Efficient Wavelet Lifting Scheme Based on Filter Optimization and Median Operator

In JPEG2000, the Cohen-Daubechies-Feauveau (CDF) 9/7-tap wavelet filter is implemented for lossy compression by a wavelet lifting scheme. However, the filter coefficients are remaining complex because they are irrational numbers. In addition, the conventional wavelet lifting scheme does not consider image edges. In this paper, we propose an efficient wavelet lifting scheme based on filter optimization and median operation and address these problems. For this purpose, we design optimal 9/7-tap wavelet filters by selecting appropriate filter coefficients. We also employ a median operator to consider image edges. Our proposed method, which is a combination of filter optimization and median lifting, improves the peak signal- to-noise ratio (PSNR) value up to 0.75 dB, compared to the well- known CDF 9/7-tap wavelet filter of JPEG2000.