AN EFFICIENT MODIFIED STRUCTURE OF CDF 9/7 WAVELET BASED ON ADAPTIVE LIFTING WITH SPIHT FOR LOSSY TO LOSSLESS IMAGE COMPRESSION

We present a modified structure of 2-D CDF 9/7 wavelet transforms based on adaptive lifting in image coding. Instead of alternately applying horizontal and vertical lifting, as in present practice, Adaptive lifting performs lifting-based prediction in local windows in the direction of high pixel correlation. Hence, it adapts far better to the image orientation features in local windows. The predicting and updating signals of Adaptive lifting can be derived even at the fractional pixel precision level to achieve high resolution, while still maintaining perfect reconstruction. To enhance the performance of adaptive based modified structure of 2-D CDF 9/7 is coupled with SPIHT coding algorithm to improve the drawbacks of wavelet transform. Experimental results shows that the proposed scaling coefficients of modified structure based on adaptive lifting for image coding technique outperforms JPEG 2000 in both PSNR and visual quality, with the improvement up to 6.0 dB than existing structure on images with rich orientation features