基于双混沌与双极性的二重水印算法

摘要

针对双水印的售棒性和信噪比不高、定位不准确的问题,提出一种基于双混沌与双极性的双重水印算法.该算法在对小波包分析的基础上,依据奇异值的稳定性,对双混沌系统进行加密,构造出抗攻击性更强的零水印.通过对小波包分解的奇偶系数和之差采用双极性量化策略,使嵌入噪声分散到奇系数上,大幅提高信噪比.实验结果表明,该算法能有效抵抗各种常规攻击,区分常规攻击与恶意篡改,并能对恶意篡改进行定位.%Aiming at the problems of dual watermark algorithm, poor robustness, low signal to noise rate and inaccurate positioning, a novel dual watermark based on wavelet packet is presented. The robust watermark possesses is constructed by taking advantage of the stability of Singular Value Decomposition(SVD) and the security of chaotic system. A new bipolar quantization is used to enhance the sensibility of fragile watermark. The algorithm makes the watermark embedding noise attribute to the odd coefficients by quantizing the difference of the sum of the odd and the even coefficient, effectively improving signal to noise rate after embedding. Experimental results show that the robust watermark can provide high robustness to conventional attacks, and malicious tampering, it has good accuracy of tamper localization.