Efficient lossy Image compression Using Adaptive Directional Lifting Based 9/7 wavelet Transform

Abstract: Traditional 2-D Discrete wavelets transform (DWT) implemented by separable 1-D transform in horizontal and vertical directions does not take image orientation features in a local window into account. However, the lifting scheme provides a general and flexible tool for the construction of wavelet decompositions and perfect reconstruction filter banks. To improve it, we propose to introduce adaptive directional lifting structure based on DWT and thereby derive a new scheme for 9/7 DWT transform, whose transform defined structure is dependent on directional angle and interpolation used there and locally adapts the filtering directions to image content based on directional lifting. We propose an adaptive version of this scheme followed by SPIHT. The experimental results show that the performance of the proposed system with SPIHT can dramatically outperform the conventional DWT up to 6.4 dB even without overhead cost.