说明：  canny边缘检测，边缘检测的目的是在保留原有图像属性的情况下，显著减少图像的数据规模。目前有多种算法可以进行边缘检测，虽然Canny算法年代久远，但可以说它是边缘检测的一种标准算法，而且仍在研究中广泛使用。
(Canny edge detection，The purpose of edge detection is to significantly reduce the size of the image by preserving the original image attributes. There are a variety of algorithms for edge detection, although the Canny algorithm is old, but it can be said that it is a standard algorithm for edge detection, and is still widely used in research.)