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论文独创性声明
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论文作者（签名）： 20 年 月 日
摘 要
随着计算机网络的迅速发展，包括数字图像在内的数字媒体得到了广泛的应用，数字媒体的数据逐渐成为人们获取信息的重要来源，但随之而来出现了一系列如随意复制、编辑、非法传播数字图像的信息安全问题，数字媒体的版权保护问题变的日益突出，数字图像水印技术由此应用而生，已成为信息安全领域的一个研究热点。
本文比较系统地研究了数字水印技术在静止图像中的应用问题。首先介绍了数字水印技术的发展背景，然后对数字水印的原理、特点、分类、典型算法、应用领域以及评价标准等等进行了简要的分析。其次，本文主要是针对目前现有数字图像水印算法实现过程比较复杂，其中重点讨论关于DCT的数字图像水印技术的嵌入，提取和水印的攻击测试等。最后对数字图像水印的特征进行分析总结。最终通过Matlab这一工具来实现其具体的过程。通过实验对比分析得到该种算法具有一定的可行性以及较好的鲁棒性。
关键词：数字图像水印，信息安全，DCT算法，Matlab.
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Abstract
With the rapid development of computer network, digital media, including digital image has been widely used, digital media data gradually become an important source of obtaining information, but there's a series of such as free to copy, edit, illegal dissemination of digital image information security, copyright protection of digital media has become increasingly outstanding, digital image watermarking technology and the application, has become a research hotspot in the field of information security.
This paper systematically studies the problems of the application of digital watermarking in still images. It first introduces the development background of digital watermarking, then the principle, characteristics, classification, application of digital watermarking field of typical algorithms, as well as the evaluation criteria and so on were analyzed briefly.Secondly, this paper is mainly aimed at the existing digital image watermarking algorithm is a complicated process, which focused on the digital image watermarking technology about DCT embedding, extraction, as well as the watermark attack test etc.. Finally on the digital image watermarking characteristics were analyzed and summarized. Finally through the tool of Matlab to realize the specific process. Through comparative analysis of the experiment of the algorithm is feasible,and better robustness.
Key words: Digital image watermarking, Information security, DCT algorithm, Matlab.
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目 录
1 绪论 ........................................................................................................................................................... 1 2 数字图像水印技术 ............................................................................................................................ 3 2.1数字图像水印技术的历史及国内外发展现状 ................................................................... 3 2.2数字图像水印的分类和基本特征 ........................................................................................... 6 2.3数字图像水印的一般模型 ......................................................................................................... 7 2.4数字图像水印的常见算法 ......................................................................................................... 8 2.5数字图像水印技术的应用 ....................................................................................................... 11 3 MATLAB简介 ........................................................................................................................................ 14 3.1 MATLAB简介 ................................................................................................................................ 14 3.2 MATLAB在数字图像水印中的应用 ..................................................................................... 14 3.2.1数字图像水印技术 ............................................................................................................. 15 3.2.2图像分析处理 ....................................................................................................................... 15 3.3 在数字图像水印实现中主要函数 ....................................................................................... 16 3.3.1图像显示,读取和输出 ...................................................................................................... 16 3.3.2变换频函数 ........................................................................................................................... 16 3.3.3攻击函数 ................................................................................................................................ 16 3.3.4比较两图像相似度函数 ................................................................................................... 17 4 数字图像水印攻击分析和评价标准 ..................................................................................... 18 4.1 影响性能的因素 ........................................................................................................................ 18 4.2 数字图像水印的常见攻击 ..................................................................................................... 18
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5 数字图像水印的设计 .................................................................................................................... 21 5.1 离散余弦叶变换 ........................................................................................................................ 21 5.2 离散余弦变换水印嵌入算法及其框图 ............................................................................. 23 5.3 离散余弦变换水印提取算法及其框图 ............................................................................. 25 5.4 水印的攻击测试程序与结果 ................................................................................................ 28 5.4.1不同噪声攻击测试 ............................................................................................................. 28 5.4.2 JPEG压缩攻击测试 ........................................................................................................... 30 5.4.3 高斯低通滤波攻击 ............................................................................................................ 31 5.4.4 其他攻击测试 ...................................................................................................................... 31 5.5实验结果分析 ............................................................................................................................... 33 致 谢 ........................................................................................................................................................ 38 参考文献 .................................................................................................................................................... 39 附 录 ........................................................................................................................................................ 40
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