A robust watermarking scheme for 3D triangular mesh models

Copyright protection of digital media has become an important issue in the creation and distribution of digital content. As a solution to this problem, digital watermarking techniques have been developed for embedding specific information identifying the owner in the host data imperceptibly. Most watermarking methods developed to date mainly focused on digital media such as images, video, audio, and text. Relatively few watermarking methods have been presented for 3D graphical models. In this paper we propose a robust 3D graphical model watermarking scheme for triangle meshes. Our approach embeds watermark information by perturbing the distance between the vertices of the model to the center of the model. More importantly, to make our watermarking scheme robust against various forms of attack while preserving the visual quality of the models our approach distributes information corresponds to a bit of the watermark over the entire model, and the strength of the embedded watermark signal is adaptive with respect to the local geometry of the model. We also introduce a weighting scheme in the watermark extraction process that makes watermark detection more robust against attacks. Experiments show that this watermarking scheme is able to withstand common attacks on 3D models such as mesh simplification, addition of noise, model cropping as well as a combination of these attacks.     

A robust color image watermarking using local invariant significant bitplane histogram

Desynchronization attacks that cause displacement between embedding and detection are usually difficult for watermark to survive. It is a challenging work to design a robust image watermarking scheme against desynchronization attacks, especially for color images. In this paper, we propose a robust color image watermarking approach based on local invariant significant bitplane histogram. The novelty of the proposed approach includes: 1) A fast and effective color image feature points detector is constructed, in which probability density and color invariance model are used; 2) The fully affine invariant local feature regions are built based on probability density Hessian matrix; and 3) The invariant significant bitplane histograms are introduced to embed digital watermark. The extensive experimental works are carried out on a color image set collected from Internet, and the preliminary results show that the proposed watermarking approach can survive numerous kinds of distortions, including common image processing operations and desynchronization attacks.     

VRML animated model watermarking scheme using geometry and interpolator nodes

Distinct from image and video watermarking, a watermarking scheme for 3D animation content is required in the 3D industry market for various applications. This paper develops a watermarking scheme for copyright protection and authentication of 3D animation content. A 3D animated model generally has a hierarchical structure with a number of transform nodes of a geometry node and an interpolator node for the timeline in contrast to a 3D polygon mesh model. The proposed scheme embeds not only a robust watermark into the geometry node for copyright protection but also a fragile watermark into the position and orientation interpolators for content authentication. We named the former “robust geometry watermarking” and the latter “fragile interpolator watermarking”. The proposed scheme performs the two watermarking schemes independently to realize simultaneously robust and fragile watermarked 3D animated model. Experimental results confirm that a watermark embedded by geometry watermarking robust to many attacks from commercial 3D editing tools while a watermark embedded by interpolator watermarking fragile to the same attacks.     

自适应于局部几何特征的三维模型水印算法

文章针对三维模型提出了一种稳健的三角网格数字水印算法,通过修改从模型中心到各顶点的向量长度来嵌入数字水印。该算法具有如下特点:以全局几何特征作为嵌入对象;将一比特的水印信息分布到整个模型之中;水印的嵌入强度自适应于模型的局部特征。实验结果表明该水印算法能抵抗网格简化攻击,噪声攻击,剪切攻击,以及它们的混合攻击,具有很高的稳健性。     

基于不变矩的抗旋转、缩放、平移鲁棒性数字水印

目前的数字图像水印对于加噪、滤波、JPEG压缩攻击具有很好的鲁棒性但抗几何类攻击仍是对数字图像水印的一个巨大挑战。将水印嵌入到图像中的不变域中,这是一种比较好的方法。然而,由于嵌入水印的原始图像和受到几何攻击后（RST变换）的图像尺度大小发生了改变,这就使得水印的嵌入和检测之间失去了同步,从而导致水印检测的失败。为了解决图像尺度大小在水印嵌入和检测时发生改变的问题,提出了一种使用零像素值模板背景图像和不变矩抗旋转、缩放、平移鲁棒性数字水印。通过零像素值模板背景图像代替图像尺度大小归一化,同时使用几何不变矩来设计水印和检测水印。经过仿真实验证明,该方法对于普通的加噪、滤波、JPEG压缩攻击具有很好鲁棒性的同时,对于旋转、缩放、平移等攻击也具有很好的鲁棒性,是一种简单、实用、可靠的数字水印方法（使用的仿真软件：Matlab 7.1）。     

Optimized SVD-based robust watermarking in the fractional Fourier domain

Digital watermarking is one of the most effective methods for protecting multimedia from different kind of threats. It has been used for many purposes, like copyright protection, ownership identification, tamper detection, etc. Many watermarking applications require embedding techniques that provide robustness against common watermarking attacks, like compression, noise, filtering, etc. In this paper, an optimized robust watermarking method is proposed using Fractional Fourier Transform and Singular Value Decomposition. The approach provides a secure way for watermarking through the embedding parameters that are required for the watermark extraction. It is a block-based method, where each watermark bit is embedded in its corresponding image block. First, the transform is applied to each block, and then the singular values are evaluated through which the embedding modification is performed. The optimum fractional powers, of the transform, and the embedding strength factor are evaluated through a Meta-heuristic optimization to optimize the watermark imperceptibility and robustness. The Artificial Bee Colony is used as the Meta-heuristic optimization method. A fitness function is employed, at the optimization process, through which the maximum achievable robustness can be provided without degrading the watermarking quality below a predetermined quality threshold Qth. The effectiveness of the proposed method is demonstrated through a comparison with recent watermarking techniques in terms of the watermarking performance. The watermarking quality and robustness are evaluated for different quality threshold values. Experimental results show that the proposed approach achieves a better quality compared to that of other existing watermarking methods. On the other hand, the robustness is examined against the most common applied attacks. It is noticed that the proposed method can achieve a higher robustness degree when decreasing the quality threshold value.     

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Fourier-Mellion变换抗仿射变换水印算法

现有的数字水印技术大多难以抵抗几何变换类攻击,如旋转、平移和尺度变换等,特别是仿射变换（旋转、平移和尺度变换混合的多种攻击）,其中一个最主要的原因是：几何变换虽然并未去除图像中的水印信息,但却使水印的检测与嵌入之间失去同步,从而导致水印检测的失效。针对以上原因提出了一种基于图像矩和傅里叶梅林变换抗仿射不变性水印算法。对于平移造成的几何攻击,在水印检测之前利用原始图像的几何矩估计水印图像所经过的几何变换,根据估计的参数对水印图像进行相应的校正和水印检测。对于旋转和尺度变换造成几何攻击,通过对数极坐标系能将笛卡尔坐标系中的旋转和缩放变换为平移的性质,结合Fourier变换来抵抗旋转和缩放攻击。实验结果证明,该方法可以获得良好的图像视觉效果,同时对于几何攻击具有很好的鲁棒性。     

抗几何失真的局部数字水印算法

抗几何攻击一直是数字水印中的难点问题,为了更好地解决这个问题,基于图像的几何不变域,提出了一种抗几何失真的局部数字水印算法.算法利用显著性检测器检测到的具有平移、缩放和旋转不变性特性的圆形显著区域来嵌入水印.如何利用显著区域构造不变区域以获得平移、缩放及旋转不变性,以及如何从不变区域中筛选出适合嵌水印的区域,为要解决的重点问题,首先将水印进行几何变换来匹配各个水印嵌入区域的形状,再不可感知地嵌入到各个水印嵌入区域中.还着重讨论了如何利用显著区域获得平移、缩放及旋转不变性.实验表明该算法能很好地抵抗一般的信号处理攻击及旋转、缩放、裁剪和线性变换等几何攻击.     

Media hash-dependent image watermarking resilient against both geometric attacks and estimation attacks based on false positive-oriented detection

The major disadvantage of existing watermarking methods is their limited resistance to extensive geometric attacks. In addition, we have found that the weakness of multiple watermark embedding methods that were initially designed to resist geometric attacks is their inability to withstand the watermark-estimation attacks (WEAs), leading to reduce resistance to geometric attacks. In view of these facts, this paper proposes a robust image watermarking scheme that can withstand geometric distortions and WEAs simultaneously. Our scheme is mainly composed of three components: 1) robust mesh generation and mesh-based watermarking to resist geometric distortions; 2) construction of media hash-based content-dependent watermark to resist WEAs; and 3) a mechanism of false positive-oriented watermark detection, which can be used to determine the existence of a watermark so as to achieve a tradeoff between correct detection and false detection. Furthermore, extensive experimental results obtained using the standard benchmark (i.e., Stirmark) and WEAs, and comparisons with relevant watermarking methods confirm the excellent performance of our method in improving robustness. To our knowledge, such a thorough evaluation has not been reported in the literature before.     

Tetrolet变换和SVD结合的盲检测稳健数字水印嵌入策略

提出了一种Tetrolet变换和奇异值分解(SVD)相结合的图像盲检测稳健数字水印算法。该算法先对二值水印图像进行双因子混沌加密预处理;对原始载体图像进行二级Tetrolet变换,并将二层低频子带系数进行分块SVD分解;最后将加密的水印信息量化嵌入SVD最大系数中。水印检测时,无需原始载体图像和原始水印图像的参与,实现水印信息盲提取,提高数字水印系统的实用性。仿真实验结果表明,在保证水印安全性和不可感知性的基础上,该算法对常规图像处理、几何攻击等均具有较好的稳健性。     

基于DFT的鲁棒三维网格模型数字水印算法

论文提出了一种基于离散傅立叶变换(DFT)的鲁棒三维网格数字水印嵌入算法,该算法首先将模型中心到顶点的长度进行DFT变换,然后通过修改DFT系数的模来嵌入水印。算法以全局特征作为嵌入对象,并且将1位水印信息分布到整个模型之中。实验结果表明该算法能够抵抗网格简化、加噪声、剪切等类型攻击以及它们的混合攻击,具有很好的鲁棒性。     

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.

     

一个基于DWT的自适应数字水印算法

本文提出了一个新的DWT域自适应数字水印算法。该算法利用小波域高、低频部分嵌入水印的优势互补特点，在载体图像的高频和低频子带分别嵌入相同水印来增强水印抵抗多种攻击的能力；水印的嵌入采用量化调制方式，其量化步长可根据人类视觉系统和载体图像的局部特点自适应地调整。此外，由于奇异值分解具有良好的性能，因而被用于高频部分水印的嵌入以提高其鲁棒性。实验结果表明水印具有良好的鲁棒性和不可见性，与相近算法相比，本文方法可以有效抵抗更多的攻击。     

基于小波域HMM模型的稳健多比特图像水印算法

稳健性是多比特图像水印的关键问题之一,提出了一种基于小波域隐马尔可夫模型(hidden Markov model,简称HMM)的多比特图像水印算法,该算法的主要特点为:(1) 利用向量HMM模型精确描述图像小波系数间的统计特性,基于此统计模型的水印盲检测系统较之传统的相关检测器,在性能上有显著的提升;(2) 结合视觉掩盖特性,自适应地调整水印嵌入强度,使之在一定的嵌入强度下,视觉主观失真较小;(3) 提出了一种适合隐马尔可夫模型树型结构的多比特数据优化嵌入策略和最大似然检测.数值仿真结果表明,该算法可以较好地利用图像小波域的低频子带以实现较大容量图像水印的嵌入,并在抵抗Stirmark平台攻击,如JPEG压缩、加噪、中值滤波和线性滤波等方面具有很强的稳健性.     

An Adaptive Image Watermarking Algorithm Based on HMM in Wavelet Domain

An adaptive image watermarking algorithm based on HMM in wavelet domain is pro- posed.The algorithm is abstracted as follows:1)the vector HMM model is employed to describe the statistical characteristic of image wavelet coefficients and the resulting HMM based detector achieves significant improvements in performance compared to the conventional correlation detector; 2)adaptive watermark embedding based on HVS analysis;3)a novel embedding strategy which is optimized for the HMM tree structure is adopted;4)the strategy of dynamical threshold is applied in watermark detection.High robust results are achieved against Stirmark attacks,such as JPEG compression,adding noise,median cut and filter.     

基于小波域HMM模型的自适应图像水印算法

An adaptive image watermarking algorithm based on HMM in wavelet domain is proposed. The algorithm is abstracted as follows: 1) the vector HMM model is employed to describe the statistical characteristic of image wavelet coefficients and the resulting HMM based detector achieves significant improvements in performance compared to the conventional correlation detector; 2) adaptive watermark embedding based on HVS analysis; 3) a novel embedding strategy which is optimized for the HMM tree structure is adopted; 4) the strategy of dynamical threshold is applied in watermark detection. High robust results are achieved against Stirmark attacks, such as JPEG compression, adding noise, median cut and filter.     

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.     

Geometrically invariant image watermarking using SVR correction in NSCT domain

Based on the support vector regression (SVR) geometric distortions correction, 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 the NSCT coefficients in small blocks. In digital watermark detecting procedure, the SVR geometrical distortions correction is utilized. Experimental results show that the proposed image watermarking is invisible, and robust against common image processing and some geometrical attacks.     

Partially compressed-encrypted domain robust JPEG image watermarking

Digital media is often handled in a compressed and encrypted form in Digital Asset Management Systems. And watermarking of the compressed encrypted media items in the compressed-encrypted domain itself is required sometimes for copyright violation detection or other purposes. In this paper, we propose a robust image watermarking technique for partially compressed-encrypted JPEG images. However, arbitrary embedding of a watermark in a partially compressed encrypted image can cause drastic degradation of the quality as the underlying change may result in random decrypted values. In addition, due to the encryption the compression efficiency may become very low. Thus the challenge is to design a watermarking technique that provides good watermarked image quality and at the same time gives good compression efficiency. While the proposed technique embeds watermark in the partially compressed-encrypted domain, the extraction of watermark can be done in the encrypted or decrypted domains. The experiments show that the watermarked image quality is good and the reduction in compression efficiency is low. The proposed watermarking technique is robust to common signal processing attacks. The watermark detection performance of the proposed scheme is better than the existing encrypted domain watermarking techniques.