Abstract: For the fusion problem of the multifocus images with the same scene, a novel multifocus image fusion algorithm based on the nonsubsampled contourlet transform (NSCT) is proposed. Firstly, source images are decomposed at different scales and directions by NSCT, thus the low frequency subband coefficients and various bandpass directional subband coefficients are obtained. Secondly, for the low frequency subband coefficients, we present a fusion rule based on the directional vector normal combined with the weighted average; while for the bandpass directional subband coefficients, we present a fusion rule based on the improved directional contrast combined with the local area energy. Finally, the fusion image is obtained through the inverse NSCT. The experimental results illustrate that the proposed algorithm is effective for retaining the original images’ information and avoiding artifacts.

Key words: image fusion, nonsubsampled Contourlet transform, fusion rule, directional vector normal, directional contrast