Abstract: Astronomical image registration is a key technology of astronomical movement study,and often there is some slight irregular motion of internal structures in the image.However,in image registration the transformation of an entire image needs to be calcu lated.In this case,no matter whether registration is based on statistical characteristics or local features,it is difficult to achieve the desired results.On this basis,image is divided into several small squares firstly,and the entropy is calculated.Then square with maximum entropy is considered as the local sub-graph to register.Scale invariant feature transform and the affine transformation are used to establish relationships between local sub-graphs to complete image registration.On the one hand,this method can reduce the time of building transform relationship.On the other hand,it ensures the registration of the image area with maximum information entropy,and it also improves the registration quality of astronomical images effectively.

Key words: Entropy,SIFT algorithm,Evenly split,Affine transformation,Transform relation