一种基于奇异值分解的数字水印算法

数字水印的出现为版权保护提供了一种新的解决途径。提出了基于奇异值分解(Singular Valuc Dccomposition)的数字水印算法。图像奇异值分解(SVD)有以下性质：分解后图像矩阵的奇异值集中反映了图像的“亮度”(能量)特性，而对应的奇异矩阵只反映了图像的“几何”特性。因而奇异值的细微变化不会影响图像的视觉效果。对图像分块并做奇异值分解，在奇异值域做数学变换以嵌入lbit的二值水印信息。该算法不同于别的算法的一个优点是：水印的提取是“盲提取”，即水印的提取不需要原图像参与。     

水印纠错编码中的最大后验概率译码

文章考虑了BCH码和重复码的级联编码,并且基于最大后验概率准则,提出了一种软判决解码方法,以及快速解码算法并分析了该快速算法的性能,实验结果表明了该算法的正确性.     

A Novel Blind Video Watermarking Scheme Based on Independent Dynamic Component

Video copyright protection has become important as it is possible to make unlimited copies of digital video without quality loss. Video watermark is the main method of video copyright protection. A novel blind video watermarking scheme is proposed in this paper, in which independent component analysis (ICA) is used to extract the common static component and relative dynamic component from the consecutive frames. And then a designed watermark is embedded into the wavelet coefficients of the obtained dynamic component according to the 4-neighboring-mean based algorithm. The binarization of the 3-level-approximate sub-image of the I-frame in each GOP (GOP-Group of Picture) is selected as the watermark for this GOP. Given such watermark, the scheme can easily resist copy attack and temporal synchronization. Besides, because the watermarks of different GOPs and their embedding positions in a GOP are different, the intra-video collusion attack can be resisted effectively and there is no possibility for inter-video collusion attack to succeed. The simulation shows the feasibility of this scheme, which can resist well temporal synchronization, copy attack, and collusion attack. Published online: February 2006     

一种互补的栅格数字地图水印算法

针对栅格数字地图的版权保护，提出一种互补的栅格数字地图水印算法.该算法利用栅格地图相比自然图像具有较高亮度，直流分量变化比较大的特点，分别将水印嵌入到地图离散余弦变换后的直流分量和高频分量.直流分量部分依据亮度控制调制幅值嵌入水印，高频部分依据高频系数分段求和的奇偶性嵌入水印.在依据几何特征对地图预校准后，按嵌入的逆过程分别提取水印，并在合成系数控制下合成水印信息.实验结果表明，所提出的互补水印算法能够抵抗各种常见的恶意攻击，具有较强的鲁棒性     

A primer on software piracy cases in the courts

As with much technological change, the law and judicial system have lagged behind in adapting to the changing world of computer and software development. Changes in software development have created new classes of criminals and contract violators, and new theories and techniques to catch them. This paper discusses the fate of one breed of computer criminal, the software pirate, before the courts.Software piracy is a relatively recent type of computer crime because software development or engineering is no longer a custom design operation for particular organizations on particular computers. Software is now being produced for mass consumption and the ‘generic’ software package is not far off. Software packages may be very valuable even though they may be stored in a compact place, (like jewelry or money) such as on a microprocessor chip or a floppy disk. Software packages may vary in price from tens of dollars to millions of dollors. As with the related and booming practice of video disk piracy, it is often easy to make multiple copies of software for a miniscule fraction of the average original development cost.Despite the widely acknowledged existence of widespread software piracy, there have been very few cases reaching the civil courts and nearly none before the criminal courts. There are several explanations: few pirates are caught, few owners of software are willing or able to press a claim in court, most cases are settled out of court, and perhaps there is not so much software piracy after all; or a combination of all of them.This paper does not try to answer the question of why there are so few cases. Instead, it presents the bare facts from the existing cases and categorizes the source of the piracy, i.e. how did the pirate or alleged pirate come to possess the software in the first instance and what happened to him or her.The presentation of cases here is not complete, for the legal reporting systems are also not up-to-date. Indeed, the phrase, “software piracy” does not appear in legal reports' indices, nor legal dictionaries. More research is needed, but the patterns found in the 31 cases here will probably continue as the sample increases. From such patterns, software owners and legal practitioners can better see what they are up against.     

基于分块图像小波变换的数字水印算法研究

提出一种基于分块图像小波变换的数字水印嵌入和提取算法,使每一个水印像素隐藏在相应的图像块的中低频小波系数之中,保证了水印的稳健性和不可觉察性,实验表明水印具有抗一般信号处理(例如图像压缩、剪切等)能力.     

美国版权终止制度及对我国的启示

在合同自由原则下,版权转让中作者的弱势地位和新作品价值的不确定性常导致版权转让不公平。从续展制度到终止制度,美国版权法却始终保障作者从其创作成果中获取充分收益。作为一项不能由作者预先有效放弃版权的规定,版权终止制度以强制性规范的形式实现了矫正正义。就我国版权转让来说,适当限制合同自由,确保获酬权是版权改革之题中应有之义,以弥补作者弱势地位之不足,维护社会公平。     

Laplace-Beltrami spectra as ‘Shape-DNA’ of surfaces and solids

This paper introduces a method to extract ‘Shape-DNA’, a numerical fingerprint or signature, of any 2d or 3d manifold (surface or solid) by taking the eigenvalues (i.e. the spectrum) of its Laplace-Beltrami operator. Employing the Laplace-Beltrami spectra (not the spectra of the mesh Laplacian) as fingerprints of surfaces and solids is a novel approach. Since the spectrum is an isometry invariant, it is independent of the object's representation including parametrization and spatial position. Additionally, the eigenvalues can be normalized so that uniform scaling factors for the geometric objects can be obtained easily. Therefore, checking if two objects are isometric needs no prior alignment (registration/localization) of the objects but only a comparison of their spectra. In this paper, we describe the computation of the spectra and their comparison for objects represented by NURBS or other parametrized surfaces (possibly glued to each other), polygonal meshes as well as solid polyhedra. Exploiting the isometry invariance of the Laplace-Beltrami operator we succeed in computing eigenvalues for smoothly bounded objects without discretization errors caused by approximation of the boundary. Furthermore, we present two non-isometric but isospectral solids that cannot be distinguished by the spectra of their bodies and present evidence that the spectra of their boundary shells can tell them apart. Moreover, we show the rapid convergence of the heat trace series and demonstrate that it is computationally feasible to extract geometrical data such as the volume, the boundary length and even the Euler characteristic from the numerically calculated eigenvalues. This fact not only confirms the accuracy of our computed eigenvalues, but also underlines the geometrical importance of the spectrum. With the help of this Shape-DNA, it is possible to support copyright protection, database retrieval and quality assessment of digital data representing surfaces and solids.A patent application based on ideas presented in this paper is pending.     

基于文本文档的版权保护技术——文本数字水印的研究

文本数字水印可以保护数字产品的版权,阻止盗版、侵权等行为。在分析了数字水印的特点及其分类的基础上,针对目前数字水印技术的研究主要集中在图像、视频和音频等方面的现象,研究了文本数字水印技术的模型和现有技术,提出基于数字水印技术的版权保护模型。     

数字水印研究中常用的测试指标(上)

数字水印作为数字媒体版权保护的有效手段，受到极大关注，但却没有一个良好的衡量手段来对数字水印算法作出合理的评测。本文总结了目前比较流行的数字水印算法衡量手段以及几种有效的数字水印的攻击手段，旨在帮助全面评测水印算法的性能，进而帮助改进数字水印算法，使数字水印算法具有更好的隐形性、稳健性、安全性，以促进数字水印走向实用化。