腐蚀运算和膨胀运算互为对偶的，用公式表示为(X B)c=(Xc B)，即X 被B腐蚀后的补集等于X的补集被B膨胀。这句话可以形象的理解为：河岸的补集为河面，河岸的腐蚀等价于河面的膨胀。你可以自己举个例子来验证一下这个关系。在有些情况下，这个对偶关系是非常有用的。例如：某个图象处理系统用硬件实现了腐蚀运算，那么不必再另搞一套膨胀的硬件，直接利用该对偶就可以实现了。-Subtraction of the source program. Note that, the first picture file named C : \ test.bmp, second picture file name is C: \ backgnd.bmp. They have the same gray scale value and palette. When executed, the two documents are ready. We although aimed at value of two plans, but in order to facilitate the, use of 256 grayscale, but to only 0and 255of two kinds of gray level.