Automated image registration by maximization of a region similarity metric

This paper presents a robust algorithm for automated registration of images related by rigid-body transformations. This algorithm uses a new region-based similarity metric , which enables accurate registration of images of large contrast diierences. Region segmentation required by the metric is accomplished using a multiscale segmentation algorithm , and minimization of this metric is done using the Powell direction set method. Experimental results are presented to demonstrate that the algorithm is eeective for aligning images from single or multiple imaging modalities without the use of any du-cial markers.