Directional wavelet transform and block-set partitioning for image coding
We propose a novel directional lifting-based block-set coding algorithm in this paper. Directional lifting wavelet transform based on region partition is firstly used to remove the correlation along the edges and reduce the amount of high-pass subband energy, then a new multi-symbol arithmetic coding based on residual classified context is exploited to code directional information. A context-based block-set partitioning method is proposed to code the directional transformed coefficients. Experimental results show that the proposed algorithm for texture-rich images outperforms JPEG2000 by 1.6 dB. Especially, the new algorithm can obtain the PSNR gain which up to 0.4 dB, comparing with JPEG2000 (EBCOT) based on directional lifting transform.