Amirkabir University of Technology AUT Journal of Electrical Engineering 2588-2910 41 1 2009 04 01 A Novel Subsampling Method for 3D Multimodality Medical Image Registration Based on Mutual Information A Novel Subsampling Method for 3D Multimodality Medical Image Registration Based on Mutual Information 11 19 273 10.22060/eej.2009.273 EN Maryam Zibaeifardi Maryam Zibaeifard is with Department of Computer Engineering and Information Technology, Amirkabir University of Technology, Tehran, Iran (email: zibaeifard@ce.aut.ac.ir). Mohammad Rahmatiii Mohammad Rahmati is with Department of Computer Engineering and Information Technology, Amirkabir University of Technology, Tehran, Iran (email: rahmati@aut.ac.ir), Corresponding author. Journal Article 2014 03 17 Mutual information (MI) is a widely used similarity metric for multimodality image registration. However, it involves an extremely high computational time especially when it is applied to volume images. Moreover, its robustness is affected by existence of local maxima. The multi-resolution pyramid approaches have been proposed to speed up the registration process and increase the accuracy of the result. In this paper, we present a new improved method of sample selection for multi-stage registration based on mutual information. Instead of down-sampling of the whole image as it is done in the pyramid methods, we propose a new technique to find a suitable subset of image samples based on image information content, which results in a better estimate of the optimal transformation. A comparison for MR images indicates that our proposed method yields better registration than subsampling method, especially when subsampling factor is low. The experimental results involving three-dimensional clinical images of CT, MR and PET are presented for rigid registration. https://eej.aut.ac.ir/article_273_4734ba6f3de83d861c3176a6273cac6d.pdf