数字音频水印技术研究

1.1 问题的提出及研究意义 ........................................................................................................... 1 1.2 数字水印技术研究现状 ........................................................................................................... 1 1.3 本文主要研究内容及章节安排 ............................................................................................... 2
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重庆大学硕士学位论文
英文摘要
pretreatment of the watermarking information in order to lower the bit error rate and improve the robustness. The proposed algorithm embeds the watermarking information in the absolute mean of low frequency sub-band coefficients in order to get a strong robustness because the mean of signal is not sensitive to de-synchronization attacks. The extraction of the watermarking is blind. Experimental results show that the scheme not only can resist the common signal processing attacks better but also has a strong robustness to common de-synchronization attacks. Keywords：Audio watermarking， DWT， Imperceptibility， Robustness， Blind extraction
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重庆大学硕士学位论文
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中文摘要..........................................................................................................................................I 英文摘要........................................................................................................................................ II 1 绪论............................................................................................................................................... 1
Supervisor: Ass. Prof. Zhu Binglian Major: Signal and Information Processing
College of Communication Engineering of Chongqing University , Chongqing, China
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重庆大学硕士学位论文
英文摘要
ABSTRACT
In recent years, the rapid development of computer and Internet technology has changed our life a lot. It is beneficial for us to access or spread the digital multimedia works via the Internet and rework them easily with all kinds of software, which brings the problem of security and ownership protection. As a new and effective solution, digital watermarking is widely attention-getting. Digital watermarking is a branch of data hiding, which protects digital works by embedding unperceivable and secret information into the works and then extracting the information according to given algorithms. Generally, imperceptibility, robustness and security are the three basic characters of watermarking. Many researches are carried on to optimize these characters now. Image and video watermarking technologies have been carried on widely in recent years. As a new technology, audio watermarking is becoming a hot topic gradually because of its application perspective. The development, status, basic principle and framework of digital watermarking are summarized in this thesis. Then the basic system, applications, classifications and metewand of audio watermarking are introduced. The thesis also summarizes the existing audio watermarking and attacking algorithms. Then based the previous works, research work on audio watermarking based on DWT are carried on, aiming at the improvement of the imperceptibility and robustness of the blind watermarking algorithms: ① Considering the character of human audio system, this thesis proposes a blind audio watermarking algorithm in wavelet domain based on Toral scramble and masking effect. Pretreatment to the watermarking image with Toral transform is given first. Initial audio information should be transformed by DWT, then the watermarking information are embedded according to the rule based on non-simultaneous masking effect. Experimental results show that the proposed algorithm has a good imperceptibility and it is a blind watermarking. The algorithm is robust to most common signal processing attacks, but weak at resisting de-synchronization attacks. ② Because most audio watermarking algorithms presented in DWT domain are not obvious to resist de-synchronization attacks, according to the improvement upon the first algorithm, another blind watermarking algorithm which is effective to resist de-synchronization attacks is proposed. The error-correcting is applied to the
April 2008
重庆大学硕士学位Βιβλιοθήκη Baidu文
中文摘要
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近年来，计算机和网络技术的飞速发展给我们的生活带来了巨大的变化。通 过网络我们可以轻松的获取和传播多媒体数字作品，并利用各种软件对其进行再 加工。在我们获得便利的同时，数字作品的安全性及版权保护问题也随之产生。 数字水印作为一种新颖的版权保护手段，在近年来得到了广泛的关注。数字 水印技术是信息隐藏技术的一个分支，它是在不影响原始作品质量的前提下，依 据某种特定的算法将秘密信息添加到作品中，并检测或提取水印，以达到保护作 品产权的目的。鲁棒性、不可感知性和安全性是数字水印的三个基本特征，目前 的研究也大都是针对这几个基本特征的优化来开展的。近年来，图像水印和视频 水印的研究已经广泛的开展起来，由于音频水印具有很好的应用前景，对它的研 究也正逐渐成为热点。 本文首先综述了数字水印技术的发展和研究现状，基本原理以及框架。详细 介绍了数字音频水印的系统模型、应用领域、分类、评价标准，并对现有的音频 水印算法以及水印攻击算法进行了总结。在分析前人工作后，本文针对小波域的 音频水印进行了研究，提出两种盲检测水印算法,分别对水印的不可感知性和鲁棒 性进行了改善： ① 提出了一种基于 HAS 掩蔽特性和图像置乱的小波域盲检测音频水印算法。 该算法首先对水印图像进行 Toral 置乱的预处理，再对原始音频信号进行离散小波 变换，根据人类听觉系统的时域掩蔽效应进行水印信息的嵌入。实验结果表明， 该算法具有很好的不可感知性，并实现了盲检测。对于常见的信号处理有比较好 的鲁棒性，但抵抗同步攻击的能力还需要改进。 ② 针对小波域水印算法普遍不能很好的抵抗同步攻击的问题，对前一章的算 法进行改进，提出了一种基于小波域的抗同步攻击音频水印算法。水印信息预处 理部分加入纠错编码以降低检测误码率，提高水印鲁棒性；在水印嵌入点的选择 上，算法考虑到信号的均值对同步攻击不敏感这一特点，将水印嵌入到小波系数 低频近似分量的绝对均值当中以增强水印抗同步攻击的能力。水印检测过程实现 盲检测。实验结果表明，该水印算法不仅对普通信号处理攻击的抵抗能力更强， 而且对于常见的同步攻击，也有很好的鲁棒性。 关键词：音频水印，离散小波变换，不可感知性，鲁棒性，盲检测
数字音频水印技术研究
重庆大学硕士学位论文
学生姓名：吴
迪 副教授
指导教师：朱冰莲 专
业：信号与信息处理
学科门类：工学
重庆大学通信工程学院
二 OO 八年四月
Study on Technology of Digital Audio Watermarking
A Thesis Submitted to Chongqing University in Partial Fulfillment of the Requirement for the Degree of Master of Engineering by Wu Di