Multifocus image fusion scheme based on nonsubsampled contourlet transform

This paper proposes a novel multifocus image fusion scheme based on nonsubsampled contourlet transform (NSCT). The selection principles for different subband coefficients in NSCT domain are discussed in detail. In order to be consistent with the characteristics of the human visual system and improve the robustness of the fusion algorithm to the noise, the NSCT-DCT energy is first developed. Based on it, the clarity measure and bandpass energy contrast are defined and employed to motivate the pulse coupled neural networks (PCNN) for the fusion of lowpass and bandpass subbands, respectively. The performance of the proposed fusion scheme is assessed by experiments and the results demonstrate that the algorithm proposed in the paper compares favorably to wavelet-based, contourlet-based and NSCT-based fusion algorithms in terms of visual appearances and objective criterion.