Source images are frequently corrupted by noise before fusion, which will lead to the quality decline of fused image and the inconvenience for subsequent observation. However, at present, most of the traditional medical image fusion scheme cannot be implemented in noisy environment. Besides, the existing fusion methods scarcely make full use of the dependencies between source images. In this research, a novel fusion algorithm based on the statistical properties of wavelet coefficients is proposed, which incorporates fusion and denoising simultaneously. In the proposed algorithm, the new saliency and matching measures are defined by two distributions: the marginal statistical distribution of single wavelet coefficient fit by the generalized Gaussian Distribution and joint distribution of dual source wavelet coefficients modeled by the anisotropic bivariate Laplacian model. Additionally, the bivariate shrinkage is introduced to develop a noise robust fusion method, and a moment-based parameter estimation applied in the fusion scheme is also exploited in denoising method, which allows to achieve the consistency of fusion and denoising. The experiments demonstrate that the proposed algorithm performs very well on both noisy and noise-free images from multimodal medical datasets (computerized tomography, magnetic resonance imaging, magnetic resonance angiography, etc.), outperforming the conventional methods in terms of both fusion quality and noise reduction.
K E Y W O R D Sbi-shrinkage, image fusion, KL-divergence, mutual information, statistical distribution 1 | INTRODUCTION Imagology plays an important role in medical science, owing to the application for the visualization of anatomy structure, function, and metabolism information. 1 Actually, singular modality medical images exhibit limitations due to the imaging mechanism. Computerized tomography (CT) images can provide bone tissue information with high resolutions, but they cannot show the soft tissue. Although magnetic resonance imaging (MRI) images are good at showing the anatomical information of soft tissue, they cannot provide metabolism information, while T2 weighted MRI (MRI-T2) and magnetic resonance angiography (MRA) images could achieve good vision of pathological tissue. 2 In practical clinical applications, the multi-modal medical image fusion technology, which combines the complementary information from multi-modal images, is helpful to facilitate a better observation of anatomical and metabolism information. 3 This technology provides an easy but very efficient access for diagnosis and assessment of disease. 4 Image fusion based on multiscale transform has become a more common approach for pixel-level image fusion and abundant research results have been achieved. For waveletbased fusion methods, wavelet transforms are performed first on each source image to obtain different sub-bands which contain decomposition information of varying