基于提升小波的多重数字音频水印

该文提出了一种在提升小波域同时嵌入鲁棒水印和易损水印的音频水印算法。原始音频信号经过提升小波变换后，将低频小波系数进行均值量化嵌入鲁棒水印，具有较好的鲁棒性和不可感知性；对高频小波系数直接进行单个系数量化嵌入易损水印，当音频内容发生篡改时，这些水印信息会发生相应的改变，从而可以鉴定原始音频的完整性。水印的提取不需要原始音频信号。实验结果表明，鲁棒水印对MP3压缩、低通滤波、加噪、重量化、重采样等信号处理攻击具有很强的鲁棒性：而易损水印对上述攻击则具有很强的敏感性。     

一种新的数字音频多水印算法

本文以同时实现数字媒体的版权保护和内容认证为目标,提出一种在同一个音频文件中嵌入三个不同水印的数字音频多水印算法.鲁棒水印经置乱预处理后,通过SCS方法(Scalar Costa Scheme)嵌入音频信号的低频小波系数中,具有良好的鲁棒性.它不仅对加噪、低通滤波等常见信号处理稳健,还具有抵抗恶意替换攻击的能力,实现了音频文件的版权保护.时域SCS算法嵌入的半易损水印对一般信号操作稳健而对恶意篡改敏感并可以对篡改区域进行定位.最后通过改进的融合信息隐藏算法在时域嵌入全易损水印,它对加之于音频信号上的任何微小变化都非常敏感,可对原始文件的完整性进行认证.实验结果表明,整个系统透明性良好.三种水印提取时均不需提供原始音频信号,具有一定的实用价值.     

一种新的基于混合域的数字音频水印

在数字水印的基础上,提出了一种基于DCT和DWT混合域的音频水印的算法。首先对原始的音频信号进行离散小波变换,得到音频信号的精细分量和近似分量,然后对这两种系数进行离散余弦变换,最后将两种不同的水印嵌入到两种系数。提取水印信息时,不管音频信号的长度如何,均采用相同的方法进行变换。实验证明,此方法可以实现不丢失音频信号的频率信息,在考虑嵌入的两种不同水印的顺序的原则下,实现嵌入和提取信息的同步。     

基于小波变换的双水印算法

数字音频水印是水印技术中重要的组成部分。而近年来对音频水印的研究远远少于图像水印,双水印的研究则更加少。因此提出了一种基于小波变换的双水印算法,在音频信号的小波变换域嵌入两个不同作用的水印,对一些音频处理有很好的鲁棒性的同时又能有效地判别音频信号的真实性和完整性。实验证明本算法的两水印分别具有很好的鲁棒性和敏感性,并实现了水印的盲提取。     

音频中同时嵌入稳健水印和脆弱水印的探讨

在同一音频作品中先后加入稳健水印和脆弱水印,通过对小波变换系数模2取余方法嵌入稳健水印,通过对离散小波变换系数采取适当的量化处理嵌入脆弱水印。讨论了嵌入参数对水印不可知性、稳健性和脆弱性的影响。     

基于DWT的数字水印算法研究

数字水印是在不影响多媒体产品（如数字图像、文档、视频、音频等）使用质量的前提下,将具有特定意义的标记（水印）,按照某种给定算法嵌入到媒体产品中,以实现对该产品的保护或认证。针对数字图像水印技术,比较系统地研究了基于DWT域的两种数字图像水印嵌入算法及对应的提取算法。实验结果表明,两种嵌入算法都有不错的效果;第一种算法对应的提取算法提取出的水印效果不很理想,第二种算法对应的提取算法提取出的水印效果较为理想。     

应用于实时通信版权保护的BTC图像水印技术

现有BTC图像水印方案多为脆弱水印技术或数据隐藏技术,不能应用于数字图像版权保护.为保护数字电视实时通信图像版权,结合Haar小波变换,提出一种稳健的BTC域图像水印算法.算法首先对载体图像BTC域两重建电平进行Haar小波变换,然后通过修改低频系数以嵌入稳健水印.水印提取时无须原始载体图像参与.仿真实验表明,算法具有...     

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。      

基于变换域离散小波变换音频水印算法研究

本文提出基于离散小波域的音频水印算法。对要嵌入水印的音频数据进行小波变换三级分解。水印图像经过置乱处理后,再进行降维处理按乘性规则嵌入到经过三级DWT分解的近似分量中,然后和三级DWT的细节分量一起经过逆变换处理产生嵌入水印的音频信号。通过上述过程的逆变换从嵌入水印的音频信号中提取出水印。     

一种基于DWT域的多目的彩色音频水印算法

提出一种在DWT域嵌入彩色图像水印的多目的音频水印算法。该算法利用方块截短编码技术对彩色图像进行压缩,然后把水印信息嵌入到原始音频信号的二级小波变换后的低频分量系数中,这样就可以嵌入与提取水印图像,同时也起到了保护版权的作用。最后根据嵌入水印后的音频文件的自身特性生成秘钥,用以检测音频文件是否受到了篡改等攻击。     

A Study of Steganographic Image Security

In this dissertation, sereral key problems in the field of steganographic image security are mainly studied and discussed: (1) A novel kind of image cryptosystem is studied. The encrypted information of secret image is embedded into an ordinary image, which can be transmitted publicly, and it will not cause attention of illegal eavesdropper. The following results are achieved: (a) The image hiding algorithm and its improved algorithm based on wavelet transform and vector quantization are propo…     

Multipurpose watermarking for image authentication and protection

We propose a novel multipurpose watermarking scheme, in which robust and fragile watermarks are simultaneously embedded, for copyright protection and content authentication. By quantizing a host image's wavelet coefficients as masking threshold units (MTUs), two complementary watermarks are embedded using cocktail watermarking and they can be blindly extracted without access to the host image. For the purpose of image protection, the new scheme guarantees that, no matter what kind of attack is encountered, at least one watermark can survive well. On the other hand, for the purpose of image authentication, our approach can locate the part of the image that has been tampered with and tolerate some incidental processes that have been executed. Experimental results show that the performance of our multipurpose watermarking scheme is indeed superb in terms of robustness and fragility.     

自适应抖动调制图像水印算法

量化步长是影响量化水印算法性能的最关键因素之一.该文根据JPEG量化表自适应地选择抖动调制中的量化步长,提出了一种新的自适应量化水印算法;并将JPEG量化表和Watson感知模型相结合提出了另一种新的自适应量化水印算法.实验结果表明该文提出的两种算法对噪声干扰和常见的图像处理具有较好的鲁棒性.此外,研究还表明JPEG量化表和Watson模型均可以用于缓解量化水印算法对噪声的敏感程度,而结合了两者的水印算法可以获得最佳性能.     

基于归一化图像的抗仿射变换攻击的水印算法

对于鲁棒的数字图像水印技术来说,仿射变换是最难对付的一种攻击。将水印嵌入到基于几何矩的归一化图像中是一种抵抗仿射攻击的方法,但由于原始图像的归一化图像和遭受了仿射攻击后的归一化图像在尺寸上不相同,这就使得嵌入和提取水印很难实现同步。本文提出了一种基于归一化图像的数字水印算法,选择归一化图像中的某个参数作为水印,嵌入水印的过程就是在原始图像的基础上叠加一个原始图像的非线性变换,使得其归一化图像的该参数处于预定的变化范围之中。实验证明此算法对于大多数StirMark攻击来说都是鲁棒的。     

Multipurpose image watermarking algorithm based on multistage vector quantization.

The rapid growth of digital multimedia and Internet technologies has made copyright protection, copy protection, and integrity verification three important issues in the digital world. To solve these problems, the digital watermarking technique has been presented and widely researched. Traditional watermarking algorithms are mostly based on discrete transform domains, such as the discrete cosine transform, discrete Fourier transform (DFT), and discrete wavelet transform (DWT). Most of these algorithms are good for only one purpose. Recently, some multipurpose digital watermarking methods have been presented, which can achieve the goal of content authentication and copyright protection simultaneously. However, they are based on DWT or DFT. Lately, several robust watermarking schemes based on vector quantization (VQ) have been presented, but they can only be used for copyright protection. In this paper, we present a novel multipurpose digital image watermarking method based on the multistage vector quantizer structure, which can be applied to image authentication and copyright protection. In the proposed method, the semi-fragile watermark and the robust watermark are embedded in different VQ stages using different techniques, and both of them can be extracted without the original image. Simulation results demonstrate the effectiveness of our algorithm in terms of robustness and fragility.     

基于容量估计的数字水印算法

为达到更好的鲁棒性和置信度,水印的嵌入应当基于容量估计.本文提出了两种基于容量估计的DCT域数字水印算法,首先利用人眼视觉特性确定水印强度,并在此强度下进行容量估计,以确定实际用于嵌入的DCT系数.它们能够满足高鲁棒性,低失真和动态调整嵌入容量的要求,具有良好的性能,可以用于数据或者图像水印的嵌入.在此基础上,本文还提出了一种将水印与JPEG相结合的嵌入和压缩算法,实验证明它能够同时满足压缩和水印嵌入的要求.     

An Oblivious Watermarking for 3-D Polygonal Meshes Using Distribution of Vertex Norms

Although it has been known that oblivious (or blind) watermarking schemes are less robust than nonoblivious ones, they are more useful for various applications where a host signal is not available in the watermark detection procedure. From a viewpoint of oblivious watermarking for a three-dimensional (3-D) polygonal mesh model, distortionless attacks, such as similarity transforms and vertex reordering, might be more serious than distortion attacks including adding noise, smoothing, simplification, remeshing, clipping, and so on. Clearly, it is required to develop an oblivious watermarking that is robust against distortionless as well as distortion attacks. In this paper, we propose two oblivious watermarking methods for 3-D polygonal mesh models, which modify the distribution of vertex norms according to the watermark bit to be embedded. One method is to shift the mean value of the distribution and another is to change its variance. Histogram mapping functions are introduced to modify the distribution. These mapping functions are devised to reduce the visibility of watermark as much as possible. Since the statistical features of vertex norms are invariant to the distortionless attacks, the proposed methods are robust against such attacks. In addition, our methods employ an oblivious watermark detection scheme, which can extract the watermark without referring to the cover mesh model. Through simulations, we demonstrate that the proposed approaches are remarkably robust against distortionless attacks. In addition, they are fairly robust against various distortion attacks     

基于SVD和SAE的医学图像多功能零水印算法

针对医学图像的版权保护和篡改定位问题,提出了一种多功能零水印算法。获取构造零顽健水印和半脆弱水印的信息矩阵,并分别与原始顽健和半脆弱水印进行异或运算,构造零顽健和零半脆弱水印图像。实验结果证明,提取的水印效果较好,算法能很好地抵抗常见攻击,特别是抵抗强度较大的攻击的效果较好。     

一种基于小波变换的数字水印算法

介绍一种采用三级小波分解的数字水印技术,利用多分辨率技术,分别将原始图像和水印图像进行三层离散小波变换,将同频带的不同层次的水印嵌入到同频带的图像当中,并取得了良好的试验结果。试验证明,该算法经过某些图像处理操作以后仍然是鲁棒的。     

基于子采样方法的DCT域盲水印技术

提出了一种增强水印鲁棒性的盲水印算法.算法在DCT(离散余弦变换)变换域,采用子采样的方法,选择嵌入水印的位置;以视觉感知模型调节嵌入水印的强度.算法的提取不需要原始图像,实现了盲提取.实验结果表明,算法不仅具有较好的不可见性,水印信息在噪声干扰、滤波、图像压缩等攻击下具有较好的鲁棒性.