数字图像水印技术综述

随着多媒体技术和网络技术的广泛应用、图像、音频、视频等多媒体内容的版权保护成为迫切需要解决的问题。数字图像水印作为版权保护的重要手段和一种新型的信息隐藏方法,近几年得到了迅速发展。本文详细介绍了数字图像水印的分类,主要属性及系统模型,并对数字图像水印的经典算法,常见攻击手段及其应用领域做了系统的论述,最后对未来的研究方向做出展望。     

图像高逼真度的自适应盲水印算法

随着计算机和网络技术的飞速发展,数字图像、音频和视频产品越来越需要一种有效的版权保护方法,所谓数字水印就是一种嵌入到图像、视频或音频数据中的不可见标志,可以用于多媒体数据的版权保护、认证和标注等。该文提出了一个有效的自适应育水印算法,在水印检测过程中不需要原始图像。原始图像经小波变换后,选择内嵌水印所需要的子带,水印根据邻居特征平均值法和奇偶判决法内嵌到频域中所选择的子带上。实验结论和攻击测试表明,该文所提议的算法能得到高逼真度的加水印图像,对如 JPEG有损压缩、中值滤波、附加噪声、伸缩、裁剪等各种图像处理的攻击有较强的稳健性。     

应用于实时通信版权保护的BTC图像水印技术

现有BTC图像水印方案多为脆弱水印技术或数据隐藏技术,不能应用于数字图像版权保护.为保护数字电视实时通信图像版权,结合Haar小波变换,提出一种稳健的BTC域图像水印算法.算法首先对载体图像BTC域两重建电平进行Haar小波变换,然后通过修改低频系数以嵌入稳健水印.水印提取时无须原始载体图像参与.仿真实验表明,算法具有...     

数字水印处理技术

近年来,数字水印技术开始广泛用于数字图像,音频,视频和多媒体产品的版权保护.本文综述了数字水印技术的起源,分类和算法.本文提出了水印处理技术基本框架和基本要求,介绍了现有的各种水印生成算法,水印嵌入算法和水印检测算法,提出了几种有效的算法和研究思路,并展望了水印处理技术的应用前景.     

变换域数字图像水印技术的研究

随着计算机和网络技术的飞速发展,多媒体信息的安全问题引起人们极大的关注.数字水印是信息安全领域的新技术,他作为版权保护和安全认证的有力工具已得到广泛的发展.简要介绍了数字图像水印技术的基本原理,着重分析了典型的变换域算法及常见的攻击方式和相应对策,通过对算法的研究,指出变换域数字图像水印的关键问题，就是水印嵌入的频带选择问题.     

一种双帧数字图像的双盲水印技术

本文提出一种新的安全水印嵌入技术:同时对两帧数字图像嵌入两种不同水印,对任意提取一幅图像的水印,无法恢复两个水印的任何信息.在获得双密钥情况下,方可恢复两幅图像的水印.从数学上证明了我们提出的新技术的有效性,并对算法安全性给予了分析.在变换域上给出了实现了双盲水印的算法,采用StirMark水印测试软件进行了一系列攻击性试验,其测试结果表明此技术提供了一种新的数字版权保护的方法.     

基于量化的扩频水印技术

随着计算机和网络技术的飞速发展，数字图像、音频和视频产品越来越需要一种有效的版权保护方法，数字水印技术为上述问题提供了一个潜在的解决方案。提出了一种基子量化的扩频水印技术，算法将水印信号与序列作扩频调制，调制信号通过量化策略嵌入到块ＤＣＴ变换系数的低频分量中，在嵌入过程中考虑到了局部图像的复杂度，能够自适应地调整嵌入强度，提取水印信号无需使用原始图像。仿真实验表明水印是不可察觉的，经过 ＪＰＥＧ有损压缩、低通与中值滤波、剪切等图像处理操作后仍是稳健的。     

Arnold变换在LSB算法中的应用研究

为了更好地进行版权保护,设计了一种基于图像置乱技术的数字图像水印算法。将经过Arnold变换的水印信号嵌入在宿主图像的LSB位平面上,提高了LSB算法的鲁棒性,保留了盲提取特点。算法通过水印信号扩展使其与宿主图像相匹配,保证了水印嵌入位置的安全性。仿真实验比较了有无Arnold变换的水印算法,结果表明使用Arnold置乱的水印算法抗噪声、剪切能力较好,说明在数字图像水印中应用图像置乱技术可以有效提高数字图像水印的性能。     

试论数字图像水印算法的研究与实现

网络时代的到来及数字多媒体技术的飞速发展与广泛应用,极大地便利了人们的日常生活。与此同时,有关数字产品版权保护的呼声也越来越高。作为一种现代化数据版权保护与认证技术,数字图像水印技术成为当前学术领域的研究焦点,具有十分重要的现实意义和应用前景。文章结合数字水印技术的特点,探讨了数字图像水印的几种重要算法,以供参考。     

基于小波变换的数字水印应用

伴随着网络技术扣多媒体技术的飞速发展，数字媒体给人们带来极大便利的同时，也面临着严峻的挑战，版权保护扣信息安全成为一个迫在眉睫的现实问题。数字水印技术作为版权保护扣信息安全的重要手段得到了广泛的研究扣应用，他通过在原始数据中嵌入秘密信息——水印来证实该数据的所有权或完整性，达到版权保护扣信息安全的目的．本文基于人类视觉系统(HVS)的特性，提出了一种小波变换域的数字水印算法，将水印图像嵌入到小波变换的不同方位的重要系数当中，文中实现了标志图像水印．实验结果表明，该水印算法对图像处理扣压缩等运算有较强的鲁棒性。     

Watermarking Hardware Based on Wavelet Coefficients Quantization Method

Progress in the digital multimedia technologies during the last decade has offered many facilities in the transmission, reproduction, and manipulation of data. However, this advancement has also brought the problem such as copyright protection for content providers. Digital watermarking is a proposed solution for copyright protection for multimedia. The goal of hardware assisted watermarking is to achieve low power usage, real-time performance, reliability, and ease of integration with existing consumer electronic devices. An efficient architecture for transform domain watermarking using quantization approach is proposed here. This architecture is optimized using pipelining. The main objective of this paper is to propose a very-large-scale integration (VLSI) architecture for robust and blind image watermarking chip. Watermarking architectures with and without pipeline are synthesized using Xilinx’s ISE for a field-programmable gate array (FPGA), and then semi-custom integrated chip is designed using UMC 0.18 μm technology standard cell library for both these architectures. The proposed optimized pipelined watermarking encoder core requires 0.027 mm² area and 0.074 mW power.     

基于攻击特性互补的数字水印检测器

数字水印是网络环境下对多媒体信息进行版权保护的一项新技术，其关键在于水印检测器能否正确检测出多媒体信息中的水印信息。这里基于图像处理的攻击特性的互补提出了一种新的数字水印相关检测器。实验结果表明：此检测器可以有效地提高水印相关检测器的性能。     

数字水印技术分析及其在电视领域的应用

数字水印是多媒体版权保护的一种有效技术手段。介绍数字水印技术的基本原理,阐述了视频数字水印应具有的特点,讨论压缩域视频数字水印算法。在此基础上,提出数字水印在电视领域的应用方案。该技术为电视版权管理的有效实施具有一定的借鉴作用。     

A Study of Steganographic Image Security

In this dissertation, sereral key problems in the field of steganographic image security are mainly studied and discussed: (1) A novel kind of image cryptosystem is studied. The encrypted information of secret image is embedded into an ordinary image, which can be transmitted publicly, and it will not cause attention of illegal eavesdropper. The following results are achieved: (a) The image hiding algorithm and its improved algorithm based on wavelet transform and vector quantization are propo…     

Multipurpose image watermarking algorithm based on multistage vector quantization.

The rapid growth of digital multimedia and Internet technologies has made copyright protection, copy protection, and integrity verification three important issues in the digital world. To solve these problems, the digital watermarking technique has been presented and widely researched. Traditional watermarking algorithms are mostly based on discrete transform domains, such as the discrete cosine transform, discrete Fourier transform (DFT), and discrete wavelet transform (DWT). Most of these algorithms are good for only one purpose. Recently, some multipurpose digital watermarking methods have been presented, which can achieve the goal of content authentication and copyright protection simultaneously. However, they are based on DWT or DFT. Lately, several robust watermarking schemes based on vector quantization (VQ) have been presented, but they can only be used for copyright protection. In this paper, we present a novel multipurpose digital image watermarking method based on the multistage vector quantizer structure, which can be applied to image authentication and copyright protection. In the proposed method, the semi-fragile watermark and the robust watermark are embedded in different VQ stages using different techniques, and both of them can be extracted without the original image. Simulation results demonstrate the effectiveness of our algorithm in terms of robustness and fragility.     

Digital watermarking for telltale tamper proofing andauthentication

In this paper, we consider the problem of digital watermarking to ensure the credibility of multimedia. We specifically address the problem of fragile digital watermarking for the tamper proofing of still images. Applications of our problem include authentication for courtroom evidence, insurance claims, and journalistic photography. We present a novel fragile watermarking approach which embeds a watermark in the discrete wavelet domain of the image by quantizing the corresponding coefficients. Tamper detection is possible in localized spatial and frequency regions. Unlike previously proposed techniques, this novel approach provides information on specific frequencies of the image that have been modified. This allows the user to make application-dependent decisions concerning whether an image, which is JPEG compressed for instance, still has credibility. Analysis is provided to evaluate the performance of the technique to varying system parameters. In addition, we compare the performance of the proposed method to existing fragile watermarking techniques to demonstrate the success and potential of the method for practical multimedia tamper proofing and authentication     

A wavelet-based watermarking algorithm for ownership verificationof digital images

Access to multimedia data has become much easier due to the rapid growth of the Internet. While this is usually considered an improvement of everyday life, it also makes unauthorized copying and distributing of multimedia data much easier, therefore presenting a challenge in the field of copyright protection. Digital watermarking, which is inserting copyright information into the data, has been proposed to solve the problem. In this paper, we first discuss the features that a practical digital watermarking system for ownership verification requires. Besides perceptual invisibility and robustness, we claim that the private control of the watermark is also very important. Second, we present a novel wavelet-based watermarking algorithm. Experimental results and analysis are then given to demonstrate that the proposed algorithm is effective and can be used in a practical system.     

一种基于DWT域的数字水印算法

数字媒体版权保护已变得十分迫切和需要，有效的版权确认方法是实现有效版权保护的前提。本文结合Arnold置乱方法，提出了一种有效的数字图像水印方法。该算法通过将置乱后的数字水印嵌入到原始载体图像的L级小波逼近子图，取得了不错的结果。实验证明，该方法嵌入的数字水印不但具有较好的不可见性。而且对图像噪声、滤波等攻击具有较好的鲁棒性。