一种简单误码检错多分辨率SPIHT算法

New multi-resolution SPIHT approach with simple error detection

由EZW算法演变而来的SPIHT算法是目前为止影响最大的小波压缩算法之一,它通过独特的扫描方式,将小波系数按照能量大小或者重要性程度编码输出。由于引入了小波树,隐藏了扫描路径,SPIHT能获得高压缩比,同时保持较高的图像质量。而后提出的多分辨率SPIHT算法能使解码器根据信道条件,选择图像还原分辨率。然而,SPIHT对路径可靠性要求严苛,任何路径信息的传输错误都会导致剩余所有码元的解码出错。许多学者就路径码元的保护提出了不同改进,却未能从根本上提高算法的抗噪性能。为此,提出了一种改进了的SPIHT算法,该算法在保持较高信噪比和不增加码元数量的基础上,使解码器具有简单误码检错能力。

SPIHT algorithm, evolving from EZW, is so far one of the most influential wavelet compression algorithms, which encodes wavelet coefficients according to their energy or significance through a unique pass. Due to the introduction of wavelet tree and the certain pass, high compression ratio was obtained as well as high quality of image or video. Multi-resolution SPIHT, being later proposed, promised resolution option based on channel condition. However, accurate path information is so demanded in SPIHT that any error of path bit will bring decoding failure of following bits. Various mechanisms were employed to protect the path information, which turn out of little help to fundamentally enhance its capability of anti-noise. The algorithm proposed in the paper provides the decoder with high PSNR and error detection without additional bits by improving the original algorithm.