Firstly

the Harris corner detector is used to detect corners

a method to describe the direction character of the corners is given and the keypoint descriptor of SIFT(scale invariant feature transform) is introduced in this method. Secondly

Euclidean distance is performed to get exact matching in the corner set. Finally

an easy and effective method to avoid wrong matches is discussed. This method is effective on brightness invariant

movement invariant and rotation invariant in the matching of digital city image sequences. This method is proved to be effective by realistic experiments

and of high practicability.