基于JPEG-LS压缩比控制的图像压缩加密算法  

Image compression encryption algorithm based on compression ratio control of JPEG-LS

作　　者：陈益刚[1] 邓家先[1] 谢凯明[1] 

机构地区：[1]海南大学信息科学技术学院,海口570228

出　　处：《计算机应用》2015年第1期93-98,共6页journal of Computer Applications

基　　金：海南省自然科学基金资助项目(613155)

摘　　要：针对传统图像压缩比控制不精细及低维混沌系统保密性不高的问题,提出一种基于连续色调静态图像的无损或近无损压缩标准(JPEG-LS)压缩比控制的图像压缩加密算法。在深入分析JPEG-LS中失真控制参数Near对图像压缩比和重建质量的影响的基础上,首先,对光栅扫描的图像数据进行梯度处理;然后,比较梯度值与Near的大小关系以决定进入游程模式进行游长编码或常规模式进行Golomb编码;再次对三维Lorenz混沌系统生成的序列进行随机性处理,采用该序列作为密钥分别对游程模式、常规模式和全模式(游程和常规两种模式)下的压缩码流进行加密;最后,对Near进行实时动态调整,实现了对图像的压缩比精细控制且提高了保密性。仿真结果表明,所提算法能够实现良好的压缩比控制,且重建图像质量比线性压缩比控制算法提高了大约0.5 d B;同时算法安全性高,能够有效抵抗熵攻击、差分攻击、穷举攻击、统计攻击等多种攻击,且加密对压缩效率基本没有影响。Concerning the problem that the traditional image compression ratio control is rough and the low-dimensional chaotic system has low confidentiality, the image compression encryption algorithm based on compression ratio control of Joint Photographic Experts Group-Lossless Standard（ JPEG-LS） was proposed. On the basis of further analysis about the distortion control parameter Near of JPEG-LS which had significant influence on the image compression ratio and reconstruction quality,the image data of raster scan was first gradient processed in causal model, the size of the gradient value and the Near were compared to determine the run-length coding in run mode or Golomb coding in normal mode, and then random processing sequence generated by three-dimensional Lorenz chaotic system was regarded as the key to encrypt the compressed code stream in run mode, conventional model and whole model（ run and conventional model）. Finally, the fine control of image compression ratio and improvement of the confidentiality were realized by dynamically adjusting Near in real-time. The simulation results indicate that the proposed algorithm has a good performance on control of the compression ratio, and its quality of reconstruction image is improved about by 0. 5 d B than that of linear compression ratio control algorithm.Furthermore, it has high security that can efficiently resist entropy attack, differential attack, brute force attack and statistical attack, etc., and the encryption has no effect on the compression efficiency.

关 键 词：JPEG-LS 压缩加密 压缩比控制 混沌系统 重建图像质量 

分 类 号：TN911.73[电子电信—通信与信息系统] TP391.413[电子电信—信息与通信工程]