楼主前一个帖子选了我的答复，你如还有，不妨把链接告诉我，我原意效劳。
The Canny edge detection algorithm is known to many as the optimal edge detector.Canny边缘检测算法对很多人来说是众所周知的最佳边缘检测工具。 Canny's intentions were to enhance the many edge detectors already out at the time he started his work.Canny的意图是提高很多在他开始自己的研究时就已过时的边缘检测工具。He was very successful in achieving his goal and his ideas and methods can be found in his paper, "A Computational Approach to Edge Detection". 他在实现自己的目标时非常成功，他的概念和方法可以在本文中看到。In his paper, he followed a list of criteria to improve current methods of edge detection. 在本文中，他遵循了一系列的准则来改进边缘检测的现有方法。The first and most obvious is low error rate.首先而最明显的是低的差错率（误码率）。 It is important that edges occuring in images should not be missed and that there be NO responses to non-edges. 以下两点很重要，即发生在图像中的边缘不应被错过，以及对非边缘“没有”响应。The second criterion is that the edge points be well localized.这第二条准则是，边缘点被很好定位。 In other words, the distance between the edge pixels as found by the detector and the actual edge is to be at a minimum.换句话说，由检测器发现的边缘像素和实际边缘之间的距离要处于最小值。 A third criterion is to have only one response to a single edge.第三个准则是对单一的边缘只有一个响应。 This was implemented because the first 2 were not substantial enough to completely eliminate the possibility of multiple responses to an edge.这一条得到了实施，因为前两条对完全消除一个边缘可能出现多次响应方面还不够充分。