基于水印的图像/视频内容安全方法研究

【作者】 牛晓莉；

【导师】 刘琚；

【作者基本信息】 山东大学 ， 通信与信息系统， 2007， 硕士

【摘要】 随着信息科技的迅速发展，人们的日常生活与工作也越来越趋向于数字化和网络化。然而，这在方便了合法使用者的同时，也为出于不同目的的盗版或侵犯生产者和消费者合法权益的非法存取、复制、篡改和传播等侵权行为提供了方便，这就使得数字产品的版权问题成为了亟待解决的问题。数字水印技术就在这种背景下应运而生，并成为当前进行数字产品版权保护的主要方法。数字水印技术就是通过一定的算法将版权信息嵌入到被保护的数字载体信号(如图像、音频、视频等)中来证明版权归属或侵权行为的技术，它已经成为多媒体信号处理领域中的一个研究热点。数字水印技术的研究和应用对版权保护、数据认证和完整性检验、使用控制、广播监控、用户跟踪等方面都有非常重要的理论意义和应用价值。按照不同的分类标准，数字水印可以分为可见水印／不可见水印，图像水印／视频水印等。针对上述内容，本论文从三个方面开展研究，主要成果有包括：1．针对拷贝攻击的水印研究拷贝攻击是指将水印从一件合法作品获得水印并复制到另一件非法作品当中。本文结合数字水印和数字签名，提出了一种基于数字签名机制的水印方案。该水印方案由于引入了表征图像信息的数字签名，可以有效地抵抗拷贝攻击。仿真结果表明了该水印方案的鲁棒性，尤其是对拷贝攻击具备抵抗能力。独立分量分析(Independent Component Analysis，ICA)技术源自著名的“鸡尾酒会”问题，它可以对由独立源信号混叠而成的观测信号进行有效盲分离。同时，该技术成功到地应用到图像特征的提取。本文提出基于ICA技术的数字签名算法，相对于现有算法能够更好地唯一表征图像，进而提高了水印方案的可靠性。2．针对可见水印去除攻击的解决方案研究可见水印具备可以直观表示版权信息的特点，但由于其直观性更容易成为攻击的目标。去除攻击是可见水印面临的主要问题，受到去除攻击的作品无法确认版权，甚至为进一步实施水印的非授权嵌入提供可乘之机。本文针对去除攻击，从不同角度出发，提出了三种利用不可见水印保护可见水印的方案，并对其优劣势进行了对比分析。该领域的研究工作为以后水印技术在此领域的研究打下一定的基础。3．基于H.264标准的视频水印研究在分析总结了现有视频水印算法，特别是基于H.264标准的视频水印算法的基础上，对基于H.264的压缩域数字水印算法进行了改进。通过仿真，实现在H.264视频中嵌入水印和提取水印的过程，证明了算法的有效性，并为今后所在的实验组在H.264视频水印方面的研究打下一定基础。数字水印的研究历史不过短短十几年，但仍有许多问题需要并值得继续进行探索和研究。论文最后对该领域的发展趋势进行了展望。更多还原

【Abstract】 With the rapid development of information technology, our daily life is becoming digitalized and network-connected. It is convenient for the legal customers, whereas it provides the chance to pirates to infringe the copyright for various illegal purposes. That makes copyright protection an urgent issue to be resolved. The technique of digital watermark is being developed under this circumstance, and has been the main method of multimedia copyright protection. Digital watermarking is to embed the copyright information, according to some particular algorithm, into digital host signal, such as image, audio, video and so on. Digital watermarking is used to authenticate the copyright, which is the focus in the field of multimedia signal processing. The research and application of digital watermark will be of great value both in theory and application for copyright protection, integrity authentication, access control, broadcast monitoring, customers tracking and the like.According to different standards, digital watermark is classified in to different categories: visible watermark/ invisible watermark, image watermark/ video watermark and so on. This thesis related these points and the main contribution includes the following parts:1. Research on copy attack resisted watermarkIn some situation, the watermark of a legal marked image may be maliciously embedded in another illegal non-marked image. This is called copy attack which can create the false positive problem and ownership ambiguity. Through analyzing digital watermark and digital signature, a novel invisible watermarking method with image signature is proposed. For digital signature which can identify different images was involved, this method can resist copy attack. The simulations show the robustness of this method.Independent component analysis (ICA) stems from the famous "Cocktail Party" problem, which can separate the observation signals mixed by some mutually independent source signals blindly and effectively. Furthermore, it has been used successfully to extract the image features. In this thesis, a digital signature algorithm based on ICA which can describe the image uniquely is proposed. The simulations show that the image signature calculated by our algorithm is better for identifying different images than the current algorithms, which benefits the watermark method.2. Research on removing attack resisted watermark methodVisible watermark is good at proving the ownership of copyrighted digital products directly. The main problem that challenges the visible watermark is removal attack.To solve this problem, three kinds of schemes utilizing invisible watermark to protect visible watermark are proposed from different points of view. Moreover, these schemes are analyzed and compared, which is useful for further research in this field.3. Research on H.264 standard based watermarkPrevious video watermark methods are summarized in this section, especially the H.264 standard based video watermark. A H.264 standard based compressed video watermark method is proposed. The simulations demonstrate the validity which builds foundation of our team’s research on H.264.The research history of digital watermarking is no more than two decades, but it is still in an underway phase. Consequently, there are still many issues which are worthwhile to be discussed and studied. At the last part of this thesis, the development trends and prospects of this field are proposed and analyzed.更多还原