基于运动、内容和帧分类的自适应视频水印算法

本文提出了一种DCT域自适应视频水印算法,根据帧分类、运动分类和视频内容将视频数据分类,并根据分类的结果在不同的区域嵌入不同强度的水印,从而提高了视频数字水印的鲁棒性.实验结果表明嵌入水印后视频重建帧水印具有良好的透明性;算法对于MPEG2压缩、多重MPEG2压缩、帧提取、MPEG2压缩与加噪声、裁剪等混合攻击具有较好的鲁棒性.     

基于Watson视觉模型的自适应视频水印

提出了一种基于Watson视觉模型的自适应视频水印，Watson视觉模型用于控制水印的嵌入强度。借助于该视觉模型，很容易权衡水印鲁棒性和感知透明性的关系。经过实验证实，该水印系统对常用的视频攻击（MPEG压缩、帧丢失、帧剪切、帧重排）是鲁棒的，同时具有感知透明性和实时性等特性。     

基于差值抖动调制的鲁棒数字水印

针对数字图像版权保护问题,提出了一种新的鲁棒水印方案.该方案首先对水印进行扩频调制,然后随机选取图像8×8分块DCT变换后的中低频系数对来嵌入水印信息,为了使水印能够抵抗JPEG压缩,提出了基于差值抖动调制的嵌入方法.最后对影响水印鲁棒性和不可见性的主要因素进行了分析.实验结果表明,该方案不仅能够抵抗JPEG压缩和剪切攻击,而且能够抵抗一定程度的低通滤波攻击.     

基于三维小波低频域的彩色视频盲水印算法

视频水印技术是保护数字视频版权的一种有效方法。提出一种基于3D DWT的彩色视频水印算法,按场景以16帧划分视频,在各子段YCbCr颜色空间上对Y分量进行二级三维小波变换,利用三维小波低频帧间系数相近而不相同的特性进行水印嵌入,并实现了水印的盲提取。实验结果表明,该算法在保证含水印视频图像质量的同时具备良好的鲁棒性,对各种视频几何攻击及MPEG压缩均具有较强的抵抗能力。     

一种基于H.264压缩域的数字水印方法

给出一种用于H.264压缩域的数字水印方法,能够大幅度提高水印的嵌入容量,同时消除水印嵌入后引起的错误累积效应.提出一种新的视觉模型,综合利用亮度和色度信息对图像块进行分类,然后选取边缘区和纹理区作为水印的嵌入区域,从而大幅度提高水印容量,最后在此基础上提出了一种补偿机制,能够消除帧内预测影响的数字水印方法.该方法能够在H.264的压缩域实时高效地嵌入和提取水印信息,并能够抵抗各种常规的攻击.     

DCT变换域中的自适应图像水印算法

提出了一种基于DCT变换的数字水印算法,该方法能够自适应地选取水印嵌入位置,依据人类视觉特性,合理地分配不同嵌入位置处嵌入的水印强度。另外,结合混沌序列和置乱技术,增强了水印的抗攻击能力。经实验验证,该方法基本上满足不可见性和鲁棒性要求,尤其具有较强的抗JPEG压缩攻击的能力。     

彩色数字水印技术的研究

提出一种基于小波变换的彩色图像水印算法。通过对彩色水印进行分解、置乱、压缩等预处理过程来提高水印的透明性及鲁棒性;通过采用多通道、分区域及控制嵌入强度等方法来提高水印的鲁棒性及容量。采用Matlab对水印的嵌入及提取过程进行仿真,并对嵌入水印后的图像进行剪切、压缩、加噪等攻击测试。仿真结果表明该算法透明性好,具有较强的抗攻击能力。     

一种实现视频水印嵌入的新方法

在研究前人提出的视频水印理论基础上,结合MPEG编解码方案和人眼视觉特性,采用在宏块的运动速度图中以十字方式嵌入水印的方法,该方法的优点是:水印的嵌入不会影响I帧的图像质量,水印的嵌入量大,不但提高了水印的不可见性,而且增强了水印的稳健性.     

一种基于小波变换的扩频数字图像盲水印算法

提出了一种基于小波变换的自适应数字图像水印算法.该算法根据原始图像的特点对水印的嵌入位置及嵌入强度进行自动调节,同时对嵌入的水印信号采用扩频的方法加入水印系统中,增强了图像抗攻击能力,提高了水印安全性.实验结果表明该算法对JPEG压缩、随机噪声攻击、剪切及加噪等具有较高的鲁棒性.     

基于压缩感知的鲁棒性水印算法

为了改进传统的变换域水印嵌入算法,以提高水印嵌入效率并减小对载体图像的影响,同时保证水印信息的完整性和鲁棒性。为此,本设计采用了压缩感知的处理方法。通过使用随机高斯矩阵作为测量矩阵对待嵌入水印信息进行压缩采样,有效减少所需的嵌入信息量,提高水印嵌入效率。此外,本设计还能保证水印嵌入的安全性。经过仿真实验验证,与传统DWT算法相比,本设计具有鲁棒性强、不可见性好、实时性更优等特点。综上所述,本设计能够有效地嵌入水印信息,提高水印嵌入效率,并在保证水印信息完整性和鲁棒性的同时,减小对载体图像的影响。该设计具有实际应用价值,可广泛应用于图像水印领域。     

一种不修改图像内容的鲁棒性水印算法

该文结合密码学和数字水印技术,提出了一种新的不修改图像内容的鲁棒性水印算法。该算法不仅对有损压缩,噪声攻击具有较好的鲁棒性,而且可以抵抗共谋攻击和多水印攻击。与Lee[1]的算法相比,它特别对剪切攻击具有较好的鲁棒性,而且计算速度快。     

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.     

An optimal image watermarking approach based on a multi-objective genetic algorithm

In accordance with the multi-objective nature of image watermarking, an optimal image watermarking approach using a multi-objective genetic algorithm is presented in this paper. Both watermarking parameters and embedding positions are often important factors affecting the performance of watermarking systems. The proposed multi-objective watermarking method can automatically optimize system parameters, and a variable-length mechanism is specially designed to search the most suitable positions for embedding watermarks. The method can also remove the difficult issue of determining optimal watermarking parameters from previous watermarking algorithms. The proposed multi-objective watermarking method directly deals with the problem of optimizing watermarking under non-dominated meaning, thus it can effectively avoid the difficulty of determining the optimally weighted factor in existing single-objective watermarking schemes. In addition, a Pareto-optimal set generated by multi-objective optimization can provide flexibility in selecting the most suitable watermarking parameters according to practical requirements.     

基于离散小波变换的QR二维条码防伪技术

基于数字水印的快速响应矩阵（QR）二维条码防伪技术的水印容量低、防伪效果差。为解决该问题,提出QR码二值图像Rand灰度化和背景图灰度化方法,以提高防伪水印容量。QR码二值图像灰度化的程度由灰度化阈值决定,并且可以根据实际应用需要灵活确定。在此基础上,设计基于离散小波变换的QR二维条码防伪水印方案,通过量化函数实现水印的嵌入和检测,利用混沌密钥生成的二维混沌序列控制水印嵌入和检测的位置。实验结果表明,该方案在确保条码信息可识别的条件下,提高了QR码防伪水印的性能。     

Reversible video watermarking through recursive histogram modification

In this study, a new reversible video watermarking method is developed. Unlike the existing reversible video watermarking algorithms that are based on motion compensated prediction or interpolation error expansion, motion compensated interpolation errors in the proposed method are watermarked in a totally different manner with the aid of recursive histogram modification algorithm developed recently for the purpose of reversible image watermarking. However,the recursive histogram modification can not be used directly for reversible video watermarking since the important problems of ensuring reversibility for each frame and distribution of total capacity among frames are encountered. In this study, novel ideas are proposed to solve the aforementioned two problems. The proposed method is tested on the video sequences commonly used in the literature. It is shown to give better performance than the existing reversible video watermarking algorithms in terms of capacity and distortion by means of computer simulations. Also, a numerical example is provided.     

Robust color image watermarking using invariant quaternion Legendre-Fourier moments

In this paper, a geometrically invariant color image watermarking method using Quaternion Legendre-Fourier moments (QLFMs) is presented. A highly accurate, fast and numerically stable method is proposed to compute the QLFMs in polar coordinates. The proposed watermarking method consists of three main steps. First, the Arnold scrambling algorithm is applied to a binary watermark image. Second, the QLFMs of the original host color image are computed. Third, the binary digital watermark is embedding by performing the quantization of selected QLFMs. Two different groups of attacks are considered. The first group includes geometric attacks such as rotation, scaling and translation while the second group includes the common signal processing attacks such as image compression and noise. Experiments are performed where the performance of proposed method is compared with the existing moment-based watermarking methods. The proposed method is superior over all existing quaternion moment-based watermarking in terms of visual imperceptibility capability and robustness to different attacks.     

基于整数小波变换和SVD的视频水印算法

提出了一种以二值图像为水印的混合整数小波变换和奇异值分解的视频水印盲提取算法。对水印图像进行混沌加密和Arnold置乱处理,选择计算复杂度低的直方图算法将视频分割为若干场景;借助密钥随机选取某些场景的亮度分量进行l级整数小波变换,再对低频子带进行分块的奇异值分解;采用量化的方法,将预处理后的水印图像嵌入奇异值分解后的最大奇异值中。在嵌入了水印的视频场景中提取所有的水印版本之后,利用对提取的所有水印信号版本进行统计求和的方法得到最终提取的水印图像。实验表明,提出的算法具有较好的透明性,对常见的处理具有较好的鲁棒性。     

以鲁棒性为目标的数字多水印研究

单个的数字水印算法或方案难以应付多种攻击方法的攻击，为此，文章对应用多水印方法提高水印抗攻击鲁棒性问题进行探讨，根据水印抵抗攻击的能力，给出了水印抗攻击鲁棒性的分类定义，同时根据这种能力提高的程度对多水印进行了分类，并由此引申出相关的命题．深入探讨了多水印带来的主要问题，并提出了解决多水印问题的多目标优化数学模型．以视频水印为例，对抗几何变换攻击和帧同步攻山的视频水印联合进行了实验，实验结果表明多目标优化模型能够有效解决多水印带来的问题，且多水印方法能够提高水印抵抗攻击的能力．     

关于能量比较的数字音频盲水印方案

提出了一种关于能量比较的数字音频盲水印方案,该方案具有以下特点：根据人类听觉系统掩蔽特性,通过能量比较自适应地寻找最佳水印嵌入点;利用离散余弦变换（Discrete Cosine Transform,DCT）的能量压缩特性,提高数字水印的隐藏效果;实现音频数字水印的高透明性和高鲁棒性的同时,实现水印的盲检测。实验结果表明,算法不但保持了在各种攻击下较好的或更好的鲁棒性,定性和定量两方面的分析,也都显示了嵌入水印后的音频信号可以更好地保留原音频信号的感知质量。     

一种抗同步攻击的自适应扩频文本数字水印

针对同步攻击这一困扰扩频水印技术的难题,提出了一类基于字符特征的文本数字水印系统编码映射规则,以及相应的扩频水印加载与检测模型;并利用字符语义在水印加载与检测过程中具备的良好鲁棒性,通过载体字符产生伪随机代码,最终生成具有同步错误修正能力的自适应扩频文本水印.分析表明,利用这种方法产生的伪随机代码具有良好的随机特性;仿真实验表明,该扩频文本水印在保持水印数据扩频特性优势的同时,抗同步攻击性能得到了显著的提高.