毕业论文__基于离散小波变换的数字水印算法.doc

编号 本科生毕业设计（论文） 题目： 基于离散小波变换的数字水印算法 物联网工程 学院 电子信息工程专业 摘 要 随着网络通信的飞速的发展以及多媒体技术的广泛应用，数字产品版权的保护问题变得越来越重要。数字水印技术已成为解决数字多媒体版权问题的主要工具。目前基于小波域的算法有很多，有简单的直接在经过小波变换的分量中嵌入水印，有两域结合的水印算法等，其中基于小波变换(DWT)和奇异值分解(SVD)结合的算法可以充分利用DWT的多分辨率特性和SVD所固有的特征．小波变换的多分辨率特性可根据各自的重要程度对图像进行分级处理，奇异值分解的奇异值的稳健性是一种内蕴特性，都增强了水印的不可见性和鲁棒性． 本文分析讨论了数字水印技术的基本原理、典型算法几数字水印攻击方法，研究了一种基于离散小波变换的数字水印算法。该算法使用推广的Arnold变换对水印进行置乱，提高了水印的安全性；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；实现了树荫的忙提取，增强了算法的适用性。本文对所提出的算法进行了仿真实验，并进行了性能分析。 实验结果表明，本文所研究的算法具有良好的鲁棒性，同时也很好地保证了水印的不可感知性。 关键字：数字水印；离散小波变换；图像置乱；人类视觉特性 ABSTRACT With the rapid development of network communication and broad appkication of multimedia techniligy,copyright protection of digital median work is becoming more and more important.Digital watermarking is viewed as an effective tool for copyright protection of multimedia data. Now algorithms based on DWT have many, including embedding watermark directly after DWT,combining two domains and so on.The algorithms based on DWT and SVD can take full account of characteristic of the multi-resolution of DWT and inherent factors of SVD.The characteristic of the multi-resolution of DWT can process an iamge at rated according to their important points,and the values of SVD is very robust.All which enhance the invisibility and robustness. At first the principle,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;In order to implement the blind extraction,this paper improves an embedding algorithm based on HVS,which enhances the applicability of the algorithm.This paper tests the algorithm,and quantity of experiment data shows that algorithm has good robustness,and the imperceptibility of watermark can be guaranteed at the sam