Multi-modal image registration by mutual information based on optimal region selection

Mutual information (MI) has been commonly used in multi-modal image registration. In this paper, we presented an optimal region selection method for MI based multi-modal image registration. Firstly, image preprocessing and initial registration were applied on the two images. Then we applied two region selection procedures to improve the performance of MI-based registration. The first procedure is hierarchical region detection that selects regions with more structure information in each of the two images. In this procedure, the images were divided into sub-images progressively, and candidate image blocks with high usability were selected based on entropy. The second procedure is optimal matching region selection based on local registration using MI. In this procedure, the regions selected in the first procedure were registered with MI, then the results are used to choose optimal matching regions with high reliability. Finally, the optimal regions were used for the entire image registration by computing the MI of the regions. The experiment results showed that this method could improve the efficiency and accuracy for MI-based image registration.