Comparative Analysis of WDR-ROI and ASWDR-ROI Image Compression Algorithm for a Grayscale Image

摘要

In this paper we have compared WDR-ROI (Wavelet Difference Reduction- region of interest) concept and ASWDR-ROI (Adaptively Scanned Wavelet Difference Reduction-region of interest) algorithm. The term difference reduction refers to the way in which WDR encodes the locations of significant wavelet transform values. The WDR algorithm combines run-length coding of the significance map with an efficient representation of the run length symbols to produce an embedded image coder. Here we have analyzed WDR-ROI algorithm for the greyscale image. ASWDR algorithm aims to improve the subjective perceptual qualities of compressed images and improve the results of objective distortion measures, especially at low bit rates, than WDR and SPIHT compressed images. ASWDR retains all of the important features of WDR: low complexity, region of interest capability, embeddedness, and progressive SNR. We have analyzed that adaptively Scanned Wavelet Difference Reduction using Region of interest concept given good results compare to Wavelet Difference Reduction algorithm. Using MATLAB Toolbox we have calculated CR, PSNR and BPP and compared their results and found that ASWDR-ROI concept provides improved PSNR value as shown in our results. ASWDR-ROI and WDR-ROI algorithms are best suited algorithm for medical images and satellite images which requires increase resolution area.