一种快速零树编码的小波图像压缩算法

A Compression Algorithm of Wavelet Image with Fast Zerotree Encoding

研究了一种新的小波变换零树编码方法，通过定义多级零树根和使用编码信息表和最优量化的方法，对不同方向的小波子带系数采用不同大小的门限和量化码书。充分利用了小波变换后各子带系数对图像恢复的重要程度和人眼的视觉特性，取得了很好的压缩效果，对小波系数只作一次零树编码，大大节约了编码时间。

This paper presents a new fast coding method of wavelet image with zerotree encoding. Based on the definition of multi-stage zerotree root and encoding imformation form, using optimized scalar quantization, this paper adopts different thresholds and different size of quantization codebood to each wavelet subband and confficients of each directions. It fully employs the importance degree of the subband coefficients and visual characteristic of mankind, which can compress the high frequency wavelet coefficients efficiently.The method only makes one time zerotree encoding, thus greatly reduces the encoding time.