提取图像sift特征，并且showkey函数在图像上直观的显示出来-Sift extracted image features, and showkey function in the image displayed on the intuitive

实现SIFT特征点的检测及图像拼接功能，主要在原来作者的基础上添加了显示全部特征点或者只显示重叠区域特征点，能够直接使用-Achieve SIFT feature point detection and image stitching function, mainly on the basis of the original author to add a point or show all the characteristics of overlap only feature points c

利用sift算法提取出特征点，并且在原图像上显示。-SIFT feature points extraction, and display