基于Contourlet变换和奇异值分解的图像零水印算法研究【毕业论文】.doc

- PAGE I - 本科毕业设计 （20 届） 基于Contourlet变换和奇异值分解的图像零水印算法研究 所在学院 专业班级 电子信息科学与技术 学生姓名 学号 指导教师 职称 完成日期 年 月 PAGE I 摘　要 【摘要】随着计算机网络技术的发展，信息安全问题日益凸显出来。水印技术作为数字媒体数据保护的一种技术，成为信息隐藏技术的一种重要研究分支，为实现有效的信息版权保护提供了一种重要的手段。然而，传统的数字水印算法是通过对原始媒体数据的修改来实现水印的嵌入，因此不可避免地存着着对原始媒体质量的破坏，而零水印技术的出现很好的解决了这一问题，成为当今水印技术的研究热点。 本文在对一般数字水印原理的简单阐述之后，提出一种基于 Contourlet变换和奇异值分解的数字图像零水印算法。首先图像经过 Contourlet变换分解为一系列局部化、方向性、多尺度的子带图像，然后使用奇异值分解对其低频子带进行分块，根据每块中第一个奇异值的大小特性“嵌入”和“提取”水印。仿真结果显示：本文提出的零水印算法不但保证了水印图像质量的无失真，而且能够较好地抵抗叠加噪声、JPEG有损压缩、剪裁等攻击，具有较强的鲁棒性。 【关键词】零水印；Contourlet变换；奇异值；数字图像。 Abstract 【ABSTRACT】With the development of computer network technology, information security issues become increasingly prominent. As a technology protection of the original data, the watermarking technology has become an important research branch of information hiding, and provided an important tool for the realization of an effective copyright protection. However, the traditional digital watermarking algorithm is based on the modifying of original data to realize the watermark embedding. Thus, there exists the degradation of the original media quality. The appearance of zero-watermark technology can solve the problem well，and becomes a research hot. In this paper, a digital image zero-watermarking algorithm based on the Contourlet transform and singular value decomposition is proposed on the basis of introducing the general principles of digital watermarking technology. First, the image is decomposed into a series of Contourlet transform localization, directional, and multi-scale sub-band image, and then the singular value decomposition is used to divide the low-frequency sub-band into blocks. Finally, the embedding and extraction of zero-watermark is realized according to the first singular value of the each block. Simulation results show that the proposed zero-watermarking algorithm not only ensures the watermarked i