摘要随着计算机技术和网络技术的迅速发展，数字多媒体信息在变得更容易获得的同时也更容易遭受非法复制、伪造、篡改、侵权等攻击，而传统的基于密码学的安全措施对这些攻击显得力不从心，出于对数字产品本身以及其原有者利益的保护，人们提出了一种实现版权保护的有效方法——数字水印技术。本文分析讨论了数字水印技术的基本原理、典型算法及数字水印的攻击方法，提出了一种基于离散小波变换的数字水印算法。该算法实现了基于小波变换的盲数字水印的嵌入和提取，提高了水印的安全性；将水印嵌入到原始图像离散小波变换的低频子带中，保证了算法的鲁棒性；利用人类视觉系统确定水印的嵌入强度，提高了水印的不可感知性。并在Matlab的环境下对该算法进行了实验。实验结果表明该算法对滤波、EG2000压缩等攻击手段具有较强的鲁棒性。24202
毕业论文关键词 数字水印系统；版权保护；离散小波变换；嵌入和提取
Image digital watermarking algorithms based on wavelet transform
ABSTRACT
With the rapid development of computer and network technology, the digital multimedia information is becoming more easily to acquire. However, illegal users can also easily access, duplicate and spread them. It becomes difficult for conventional safety measures which based on the cryptology to protect the digital product security as well as the owner’s benefits. So an effectual solution to copyrights protection has been developed——the technology of Digital Watermarking. At first the princip1e, typical algorithms and attack analysis of digital watermark is described. Then, a watermarking algorithm based on DWT is proposed. The watermark image is scrambled by a generalized Arnold transform so as to improve the security of the watermark; the watermark is embedded into the middle-frequency subband which guarantees the robustness of the algorithm. we have had a experiment on the algorithms in the environment of Matlab. The result of the experiment shows this algorithms has great robustness to attack means of the filter, compressed EG2000.
Keywords The system of the Digital Watermarking; Copyrights Protection ; DWT; Embedding and extracting
目 录
1 绪论 1
1.1 研究背景 1
1.2 研究目标及意义 1
1.2.1 研究目标 1
1.2.2 研究意义 2
1.3 研究现状 2
1.3.1 空间域水印 3
1.3.2 变换域水印 3
2 数字水印技术 5
2.1 数字水印简介 5
2.2 数字水印应用 6
2.3 数字水印条件 8
2.4 数字水印嵌入与提取 9
2.5 数字水印攻击算法 11
3 小波变换 13
3.1 连续小波变换理论 13
3.2 离散小波变换算法 14
3.3 图像小波分解 15
4 基于小波变换的盲数字水印的嵌入和提取算法研究 18
4.1 水印生成 18
4.1.1 水印选择 18
4.1.2 水印预处理 18
4.2 小波分解 19
4.3 水印嵌入提取 20
4.3.1水印嵌入 20
4.3.2 水印提取过程 21
4.4 水印评测 21
4.4.1 不可感知性 21
4.4.2 鲁棒性 22
5 Matlab仿真实验 24
5.1 Matlab简介 24
5.1.1 Matlab优点 24
5.1.2 Matlab函数 24 基于数字图像水印技术应用研究:http://www.youerw.com/tongxin/lunwen_17598.html