【作者】 卢毅；

【导师】 曾洁； 贾世杰；

【作者基本信息】 大连交通大学 ， 交通信息工程及控制， 2008， 硕士

【摘要】 随着计算机网络的快速发展,网络上传输的信息模式发生了翻天覆地的变化,信息的交流变得更加快捷,形式也呈现多样化。尤其是数字图像形式的传播也变得越来越普遍。由于数字内容很容易复制、修改,网络上传播的数字内容存在着大量的盗版和侵权问题,因此对知识产权的保护越来越引起重视。数字水印作为信息安全领域的一门新兴学科,己经引起了人们的极大关注。作为信息隐藏技术在计算机领域的一项重要应用,数字水印为保护多媒体信息的版权及信息的合法使用提供了一种新的解决思路。将水印嵌入到数字化媒体中,然后通过对水印的检测和提取来对数字产品的使用情况进行跟踪,从而实现隐藏传输、秘密存储、版权保护等功能。小波分析由于具有多分辨率和多尺度分析特性,在图像处理方面得到了广泛应用。利用小波分析可以更好地控制水印信息在图像中的分布,从而协调解决稳健性和不可见性之间的矛盾。本文以静止图像作为研究对象,首先阐述了图像数字水印的基本原理和特征,介绍了数字水印的常见算法及图像数字水印评估方法,同时介绍了小波分析的基础理论及其在图像数字水印中的应用与发展前景。通过对水印信号的选择,小波基、分解级数和小波系数选择的确定及人类视觉掩蔽特性的利用等几个重要问题的分析,为了解决水印鲁棒性和不可见性的矛盾问题,提出了基于小波变换自适应图像数字水印算法。并通过剪切、加噪、滤波、锐化、模糊等几种攻击对该算法进行了测试与性能评估,实验结果表明该算法对一般攻击与图像处理具有较强的的鲁棒性。最后,总结了研究结果并对数字水印的进一步发展进行了展望。更多还原

【Abstract】 With the rapid development of computer networks, the information transmission model has undergone enormous changes, the exchange of information has become more efficient and the form of information has been diversified. Especially, the form of digital image transmission is becoming more prevalent. As digital information can be copied and modified easily, there are a large number of infringement and piracy issues in the network transmission of digital content. Consequently more and more attention has been paid to the protection of intellectual property rights. Digital watermarking as a new information security has attracted people’s attention. As one of the important applications of information hiding technology in the computer field, digital watermarking provides a new solution to protect the copyright of multimedia information, and the legitimate use of information. It embeds watermarks into digital multimedia, then by the detection and extraction of watermark to track the use of digital products, thus carries out the functions such as hidden transmission, secret storing, copyright protection.Wavelet analysis has been widely used in image processing due to its multiresolution and multiscale analysis characteristics. In addition, using wavelet analysis can better control the distribution of watermark information in an image, thus resolve the contradiction between robustness and imperceptibility harmoniously.This thesis takes still images as example, firstly expounds basic theory and character of image digital watermarking, and introducts the common algorithms and performance evaluation methods of watermarking, at the same time introduces the basic theory of wavelet analysis and its applications and development prospects in image digital watermarking. By the selection of watermark signal, choosing of wavelet bases, decomposing level and wavelet coefficients, and the use of human visual system(HVS). To solve the contradiction between robustness and imperceptibility of watermarking, an algorithm based on adaptive wavelet digital image watermarking is proposed. The algorithm is tested and capability evaluated through several attacks ,such as cutting, adding noise, filtering, sharpening, fuzzy, the results show that the algorithm has highly robustness to resist general attack and image processing.Finally, the findings have been summarized and the further development of the digital watermarking has been predicted.更多还原