A PERFORMANCE AND ANALYSIS OF EZW ENCODER FOR IMAGE COMPRESSION
Vikas Goyal · Figshare · 2015
Current image coding systems use wavelet transform, which decompose the image into different levels, where the coefficients in each sub band are uncorrelated from coefficients of other sub bands. As a result the coefficients in each sub band can be quantized independently of coefficients in other sub bands with no significant loss in performance. But the coefficient in each sub band requires different amount of bit resources to obtain best coding performance. This results in different quantizer with each sub band having its own bit rate. This gives an issue to bit allocation under image processing. Hence sub band coding can be used for achieving high bit rate. Embedded zerotree wavelet (EZW) encoder is designed to use wavelet transform. EZW coding exploits the multi-resolution properties of the wavelet transform to give a computationally simple algorithm with better performance. A performance analysis of image compression system for various formats of image is considered with EZW based on different wavelets. The main purpose of this paper is to investigate the impact of different wavelets on image compression using EZW. The effect of the level of wavelet decomposition on compression efficiency is analyzed. The Haar, Dauhechies 4 and bio-orthogonal wavelets are used. The compression simulations are done on few modalities of images. The qualitative and quantitative results of these simulations are presented.