说明：  用matlab检测二值图像的边缘.二值图像 binary image 每一像元只有两种可能的数值或灰度等级状态的图像。 其实就是单色图像。 除了黑，就是白，没有中间过渡，没有灰度的图像。 要么黑，要么白，而且所有的黑都是一个色。
(Detected by matlab binary image of the edge. Binary image binary image for each pixel there are only two possible values, or gray-scale image of the status hierarchy. In fact, the image is monochrome. In addition to black, is white, there is no transition between, no gray-scale images. Either black or white, and all black is a color.)