Combining Digital Watermarks with Two-Color Bitmap Image

A technology for combining digital watermarks with two-color bitmap image based on the threshold watermarking method is presented. Our technology doesn't add any thing to the digital media, but combines the watermarks in two-color bitmap image by looking for some characteristic values in the bitmap and uses the relationship between the watermarks and the characteristic values to prove the copyright protection. The choice of the characteristic values depends on the choice of a cryptographic key known by the owner of the bitmap. The benefit of using a cryptographic key is to combine the watermarks with the bitmap in a high secure way.     

A robust method for fingerprinting digital images

In this paper, a method to fingerprint digital images is proposed, and different watermarked copies with different identification string are made. After determining the number of the customers and the length of the watermark string, this method chooses some values inside the digital image using a characteristic function, and adds watermarks to these values in a way that can protect the product against the attacks happened by comparing two fingerprinted copies. The watermarks are a string of binary numbers -1s and 1s. Every customer will be distinguished by a series of 1s and -1s generated by a pseudo-random generator. The owner of the image can determine the number of customers and the length of the string as well as this method will add another watermarking values to watermark string to protect the product.     

块奇异值分解和量化实现的图像数字水印算法

讨论了当前将水印嵌入在块奇异值分解（SVD,singular value decomposition）后最大奇异值中的图像数字水印算法不足,进而提出了两种新的将水印嵌入在块SVD后最大奇异值除外的其余奇异值中的图像数字水印算法。两种新算法均采用了量化嵌入策略,从而使两种算法在提取水印时无需任何原始信息的帮助。实验结果表...     

A digital signature-based visual cryptography scheme for image discrimination and management

Visual cryptography is a cryptographic technique which emerges in the information security domain in recent years. Each of the sharing sub-keys may be a stochastic noise image or a significative image with no information on the original key. But a mass of sub-keys have to be saved actually, which faces the problem of inconvenient discrimination and management. This paper presents a visual cryptography scheme based on the digital signature for image discrimination and management, ap-plying the digital signature and the time-stamp technology to the visual cryptography scheme. The scheme both solves the problem on the storage and management of the sharing sub-keys, increases the verification of image contents, thus enhances the validity of storage and management without security effect.     

基于Logistic混沌映射的DCT域脆弱数字水印算法

本文提出了一种新的混沌脆弱数字水印算法.利用混沌系统对初值的极端敏感性和块不相关水印技术,将图像DCT次高频系数和水印密钥合成为logistic混沌映射初值从而生成水印,再将水印嵌入到图像DCT的高频系数中得到水印图像.利用图像DCT系数之间的关系,实现了水印的盲检测.实验结果表明,该算法可以精确检测到对水印图像的一个像数点的改变,并具有良好的定位篡改能力.     

基于小波变换的双水印算法

数字音频水印是水印技术中重要的组成部分。而近年来对音频水印的研究远远少于图像水印,双水印的研究则更加少。因此提出了一种基于小波变换的双水印算法,在音频信号的小波变换域嵌入两个不同作用的水印,对一些音频处理有很好的鲁棒性的同时又能有效地判别音频信号的真实性和完整性。实验证明本算法的两水印分别具有很好的鲁棒性和敏感性,并实现了水印的盲提取。     

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…     

利用图像边缘变化特性寻找模糊处理痕迹

目前在图像认证技术中,一种不同于水印认证的盲检测技术发展迅速,这种认证技术不需要事先插入认证数据,只是根据图像本身的数据特征进行认证,其中对于图像处理痕迹的检测是盲检测的重要手段之一。本文提出了一种针对图像高斯模糊处理痕迹的检测算法,根据图像处理中高斯模糊的基本特性,首先对被检测原始图像采用不同的高斯半径进行二次模糊处理,然后用提出的算法来比较二次模糊后图像边缘的变化情况,算法可以从中发现原始图像的高斯模糊特性,从而发现原始图像中异常模糊处理的痕迹。仿真实验表明这种方法对于实现图像篡改的被动盲检测具有较好的应用价值。      

自适应图像水印块分类准则分析

为保证水印算法的良好性能,许多文献研究自适应水印技术.文中研究自适应数字水印算法的关键技术--图像分类准则,这些准则将原始图像按照图像块的多个特性参数分成不同的类,使得水印嵌入过程能够考虑人类视觉系统的特点,在不同的类中嵌入不同的水印能量,从而使算法具有自适应能力.分析表明,采用这些分类准则可以较好地解决数字水印方案中不可见性与鲁棒性之间的矛盾.     

Watermarking on Colored Images

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Hidden digital watermarks in images

An image authentication technique by embedding digital "watermarks" into images is proposed. Watermarking is a technique for labeling digital pictures by hiding secret information into the images. Sophisticated watermark embedding is a potential method to discourage unauthorized copying or attest the origin of the images. In our approach, we embed the watermarks with visually recognizable patterns into the images by selectively modifying the middle-frequency parts of the image. Several variations of the proposed method are addressed. The experimental results show that the proposed technique successfully survives image processing operations, image cropping, and the Joint Photographic Experts Group (JPEG) lossy compression.     

小波域的扩频数字图像水印算法

该文利用小波变换良好的时频局部特性,提出了基于小波变换的数字图像水印嵌入方案,提高了数字水印的隐蔽性;把扩频通信的概念和方法引入数字水印系统中,采用了扩频理论中的伪随机序列进行处理,提高了数字水印的稳健性,同时扩频通信的多址原理也将对实现多重水印起一定的作用。该文详细讨论了该算法的视觉效果,抗JPEG压缩、抗随机噪声和抗尺寸变换能力,以及多重水印的实现。     

一种低复杂度的基于小波的彩色图像水印算法

根据图像小波变换系数的特点,提出了一种双彩色水印新算法:把彩色宿主图像的R,G,B分量分别经过p级小波分解,使它们各自的低频系数LLp个数等于水印的尺寸大小,然后将R,G,B分量的LLp系数分别加上加权后的彩色水印R,G,B分量的灰度值,将这些变化了的低频系数和没有变化的高频系数一起经过小波逆变换即得彩色水印图像.这种水印算法复杂度低,实验证明该水印具有较好的不可见性、鲁棒性.     

一种曲波域鲁棒数字图像水印算法

提出了一种数字图像水印算法基于特殊选择的傅里叶采样卷绕的快速离散曲波变换.利用Arnold变换对水印信号进行置乱加密,将置乱后的信号进行多次重复来增加冗余度.按照曲波系数分布的特点,选择合适的尺度和系数对水印信号进行嵌入.实验结果表明,该算法对JPEG、加噪、滤波等图像处理具有好的鲁棒性,同时具有好的不可见性.     

Digital images authentication scheme based on bimodal biometric watermarking in an independent domain

With the growing accessibility and usability of internet there is a growing concern over content protection of digital images. Recently, to eliminate the traditional use of passwords and to ensure that the access to the image is restricted only to legitimate users, security solutions are increasingly combined with biometrics. Consequently, biometric-based watermarking algorithms, that involve embedding the identity of the owner, are proposed to solve ownership disputes. This paper presents a new scheme for protecting and authenticating invisibly watermarked digital images. It applies Independent Component Analysis to the cover image and enables the insertion of two independent watermarks based on fingerprint and iris biometrics. In this approach biometric techniques are used for watermarks generation and for owners authentication. The main advantage of proposed algorithm is construction of ICA based watermarking domain to enable insertion of two independent watermarks, that improve authentication accuracy and makes scheme more robust.     

一种用于图像篡改定位与恢复的双水印算法

引入虚拟水印的概念,结合自恢复技术,小波变换等水印技术,提出了一种新的数字图像双水印嵌入算法。文中将原图像二次小波变换后的低频分量LL₂作为第一重水印,将数字产品公司标识作为第二重水印,同时利用双水印技术所特有的属性,在两重水印之间构筑函数关系,将其结合在一起。实验结果表明,该算法简单高效,可同时具有水印恢复、版权认证和篡改区定位恢复等多方面的功能。     

Circularly symmetric watermark embedding in 2-D DFT domain

In this paper, a method for digital image watermarking is described that is resistant to geometric transformations. A private key, which allows a very large number of watermarks, determines the watermark, which is embedded on a ring in the DFT domain. The watermark possesses circular symmetry. Correlation is used for watermark detection. The original image is not required in detection. The proposed method is resistant to JPEG compression, filtering, noise addition, scaling, translation, cropping, rotation, printing and rescanning. Experimental results prove the robustness of this method against the aforementioned attacks.     

Content protection in grayscale and color images based on robust digital watermarking

The concept of digital rights management architecture for multimedia will be presented in this paper, with focus on robust digital image watermarking, which is able to undergo geometrical attacks performed against the embedded watermarks. Geometrical attacks are still an open problem for many digital watermarking algorithms used in present time. Most of geometrical attacks can be described by using affine transforms. A new approach to improve robustness against geometrical attacks is presented. The discrete Fourier transform and log-polar mapping are used for watermark embedding and for watermark detection. Some attacks against the embedded watermarks are performed and the results are given. Also two modifications, usage of the proposed method as a synchronization template and implementation for the color images, are presented and experimental results are given too.     

无线数字图像通信关键技术研究

文中研究了无线数字图像通信关键技术,采用理论结合实践的方法,立足无线数字图像通信的概念和技术特点,分析了无线数字图像通信技术的研究现状,并分析了实现无线数字图像通信的关键技术以及无线数字图像传输过程中的差错控制方法。研究结果表明,无线数字图像通信是一种新型的通信技术,可实现图像的有效、快速、安全传输,加强对无线数字图像通信关键技术的分析与研究,有利于促进该技术的持续、稳定发展。     

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.