基于改进零树编码的ROI图像联合压缩加密算法

Algorithm on Joint Compression and Encryption of Image's Region of Interest Based on Improving Zero-Tree Coding

提出了一种能灵活控制感兴趣区域(Region Of Interest,R0I)的重建质量且将图像的压缩与加密同步实现的编码算法.该算法将图像进行ROI划分后利用加权因子灵活控制其编码量,再通过结合改进零数的压缩算法与算术编码,使用密钥对压缩产生的原始上下文与原始判决进行修正,从而实现ROI的联合压缩加密.实验结果表明,当密钥正确时,ROI的重建质量随着加权因子的变化而变化;当密钥出错时,ROI重建质量急剧下降,图像实现分区域加密,从而验证了本文所提出算法的可行性.

In this paper, we propose a coding algorithm which could flexibly control the reconstruction quality of image’s region of interest（ROI） and synchronously implement image compression and encryption. The algorithm uses the weighted factor to control the amount of coding after dividing ROI of image. Through combining improving zero-tree compression algorithm and arithmetical coding, the original context and original sentence from compression is amended by taking advantage of the key to realize joint compression and encryption of ROI. The results indicate that reconstruction quality of ROI changes with the change of weighted factor when the key is right. On the contrary, reconstruction quality of ROI reduces dramatically and image conducts regional encryption when the key is fault, which proves the algorithm we put forward is feasible.