基于小波变换的数字水印技术研究

泉州师范学院毕业论文（设计）题目基于小波变换的数字水印技术研究物理与信息工程学院电子信息科学与技术专业07级1班学生姓名朱志攀学号070303033指导教师陈木生职称讲师完成日期2011年4月10日教务处制1基于小波变换的数字水印技术研究物理与信息工程学院电子信息科学与技术专业070303033朱志攀指导教师陈木生讲师【摘要】：随着网络与多媒体技术的发展，数字媒体作品版权的标识及保护问题越来越突出。数字水印技术通过将水印信息嵌入原始数据中来证明数字作品的版权，是解决这个问题的一种有效方法。本文提出一种基于小波变换的图像数字水印算法，通过将低频子图分块并量化其小波系数，实现水印的嵌入和提取，并对其进行抗噪声、JPEG压缩、旋转等实验。对于旋转攻击，该算法结合了图像的归一化技术。实验结果表明，该算法对常见图像处理和旋转都有较好的鲁棒性。【关键词】：数字水印；小波变换；鲁棒性；量化；抗旋转2目录第一章绪论··············································································································31.1研究背景············································································································31.2研究现状············································································································31.3研究意义············································································································4第二章数字水印技术简介·····························································································52.1数字水印的概念···································································································52.2数字水印的特点···································································································52.3数字水印的分类···································································································52.4数字水印系统······································································································62.5数字水印的性能评估·····························································································7第三章小波变换理论···································································································83.1小波分析基础······································································································83.2小波变换简介······································································································83.2.1离散小波变换·····························································································83.2.2小波域数字水印的优点·················································································9第四章本文数字水印技术的实现··················································································104.1水印的嵌入和提取······························································································104.1.1水印的嵌入过程························································································104.1.2水印的提取过程························································································114.1.3实验结果·································································································114.2抗攻击实验·······································································································124.2.1抗噪声实验······························································································124.2.2抗JPEG压缩实验······················································································124.2.3滤波实验·································································································134.2.4抗剪切实验······························································································144.2.5抗旋转实验······························································································15第五章结论·············································································································17参考文献··················································································································17致谢·····················································································································18英文翻译··················································································································193第一章绪论1.1研究背景随着网络和多媒体技术的发展,数字媒体逐渐被广泛应用，各种形式的多媒体数字作品如图像、视频、音频等纷纷以网络的形式发表。人们可以通过Internet发布自己的多媒体作品和进行网络交易等，但随之而来的问题是：任何人都可以通过网络很轻易地获取他人的原始作品，特别是数字化的图像、音频、视频等，盗用者不仅可以通过非法手段得到电子数据，而且可以不经过作者的同意而对原始作品进行复制、修改、生产和再传输等，这些不法行为严重侵犯了作者的版权，对版权所有者造成了巨大的经济损失，对信息安全造成巨大的冲击[1]。版权保护已经成为一个迫切需要解决的现实问题，媒体信息的数字化和网络化给版权保护带来了新的难度。传统的加解密系统已经不能有效地解决版权保护问题。因为，经过加密后只有被授权持有解密密钥的人才能够存取数据，这样自己的作品就无法向更多的人展示；而且数据一旦被解密，就完全处于解密人的控制之下，原创作者无法追踪作品的复制和再次传播。为了解决这一问题,仅仅依靠传统的加密技术已经远远的不能满足人们的要求了,而以将特定的数字标志信息隐藏在数字作品中为特征的数字水印技术却在此方面发挥了巨大的作用。作为信息隐藏技术的一个重要分支,数字水印技术可以说是信息时代特有的产物,正是由于数字作品的知识产权保护及其他一系列需求促使了数字水印的出现。数字水印技术被认为是解决网络化和数字化时代数字作品版权保护的一种有效方法。数字水印技术是将具有一定意义的标识信息嵌入原始的媒体数据中，这些信息就是水印信息，它与原始数据紧密结合，且随之一起被传输。在接收端，水印信息被提取出来，可用于广播监视、数字签名、数字指纹、内容认证和秘密通信等。因而数字水印被认为是抵抗多媒体盗版的“最后一道防线”[2]。在我国，现行的税务发票、增值税发票、伪造制假造成税款大量的流失。长期来，猖獗的伪造发票现象给国家造成了数目巨大的税款流失。因而从数字水印技术自身来讲，它具有巨大的经济价值和广泛的应用前景，已经成为了多媒体信号处理中的一个研究热点。1.2研究现状数字水印技术是当前多媒体信息安全研究领域发展较快的热点技术之一，它涉及了不同学科领域的理论和思想，如信号处理、编码理论和数字通信、算法设计等技术，还包括法律和公共策略等问题，有着良好的应用前景[3]。从1993年Caronni正式提出数字水印到现在的十几年时间里，它已经引起国内外很多公司、研究机构等的极大关注。在国外方面，《IEEE会报》、《IEEE图像处理》、《IEEE消费电子学》、《IEEE通信选题》等很多国际著名的期刊都组织了数字水印的专题新闻报道或技术专刊。在1999年第三届信息隐藏国际学术研讨会上，数字水印成为主要焦点，全部33篇文章中有18篇是关于数字水印的研究。以麻省理工学院媒体实验室为代表的一批美国研究机构及企业已经申请了数字水印方面的专利。美国版权保护技术组织（CPTWG）也成立了专门的数据隐藏小组（DHSG）用于制定版权保护水印的技术标准。目前，已支持或开展数字水印技术研究的机构不仅有政府部门，也有知名企业和大学，它们包括美国财政部、美国空军研究院、美国版权工作组