基于二进制小波变换和改进SPIHT算法的图像编码方法

提出了一种基于二进制小波变换和改进SPIHT算法的图像编码方法.二进制小波变换将图像从实数域变换到实数域,消除像素之间的空间冗余性,得到了具有整数准确度的紧致描述.针对传统SPIHT算法解码图像视觉效果差的缺点,提出了改进方法.根据图像分析结果,将二进制小波变换变换系数按视觉重要性重新排序,通过对视觉重要系数优先编码,把量化误差集中在视觉不敏感区域,从而在不影响编码率失真性能的同时,有效地提高了解码图像的视觉效果.实验结果表明,和其它流行的编码算法相比,本文算法对不同性质的图像具有最优的编码性能和视觉效果.

An Image Coding Algorithm Based on Binary Wavelet Transform and Modified SPIHT

An image coding algorithm based on binary wavelet transform (BWT) and modified SPIHT is proposed. With the BWT, it eliminates spatial correlation and achieves compact representation of an image with integer precision, by mapping image pixels from real field to real field. Modified approach also presented to improve the poor visual quality of the traditional SPIHT algorithm. In our method, BWT coefficients are reordered according to their perceptual importance. The visually important coefficients are transmitted as early as possible, whereas those compression distortions are distributed in less visual significant regions. In this way, the visual qualities of decoded images are significantly improved without impairing the rate-distortion performance of the encoder. Experimental results show that the proposed algorithm achieves optimal compression performance and visual quality for images with various characteristics, as compared with other popular compression algorithms.