Lifting-based Directionlet Transform for Image Coding

In this paper, a new lifting scheme of directionlet transform(LDT) is presented, the corresponding multi-directional and anisotropic transform has lattice-based separable filtering and subsampling along any two directions with rational slopes. We design an adaptive compression algorithm based on LDT, using the quad-tree segmentation resulting optimized directions. Experimental results show that our proposed compression algorithm for image coding outperforms the standard wavelet-based SPIHT and JPEG2000 both in terms of PSNR and visual quality, especially at the low-rate.