Efficient Compression of 4D fMRI Images using Bandelet Transform and Fuzzy Thresholding

Medical image compression techniques should give high compression ratios apart from preserving vital information in medical images. In this paper we propose a compression technique for four-dimensional functional Magnetic Resonance Images (fMRI). The proposed technique uses bandelet transform to capture the anisotropic regularity of edge structures apart from capturing regularity information from smooth regions. Then fuzzy thresholding is performed to retain the important bandelet coefficients. To further improve the compression we make use of variable length encoding technique viz., arithmetic coding. The proposed method is applied to 4D fMRI images and the results are compared with bandelet based ordinary thresholding. Test results show that the proposed method gives better results in terms of PSNR and compression ratio.