Abstract: This paper proposed a novel method of medical image fusion based on nonsubsampled contourlet transform (NSCT) against the existing problems of medical image fusion by traditional multi-scale transform. Considering regional relativity of the adjacent low frectuency sub-band,a fusion rule based on local area energy was adopted in low frequency sulrband coefficient according to characteristics of medical image. When choosing the bandpass directional sulrband coefficients, the paper made best use of directional characteristics of NSCT. A fusion rule based on sum-modified-laplacian (SMI)was presented in bandpass directional sulrband coefficients. The experiment results show that the proposed method can avoid image distortion and achieve a good effect of image fusion compared with traditional fusion methods.

Key words: Nonsubsampled contourlet transform(NSC7)，Medical image fusion, Local area energy, Sum-modified-laplacian(SMI)