Non-rigid multimodal image registration using mutual information

A fully automated voxel-based algorithm for multimodal non-rigid image registration using a mutual information based similarity criterion is presented. The image deformation vector field is found by dividing images into overlapping neighborhood regions and translating these regions to locally increase the similarity criterion. The calculated displacement in each region is assigned to the centered pixel of each neighborhood region and propagated to its neighbors with a Gaussian window function assuring continuity and smoothness of the deformation field. Initial experiments on 2D test data qualitatively demonstrate the feasibility of this approach.