Abstract: Feature extraction is an important technology in digital image processing and computer vision．And making use of feature descriptor to construct the image feature point is a crucial step in the image feature extraction and image registration．SIFT feature point detection operator has the advantages of translation,rotation and scaling invariance．So,it is widely used in image registration．We mainly improved the 64dimensional description operator based on the SIFT characteristics．The simulation results prove that the improved algorithm has higher accuracy than the original algorithm,and the time complexity is reduced.

Key words: Feature extraction,Feature point,SIFT,Image registration