【作者】 徐育利；

【导师】 张帆；

【作者基本信息】 河南大学 ， 计算机应用技术， 2010， 硕士

【摘要】 信息技术与因特网的迅猛发展为多媒体信息的存取和交换提供了极大的便利,但同时数字化技术精确、廉价、大规模的复制功能和因特网在全球传播的巨大能力,为版权保护带来了极大的冲击。使数字产品很容易被篡改、非法传播、蓄意攻击。如何对版权进行保护已经引起了人们的极大关注。数字水印技术是进行版权保护的一种重要手段,成为信息安全领域的一个研究热点。本文主要研究了基于结构相似度的图像认证水印算法与基于Contourlet的数字水印算法。其中包括水印嵌入算法,水印的提取算法,以及水印的不可见性,和对含水印的图像做出的各种攻击,包括加噪声,剪切,从而对水印图像做出评价。1.HVS的主要功能是从视野中提取结构信息,结构相似性可以从高层次上模拟HVS的整体功能。本文利用对结构信息的度量可以作为图像感知的近似这一理论,结合人类视觉系统特点,提出了基于结构相似度的图像认证水印算法。该算法通过标出在原始图像中可修改的位置,对这些特定的位置加入水印。通过实验,验证了该算法更符合人类的视觉效果,水印信息不容易被察觉到。2.通过考虑到小波重要树的构成,利用Contourlet变换,根据Contourlet系数之间的父子关系,构造出Contourlet重要子树,将水印信息嵌入到Contourlet重要子树中。该算法通过设置阈值来选择重要系数。通过实验,验证了该算法的可行性。更多还原

【Abstract】 With the rapid development of information technology and internet, they provided immense facilitating to multimedia information access and exchange, but the digital technology has some features, such as accurate, low-priced, it is possible for the large-scale duplication at the same. It had a negative impact on copyright protection, because Digital products can easily be tampered with, illegal dissemination and deliberate attacks. How to protect copyright has attracted people’s great concern. The digital watermarking technique has been regarded as a promising way to protect the copyright of digital products. It becomes a hot spot in a research field of the information security.This paper proposes the digital watermarking algorithm based on SSIM and based Contourlet. They included the watermarking embedding and extraction algorithms, as well as the watermark invisibility and make a variety of attacks for the image after embedding watermarking, such as additive noise, filtering, shear and so on, thus give a result of the evaluation.The main function of HVS is highly adapted for extracting structural information from a scene; the structural similarity simulates the overall function of HVS from a high level, therefore this paper use that a measure of structural similarity can provide a good approximation to perceived image quality.According to this theory, and combined with human visual system features, in this paper, we proposed the digital watermarking algorithm for image authentication,which based on SSIM, this algorithm can embed watermarking in some particular locations by marked some palaces which can be changed in the original image. Experimental demonstrate the effectiveness of the proposed method.Trough considering the important wavelet tree structure, we use the Contourlet transform, and according to parent–child relationship in Contourlet coefficients, the important sub-tree based on controulet , which is formed .Embedding watermarking in the important sub-tree. This algorithm choose important coefficient through setting up threshold value. Experiment shows this algorithm of the feasibility.更多还原