A new algorithm of blind color image watermarking based on LU decomposition

This paper proposes a new algorithm of blind color image watermarking based on LU decomposition. Because of the first column the second row element and the first column the third row element of the lower triangular matrix, which obtained by LU decomposition, have higher similarity, and the color image watermark can be embedded into these elements by slightly modifying rules, which can enhance the watermark invisibility. In addition, Arnold transform is applied to improve the watermark security and the Hash pseudo-random number algorithm based on MD5 is used to improve the watermark robustness. In extraction process, the watermark embedding strength and private key are needed to extract watermark information from the attacked host image with blind manner. Experiment results reveal that the proposed method outperforms other related methods in the aspects of the invisibility, robustness, embedding payload and computational complexity.     

基于Baker映射与时空混沌相结合的CT-QR域双彩色鲁棒盲水印算法

针对彩色水印图像的盲提取算法抗几何攻击鲁棒性不强的问题,提出一种Baker映射与时空混沌相结合的轮廓波变换(Contourlet transform,CT)和QR分解双彩色强鲁棒盲水印算法。首先将彩色水印分离成RGB分量,对三个分量分别进行Baker映射与时空混沌相结合的预处理操作,然后对载体图像的RGB分量分别进行Contourlet变换,分块QR分解得到酉矩阵,最后根据嵌入规则将加密后的水印分通道的嵌入到酉矩阵中。水印提取时利用Radon变换对图像进行几何校正可提高其几何攻击的鲁棒性。仿真结果表明,该算法不仅使嵌入水印后的图像具有良好的不可见性,而且能有效抵抗加噪、滤波、JPEG压缩、剪切、平移、旋转、马赛克、篡改等攻击,NC值均在0.9以上,对组合攻击也有较强的鲁棒性。      

Robust image watermarking based on multiband wavelets and empirical mode decomposition.

In this paper, we propose a blind image watermarking algorithm based on the multiband wavelet transformation and the empirical mode decomposition. Unlike the watermark algorithms based on the traditional two-band wavelet transform, where the watermark bits are embedded directly on the wavelet coefficients, in the proposed scheme, we embed the watermark bits in the mean trend of some middle-frequency subimages in the wavelet domain. We further select appropriate dilation factor and filters in the multiband wavelet transform to achieve better performance in terms of perceptually invisibility and the robustness of the watermark. The experimental results show that the proposed blind watermarking scheme is robust against JPEG compression, Gaussian noise, salt and pepper noise, median filtering, and ConvFilter attacks. The comparison analysis demonstrate that our scheme has better performance than the watermarking schemes reported recently.     

A new facet in robust digital watermarking framework

Generally, in watermarking techniques the size of the watermark is very small when compared to the host image. On the contrary, this is an attempt in which a new facet in watermarking framework is presented where the size of host image is very small when compared to the watermark image. The core idea of the proposed technique is to first scale up the size of host image equal to the size of watermark using chaotic map and Hessenberg decomposition followed by the redundant wavelet transform. A meaningful gray scale watermark is embedded in the low frequency sub-band at the finest level using singular value decomposition. To prevent ambiguity and enhance the security, a binary watermark is also embedded in loss-less manner which ensures the authenticity of the watermarked image. Finally, a reliable watermark extraction scheme is developed for extracting both the watermarks. The experimental results demonstrate better visual imperceptibility and resiliency of the proposed scheme against intentional or un-intentional variety of attacks.     

A Robust Watermarking Scheme Using Sequency-ordered Complex Hadamard Transform

This paper presents a robust phase watermarking scheme for still digital images based on the sequency-ordered complex Hadamard transform (SCHT). The transform matrix of the SCHT exhibits sequency ordering which is analogous to frequency in the discrete Fourier transform (DFT). Hence, sequency-based image analysis can be performed for image watermarking while providing simple implementation and with less computational complexity for computation of the transform. As the SCHT coefficients are complex numbers which consist of both magnitudes and phases, they are suited to adopt phase modulation techniques to embed the watermark. In this proposed scheme, the phases of the SCHT coefficients in the sequency domain are altered to convey the watermark information using the phase shift keying (PSK) modulation. Low amplitude block selection (LABS) is used to enhance the imperceptibility of digital watermark, and amplitude boost (AB) method is employed to improve the robustness of the watermarking scheme. Spread spectrum (SS) technique is adopted to increase the security of watermark against various unintentional or intentional attacks. In order to demonstrate the effectiveness of the proposed watermarking scheme, simulations are conducted under various kinds of attacking operations. The results show that the proposed scheme is able to sustain a series of attacks including common geometric transformations such as scaling, rotating, cropping, painting, and common image-processing operations such as JPEG compression, low-pass filtering, sharpening, noising and phase perturbation, etc. Comparisons of the simulation results with the other schemes are also mentioned and the results reveal that the proposed scheme shows better robustness.     

基于QR分解的强鲁棒性双彩色盲水印算法

提出了一种将彩色快速识别(QR)码作为水印嵌入彩色宿主图像的强鲁棒性盲水印算法。首先 对彩色宿主图像分通道进行离散小波 变换(DWT)和分块QR分解得到非重叠的酉矩阵,然后将QR码分通道置乱加密归一化后嵌入到 宿主图像对应通道 酉矩阵的系数差中。仿真实验结果表明,本算法在满足不可见性的同时具有较强的鲁棒性; 相比现有算法, 本算法不仅能够抵抗旋转和裁切攻击,在JPEG压缩和噪声滤波攻击方面的抵抗能力也有较 大提升;而且本算法属于盲水印技术,具有较大的实际应用价值。     

Image-adaptive watermarking using visual models

The huge success of the Internet allows for the transmission, wide distribution, and access of electronic data in an effortless manner. Content providers are faced with the challenge of how to protect their electronic data. This problem has generated a flurry of research activity in the area of digital watermarking of electronic content for copyright protection. The challenge here is to introduce a digital watermark that does not alter the perceived quality of the electronic content, while being extremely robust to attack. For instance, in the case of image data, editing the picture or illegal tampering should not destroy or transform the watermark into another valid signature. Equally important, the watermark should not alter the perceived visual quality of the image. From a signal processing perspective, the two basic requirements for an effective watermarking scheme, robustness and transparency, conflict with each other. We propose two watermarking techniques for digital images that are based on utilizing visual models which have been developed in the context of image compression. Specifically, we propose watermarking schemes where visual models are used to determine image dependent upper bounds on watermark insertion. This allows us to provide the maximum strength transparent watermark which, in turn, is extremely robust to common image processing and editing such as JPEG compression, rescaling, and cropping. We propose perceptually based watermarking schemes in two frameworks: the block-based discrete cosine transform and multiresolution wavelet framework and discuss the merits of each one. Our schemes are shown to provide very good results both in terms of image transparency and robustness     

Progressive Watermarking Techniques Using Genetic Algorithms

An innovative watermarking scheme based on progressive transmission with genetic algorithms (GAs) is proposed. We implement the watermarking embedding and extraction systems in the transform domain, and apply the JPEG spectral selection mode for scalable transmission of the watermarked image. By employing a GA with a proper fitness function into the watermarking system, both the watermark imperceptibility and watermark robustness requirements are considered and optimized. The number of embedded bits, or the watermark capacity, is much larger than that in other existing algorithms in the literature. Also, the watermark capacity in the proposed algorithm lies within the theoretical limit. In addition, the embedded watermark can be partly extracted at the receiver side even when the watermarked image is being transmitted. Simulation results show both the robustness and the effectiveness of progressive transmission under different attacking schemes and different bandwidth variations. The proposed scheme is directly applicable to scalable coding of multimedia, such as MPEG-4 scalable video coding.     

基于DCT的自适应多重彩色图像盲水印算法

针对现有图像水印算法的一些不足,提出了一种基于离散余弦变换的自适应多重彩色图像盲水印算法。该算法根据彩色载体图像内容特点,将预处理后的不同二值图像水印自适应地嵌入到其绿色分量的离散余弦变换低频系数和中频系数,实现了不同水印在彩色载体图像中的嵌入及盲提取。实验结果表明,该算法在保证不可觉察性的前提下能够较好地抵抗各类常规攻击,具有良好的稳健性。     

一种解决版权问题的数字水印方案

大部分水印技术侧重于水印的不可见性和稳健性,而版权保护问题并未得到真正解决。该文提出的数字水印方案可以有效地解决这一问题。通过一种新颖的水印构造方法,有效地消除了在解决版权问题中对使用原始图像的限制。盲与非盲水印检测时水印的不可见性和稳健性均得到很大提高。实验结果证明该数字水印方案对于版权攻击是有效的,对各种失真都具有较强的稳健性。     

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.     

Hiding digital watermarks using multiresolution wavelet transform

In this paper, an image accreditation technique by embedding digital watermarks in images is proposed. The proposed method for the digital watermarking is based on the wavelet transform. This is unlike most previous work, which used a random number of a sequence of bits as a watermark and where the watermark can only be detected by comparing an experimental threshold value to determine whether a sequence of random signals is the watermark. The proposed approach embeds a watermark with visual recognizable patterns, such as binary, gray, or color image in images by modifying the frequency part of the images. In the proposed approach, an original image is decomposed into wavelet coefficients. Then, multi-energy watermarking scheme based on the qualified significant wavelet tree (QSWT) is used to achieve the robustness of the watermarking. Unlike other watermarking techniques that use a single casting energy, QSWT adopts adaptive casting energy in different resolutions. The performance of the proposed watermarking is robust to a variety of signal distortions, such as JPEG, image cropping, sharpening, median filtering, and incorporating attacks     

Digital watermarking robust to geometric distortions.

In this paper, we present two watermarking approaches that are robust to geometric distortions. The first approach is based on image normalization, in which both watermark embedding and extraction are carried out with respect to an image normalized to meet a set of predefined moment criteria. We propose a new normalization procedure, which is invariant to affine transform attacks. The resulting watermarking scheme is suitable for public watermarking applications, where the original image is not available for watermark extraction. The second approach is based on a watermark resynchronization scheme aimed to alleviate the effects of random bending attacks. In this scheme, a deformable mesh is used to correct the distortion caused by the attack. The watermark is then extracted from the corrected image. In contrast to the first scheme, the latter is suitable for private watermarking applications, where the original image is necessary for watermark detection. In both schemes, we employ a direct-sequence code division multiple access approach to embed a multibit watermark in the discrete cosine transform domain of the image. Numerical experiments demonstrate that the proposed watermarking schemes are robust to a wide range of geometric attacks.     

Ergodic chaotic parameter modulation with application to digital image watermarking.

This paper presents a novel technique for image watermarking based on chaos theory. Chaotic parameter modulation (CPM) is employed to modulate the copyright information into the bifurcating parameter of a chaotic system. The system output is a wideband signal and is used as a watermark to be inserted into the host image. In the detection, a novel method based on the ergodic property of chaotic signal is developed to demodulate the embedded copyright information. Compared to previous works on blind watermarking, the proposed technique can effectively remove the interference from the host image and, thus, improve the detection performance dramatically. Simulation results show that the ergodic CPM approach is effective for image watermarking in terms of noise performance, robustness against attacks, and payload. In addition, its implementation is very simple and the computation speed is fast. Compared to holographic transform domain method and the conventional spread spectrum watermarking scheme, the proposed technique is shown to be superior.     

基于DWT-QDFT的硬拷贝彩色图像全息水印

提出了一种基于离散小波变换(DWT)及四元数傅里 叶变换(QDFT)的鲁棒性全息水印算法。首先对RGB彩色图像的三个色彩分量分 别做DWT,取变换后的3个低频部分组成纯四元数矩阵;随后对其进行QDFT ,将全息水印通过替代QDFT的实部的中频系数进行嵌入,再经过逆QDFT及小波重构得到含有 水印的彩 色图像。攻击测试结果表明,本文算法对于常规的信号处理有很好的鲁棒性;打印扫描实验 证明,本文算法具有抵 抗硬拷贝攻击的能力。四元数傅立叶变换的引入,实现了小波低频系数的嵌入保证了算法的 鲁棒性,同时 又结合了四元数在处理彩色图像中的优势,双变换域的采用与全息方法的结合实现了算法应 用于硬拷贝彩 色图像中鲁棒性及不可见性之间的平衡。本文全息水印方案可以应用于印品水印防伪领域。     

Robust digital watermarking algorithm based on continuous hyperchaotic system and discrete wavelet transform

Many digital watermarking methods have been pro-posedin the last fewyears[1 ,3].It is a tradeoff problemsince whenthe robustness of a watermarkincreases ,theperceptual quality of the contents will be degraded.Hence,the main goal of i mproving a watermarki…     

基于FFT域的手机彩信盲检测图像水印

移动通信的发展使得手机彩信广泛使用,针对彩信图像的数字权利管理,提出了基于FFT域的高容量、强鲁棒性、盲检测图像水印算法.该算法对图像亮度矩阵的频谱幅度采样点的大小关系进行调制,可以抵抗图像长宽不等任意缩放、图像基本旋转、格式转换以及常规图像处理攻击等对水印系统的影响.该算法运用FFT变换的感知模型,采用自适应的通知编码和通知嵌入技术,控制了水印嵌入的增益,提高图像的保真度,增强抵抗攻击的能力.实验证明,该算法是有效的,可以满足实时计算的要求.     

BGGMM-HMT based locally optimum image watermark detector in high-order NSST difference domain

Imperceptibility, robustness and data payload are three main requirements of any image watermarking systems to guarantee desired functionalities, but there is a tradeoff among them from the information-theoretic perspective. How to achieve this balance is a major challenge. In this paper, we propose a new statistical image watermarking scheme, which is based on the high-order difference coefficients in nonsubsampled Shearlet transform (NSST) domain and the bounded generalized Gaussian mixture model-based hidden Markov tree (BGGMM-HMT). In the watermark embedding process, we use a nonlinear embedding approach to hide the digital watermark into the robust high-order difference coefficients, which can achieve better imperceptibility. In the watermark detection process, high-order difference coefficients are accurately modeled by using BGGMM-HMT, where the distribution characteristics of high-order difference coefficients can be captured through BGGMM, and the scale dependencies of high-order difference coefficients can be captured through HMT. Statistical model parameters are then estimated by combining the approach of minimizing the higher bound on data negative log-likelihood function and upward–downward algorithm. Finally, an image watermark detector based on BGGMM-HMT is developed using the locally optimum (LO) decision rule. For the proposed detector, the receiver operating characteristic (ROC) expression is derived in detail. We evaluate the proposed scheme from different aspects and compare it with the state-of-the-art schemes. After a large number of experimental tests, the encouraging results obtained prove the effectiveness of our watermarking scheme.     

基于自嵌入鲁棒双水印的图像认证算法

通过构造鲁棒零水印并鲁棒的嵌入到图像自身来实现完全盲检测的鲁棒水印方案,从而完成数字图像的全盲版权认证。首先利用整数小波变换构造鲁棒零水印:将原始图像进行三级整数小波变换,并将变换后获取的第三级低频子带(LL3)系数二值化来构造鲁棒零水印。然后利用一种基于奇异值分解(SVD,singular value decomposition)的鲁棒水印方案,将构造的鲁棒零水印嵌入到图像小波变换域低频子带(LL1)的分块奇异值分解的U矩阵的系数中。利用超混沌系统设计了随机置乱和加密方案。在鲁棒嵌入之前,先将二值零水印进行置乱分散并加密,增强了方案的鲁棒性和构造水印安的全性。实验结果证明了所提出的方案的有效性。     

A dual cepstrum-based watermarking scheme with self-synchronization

This study presents a supplementary cepstrum-based scheme to achieve blind audio watermarking via the mean-value manipulation. The proposed scheme can work with the conventional statistical mean manipulation to double the watermark capacity under the same framework. As these two cepstral schemes affect the spectrum in low frequencies in a superposition manner, the developed watermarking system employs the conventional scheme to initiate a start and the new one to actually embed watermark bits. During the embedding phase, the rapid variations between frames caused by the watermarking process are avoided by adding a transition space. In addition, the watermarking system maintains data synchronization through the insertion of a sinusoid-like signal which keeps synchronization with the frame rate. Experimental results confirm the robustness of the proposed scheme against various attacks, including time-scaling and time-shifting that many other watermarking techniques failed to survive through.