基于小波矩的抗几何攻击数字图像水印算法研究

针对旋转、缩放和平移等几何攻击破坏水印检测同步,从而导致水印检测失败等问题,利用归一化图像的缩放、平移不变性及小波矩的旋转不变特性,结合奇偶量化技术,提出了一种有效抵抗几何攻击的数字图像水印新算法。首先利用图像归一化技术将原始载体映射到几何不变空间内;然后计算归一化图像的小波矩,并选取部分稳定的低阶小波矩用于水印嵌入;最后利用奇偶量化方法将水印信息嵌入到所选小波矩的不变量内。仿真实验结果表明,该图像水印方案不仅具有良好的透明性,而且具有较强的抵抗常规信号处理、几何攻击、联合攻击等能力。     

基于Tchebichef矩的几何攻击不变性第二代水印算法

提出了一种基于原始图像的Tchebichef矩实现的几何攻击不变性第二代盲水印算法,利用原始图像的Tchebichef矩估计图像可能经历的几何攻击的参数来还原图像,其中,原始图像的Tchebichef矩可作为水印检测器的密钥.水印嵌入过程结合人类视觉系统的特性,且可在任何图像变换域中实现,给出了小波域的一种实现方法.水印检测过程采用独立分量分析技术不仅可以检测到水印而且可以提取水印,实现了真正意义上的盲检测.实验结果表明,该水印算法对于通用水印测试软件Stirmark提供的各种攻击具有很好的鲁棒性.     

Geometric attack resistant image watermarking based on MSER

Geometric distortions are simple and effective attacks rendering many watermarking methods useless. They make detection and extraction of the embedded watermark difficult or even impossible by destroying the synchronization between the watermark reader and the embedded watermark. In this paper, we propose a blind content-based image watermarking scheme against geometric distortions. Firstly, the MSER detector is adopted to extract a set of maximally stable extremal regions which are affine covariant and robust to geometric distortions and common signal processing. Secondly, every original MSER is fitted into an elliptical region that was proved to be affine invariant. In order to achieve rotation invariance, an image normalization process is performed to transform the elliptical regions into circular ones. Finally, watermarks are repeatedly embedded into every circular disk by modifying the wavelet transform coefficients. Experimental results on standard benchmark demonstrate that the proposed scheme is robust to geometric distortions as well as common signal processing.     

基于奇异值分解的、抗几何失真的数字水印算法

许多现有的适用于图像的数字水印对几何失真都是很敏感的。尤其是此类失真会严重妨碍对水印的盲提取。为此，提出了一种基于奇异值分解的数字水印算法，它对常见的几何失真是稳健的。此水印是被嵌入到图像分解后的奇异值之中。根据奇异值分解的代数性质，严格证明了嵌入了水印的图像在受到转置、镜像、旋转、放大和平移等几何失真后，其奇异值是不变的。在经过了上述的几何失真、一般的信号处理操作或JPEG压缩以后，嵌入的水印能够被可靠地提取和检测。实验结果表明本算法具有很好的稳健性。     

基于傅里叶-梅林矩的抗几何攻击图像水印算法

如何有效抵抗几何攻击是数字图像水印研究领域的热点问题之一,一个微弱不可觉察的几何攻击就可能使绝大多数水印算法失效。以不变矩理论为基础,提出了一种基于正交傅里叶-梅林矩的可有效抵抗几何攻击的图像水印新算法。结合傅里叶-梅林矩的几何不变特性,计算出原始图像的傅里叶-梅林矩;根据稳定矩的选取规则选取部分稳定的傅里叶-梅林矩,采用量化调制策略将水印信息嵌入到所选矩的幅值中;将傅里叶-梅林矩修改前后的重构差值图像叠加到原始载体图像中,得到含水印图像。仿真实验表明,该算法不仅具有较好的不可感知性,而且对常规信号处理和几何攻击均具有较好的鲁棒性。     

基于DWT-DCT和Zernike矩的灰度级鲁棒性水印算法

鲁棒性是数字水印极为重要的指标.目前大多数文献中的鲁棒性水印方案对常规信号处理攻击均具有良好的鲁棒性,但抗几何攻击的鲁棒性相对较弱.提出了一种新的灰度级鲁棒性水印算法,对常规信号处理攻击和几何攻击均具有良好的鲁棒性.水印算法的鲁棒性由以下3方面获得:1)选择载体图像的内切圆盘作为Zernike矩的计算域,选择内切圆盘的内接正方形作为水印的嵌入区域.2)在载体图像嵌入区域的层叠DWT-DCT域嵌入水印,获得对常规信号处理攻击的强鲁棒性.3)保存原始含水印图像的2个Zernike矩作为校正几何攻击的参数,获得抗几何攻击能力.实验结果表明,该水印算法嵌入容量大,不仅对大角度旋转和大尺度缩放等几何攻击具有很好的鲁棒性,而且可以有效地抵抗有损压缩和常规信号处理攻击.     

Contourlet-based image and video watermarking robust to geometric attacks and compressions

In this paper, we first propose a new blind image watermarking scheme robust to geometric attacks and compressions. The scheme is based on contourlet transform (CT) and principal component analysis (PCA). The scheme uses the principal components of the largest contourlet coefficients of the last directional subband of the cover image to embed the watermark. Meanwhile, with the noise visibility function (NVF), the watermarking strength is adjusted adaptively to preserve the perceptual quality of the image. The watermark can be detected with high accuracy after various possible distortions. The normalized correlation (NC) between the original watermark and the watermark extracted from the distorted watermarked image is used as the robustness evaluation criterion. The simulation results demonstrate that the proposed scheme has good performance in terms of both quality and robustness against a variety of image-processing attacks, such as rotation, scaling and image compressions. Then we extend the scheme to blind video watermarking. The performance of the video watermarking scheme is evaluated against video attacks like rotation, frame averaging, noise additions and video compressions. The introduction of the CT produces robustness against image and video compressions, and the PCA yields resistance to geometric attacks.

     

基于QR分解的Contourlet域抗几何攻击水印算法

为了提高数字水印产品的抗几何攻击能力,提出一种基于QR分解的Contourlet域抗几何攻击水印算法。该算法首先对宿主图像Contourlet变换后的低频子带进行分块QR分解,通过轻微修改各子块Q矩阵第一列第二行元素和第三行元素的大小关系嵌入Arnold置乱后的水印信息,并且利用R矩阵对各子块进行相应的视觉失真补偿操作。在水印提取前,利用尺度不变特征变换SIFT特征点具有的旋转、缩放和平移不变性对几何失真含水印图像进行几何校正,恢复水印的同步性,使算法具备抵抗几何攻击的能力。实验结果表明,该算法的不可见性良好,而且对于常规攻击和多种几何攻击都具有较好的鲁棒性。     

基于改进的不变质心和小波域的鲁棒数字图像水印方法

利用图像不变质心在图像中的相对位置对平移、旋转和缩放的不变性,提出了一种抗几何攻击的图像盲水印算法。算法首先根据水印比特的长度自适应地对原始图像进行特定级的小波分解,并修改某些相对稳定的最低一级的低频子图的小波系数,通过将修改后的系数进行小波重构来嵌入水印接下来以含水印图像的基于改进的不变质心的不变特征矩阵为基础,与Rijndacl加密技术相结合,生成相关的二值逻辑表作为密钥向第三方认证,达到版权保护的目的。该算法在提取水印时不需要原始载体图像和原始水印。实验结果表明,该算法时间复杂度低,能有效抵抗JPEG压缩、裁剪、噪声等常规攻击以及平移、旋转、缩放等几何攻击.     

Quickly tracing detection for spread spectrum watermark based on effect estimation of the affine transform

Recently, watermarking synchronization and spread spectrum watermarking schemes have become two interesting, new focuses of study. In this paper, we propose a method based on the synchronization pre-estimation in order to resist geometric attacks. First, we utilize the global features by testing them against translation, rotation and scaling, and present a simple method to estimate the geometric transform kernel of the two-dimensional gray image. Maps, applying some correlative barycenters to the original are produced that can accurately reflect the affine transform feature of the image. Furthermore, unknown variables existing in the kernel of the transform are calculated. Secondly, the watermark is directly embedded in the spatial domain. Watermarking tracing is well performed on the watermarked image instead of performing an inverse geometrical transform on it. Experimental results show that the proposed scheme can work well under several kinds of geometrical attacks.     

基于DD-DT CWT 和SIFT 的体数据数字水印算法

为了确保三维体数据数字模型信息在网络传输过程中的安全性、完整性,对体数 据数字水印算法进行研究。提出基于双密度双树复小波变换的体数据数字水印嵌入算法,算法 提高了水印的嵌入容量,在兼顾水印不可见性的同时提高了水印抵抗压缩、噪声等攻击的能力; 提出基于尺度不变特征变换的体数据数字水印提取算法,实现了水印嵌入和提取时的同步性, 提高了水印抵抗旋转、缩放等几何攻击的能力。实验证明：算法不可见性好,实现速度快,在 盲检测下能够抵抗压缩、滤波、噪声、平移、旋转、缩放、剪切等攻击,具有较好的鲁棒性。     

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。     

A New Technique for Digital Image Watermarking

In this paper, a new technique is proposed for rotation, scaling and translation （RST） invariant image watermarking based on log-polar mappings （LPM） and phase-only filtering （POF）. The watermark is embedded in the LPM of Fourier magnitude spectrum of the original image, and a small portion of resulting LPM spectrum is used to calculate the watermark positions. This technique avoids computing inverse log-polar mapping （ILPM） to preserve the quality of the watermarked image, and avoids exhaustive search to save computation time and reduce false detection. Experimental results demonstrate that the digital watermarking technique is invariant and robust to rotation, scaling, and translation transformation.     

基于运动矢量的抗几何攻击视频水印方案

许多数字图像和视频水印方案都无法抵挡几何变换攻击,即使是轻微的旋转、缩放、平移也将会破坏水印的同步,这就使得水印难以检测出来。为解决此难题,提出了一种新颖的视频水印算法。该算法利用了运动矢量特征的相对关系不易随几何失真变换而改变的特性,使得水印具有内在的抗几何失真的鲁棒性。该算法中,水印嵌入和检测时,不仅可根据平均运动矢量的方向和幅度确定水印模板的位置和方向,而且水印检测不需要原始视频。实验表明,该水印算法对几何变换攻击具有较强的鲁棒性。     

RST transforms resistant image watermarking based on centroid and sector-shaped partition

A novel digital watermarking scheme featuring centroid-based sectoring is proposed in this paper. To get higher robustness against geometric attacks, such as rotation, scaling, and translation (RST), a delicate synchronization mechanism was developed and incorporated into the proposed approach. During the process of watermark embedding, the original image was partitioned into sectors based on the image centroid. Synchronization information as well as the message bits is then embedded into these sectors. With the help of the centroid-based sectoring and synchronization information, the proposed approach is capable of restoring the correct sectoring even if it has experienced severe geometric distortion. This attribute ensures the correct recovery of embedded watermarks and contributes to the robustness of the proposed scheme. A series of experiments have been conducted to verify the feasibility and effectiveness of the proposed approach. Experimental results show that the proposed scheme possesses good robustness against RST attacks and considerable robustness against other common image processing attacks.     

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.     

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.     

一种新的空域抗几何攻击图像水印算法

提出了一种基于特征与量化的空域抗几何攻击图像水印算法---FAQ算法. 采取的主要方法有: 1)利用图像中的局部最稳定特征点生成具有几何不变性的圆形特征区域, 用于水印的同步; 2)将特征区域分解为具有旋转不变性的扇形区域, 并在空域利用奇偶量化嵌入水印; 3)设计了一种奇偶检测器盲提取水印. 实验结果表明FAQ算法能获得很高的图像质量, 且能有效地抵抗常规信号处理攻击、旋转/缩放/平移(Rotation/scaling/translation, RST)攻击及其组合攻击.     

A self-adaptive image normalization and quaternion PCA based color image watermarking algorithm

This paper proposes a novel robust digital color image watermarking algorithm which combines color image feature point extraction, shape image normalization and QPCA (quaternion principal component algorithm) based watermarking embedding (QWEMS) and extraction (QWEXS) schemes. The feature point extraction method called Mexican Hat wavelet scale interaction is used to select the points which can survive various attacks and also be used as reference points for both watermarking embedding and extraction. The normalization shape image of the local quadrangle image of which the four corners are feature points of the original image is invariant to translation, rotation, scaling and skew, by which we can obtain the relationship between the feature images of the original image and the watermarked image which has suffered with geometrical attacks. The proposed QWEMS and QWEXS schemes which denote the color pixel as a pure quaternion and the feature image as a quaternion matrix can improve the robustness and the imperceptibility of the embedding watermarking. To simplify the eigen-decomposition procedure of the quaternion matrix, we develop a calculation approach with which the eigen-values and the corresponding eigen-vectors of the quaternion matrix can be computed. A binary watermark image is embedded in the principal component coefficients of the feature image. Simulation results demonstrate that the proposed algorithm can survive a variety of geometry attacks, i.e. translation, rotation, scaling and skew, and can also resist the attacks of many signal processing procedures, for example, moderate JPEG compression, salt and pepper noise, Gaussian filtering, median filtering, and so on.     

基于SIFT特征点匹配的水印图像几何校正算法*

为了有效实现水印图像的水印检测与水印嵌入之间的同步,提出一种应用SIFT(scale invariant feature transform)特征点匹配估计水印图像几何变换参数的校正算法.用两个稳定而又相距最远的图像SIFT特征点的变化估计图像所经历的旋转和缩放参数,校正之后,再用一个稳定的SIFT特征点的变化校正图像...