Registration of SPECT and MR brain images using a fuzzy surface
J. B. Antoine Maintz, Petra A. van den Elsen, Max A. Viergever · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1996
Surface (e.g., skin or cortex) based methods to register SPECT and MR images are well known and widely used. Such methods have the disadvantage of needing some kind of segmentation to obtain the surface, which is often a high-level task and possibly error-prone. Also, when reducing the gray-valued images to surfaces, i.e., binary structures, valuable information may be lost in the process. We propose to use the same surfaces, but in a fuzzy way, i.e., we determine the 'surfaceness,' thus retaining more information and avoiding binary segmentation. Such surfaceness can be computed using various techniques. We found a simple morphological approach (which is easy to implement and has very low computational complexity) to be quite sufficient. The resultant surfaceness images are subsequently registered by optimizing the cross-correlation value. The optimization is done using a hierarchical approach to cut the number of required computer operations down to an acceptable level.