基于二维小波分解的图象编码

IMAGE CODING USING 2D WAVELET TRANSFORM

本文给出了一个基于二维小波（Ｗａｖｅｌｅｔ）分解来进行图象压缩编码的方法。这里是使用正交小波变换来由行图象分解（即在正交小波基上分解），得到一个图象的多分辨率表示，各频道分量对图象结构的把握是整体的，从更大程度上解除了图象象素之间的相关性，克服了由ＪＰＥＧ方法进行图象压缩编码而产生的块效应。对图象进行二维正交小波分解后，我们使用ＣＶＱ（ＣｌａｓｓｉｆｉｅｄＶｅｃｔｏｒＱｕａｎｔｉｚａｔｉｏｎ）对小波系数进行编码，得到了较高的编码效率和重建图象质量。

n this paper,an image coding scheme combining the advantages of bothdiscrete wavelet transform (DWT) and classified vector quantization (CVQ) isproposed.We decompose an image into a multifrequency channel representation on a setof orthonormal wavelet base and then use classified vector quantization technique to codethe coefficients and enable the system to compress an image to a low bit rate. Simulationresults showed that the proposed approach allow good subjective image quality to beobtained.The improvement in quality is even more pronounced at low bit rates, if thisalgorithm is compared to those algorithm employing CVQ or DCT alone.