marginal results.