一种小波变换域上的高鲁棒灰度水印

为了提高灰度水印抵抗滤波,加噪等常见攻击以及几何攻击的能力,提出了一种小波变换域上的高鲁棒水印方案。首先对灰度水印提出了一种新颖的数据压缩方法,并且从中提取出用于水印同步的参考比特。对于受到几何攻击的水印图像,提出了在低频子带上使用图像的主轴和边缘轮廓以获得旋转和缩放参数,从而能准确快速地恢复图像。同时在中频子带上采取了一种对参考比特进行高效匹配的办法来进一步实现水印的同步。实验表明除了一般图像处理之外,对于几何变形攻击本方案具有很好的鲁棒性。     

Novel robust image watermarking based on subsampling and DWT

This paper presents a robust digital image watermarking scheme based on subsampling and DWT. Subsampling is firstly used to construct a subimage sequence as a video segment. Then, a random watermark sequence satisfied with Gaussian distribution is block-wised embedded into the DWT domain of these subimages repeatedly using the video watermarking technique. And watermark is detected through computing correlation between watermark and watermarked frames. The experiment results demonstrate that the proposed scheme achieves good robustness against JPEG compression, common image processing operation and geometric distortions. Furthermore, the proposed watermarking scheme is also robust against linear collusion and other video watermarking attacks.     

基于NMF和SVD相结合的Contourlet域鲁棒水印算法*

为了提高变换域数字水印技术的鲁棒性,提出了一种在Contourlet域将非负矩阵变换(NMF)与奇异值变换(SVD)相结合的鲁棒水印算法。宿主图像经过Contourlet变换后,对低频子带进行非负矩阵变换,然后对非负基向量组W进行奇异值分解,最后将经过Arnold置乱的水印图像嵌入到奇异值中。实验结果表明,该图像水印算法在获得良好视觉效果的同时,对于加噪声、滤波、剪切等图像攻击有较好的鲁棒性。     

一种新的基于伪Zernike矩的图像盲水印算法

抵抗几何攻击的鲁棒性是目前数字水印技术中的热点也是难点。提出一种新的基于伪Zernike矩的图像盲水印算法,首先计算图像归一化后的伪Zernike矩,然后选取部分合适的矩通过量化调制嵌入水印信息。水印提取时,利用伪Zernike矩的相位信息估计旋转角度进行几何校正,以提高矩的几何不变性。实验结果表明,本算法对于抗几何攻击尤其是旋转攻击具有很好的鲁棒性,同时也能抵抗常规的信号处理攻击。     

一种基于多尺度空间的图像水印算法

当前数字水印对常见的图像处理攻击如高斯噪声、中值滤波、有损压缩等具有较强的抵抗能力,但其抵抗剪切、缩放等几何攻击的能力较差。因此,为提高数字水印的鲁棒性,结合尺度不变特征变换算子和视觉感知模型,提出一种基于不变特征的水印嵌入方法。基于广义高斯分布模型对小波系数进行刻画,并根据二值假设检验理论确定水印的检测阈值,由此进一步给出水印虚警和漏警之间的工作特性曲线关系。实验仿真结果表明提出的水印方法在抗压缩、叠加噪声、缩放、剪切、旋转等攻击时具有较好的鲁棒性能。     

基于Harris-Laplace特征区域的遥感图像水印算法

针对现有遥感影像数字水印算法多为全局水印算法,抵抗旋转、行列剪切、水平镜像以及联合几何攻击能力较差,提出一种基于Harris-Laplace特征区域的局部化遥感影像水印算法。算法依据密钥生成一个随机序列,对其实施二值化,并选取一段作为待嵌入的数字水印;在宿主遥感影像中提取Harris-Laplace特征点,并依据其确定水印嵌入特征区域;最后,根据待嵌入的水印信息,将所选特征区域进行圆环划分,利用奇偶量化方法将水印嵌入其中。实验证明该算法对JEPG压缩、噪声及滤波等常规信号处理具有较好鲁棒性的同时,能够更好地抵抗旋转、缩放、平移及其联合等几何攻击。     

基于Contourlet变换的遥感影像数字水印方案

针对现有变换域遥感影像数字水印算法存在的问题,提出一种基于Contourlet变换的遥感影像数字水印方案。算法首先对宿主遥感影像进行图像归一化;然后,对水印图像进行Arnold置乱预处理,并将置乱后的水印图像利用行扫描形成一维向量,得到二值水印序列作为数字水印信息;最后对宿主遥感影像进行Contourlet变换,并通过奇偶量化将水印嵌入所选Contourlet变换系数中。实验证明该算法对JEPG压缩、滤波和噪声以及旋转、缩放、平移等几何攻击均具有较好的鲁棒性。     

Hybrid robust watermarking for color images

In this paper, we present a blind and highly robust watermarking scheme method for color images by combining the advantages of both spatial and frequency domain. Watermark is generated for each channel (RGB) of the color image by extracting spatial domain features using Gray Level Co-occurence Matrix as well as a unique identification number. The watermark is embedded in Principal Component Analysis (PCA)-based less correlated low and high frequency sub bands in such a way that the perceptual quality of the image is preserved. Imperceptibility is achieved by embedding the watermark in less correlated sub bands and robustness is achieved by spreading the watermark using Laplacian Pyramid in contourlet transform. Simulation results show that the proposed scheme can survive various image processing and signal processing attacks. The proposed method achieves high transparency, imperceptibility and robustness compared to some of the existing schemes.     

基于二维码图书版权保护的数字水印算法

版权保护一直是图书出版领域的难题之一.根据二维码和主成分分析（PCA）算法的特点,提出一种基于二维码图书版权保护的新的数字水印算法,算法首先对二维码载体图像进行主成分分析（PCA）,提取出既含有高频分量又含有低频分量的主成分系数,采用Arnold算法将版权信息水印加密干扰后嵌入到提取出的主成分系数中.实验结果显示,新算法在几何攻击、噪声、图像亮度和对比度的增减等攻击都有很好的鲁棒性.     

A robust semi-blind watermarking for color images based on multiple decompositions

In this paper, a robust semi-blind watermarking scheme for color images, based on multiple decompositions is proposed to preserve the copyrights of the owner. Using multiple decompositions, the gray watermark is embedded into a host color image. Prior to that, to enhance security the gray watermark is encrypted with Arnold transform and SVD by generating secret keys. The luminance component of the given host image is subjected to discrete wavelet transform(DWT), contourlet transform(CT), Schur decomposition and singular value decomposition(SVD) in sequence and finally the watermark is embedded. In the semi-blind extraction process, the watermark is extracted without the help of the original host image. Experimental results show that the proposed watermarking scheme has better visual imperceptibility and high robustness against image & signal processing attacks compared to other methods.     

A new SVM-based image watermarking using Gaussian-Hermite moments

Geometric attack is known as one of the most difficult attacks to resist, for it can desynchronize the location of the watermark and hence causes incorrect watermark detection. It is a challenging work to design a robust image watermarking scheme against geometric attacks. Based on the support vector machine (SVM) and Gaussian-Hermite moments (GHMs), we propose a robust image watermarking algorithm in nonsubsampled contourlet transform (NSCT) domain with good visual quality and reasonable resistance toward geometric attacks in this paper. Firstly, the NSCT is performed on original host image, and corresponding low-pass subband is selected for embedding watermark. Then, the selected low-pass subband is divided into small blocks. Finally, the digital watermark is embedded into host image by modulating adaptively the NSCT coefficients in small block. The main steps of digital watermark detecting procedure include: (1) some low-order Gaussian-Hermite moments of training image are computed, which are regarded as the effective feature vectors; (2) the appropriate kernel function is selected for training, and a SVM training model can be obtained; (3) the watermarked image is corrected with the well trained SVM model; (4) the digital watermark is extracted from the corrected watermarked image. Experimental results show that the proposed image watermarking is not only invisible and robust against common image processing operations such as filtering, noise adding, JPEG compression, etc., but also robust against the geometric attacks.     

基于双重加密和Contourlet变换的数字图像盲水印算法

提出了一种演化密文与规则的加密方法,以细胞自动机的初态和规则作为演化对象,寻找满足经过迭代后能得到原文的细胞自动机的初态和规则。由于某些原文只在某些特殊规则下才存在满足完全匹配的密文,而且匹配度越高搜索越耗时,所以引入了校验信息,以最大演化代数作为演化计算的终止条件,寻找迭代后与原文最接近的密文,再通过校验获得完整的原文。通过实验得出：此种加密方法具有较大的密钥空间和良好的置乱效果,而且细胞自动机的邻居半径越大,演化计算的表现越稳定。     

一种HVS和Contourlet结合的图像水印算法

提出了一种Contourlet域的图像水印算法.首先对图像进行多层分解;然后利用视觉系统的亮度纹理特性,把伪随机序列组成的水印信号自适应地嵌入到能量最大的子带中;最后经过逆变换得到嵌入水印后的图像.该算法解决了直接嵌入边缘扭曲的问题,检测端使用基于相关的盲检测.实验结果表明,该算法能够在满足不可见性的条件下抵抗JPEG压缩、加噪和剪裁等攻击,具有很强的鲁棒性.     

基于SIFT的NSCT-SVD域水印算法

提出一种利用尺度不变特征变换（SIFT）关键点对图像几何校正的非抽样Contourlet变换-奇异值分解域（NSCT-SVD）彩色图像水印算法。该算法利用蓝色与绿色分量的NSCT域低频子块的最大奇异值的关系,在蓝色分量上嵌入经过混沌加密的水印信息。水印检测时,先利用红色分量NSCT域低频系数上匹配的SIFT关键点信息对被检测图像进行几何攻击校正,恢复了水印的同步信息后再提取水印。实验结果表明,该算法对于噪声、滤波、压缩以及各类几何攻击具有较好的鲁棒性。     

基于奇异值分解和小波变换的抗几何失真数字水印新方法

目前,大多数鲁棒图像水印所面临的最大问题就是几何攻击,而现有水印技术大都难以抵抗几何变换类攻击,如旋转、尺度变换等,由于几何攻击破坏了水印分量的同步,即使微小幅度的图像旋转或尺度变换都可能导致水印检测过程失败.提出了一种基于奇异值分解和小波变换的方法来盲提取受到几何攻击后的图像中的水印,即利用了奇异值对几何失真的稳健性,又利用了小波变换对一般攻击的稳健性.实验证明,提出的方法对几何攻击具有很好的鲁棒性.     

基于直方图调整的抗几何攻击图像水印

几何攻击被公认为是数字图像水印技术走上商用的瓶颈之一。本文根据图像几何变换过程中灰度值统计特征的稳定性原理,提出了一种基于直方图调整的抗几何攻击数字图像水印算法。首先根据图像灰度均值选取一个灰度区间,然后通过调整位于该灰度区间内的图像直方图来嵌入水印信息。在提取水印时无需提供原始图像,实现盲检测。实验结果表明本算法不仅具有很好的隐蔽性,而且对诸如旋转、缩放、平移、仿射变换、剪切等几何攻击和常规信号处理均具有很强的鲁棒性。     

基于奇异值分解和Contourlet变换的图像水印算法

在分析抵抗几何攻击的几种方法以及Contourle变换的特点基础上,提出了一种基于Contourlet变换的水印算法.图像进行Contourle变换后,对各子带进行奇异值分解,选择所有子带奇异值中较大的数据作为水印植入点,这样将水印分散植入各个子带中,提高抗攻击能力.实验结果表明,该算法能够抵抗加噪和剪裁等攻击,具有较强的鲁棒性,提高了水印识别的可靠性.     

Robust localized image watermarking based on invariant regions

The robustness of the localized watermarking methods mainly depends on the robustness of the feature locating the watermark. Based on the mean luminance of the disk, a rotation and scale invariant feature extraction algorithm is proposed. A theoretical verification of the rotation and scale invariance of extracted feature points in the continuous image is further performed. The extracted feature points are used to construct rotation and scale invariant circular regions, where the watermark is embedded after affine normalization. Experimental results show that the constructed regions fit the watermarking applications much better than those in previous feature-based watermarking schemes from the aspect of robustness against common attacks including filtering, JPEG compression, cropping, rotation and scaling, and the proposed localized image watermarking scheme has better robustness than previous feature-based watermarking schemes against common signal process and geometrical attacks while maintaining imperceptibility.     

基于SIFT和伪Zernike矩归一化的抗几何攻击水印

提出一种基于SIFT和伪Zernike矩归一化的抗几何攻击水印方案。首先用SIFT方法提取载体图像的特征点,筛选得到关键点。然后在关键点确定载体图像的方形子区域嵌入水印。嵌入时计算方形子区域的伪Zernike矩值,并对矩值作归一化处理,选择部分低阶矩幅值抖动量化嵌入水印。为抵抗几何攻击,检测前进行基于SIF关键点的几何失真校正,对校正后的图像提取水印。实验结果表明该算法对旋转、剪切、JPEG、压缩、噪声、中值滤波等攻击有很好的鲁棒性。     

PCA-DTT 2D-DHCES based attack resilient imperceptible image watermarking

Most schemes exhibit low robustness due to LSB’s (Least Significant Bit) and MSB’s (Most Significant Bit) based information hiding in the cover image. However, most of these IW schemes have low imperceptibility as the cover image distortion reveals to the attacker due to information hiding in MSB’s. In this paper, a hybrid image watermarking scheme is proposed based on integrating Robust Principal Component Analysis (R-PCA), Discrete Tchebichef Transform (DTT), and Singular Value Decomposition (SVD). A grayscale watermark image is twisted/scrambled using a 2D Discrete Hyper-chaotic Encryption System (2D-DHCES) to boost up the robustness/heftiness and security. The original cover image is crumbled into sparse components using R-PCA and using DTT the substantial component is additionally decomposed and the watermark will be embedded in the cover image using SVD processing. In DTT, scarcer coefficients hold the utmost energy, also provide an optimum sparse depiction of the substantial image edges and features that supports proficient retrieval of the watermark image even after unadorned image distortion based channel attacks. The imperceptibility and robustness of the proposed method are corroborated against a variety of signal processing channel attacks (salt and pepper noise, multi-directional shearing, cropping, and frequency filtering, etc.). The visual and quantifiable outcomes reveal that the proposed image watermarking scheme is much effective and delivers high forbearance against several image processing and geometric attacks.