SIFT特征是图像的局部特征，其对旋转、尺度缩放、亮度变化保持不变性，对视角变化、仿射变换、也保持一定程度的稳定性.本程序采用MATLAB和c语言联合编程。(SIFT feature is a local feature of the image. It keeps invariant to rotation, scale scaling and luminance change, and also keeps a certain degree of stability to the change of view angle, affine transformation. This program is programmed by MATLAB and C language.)