Abstract: SIFT algorithm has distinctive advantages in the field of image processing.However,with the development of the SIFT algorithm,it still has some disadvantages such as the large amount of data processing,slow computing speed.To address these issues,a SIFT algorithm based on block matching was proposed.It reduces the time of feature extraction and matching by extracting the overlapping areas.For the rigid transformation of a image,the core of the algorithm is to calculate the image block segmentation and overlapping areas.In the first step, a small number of seed points are selected to estimate the associated transformation matrix of two images.Then,the original image is cut into pieces and the relevant block is found by the transformation matrix.In the second step,all of the matching feature points are detected on the block.Finally,RANSAC algorithm is used to remove error matching points to improve the matching accuracy.The experimental results show that the improved SIFT algorithm of block matching has better real-time and robustness than the standard SIFT algorithm,and it has a certain application value in the actual image matching.

Key words: Block matching,SIFT,Robustness,RANSAC,Transformation matrix