基于最速下降法的JPEG2000快速率控制方法  

Rate control algorithm based on steepest-descent for JPEG2000

作　　者：李诗高[1] 秦前清[1] 

机构地区：[1]武汉大学国家多媒体软件工程技术研究中心,武汉430079

出　　处：《计算机应用》2010年第7期1825-1827,1831,共4页journal of Computer Applications

基　　金：国家科技支撑计划项目(2006BAB10B03)

摘　　要：研究实现了基于最速下降法(SD)的JPEG2000率控制方法。该方法的主要特点是:通过多次迭代依次选择失真率比值最大的编码遍作为最终的压缩码流;并针对最速下降法排序时间复杂度大的缺点,引入了最大堆排序结构,大大提高了在每次迭代更新过程中的排序和查找效率。该方法在率控制的过程中进行备选编码遍的编码过程,既消除了JPEG2000编码的冗余性,又减少了率分配的时间。实验结果表明,该方法显著减少了编码和率控制的时间复杂度,提高了压缩编码效率。A fast rate control algorithm based on Steepest-Descent（SD） was proposed for JPEG2000.The essence of this algorithm is an iterative selection process.In each iteration step,the code passes with maximal ratio of decrease in distortion to increase in bit rate were chosen and reserved as a part of the final compression code-stream.Considering the high time complexity of the sorting process in each iteration step,the max-heap structure was introduced into this algorithm to reduce the time complexity.By encoding the candidate passes in the course of rate control,this algorithm not only eliminates the encoding redundancy existing in JPEG2000,but also decreases the time spent on the rate allocation procedure.The experimental results show that this method significantly reduces the time complexity of the processes of rate allocation and encoding and improves the coding effciency compared with JPEG2000.

关 键 词：图像压缩 JPEG2000 率控制 优化截断的嵌入式分块编码 最速下降法 

分 类 号：TP391.41[自动化与计算机技术—计算机应用技术]