以下是差影法的源程序。要注意的是，第一幅图的文件名为c:\\test.bmp，第二幅图的文件名是c:\\backgnd.bmp。它们有着相同的灰度值和调色板。执行时，这两个文件已经准备好。

我们针对的虽然是二值图，但为了处理的方便，用的是256级灰度图，不过只用到了0和255两种灰度级。-Subtraction law of the source. To be noted is, a document of the plan called c : \\ test.bmp, second graph in the paper were c : \\ backgnd.bmp. They share the same values and gray palette. When implemented, these two documents have been prepared. Our target is worth two plans, but in order to facilitate the use of 256 grayscale. But only uses two 0 and 255 gray levels.