说明：  匹配特征、相似性程度以及匹配策略是图像匹配的三个技术难点。文章深入讨论了这三个方面所涉及的各种方法并评估和比较了他们的优缺点，指出了存在的问题。
(Matching features, as well as the degree of similarity matching strategy is three image matching technical difficulties. Depth article discusses the various methods involved in these three areas and to assess and compare their advantages and disadvantages, pointed out the existing problems.)