Speed-up keypoint mapping technique by multi-resolution and global information

This work deals with the problem of high computation complexity in image registration. A hierarchical multiresolution strategy is utilized to speed up the processing of SIFT by starting on a low resolution octave. The initial affine transformation model will be achieved. In subsequent multiresolution octaves, we apply the transformation affine model getting from upper octave to current octave, then, combined with geometrical distribution of matched keypoints to further remove incorrect mappings and update affine transformation model. The strategy ends with the best affine transformation model on the bottom octave(full-size image). Experimental results show that the proposed method can achieve comparative accuracy with less computational than original SIFT