基于小波变换的CDMA图像盲水印算法

提出了一种盲扩展谱水印算法,将水印信息重复的嵌入到图像多层小波分解的系数中.通过对数字图像小波变换结构的研究和分析,利用扩展谱将信息嵌入到LH和HL子带,结合噪声视觉函数在水印的透明性和鲁棒性之间实现了较好的平衡,提高了信息隐藏的安全性,并运用CDMA(Code Division Multiple Access)理论实现了水印信息的盲提取.大量的试验结果表明,该算法对于常见的图像处理操作,特别是对于JPEG压缩和多种噪声攻击有较好的鲁棒性.     

基于反攻击的数字图像水印方法

在实际应用中 ,加有水印的数字图像不可避免会遭到一些有意或无意的攻击 .针对一些常用的攻击方法 ,提出了一种反攻击方法和相应的水印算法 ;算法自适应地选择水印嵌入位置和确定水印序列长度 ;水印嵌入在 DWT域进行 ;根据人眼视觉掩蔽特性确定水印嵌入强度 .实验结果表明该方法具有较好的图像自适应性和水印不可见性 ;对JPEG压缩、图像加噪声和图像滤波等常见的攻击方法具有极强的鲁棒性     

基于DWT和DCT域的盲水印算法

结合小波变换和离散余弦变换的特性,在灰度图像中嵌入二值图像,采用Arnold变换对水印图像进行预处理,根据人眼视觉系统(HVS)的掩蔽特性选择合适的分块,将水印信息嵌入到较好块的中频系数中,提高水印的鲁棒性,实现了盲水印提取.实验结果证明,该算法对JPEG压缩、剪切、滤波和噪声等常见的处理操作有较好的鲁棒性.     

基于PCNN与粗集理论的细胞图像二重数字水印算法*

结合脉冲耦合神经网络与粗集理论,提出了一种空频域结合的二重水印算法,用于生物细胞图像的版权保护。首先在小波变换域中用粗集理论的方法找出水印嵌入位置,嵌入第一重水印信息,在此基础上,找出图像空间域中纹理复杂区域再次嵌入水印;然后讨论了水印的提取方法;最后进行了鲁棒性检测。仿真表明,该算法具有较强的不可见性和较好的鲁棒性,能准确地提取出水印信息,可以有效地对生物细胞图像进行版权保护。     

一种基于纠错编码技术的盲数字水印算法

目前基于离散余弦变换的图像数字水印技术水印大多都不能盲提取.提出一种基于量化的鲁棒性数字水印技术.首先,对水印信息进行纠错编码提高水印的鲁棒性,并通过Arnold置乱对水印信息进行加密;然后将原始载体图像经过8×8分块DCT变换后,根据预处理后的水印数据量选定水印嵌入位置;最后对DCT系数进行量化同时完成水印信息的嵌入.本算法实现了水印的盲提取.实验表明,文中水印方法实现简单,具有较好的稳健性和不可见性,能有效抵抗噪声、JPEG有损压缩、滤波等恶意攻击.     

基于异性扩散方法的数字图像水印研究

基于人类视觉系统的特性,提出一种结合各向异性扩散和小波域的数字水印算法。根据各向异性扩散在图像处理中具有良好的边缘保持与增强的作用,首先对原图像进行各向异性扩散,在其小波分解高频区域求解噪声敏感模型,确定水印嵌入合适位置,最后把水印信息嵌入到原图像的小波域的等同位置。实验证明了算法在保证水印不可见性的同时,具有较好的鲁棒性。运用各向异性扩散方法的结果也提高了水印方法的安全性。     

基于四元数傅里叶梅林变换的RST不变彩色图像水印算法

提出一种基于四元数傅里叶梅林变换(QFMT)的RST(旋转、缩放和平移)不变彩色图像水印算法,利用图像的不变质心生成具有平移稳定性的圆形特征区域,对这个圆形区域进行QFMT。利用QFMT幅度谱具有旋转和缩放不变性,在QFMT幅度谱中嵌入水印信息。该算法不仅可以抗RST攻击,大大提升水印的鲁棒性,而且可以把水印嵌入所带来的误差扩散到载体图像的各个颜色分量之中,扩大水印嵌入的容量。实验结果表明,该方法具有较好的抗压缩性,对RST等攻击有良好的鲁棒性。     

基于置乱和混沌加密的DCT域公开水印技术研究

目前有很多基于离散余弦变换(DCT)的水印算法,但很少讨论到公开水印传播的安全性问题.为进一步增强水印系统的安全性,文中将嵌入的水印信息进行置乱和混沌加密处理,然后选择中频系数为嵌入水印的位置.实验结果表明,该公开水印算法除了能较好地保证水印的安全性外,对图像剪切、中值滤波、JPEG压缩和噪声干扰等常见图像处理操作有较高的鲁棒性.同时,嵌入水印具有很好的透明性,水印的提取无须求助于原图像.     

基于DCT的图像水印算法研究与实现

对于数字媒体信息安全方面提出了一种基于DCT变换的数字图像盲水印嵌入算法.通过对水印图像进行置乱加密与随机产生嵌入位置来保证水印安全性,并由MATLAB实验证明此算法具有较好的不可见性,能够抵御JPEG压缩、均值滤波、图像锐化和部分剪切的攻击,具有较好的鲁棒性,并且该盲水印嵌入算法中,对嵌入水印的提取不需要原始图像.这给数字图像的版权检测提供了便利.     

基于压缩感知的鲁棒性水印算法

为了改进传统的变换域水印嵌入算法,以提高水印嵌入效率并减小对载体图像的影响,同时保证水印信息的完整性和鲁棒性。为此,本设计采用了压缩感知的处理方法。通过使用随机高斯矩阵作为测量矩阵对待嵌入水印信息进行压缩采样,有效减少所需的嵌入信息量,提高水印嵌入效率。此外,本设计还能保证水印嵌入的安全性。经过仿真实验验证,与传统DWT算法相比,本设计具有鲁棒性强、不可见性好、实时性更优等特点。综上所述,本设计能够有效地嵌入水印信息,提高水印嵌入效率,并在保证水印信息完整性和鲁棒性的同时,减小对载体图像的影响。该设计具有实际应用价值,可广泛应用于图像水印领域。     

Analysis of position based watermarking

This paper extends the position based watermarking (PBW) technique introduced by Borges and Mayer (Position based watermarkings, 2003) and provides a detailed performance analysis considering additive white Gaussian noise and collusion attacks. We significantly improve the tradeoff between fidelity and robustness of our previous research on this subject by exploiting the informed embedding and informed coding paradigms. In contrast to traditional watermarking approaches such as least significant bit embedding, spread spectrum modulation and dirty paper codes, the content of the embedded watermark blocks do not need to carry information. Our unique approach maps the information according to specific locations in the image where we embed small watermark blocks. We provide theoretical analyses and experimental results to compare with the performance of the spread spectrum technique. These analyses and experiments confirm our superior tradeoff between robustness and transparency and also show the superior robustness of PBW to collusion attacks.     

A new watermarking scheme for colour image using QR decomposition and ternary coding

At present, the binary images are often used as the original watermark images of many watermarking methods, but partial methods cannot be easily extended to colour image watermarking methods. For resolving this problem, we propose a new watermarking method using ternary coding and QR decomposition for colour image. In the procedure of embedding watermark, the colour image watermark is coded to ternary information; the colour host image is also separated into image blocks of sized 3?×?3, and these image blocks are further decomposed via QR decomposition; then, one ternary watermark is embedded into one orthogonal matrix Q of QR decomposition by the proposed rules. In the procedure of extracting watermark, the proposed method uses the blind-manner to extract the embedded ternary information. The novelty of this scheme lies in the proposed ternary coding for watermark image, which can improve the imperceptibility, embedded watermark capacity and real-time feature of the watermarking scheme. The results of simulation show the presented technique is better than other compared schemes with respect to imperceptibility, embedded watermark capacity and real-time feature under the similar robustness.

     

基于多尺度分解与预测误差扩展的可逆图像水印算法

针对现有可逆图像水印算法中嵌入量与图像视觉质量之间的矛盾,提出了一种基于多尺度分解与预测误差扩展的可逆图像水印算法。首先,对原始图像进行多尺度分解,将其分解为同质块和非同质块;其次,通过对同质块进行预测误差扩展来嵌入水印信息;最后,通过计算非同质块信息熵,根据嵌入水印信息量选择合适的非同质块,通过对选取的非同质块进行整数小波变换,在中高频中嵌入剩余水印信息。实验结果表明,该算法易于实现且完全可逆,能有效提高水印嵌入量,具有较高的视觉质量。     

一种基于混沌变换的自适应盲水印

提出一种基于混沌变换技术的双密钥小波域图像数字水印算法,首先利用其中一个密钥产生一个随机数子,用来决定对小波变换后的载体图像的哪一个方向做进一步多分辨分解,确定嵌入水印的位置;然后利用另一密钥对二值水印图像进行随机置乱;根据嵌入位置的自带的自身特点,计算出三个阈值s、s1和s2,将经过随机置乱处理的含版权信息的二值水印图像嵌入到将水印嵌入到水平、垂直和对角方向的子带.在水印检测过程中,提出一种不需要载体图像相关信息的盲检测水印算法.首先根据其中一个密钥找到水印所在的位置,同样计算出相应的s*、s*1和s*2,然后再用另一个密钥重构水印图像.实验证明,提出的水印方案具有较好的抗攻击性,使用双密钥具有很好的安全性.     

Reduced reference stereoscopic image quality assessment using digital watermarking

In this paper, a novel reduced-reference stereoscopic image quality assessment (RR-SIQA) algorithm is proposed by means of an unconventional use of watermarking technique. Watermarking techniques are usually employed for authenticity verification and copyright protection. Here, watermarking technique is adopted to provide a new approach for RR-SIQA. Firstly, the features of image are extracted in reorganized discrete cosine transform domain, and then embedded into the stereoscopic image as invisible hidden information. In order to improve the reliability of the watermarking, some channel coding techniques are applied before the process of embedding watermark. At the receiver, the watermark can be decoded and used to measure the quality of the distorted stereoscopic image. The proposed algorithm overcomes the limitations of other existing methods that require an auxiliary channel. Experimental results illustrate that the proposed algorithm has a good consistency with subjective quality scores, and can reflect the visual perception of stereoscopic image effectively.     

A robust associative watermarking technique based on vector quantization

In this paper, the concepts of vector quantization (VQ) and association rules in data mining are employed to propose a robust watermarking technique. Unlike ordinary or traditional watermarking techniques, our approach hides association rules of the watermark, instead of the whole watermark; in other words, the embedded information is the association rules of the watermark. First, VQ encoding is performed on the original image and watermark to generate the index tables, and from which association rules are further mined. Subsequently, by embedding the association rules of the watermark into the association rules of the original image, the purpose for watermarking is accomplished. Finally, VQ decoding technique is applied to reconstruct the watermarked image from the watermarked index table. Experimental results show that our proposed method achieves effective resistance against several image processings such as blurring, sharpening, adding in Gaussian noise, cropping, and JPEG lossy compression. Moreover, the embedding capacity is also significantly increased, so any a complex watermark image is still acceptable in this method.     

基于YIQ色彩空间的彩色图像盲水印算法*

提出了一种将彩色图像作为数字水印嵌入到彩色宿主图像中的新算法,用于图像版权保护。将彩色水印图像进行一维数字化处理,并将彩色宿主图像由RGB色彩模式转换成YIQ色彩模式,采用整数小波变换将彩色水印嵌入到彩色图像YIQ色彩空间的Y分量中。彩色水印的提取不需要原始水印和原始宿主图像。实验表明：该数字水印算法不仅具有良好的透明性,而且对诸如叠加噪声、JPEG压缩、几何剪切、平滑滤波等攻击具有很强的鲁棒性。     

一个新的基于DCT的自适应数字水印算法

本文提出了一个利用DCT系数的关系来进行水印嵌入和提取的算法。该算法利用人类视觉系统HVS的特点，通过巧妙调整DCT系数之间的相互关系来嵌入水印．从而使得图像在嵌入一个比较稳健的水印后的视觉失真尽可能最小。水印提取不需要原始图像。实验结果表明本算法的图像保真度较好，并对JPEG压缩、剪切等常见的图像处理方法具有较好的稳健性，并优于文献上的相关算法。     

基于Logistic混沌映射和IWT-SVD量化的盲鲁棒水印算法

为了提高数字水印的鲁棒性以及水印嵌入位置的保密性,提出了一种基于Logistic混沌映射和整数小流变换—奇异值分解(IWT-SVD)量化的盲鲁棒水印算法:对二值水印图像进行Arnold置乱,对原始载体图像进行8×8分块,利用生成的Logistic混沌序列选择嵌入水印的图像块,充分保证了水印嵌入位置的保密性;对选中的图像块进行二级IWT分解,对得到的二级低频子带系数进行SVD;将置乱后的水印信息嵌入.算法不需要原始载体图像,实现了水印的盲提取,更具实用性.仿真实验结果表明:算法对常规图像处理操作、压缩攻击和剪切攻击均具有较强的稳健性.     

Robust image watermarking technique using triangular regions and Zernike moments for quantization based embedding

Watermarking is a tool to embed information in the image to provide authentication, copyrights protection, copy control, etc. Some watermarking techniques are robust to intentional /unintentional attacks on the watermarked image. In this study, we propose a robust watermarking approach that can resist geometrical attacks. The proposed technique exploits both the robust image feature points and local Zernike moments for embedding the information. Delaunay tessellation is employed to divide image into distinct triangular segments based on robust features. These features are identified using Harris detector. Zernike moments are calculated for each selected triangular segment, and then the watermark is embedded in the magnitude of Zernike moments using dither modulation. It can be observed from the experimental results that by using proposed approach, the watermark can be detected even in the presence of geometrical distortion, i.e. rotation, cropping, and scaling, and JPEG compression attack.