最大值：扫描法：设第一个象素灰度级为最大值，然后与后一个象素灰度级比较，如果后面的大，则把后一象素值赋给最大值，依次逐一比较到图象最后的一个象素，找出最大值。-Max: scanning method: the first pixel-based gray-scale for the maximum, and then after a pixel with gray-scale comparison, if the back of the large, while the latter is assigned to the maximum pixel value, followed by one by one compared to the Finally, a pixel image to find out the maximum.