A Segmentation-Based Image Coding Algorithm And Imitated Application Based On Embedded Wavelet Zero-Tree Coding Scheme

Image is very important medium at application of multimedia. Because of limitation of transmission bandwidth and storage capacity, so image compression became one of critical techniques at information transmission system. In recent decade, the technique of wavelet transform has been applied and studied extensively because of its good features of time-frequency and human visual system.In this paper, a improved low bit rate image compression algorithm, namely embedded wavelet zero-tree segmntation-based image coding, is put forward about still images based on embedded wavelet zero-tree image coding scheme. First, image is divided subband images of various scales by wavelet transforming. Then at this algorithm the coefficient in horizontal vertical and diagonal orientation sub-images of all scales are quadtree segmented at threshold T criterion. At last these uniform blocks are encoded based on EZW. This improved coding algorithm not only is with the property of EZW but also let unimportant coefficient becoming image blocks to represent so that we can effectively apply the wavelet coefficients of image, low bit-ratio and intensify the visual effective of reconstruction images at the same time. To the embedded zerotree wavelet algorithm(EZW) this paper's coding algorithm is similar the properties which are yielding a fully embedded code, terminating the encoding and decoding at any point respectively under requirement of rate-constrained or distortion-constrained, absolutely no training and no pre-stored codebooks. Through the experimental and simulated results, we can demonstrate that the reconstruction images are good, and the peak signal-to-noise ratio (PSNR) of the reconstructed image is improved (mean improved PSNR is about 0.37-0.46dB ) compared to embedded zero-tree wavelet encoding (EZW) algorithm at the same bit-ratio.