基于视觉模型的迭代AQIM水印算法

 自适应量化索引调制算法（AQIM）通过Watson视觉模型来计算量化步长,使得量化步长可以随着待量化系数自适应变化,从而获取了比传统量化索引调制算法（QIM）更好的不可见性和鲁棒性.但即使在没有干扰的情况下,该算法在检测时计算的量化步长与嵌入时计算的量化步长也不一致,这就导致水印不能够完整可靠地提取.本文在分析该算法存在问题的基础上,提出了一种改进的迭代AQIM水印方案,仿真实验表明该方案比原算法具有更好的性能.     

Joint trellis-coded quantization watermarking for JPEG2000 images

Watermarking in the Joint Photographic Experts Group (JPEG)2000 coding pipeline is investigated in this paper. A joint quantization and watermarking method based on trellis-coded quantization (TCQ) is proposed to reliably embed data during the quantization stage of the JPEG2000 part 2 codec. The central contribution of this work is the use of a single quantization module to jointly perform quantization and watermark embedding at the same time. The TCQ-based watermarking technique allows embedding the watermark in the detail sub-bands of one or more resolution levels except the first one. Watermark recovery is performed after image decompression. The performance of this joint scheme in terms of image quality and robustness against common image attacks was estimated on real images.     

A Hybrid Approach of DWT and DCT for Rational Dither Modulation Watermarking

In this paper, on the basis of the theories and methods of Watson’s perceptual model and rational dither modulation (RDM), a hybrid quantization-based watermarking in the discrete wavelet transform (DWT) and discrete cosine transform (DCT) domains is studied. In the design of the quantization-based watermarking, quantization step-size plays an important role in many watermarking algorithms. RDM at both the embedder and decoder adopts a gain-invariant adaptive quantization step-size. Therefore, we investigated combining the modified Watson’s perceptual model with RDM. Its improved robustness is due to the embedding in the high entropy region of low-frequency sub-band image and adaptive control of its quantization step-size. The Euclidean distance decoder is used to extract the watermark data. The performance of the proposed scheme is analytically calculated and verified by simulation. Experimental results confirm the imperceptibility of the proposed watermarking and its higher robustness against attacks compared to alternative watermarking methods in the literature.     

Robust watermarking against print and scan attack through efficient modeling algorithm

This article proposes a blind discrete wavelet transform-discrete cosine transform (DWT-DCT) composite watermarking scheme that is robust against print and scan distortions. First, two-dimensional DWT is applied to the original image to obtain the mid-frequency subbands. Then, a one-dimensional DCT is applied to the selected mid-frequency subbands to extract the final coefficients for embedding the watermark. To specify watermarking parameters, we utilize a Genetic Algorithm to achieve a predefined image quality after watermark insertion. Suitable locations for watermarking are determined by analyzing the effect of a modeling algorithm. This model simulates noise and nonlinear attacks in printers and scanners through noise estimation and system identification methods. The experimental results demonstrate that the proposed algorithm has a high robustness against print and scan attack such that its robustness is higher than related watermarking algorithms.     

A Novel Audio Watermarking Algorithm for Copyright Protection of Digital Audio

Digital watermark technology is now drawing attention as a new method of protecting digital content from unauthorized copying. This paper presents a novel audio watermarking algorithm to protect against unauthorized copying of digital audio. The proposed watermarking scheme includes a psychoacoustic model of MPEG audio coding to ensure that the watermarking does not affect the quality of the original sound. After embedding the watermark, our scheme extracts copyright information without access to the original signal by using a whitening procedure for linear prediction filtering before correlation. Experimental results show that our watermarking scheme is robust against common signal processing attacks and it introduces no audible distortion after watermark insertion.     

一种基于特征的自适应水印算法

基于图像多尺度空间理论和扩频机制以及视觉感知模型的特性,给出一种基于特征的数字图像水印算法。算法采用尺度不变特征变换算子提取图像的局部不变特征区域,根据信噪比特点自适应选取水印嵌入强度因子,将一幅二值水印图像嵌入到原始图像中,实现了数字水印的不可感知性和鲁棒性。仿真结果表明,该算法对添加噪声、压缩、旋转等常见的图像处理攻击具有较强的鲁棒性。     

Localized image watermarking in spatial domain resistant to geometric attacks

Watermark robustness to geometric attacks is still a challenging research field. In this paper, a novel robust image watermarking scheme is proposed for resisting such attacks. Watermark synchronization is first achieved by local invariant regions which can be generated using scale normalization and image feature points. The watermark is embedded into all the local regions repeatedly in spatial domain. During embedding, each circular region is first divided into homocentric cirque regions. Then the watermark bits are embedded by quantizing each cirque region into an “odd” or “even” region using odd–even quantization. In the decoder, an odd–even detector (OED) is designed to extract the watermark from the distorted image directly. Localized embedding achieves good invisibility and repeated insertion enhances watermark robustness. Simulation results show that the proposed scheme is robust to both geometric attacks and traditional signal processing attacks.     

Watermarking 3D models using spectral mesh compression

We propose a robust and imperceptible spectral watermarking method for high rate embedding of a watermark into 3D polygonal meshes. Our approach consists of four main steps: (1) the mesh is partitioned into smaller sub-meshes, and then the watermark embedding and extraction algorithms are applied to each sub-mesh, (2) the mesh Laplacian spectral compression is applied to the sub-meshes, (3) the watermark data is distributed over the spectral coefficients of the compressed sub-meshes, (4) the modified spectral coefficients with some other basis functions are used to obtain uncompressed watermarked 3D mesh. The main attractive features of this approach are simplicity, flexibility in data embedding capacity, and fast implementation. Extensive experimental results show the improved performance of the proposed method, and also its robustness against the most common attacks including the geometric transformations, adaptive random noise, mesh smoothing, mesh cropping, and combinations of these attacks.     

基于H.264误差漂移补偿的鲁棒性视频水印算法

针对现有基于H.264的视频水印算法存在误差漂移的问题,在分析了误差漂移产生原因的基础上,提出了一种抑制误差漂移的鲁棒性视频水印新算法.通过调制H.264编码中Ⅰ帧量化后的4 ×4 DCT系数来实现水印的嵌入,并对帧内预测量化后满足特定条件的DCT子块的最后一行、列进行补偿和对帧间预测进行补偿,有效地抑制了帧内、帧间误差漂移.另外,该算法结合CAVLC编码来调制量化后的DCT残差系数,使整体码流变动较小,并且算法能够根据不同视频序列自适应地调节嵌入容量及嵌入位置,具有较好的灵活性和鲁棒性.在水印提取过程中,不需要原始视频的参与,即可实现盲提取.仿真实验结果表明,该算法在具有良好不可见性的前提下,对压缩码率影响较小,能够较好地抵抗噪声、帧剪切、重编码等攻击.     

Quantization index modulation: a class of provably good methods fordigital watermarking and information embedding

We consider the problem of embedding one signal (e.g., a digital watermark), within another “host” signal to form a third, “composite” signal. The embedding is designed to achieve efficient tradeoffs among the three conflicting goals of maximizing the information-embedding rate, minimizing the distortion between the host signal and composite signal, and maximizing the robustness of the embedding. We introduce new classes of embedding methods, termed quantization index modulation (QIM) and distortion-compensated QIM (DC-QIM), and develop convenient realizations in the form of what we refer to as dither modulation. Using deterministic models to evaluate digital watermarking methods, we show that QIM is “provably good” against arbitrary bounded and fully informed attacks, which arise in several copyright applications, and in particular it achieves provably better rate distortion-robustness tradeoffs than currently popular spread-spectrum and low-bit(s) modulation methods. Furthermore, we show that for some important classes of probabilistic models, DC-QIM is optimal (capacity-achieving) and regular QIM is near-optimal. These include both additive white Gaussian noise (AWGN) channels, which may be good models for hybrid transmission applications such as digital audio broadcasting, and mean-square-error-constrained attack channels that model private-key watermarking applications     

数字音频信号中的频域扰动调制水印嵌入

扰动调制是一种非线性水印技术,已应用于数字图像。本文结合听觉特性,利用这一技术将水印信号嵌入在数字音频频域中。实验表明水印的嵌入不会被人耳觉察,并且该方案在抵抗各种常见的攻击方面表现出良好的稳健性。     

Wavelet-based watermarking for color images through visual masking

In this paper, a wavelet-based watermarking scheme for color images is proposed. The watermarking scheme is based on the design of a color visual model that is the modification of a perceptual model used in the image coding of gray scale images. The model is to estimate the noise detection threshold of each wavelet coefficient in luminance and chrominance components of color images in order to satisfy transparency and robustness required by the color image watermarking technique. The noise detection thresholds of coefficients in each color component are derived in a locally adaptive fashion based on the wavelet decomposition, by which perceptually significant coefficients are selected and a perceptually lossless quantization matrix is constructed for embedding watermarks. Performance in terms of robustness and transparency is obtained by embedding the maximum strength watermark while maintaining the perceptually lossless quality of the watermarked color image. Simulation results show that the proposed scheme is more robust than the existing scheme while retaining the watermark transparency.     

Robust Audio Watermarking Algorithm Based on Empirical Mode Decomposition

A novel robust audio watermarking algorithm based on empirical mode decomposition is proposed.The intrinsic feature of the final residual decomposed from the audio frame is selected to embed watermark and the algorithm works by shifting each element of the final residual to make its sum greater or less than 0.The experimental results show that the proposed algorithm does not change the property of the final residual after embedding watermark and the watermark is robust against various kinds of attacks.Compared with existing classic algorithms based on Empirical mode decomposition (EMD),the proposed algorithm largely improves both the robustness and imperceptibility of watermarking.     

一种基于量化方法的3D模型盲水印算法

相对非盲算法而言,盲算法因在水印检测时不需要传输原始载体而使其应用更为广泛。虽然盲水印算法的鲁棒性稍弱,但仍有提高的空间。该文提出一种3D网格盲水印算法,利用伪随机数产生经过模型质心的直线,选取以直线与模型交点为球心的球形邻域作为嵌入对象,水印信息是通过抖动调制邻域内顶点的重心来嵌入的。因为重心依赖于球形邻域所有顶点坐标,所以需解决由调整后的重心逆向估计邻域内顶点坐标问题,文中给出相应的算法。水印算法除了具有抵御顶点重排的免疫力外,也把每比特水印关联到直线与模型的多个交点和多个交点的球形邻域内的成组顶点上,能较好地抵抗剪切攻击和随机噪声。实验数据说明了算法的鲁棒性能。     

自适应的混合域音频水印新算法

本文结合小波包变换和离散余弦变换，提出了一种基于听觉模型的混合域自适应音频盲水印算法，在不引入听觉失真的前提下，实现了自适应的水印嵌入。算法首先对音频信号进行小波包分解，使得分解后的子带更接近人耳临界频带。其次对每个子带的小波包系数进行离散余弦变换，计算出子带掩蔽阈值。根据子带掩蔽阈值自适应的选取噪声敏感度小的音频段作为水印嵌入段，选取功率值低于掩蔽阈值的频域系数作为水印嵌入位置，同时采用噪声掩蔽比调整水印嵌入强度。二值水印图像通过量化索引调制的方法嵌入到音频信号的中低频系数中，提取水印时不需要原始音频载体。本算法在水印容量、不可感知性和鲁棒性之间达到了很好的平衡，水印容量在576.7bps到689.5bps之间，算法对添加噪声、重新量化、重新采样、低通滤波和MP3压缩均具有很好的鲁棒性。      

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.     

Towards robust image watermarking: combining content-dependent key,moment normalization,and side-informed embedding

In digital watermarking, robustness is still a challenging problem if different sets of attacks need to be tolerated simultaneously. In this paper, we deal with this problem by using an integrated solution involving side-informed embedding, moment normalization, and content-dependent watermarks. First, a new image watermarking method based on the concept of communications with side information is proposed. We investigate the characteristics of mean filtering in formulating new watermark embedding and extraction processes. Second, regarding resistance to geometrical attacks, we do not rely on the concept of pilot signals because they are vulnerable to synchronization removal attacks. We instead use block-based watermarking and moment normalization mechanisms to recover geometrical distortions. Third, regarding resistance to the copy attack, the content-dependent watermark is employed to avoid treating an un-watermarked image as one that has been watermarked. The robustness of our approach has been verified using both the StirMark and the copy attack.     

Geometrically invariant image watermarking based on fast Radial Harmonic Fourier Moments

In order to reduce the time complexity and improve the reconstruction performance of traditional method for Radial Harmonic Fourier Moments (RHFMs), we introduce a fast and precise method by using FFT and based on the which, this paper proposes a novel image watermarking algorithm which is robust to geometric attacks. We firstly compute the RHFMs of the original image by using the proposed method and select the robust RHFMs which are suitable for watermark embedding. Then the watermark is embedded by modifying the magnitudes of RHFMs based on quantization. In the decoder, the watermark can be extracted from the magnitudes of RHFMs directly without using the original image. Simulation results show the proposed algorithm provides an excellent watermark invisibility and can be resilient to geometric attacks and common image processing attacks effectively.     

A new video watermarking algorithm based on 1D DFT and Radon transform

In this paper, we propose a new video watermarking algorithm based on the 1D DFT (one-dimensional discrete Fourier transform) and Radon transform. The 1D DFT for a video sequence generates an ideal domain, in which the spatial information is still kept and the temporal information is obtained. With detailed analysis and calculation, we choose the frames with highest temporal frequencies to embed the fence-shaped watermark pattern in the Radon transform domain of the selected frames. The adaptive embedding strength for different locations keeps the fidelity of the watermarked video. The performance of the proposed algorithm is evaluated by video compression standard H.264 with three different bit rates; geometric attacks such as rotation, translation, and aspect-ratio changes; and other attacks like frame drop, frame swap, spatial filtering, noise addition, lighting change, and histogram equalization. The main contributions of this paper are the introduction of the 1D DFT along temporal direction for watermarking that enables the robustness against video compression, and the Radon transform-based watermark embedding and extraction that produces the robustness against geometric transformations. One of the most important advantages of this video watermarking algorithm is its simplicity and practicality.     

Robust and secure fractional wavelet image watermarking

This paper presents an efficient fractional wavelet transform (FWT) image watermarking technique based on combining the discrete wavelet transform (DWT) and the fractional Fourier transform (FRFT). In the proposed technique, the host image is wavelet transformed with two resolution levels, and then, the middle frequency sub-bands are FRFT transformed. The watermark is hidden by altering the selected FRFT coefficients of the middle frequency sub-bands of the 2-level DWT-transformed host image. Two pseudo-random noise (PN) sequences are used to modulate the selected FRFT coefficients with the watermark pixels, and inverse transforms are finally applied to get the watermarked image. In watermark extraction, we just need the same two PN sequences used in the embedding process and the watermark size. The correlation factor is used to determine whether the extracted pixel is one or zero. The proposed fractional wavelet transform (FWT) image watermarking method is tested with different image processing attacks and under composite attacks to verify its robustness. Experimental results demonstrated improved robustness and security.