【作者】 章振平；

【导师】 龙沪强；

【作者基本信息】 上海交通大学 ， 信号与信息处理， 2007， 硕士

【摘要】 JPEG2000静止图像压缩标准和Motion-JPEG2000运动图像压缩标准具有压缩效率高、抗误码能力强、码流渐进传输等优异的压缩特性,将得到越来越广泛的应用。码率控制是JPEG2000和Motion-JPEG 2000编码的重要过程,其算法的优劣直接决定着整个编码效率的高低和压缩图像质量的好坏。因此,研究并提出更为高效的JPEG 2000码率控制算法,以减少编码计算冗余、提高编码速度和减少内存资源消耗,对于图像和视频的JPEG2000编码软硬件实现都具有重要的现实意义。对于JPEG2000编码,本文首先详细叙述了JPEG2000压缩标准的主要编码过程,以及图像编码码率控制的基本理论。这部分是进一步讨论JPEG2000的码率控制问题的背景知识和相关理论基础。然后,本文较为全面地介绍了JPEG 2000码率控制的两种机制,以及标准推荐的压缩后率失真优化算法,并分析了该算法存在的编码效率低、计算冗余大的缺点。最后,在充分分析目前学者提出的一种较有效的码率控制算法的基础上,针对其存在着编码图像质量下降的不足,本文提出了一种更为高效的算法:改进的联合熵编码和率控制算法VIREC (Variable number-of-passes Integrated Rate-control and Entropy-coding),该算法根据各个码块所在子带的能量权重系数的大小,选择不同的每更多还原

【Abstract】 JPEG2000 and Motion-JPEG2000 have a very large potential application fields due to their excellent compression performance and many attractive features. Rate control is a very important part in JPEG2000 encoding. The more efficient a kind of rate control algorithm is,the higher coding efficiency, and the better image quality. Therefore, it is significant for JPEG2000 coding’s software and hardware solution using more efficient rate-control algorithms.In terms of JPEG2000 coding, JPEG2000 standard’s major coding step and classic rate-distortion theory are firstly described in the dissertation, and this is the background knowledge of JPEG2000 rate-control. Then, two rate-control mechanisms and the rate control technical recommended by the JPEG2000 standard which is named Post-coding Rate Distortion Optimization are introduced in detail. The algorithm, however, has the disadvantage of high computation redundancy. In order to improve the coding efficiency, a more efficient rate control technical is proposed which is named with VIREC (Variable number-of-passes Integrated更多还原