数字水印技术的研究

当今时代,作为计算机领域的研究热点,数字水印技术得到了广泛的应用。本文介绍了数字水印技术的基本原理、数字水印的特征及其分类,并对典型的水印算法及其应用领域进行了阐述。最后,分析指出了数字水印技术的研究现状与发展前景。     

易损数字水印技术：研究与应用

1.引言随着数字化和网络化的发展,出现了数字多媒体的版权和完整性保护等问题。为了解决这些问题,人们开始做各方面的研究,而数字水印技术是其中的一个主要研究方向,并且得到了越来越多的关注。当前研究的数字水印,按其特性主要可以分为两类:鲁棒数字水印和易损数字水印。鲁棒数字水印(Robust Watermarking),要求对多媒体数据进行操作时,不会或者很难去除或破坏嵌在数据中的数字水印,也就是要求保证水印的鲁棒性。主要用于数字产品的版权保护,比如在数字作品中表示著作权信息,如作者、作品序号等,它要求嵌入     

数字水印综述

数字水印将感觉不到的信号嵌入到声频、视频和图像中以实现不同的目的.例如：添加标题和版权保护.首先介绍了有关数字水印的基本原理、重要属性及其主体框架.然后,将数字水印按不同角度划分为不同种类.讨论了各种各样的数字水印算法以及数字水印在不同领域的应用,并简要介绍了对数字水印的攻击.最后,给出了数字水印当前的研究现状和发展形式及前景.     

Entropy based spatial domain image watermarking and its performance analysis

Digital image watermarking technique based on LSB Substitution and Hill Cipher is presented and examined in this paper. For better imperceptibility watermark is inserted in the spatial domain. Further the watermark is implanted in the Cover Image block having the highest entropy value. To improve the security of the watermark hill cipher encryption is used. Both subjective and objective image quality assessment technique has been used to evaluate the imperceptibility of the proposed scheme.Further, the perceptual perfection of the watermarked pictures accomplished in the proposed framework has been contrasted and some state-of-art watermarking strategies. Test results demonstrates that the displayed method is robust against different image processing attacks like Salt and Peppers, Gaussian filter attack, Median filter attacks, etc.

     

一种攻击Digimarc水印的新算法

近年来,数字水印技术开始广泛用于电子产品的版权保护,大量的数字水印方案被提了出来。在数字水印技术的开发方面,Digimarc公司是一个领导者。Digimarc水印技术为保护版权提供了一种强有力的工具。论文提出了一种新的针对Digimarc数字水印的攻击算法,该算法能够在保证电子产品质量的前提下很容易地删除Digimarc水印。实验结果表明这种算法非常有效。     

基于陷阱策略的音频数字水印新方法

数字水印已经成为实现多媒体版权保护的一项重要技术.提出在嵌入鲁棒性水印的同时考虑攻击的行为特征,辅以陷阱策略抵制各种攻击.水印以量化音频DCT系数的方式嵌入,在提取时针对攻击的行为特征以不同方式提取水印.算法嵌入的水印为一幅二值图像,能抵制随机裁剪、AD及DA转换、低通滤波等去同步型攻击,提取的水印可以直接分辨.与cocktail水印方法相比,所提方法的鲁棒性高,提取水印时不需要原始音频.实验结果说明我们的音频水印方法十分有效.     

An efficient and robust watermarking approach based on single value decompression,multi-level DWT,and wavelet fusion with scrambled medical images

This paper offers a medical image watermarking approach based on Wavelet Fusion (WF), Singular Value Decomposition (SVD), and Multi-Level Discrete Wavelet Transform (M-DWT) with scrambling techniques for securing the watermarks images. The proposed approach can be used for providing multi-level security in various applications such as military, copyright protection, and telemedicine systems. The key idea of the projected approach is to first combine two digital watermark images into a single fused watermark to increase the embedded information payload. Then, the fused watermark is scrambled using Arnold and Chaotic algorithms. Finally, the scrambled fused watermark is embedded in the cover image using the SVD and three-level DWT algorithms. The selection of the Arnold and chaotic for watermark encryption is attributed to confirm robustness which resists several types of multimedia attacks and upturn the security level. This paper also presents a comparative study of the proposed approach for different digital images to determine its robustness and stability. Several simulation results reveal that the proposed system improves the capacity and security of embedded medical watermarks without affecting the cover image quality. In conclusion, the proposed approach achieved not only precise acceptable perceptual quality with admired Peak Signal-to-Noise Ratio (PSNR) values but similarly high Correlation Coefficient (Cr) and SSIM values in the existence of severe attacks.

     

基于特征子空间的数字水印技术

根据特五子空间的原理，提出了一种新颖的基于特征子空间的数字水印算法，水印可以嵌入到不同的子空间中从而可以发展为多水印算法，由于特征子空间之间的正交特性，不同子空间中的水印相互独立，其稳健性不随水印数目的增加而变化，水印强度参数根据视觉系统的照度掩蔽和纹理掩蔽特性适当地进行调整，从而同时保证二值水印图像的稳健性和不可见性，该文就单水印，双水印以及多水印情形进行了仿真并进行JPEG压缩，图像缩放，剪切等失真测试，实验结果表明该算法具有很好的感知质量和稳健性并验证了以上分析。     

基于脆弱性数字水印的图象完整性验证研究

计算机网络技术的飞速发展与信息媒体的数字化 ,使得在网络环境中对数字产品实施有效的内容保护成为一个迫在眉睫的现实问题 .传统的数字签名技术只是用于对通信领域的信息传送进行篡改检测 ,而脆弱性数字水印技术则为网络环境下多媒体的内容保护提供了一个有效的解决方案 .与鲁棒性水印不同的是 ,脆弱性水印主要用于检测发生在多媒体数据中的篡改 ,并对其定位 .为了推动我国在此前沿领域研究工作的进一步深入 ,这里就当前脆弱性数字图象图象水印技术的基本特征、一般原理、研究现状、攻击方法及发展方向进行一个综述 .     

A blind watermark algorithm in SWT domain using bivariate generalized Gaussian distributions

Imperceptibility, robustness, and payload are three main requirements of any audio watermarking systems to guarantee desired functionalities, but there is a tradeoff among them from the information-theoretic perspective. Generally, in order to enhance the imperceptibility, robustness, and payload simultaneously, the human auditory system and the statistical properties of the audio signal should be fully taken into account. The statistical model based transform domain multiplicative watermarking scheme embodies the above ideas, and therefore the detection and extraction of the multiplicative watermarks have received a great deal of attention. Although much effort has been made in recent years, improving the ability of imperceptibility, watermark capacity, and robustness at the same time remains a challenge within the audio watermarking community. In this paper, we propose a blind audio watermark decoder in stationary wavelet transform domain based on bivariate generalized Gaussian distributions, wherein both the local statistical properties and inter-scale dependencies of the stationary wavelet transform coefficients of digital audio are taken into account, and also the adaptive nonlinear watermark embedding strength functions are designed. The results of our tests with different host audios, digital watermarks, and various attacks, we experimentally confirm that the proposed approach performs well compared to the state-of-the-art audio watermarking methods.

     

数字水印安全性攻击的特点分析

数字水印是近年来出现的数字产品版权保护技术,目的是保护数字产品的合法拷贝和传播。数字水印研究主要分为算法设计和攻击分析两个方面。该文较为系统地分析了当前关于数字图像水印的常用攻击方法,讨论了数字水印技术未来可能出现的研究热点。     

离散余弦变换域图像数字水印技术

基于变换域的水印技术由于其较好的鲁棒性和安全性成为了目前水印技术领域研究的热点.详细地分析了目前离散余弦变换域的图像数字水印技术,对离散余弦变换域的算法进行分类比较,并对拉伸因子a的取值以及对图像水印嵌入效果的影响进行了讨论,提出了一些有效的水印方案,实验结果表明了其对常见攻击的抵抗性.分析和讨论了DCT变换域图像数字水印技术在嵌入水印方面的实现.     

一种带纠错编码的小波域盲水印算法

先前众多的DWT(discretewavelettransform)域水印算法几乎都是私有水印或易脆水印,而针对版权保护的鲁棒的、公开的小波域水印算法却极少。文章提出了一种小波域盲水印算法,水印嵌入到小波分解的高频子带,通过采用小波系数的数字化编码技术实现了盲水印的提取。水印在提取过程中不需要任何原始图像信息。为提高水印的鲁棒性,引入了简单的纠错编码机制。     

自适应二维数字水印系统

随着因特网和数字技术的发展,数字媒体已成为人们获取知识的主要手段,但这也带来了一系列问题如作品侵权、非法复制和传播等.为了解决这些问题,数字水印技术作为版权保护的重要手段,已得到广泛的研究和应用.为实现水印图象的叠加,提出了一种以灰度图象为水印的空域二维自适应数字水印算法,该方法首先将水印图象进行8×8分块,并进行DCT变换,然后对每块的DCT系数进行量化和调整,最后,取出每块的部分DCT系数来构成水印信号.同时为了实现自适应,还将载体图象按8×8分块,并利用视觉掩蔽特性对载体图象象素进行分类,再根据块分类结果,将水印信号以不同强度嵌入到载体图象中.实验结果表明,该算法具有较好的鲁棒性.最后还对该技术今后的研究指出了一些可能的方向.     

数字水印技术综述

数字水印作为一种将特殊信息嵌入媒体数据的技术,近年来已成为国内外研究的热点并有着广泛的应用前景．通常数字水印被应用于数字图像、音频、视频以及其他媒体产品上以进行版权保护和验证多媒体数据的完整性．首先介绍了数字水印技术的特点和应用领域,并对其基本原理和评价标准进行了阐述,同时对数字水印的各种算法进行了分类研究与深入分析,并对不同算法进行了安全性与性能的横向比较,最后指出了数字水印今后的研究方向．     

常用数字图像水印攻击方法及基本对策

数字水印是近年来出现的数字产品版权保护技术，目的是保护数字产品的合法拷贝和传播．数字水印研究主要分为算法设计和攻击分析两个方面．较为系统地论述了当前关于数字图像水印的常用攻击方法以及主要的对抗策略，分析了它们的优缺点，讨论了数字水印技术未来可能出现的研究热点．     

数字水印技术在MMS中的应用与实现

数字水印技术是数字产品版权保护领域中的研究热点,是一种全新的保护多媒体信息安全的技术。许多专家对数字水印算法进行了深刻的广泛的研究．并取得了一定的成果,本文首先简单介绍了数字水印技术的一般的基本原理,同时对多媒体短信（MMS）基本含义作了一个简单的介绍．详细阐述了利用数字水印技术在多媒体短信（MMS）中进行信息隐藏的理论,同时简单分析了数字水印技术在未来多媒体短信（MMS）的应用潜力。     

A multimedia application for watermarking digital images based on a content based image retrieval technique

The current work is focused on the implementation of a robust multimedia application for watermarking digital images, which is based on an innovative spread spectrum analysis algorithm for watermark embedding and on a content-based image retrieval technique for watermark detection. The existing highly robust watermark algorithms are applying “detectable watermarks” for which a detection mechanism checks if the watermark exists or not (a Boolean decision) based on a watermarking key. The problem is that the detection of a watermark in a digital image library containing thousands of images means that the watermark detection algorithm is necessary to apply all the keys to the digital images. This application is non-efficient for very large image databases. On the other hand “readable” watermarks may prove weaker but easier to detect as only the detection mechanism is required. The proposed watermarking algorithm combine’s the advantages of both “detectable” and “readable” watermarks. The result is a fast and robust multimedia application which has the ability to cast readable multibit watermarks into digital images. The watermarking application is capable of hiding 2¹⁴ different keys into digital images and casting multiple zero-bit watermarks onto the same coefficient area while maintaining a sufficient level of robustness.     

A lossless data hiding scheme for medical images using a hybrid solution based on IBRW error histogram computation and quartered interpolation with greedy weights

In the digital world, watermarking technology is a solution for data hiding and completely essential for management and secure communications of digital data propagated over the internet-based platforms. Reversible watermarking is a quality-aware type of watermarking which has been applied in managing digital contents such as digital images, texts, audios and videos. Reversible watermarking is also known as lossless watermarking due to its preservation of all details of host and hidden data. One of the important uses of this kind of watermarking is to manage medical data regarding DICOM images. In the recent years, a new type of reversible watermarking technology entitled interpolation-based reversible watermarking has been introduced, and we are going to enhance it for DICOM images by using a hybrid approach based on computing error histogram and by applying an image interpolation with greedy weights (adaptive weighting). In practice, simulation results clearly show better performance of the proposed scheme compared to the previous techniques using interpolation-based reversible watermarking on different DICOM images.

     

数字水印技术在MMS中的应用与实现

数字水印技术是数字产品版权保护领域中的研究热点,是一种全新的保护多媒体信息安全的技术。许多专家对数字水印算法进行了深刻的广泛的研究,并取得了一定的成果,本文首先简单介绍了数字水印技术的一般的基本原理,同时对多媒体短信(MMS)基本含义作了一个简单的介绍,详细阐述了利用数字水印技术在多媒体短信(MMS)中进行信息隐藏的理论,同时简单分析了数字水印技术在未来多媒体短信(MMS)的应用潜力。