An efficient codec of 2D adaptive directional lifting based on CDF9/7 with improved SPIHT algorithm for lossy to lossless image coding

摘要

Lifting is an efficient algorithm to implement the discrete wavelet transform in order to overcome the drawbacks of the conventional wavelet transform that does not provide a compact representation of edges which are not in horizontal and vertical directions. The lifting scheme provides a general and flexible tool for the construction of wavelet decompositions and perfect reconstruction filter banks. It has been adopted in JPEG 2000. The paper follows this research line, improved SPIHT based on adaptive coding becomes analyzed and tuned with two dimensional Adaptive Directional Lifting based on CDF 9/7 has structured for lossy to lossless JPEG 2000 image coding. The proposed 2D-ADL scheme incorporates the directionally spatial prediction into the conventional lifting based on 9/7 wavelet transform and forms a novel, efficient and flexible lifting structure with proposed scaling coefficients. In order to obtain better compression on image edge, an improved Set Partitioning In Hierarchical Trees (ASPIHT) algorithm based on prior scanning the coefficients around which there were more significant coefficients was replaced with conventional SPIHT. Although, the proposed 2D-ADL based on CDF9/7 scheme followed by ASPIHT codec significantly reduce edge artifacts and ringing and outperforms the conventional 1D lifting scheme followed by SPIHT upto 12dB as reported.