Introduction - If you have any usage issues, please Google them yourself
Algorithm description SIFT features not only have scale invariance, but also can obtain good detection results even if the rotation angle, image brightness or shooting angle are detected. The whole algorithm is divided into the following parts: (1) tectonic scale space: DoG scale space (2) detecting the spatial extreme points of DoG scale (3) remove bad feature points (4) assign a 128 dimensional direction parameter to the feature point. Each key point contains three information: location, scale and direction. (5) generation of key point descriptors: Firstly, the coordinate axis is rotated as the direction of the key point to ensure the rotation invariance. Take the key point as the center and take the window of 8 x 8. (6) feature matching is performed at last.