鲁棒性音频水印算法的研究

单位代码： 10293
密
级：
硕 士 学 位 论 文
论文题目：
鲁棒性音频水印算法的研究
学 姓 导 学 研 科 究 专 方
号 名 师 业 向
1010010511 白树锋 邓立新 信号与信息处理 现代语音处理与通信技术 工学硕士 2013-02-26
申请学位类别 论文提交日期
Research on Robust Audio Watermarking Algorithms
摘要
近年来数字化产品版权问题日益突出，在这种情况下数字水印技术引起了信息安全领 域众多专家和学者的关注。其中音频在传输过程中会出现遭到篡改、非法复制等问题，而 数字水印技术可将标志性数字信息或者隐秘信息嵌入音频中，实现信息的隐藏或者版权认 证。本文着重音频水印的鲁棒性和不可感知性研究，首先设计了一种基于经典水印算法的 鲁棒性音频水印算法；其次利用所选音频的稳定特征，在音频载体不失真的情况下用不同 方法构造音频的特征信息序列，实现水印的零嵌入。本文主要研究工作和成果如下： （1） 设计了一种基于 BTC 编码的灰度图像嵌入音频的水印算法。 首先利用 BTC 编码对灰 度图像进行压缩以减轻对音频载体影响，然后对音频进行自适应分帧，同时为抵抗缩放攻 击对各分帧均值化， 再将 BTC 编码得到的二值图像以自适应量化的方式嵌入到音频载体的 变换域低频系数中，以达到能够抵抗多种常见攻击，并以较高的视觉效果实现版权认证功 能。 （2）设计了一种基于均值插值运算的音频零水印算法。该算法首先将原始音频三层小波 分解后的近似分量进行离散余弦变换，然后选择某些通过与原偶数点系数比较构造音频特征序列，最后将特征序列与版权 水印图像异或运算， 得到用于认证音频版权的水印信息。仿真显示该算法具备很好的鲁 棒性。 （3）针对前一种零水印算法抵抗部分攻击方式不是特别好的状况，在前人零水印的研究 基础上设计了一种 DCT 域的鲁棒音频零水印算法，利用直流分量大小不易改变的特点构 造特征序列。为降低水印提取误码率，对经混沌加密后的版权图像进行了 BCH 纠错编码。 仿真结果显示此零水印算法具备非常好的鲁棒性。
关键字：音频，数字水印，离散余弦变换，离散小波变换，零水印
I
Abstract
In recent years, digital product copyright issues have become increasing prominence so that digital watermarking technology has attracted the attention of many experts and scholars in this case .The thesis has researched mainly on the algorithms of audio digital watermarking. It analyzes the theory of audio watermarking and the characters of audio and implementations of common watermarking algorithms. From the point of improving the watermarking imperceptibility and robust, three digital audio watermarking algorithms are proposed based on the analysis and comparison of existing algorithms. The main research work are as follows: (1) An gray image embedded audio watermarking algorithm is proposed based on BTC. Firstly a gray image is compressed to reduce the impact on the audio carrier. Then the audio is sub-framed adaptively and averaged for each sub- frame so as to resist to scaling attacks. Secondly the binary image obtained by BTC is embedded into the low-frequency coefficients of the transform domain of audio carrier, with the purpose of resisting many common attacks and copyrighting authentication in high visual effects. (2) An audio zero-watermarking algorithm is proposed based on the mean value interpolation operation. Firstly the approximate component of three level wavelet decomposition of the original audio, then it be processed by discrete cosine transform. The DCT coefficients of even-numbered points in the selected number are applied mean interpolation operation to generate a new coefficient set, producing audio characteristic sequence with comparison with the original even point coefficient. Finally the characteristic sequence can do XOR with the copyright watermark image to get copyright information.The simulation results show that the algorithm has good robustness characteristic. (3) Considersing that zero-watermarking algorithm in chapter four is not in good condition on resisting to partical attacks, an robust audio zero-watermarking algorithm in DCT domain is improved. Audio characteristic sequence can be structured by the DC component set, because it is not easy to be changed. Applying the BCH coding technique to image of chaotic encryption can reduce the bit error rate under attack. The simulation results show that such a zero watermark algorithm has very good robustness characteristic. Key Words: audio; digital watermarking; discrete wavelet transform; discrete cosine transform; zero-watermarking.
Thesis Submitted to Nanjing University of Posts and Telecommunications for the Degree of Master of Engineering
By Shu-feng Bai Supervisor: Prof. Li-xin Deng February 2013
II
目录
摘要 ....................................................................................................................................................................... I Abstract ................................................................................................................................................................ II 目录 .................................................................................................................................................................... III 第一章 绪论 ........................................................................................................................................................ 1 1.1 引言 ............................................................................