基于LDPC码的自适应视频水印算法研究  

A Study of Adaptive Video Watermarking Algorithm Based on Low-Density Parity-Check Codes

作　　者：许拔[1] 张仲明[1] 何英亮[2] 张尔扬[1] 

机构地区：[1]国防科学技术大学电子科学与工程学院,湖南长沙410073 [2]湖南大学计算机与通信学院,湖南长沙410082

出　　处：《信号处理》2010年第3期441-447,共7页Journal of Signal Processing

摘　　要：根据视频水印系统和数字通信系统相似的特性,提出了一种基于LDPC码的自适应视频水印算法。水印信息经随机置换与LDPC编码,对经过二次整数变换之后的直流分量进行修改实现水印的嵌入。为了兼顾水印的不可见性与鲁棒性的要求,算法根据水印长度和变换之后系数的大小自适应地选择嵌入水印的组及系数的改变强度。实验结果表明:该算法能够保证很好的视频质量,较之基于DCT变换的水印算法嵌入速度更快,并实现了水印的盲提取。对于常见的视频攻击有较强的鲁棒性,在码率高于汉明界推导出的下限的情况下,算法鲁棒性随着码率的减小而增强。According to the comparability between the Video Watermarking System and the Digital Communication System, an adaptive video watermarking algorithm based on LDPC is proposed in this paper. The watermarking information that is stochastically permuted and coded by LDPC is embedded in the modified DC components which are attained by Integer Transform twice. To balance between invisibility and robustness of watermark, it utilizes the length of the watermark and the value of the transformed coellieients to adaptively select the groups to embed watermark and the intensity of the coefficients modification. Experimental results show that the proposed approach can achieve fine video quality and can run faster than the algorithm based on DCT. Moreover, the watermark can be extracted blindly and it is robust to common video attacking. Especially, the robustness of the algorithm becomes stronger along with the decrease of the rate as the code rate is above the lower limit conducted by the Hamming Bound.

关 键 词：低密度奇偶校验码 整数变换 自适应视频水印 汉明界 

分 类 号：TP391.41[自动化与计算机技术—计算机应用技术]