Department of Electrical and Computer Engineering, The Johns Hopkins University, Baltimore, MD 21218, USA.
IEEE Trans Image Process. 2002;11(11):1271-83. doi: 10.1109/TIP.2002.804279.
It has been well established that state-of-the-art wavelet image coders outperform block transform image coders in the rate-distortion (R-D) sense by a wide margin. Wavelet-based JPEG2000 is emerging as the new high-performance international standard for still image compression. An often asked question is: how much of the coding improvement is due to the transform and how much is due to the encoding strategy? Current block transform coders such as JPEG suffer from poor context modeling and fail to take full advantage of correlation in both space and frequency sense. This paper presents a simple, fast, and efficient adaptive block transform image coding algorithm based on a combination of prefiltering, postfiltering, and high-order space-frequency context modeling of block transform coefficients. Despite the simplicity constraints, coding results show that the proposed coder achieves competitive R-D performance compared to the best wavelet coders in the literature.
已经充分证明，在率失真（R-D）意义上，最先进的小波图像编码器比块变换图像编码器具有很大的优势。基于小波的 JPEG2000 正在成为新的高性能静止图像压缩国际标准。人们经常问的一个问题是：编码改进有多少是由于变换，有多少是由于编码策略？当前的块变换编码器，如 JPEG，存在较差的上下文建模问题，无法充分利用空间和频率意义上的相关性。本文提出了一种简单、快速、高效的自适应块变换图像编码算法，该算法基于预滤波、后滤波以及块变换系数的高阶空间频率上下文建模的组合。尽管存在简单性约束，但编码结果表明，与文献中最好的小波编码器相比，所提出的编码器在 R-D 性能方面具有竞争力。
