基于混沌系统与跳频技术的数字水印方法研究

【作者】 王朋飞；

【导师】 冯桂；

【作者基本信息】 华侨大学 ， 计算机应用技术， 2006， 硕士

【摘要】 多媒体和网络通信技术的迅猛发展为多媒体信息的处理、发布和存储提供了极大便利,同时也给网络普及带来负面影响,如盗版侵权行为等数字信息安全问题。数字水印技术的出现,为解决这些问题提供了新方法,它能确定多媒体信息的来源、作者、所有者、发布者、合法使用者或数据完整性等。本文就数字水印技术的一些关键问题进行研究,设计了新算法并给出相应的实验结果和分析。论文首先对数字水印技术的基本概念和理论进行梳理和总结。为解决水印信息加密问题,我们在第三章提出混沌有序化算子方法,设计了水印信息加密的置乱模块和替代模块;还给出了空间域和变换域数字图像加密算法,密文图像可以经过有损压缩再传输,经过解密得到低失真的明文图像。实验结果和分析表明所提加密方法安全高效。第四章根据直流和交流信号的合成和分离方法,探索了一条频率域鲁棒性水印的新思路。在载体DCT域的中频系数中建立近似直流信号,把水印图像置乱并调制成交流信号,水印的嵌入和检测过程转化为直流和交流信号的合成和分离过程。实验结果和分析表明,所提水印算法具有嵌入水印信息量大、鲁棒性强等优点。第五章借鉴跳频思想提出了虚拟通道技术,并据此设计了一种在载体中嵌入灰度图像作为水印的算法。通过修改载体频率域系数,载体通道可被看成虚拟水印通道,它由若干个缺损的水印子通道构成。水印提取既不需要原始载体也不需要原始水印参与。实验结果和分析表明嵌入的水印具备很好的不可见性和鲁棒性。论文最后对科研工作进行总结,并对水印技术进行展望。更多还原

【Abstract】 The rapid growth of multimedia manipulation tools and network access leads to convenience of multimedia information processing, distribution and storage. At the same time, multimedia information security problems including copyrights piracy emerge as side effects of the popularity of digital representation and distribution over network. Digital watermarking has been demonstrated to be very effective in identifying the source, creator, owner, distributor, authorized consumer, or integrity of a media document (usually an image). In this dissertation, several important problems about digital watermarking are studied. Novel algorithms are proposed and the experimental results are given.The background and overview of digital watermarking are introduced in chapter 1 and chapter 2.To solve the problem of watermark encryption, a novel permutation operator is proposed, based on which the permutation scheme and the substitution scheme for watermark encryption are designed; Encryption algorithms in spatial domain and transform domain are proposed. The ciphered image can be JPEG compressed before it is transmitted, and low-distortion plain image can be obtained after decrypting the compressed encryption image. Experimental results and analysis demonstrate that the algorithms are of favorable security and efficiency.A novel digital watermarking scheme based on synthesis and separation method of direct and alternating signal is proposed in chapter 4. A direct signal is founded in host image in DCT domain, and the modulated watermark is regarded as alternating signal, so watermark embedding and extracting are similar with direct and alternating signal synthesizing and separating. Experimental results show that embedded watermark has a certain capacity and robustness.A virtual channel technique, which is based on frequency hopping technique, is proposed in chapter 5. A novel blind watermarking algorithm based on virtual channel technique is designed, by which a gray-scale image is embedded into host更多还原