三维几何模型数字水印技术及算法研究

【作者】 周昕；

【导师】 石教英；

【作者基本信息】 浙江大学 ， 计算机系统结构， 2002， 硕士

【摘要】 多媒体数据的数字化为多媒体信息的存取、处理和传播提供了极大的便利，也极大的提高了信息表达的效率和准确性。但是一个明显的副作用是：多媒体数据的非法传播和拷贝非常容易，而且质量不受损害。在当今这个信息时代，对于多媒体作品的创作者、发行人和版权持有人来说，知识产权保护已成为一项最为紧迫的任务。起源于信息隐藏技术的数字水印技术，为实现有效的知识产权保护提供了一条崭新的思路，近年来已成为多媒体信息安全研究领域的一个热点问题。 当前的数字水印技术大都是针对静止图象，视频流和音频流这些媒体数据类型的，而对三维几何模型数据的水印技术的研究工作相对较少。但是，随着越来越多的基于CAD的三维数据在互联网上的传播，对于那些在虚拟网络中提交或出售三维数据产品的公司或版权所有人来说也将同样面临一些与版权相关的问题。他们迫切需要一种能够防止未经授权而非法使用他们的数据材料的方法。数字水印技术，这种新型的信息版权保护手段在这个领域具有广泛的应用前景。 本文第一章介绍了信息隐藏和数字水印技术的基础概念，简单介绍了图象数字水印的一些基本概念，重点阐述了三维几何模型数字水印的定义、产生背景、主要分类和基本要求，并给出了一个三维几何模型数字水印系统的基本工作流程。对现有的一些典型的三维几何模型数字水印算法做了分析，分别指出了各算法的优势和不足之处。对三维几何模型数字水印的攻击方法做了分类和讨论。给出了对三维几何模型数字水印技术将来研究方向的讨论。最后给出全文的大纲。 第二章阐述了三维几何模型数字信号处理的思想，介绍了三维几何模型数字信号处理的背景和一些相关工作。通过为任意网格构造一个全局平面参数化，数字图像水印的所有算法都可以应用到三维模型，这种方法基本解决了三维几何模型数字水印的难点和问题。本文后续章节介绍的各种水印算法都是基于这种平面参数化方法。 第三章介绍了DCT数字水印技术的背景和相关工作，采用本文第二章提出的平面参数化方法，分别给出了NEC实验室的COX等人［Cox971］、Piva［Piva98］等人和Fotopoulos等人［FotopoulosOO］提出的图象DCT水印算法在三维几何模型上的应用模型。实验表明这些算法具有较好的透明性和强壮性。 第四章介绍了DWT数字水印技术的背景和相关工作，采用本文第二章提出的平面参数化方法，分别给出了Wang［Wang98］和Xia［Xia98］提出的图象DWT水印算法在三维几何模型上的应用模型。 第五章总结全文，并给出了将来的一些研究方向。更多还原

【Abstract】 Digitized multimedia data facilitate the processing, distribution and storage of multimedia information, enhance the efficiency and accuracy of information presentation. But the undesirable side effects are obvious: the unauthorized redistribution of the copyrighted multimedia data without loss of fidelity. Intellectual property protection is one of the most pressing concerns for content creators and owners who distribute and deliver their content in the Information Era. Digital watermarking, which originates from steganography, provides a novel way for the protection of intellectual property rights, and becomes a hot spot in the research field of multimedia data security in recent years. Current watermarking technology focuses on media types like still images, and video and audio streams. In contrast, the problem of watermarking 3D models has received less attention from researchers. But, more and more CAD-based 3D data is entering the World Wide Web. Accordingly, companies or copyright owners who present or sell their products in virtual space will face copyright-related problems. The straightforward demand is to prevent their 3D-based material from unauthorized use. As a new way for the protection of information copyright, digital watermarking will possess extensive application perspective in this area. In Chapter 1, we first describe the basic concepts of Steganography and digital watermarking, and introduce some basic concepts of digital image watennarking. Then we expound the definition, background, classification and requirements about digital watermarking of 3D models. We propose a general framework of digital watermarking system of 3D models. Then, we analyze the state of art of digital watermarking algorithms of 3D models. Following this, we give a discussion about the robustness of watermarks, i.e., attack analysis. We still discuss some possible research directions. We also briefly introduce some programming environments and software toolkits involved in our thesis. Finally, we outline the thesis. In Chapter 2, we present the idea of mesh watermarking based on digital geometry processing (DGP). We first introduce the background of DGP and some related work. By constructing planar parameterization for arbitrary meshes, all kinds of image frequency-domain watermarking algorithms can be applied to 3D models. The algorithms described in the following chapters are all based on this parameterization algorithm. In Chapter 3, we first introduce the background and related work of DCr-based digital watermarking algorithms. Then we apply the image D(T-based watermarking algorithms, which had been presented by Cox, Piva and Fotopoulos, to 3D models. Experimental results and attack analysis show that these algorithms are transparent, robust, accurate and cost-efficient. In Chapter 4, we first introduce the background and related work about DWT-based digital watermarking technology. Then we apply the image DWT-based watermarking algorithms, which had been presented by Wang and Xia, to 3D models. Experimental results and attack analysis are given. In Chapter 5, we conclude the thesis, together with some possible research directions in the future.更多还原