关键词: 图像配准, 互信息, 粗配准, 灰度压缩, 遗传算法, 单纯形法

Abstract: The medical image registration based on mutual information is a high-precision registration method，which can reach sub-pixel accuracy with no need to extract anatomical features from images.But it can not meet the need of real-time clinic due to its low speed.This paper proposes a speed program：a rough registration to narrow the range of mutual information search，a method of gray-scale compression based on a gray histogram for speeding up mutual information computation，a hybrid optimization algorithm of genetic algorithm and simplex method for convergence acceleration.Experiments show that the modified method can significantly reduce the registration time.

Key words: image registration, mutual information, rough registration, gray-scale compression, genetic algorithm, simplex method