Science Letters:A new asymmetric watermarking scheme based on a real fractional DCT-I transform

INTRODUCTIONDue to the ease of transmitting digital data and copying without loss of quality, the unauthorized distribution of digital multimedia contents has be-come easy and popular. Digital watermarking is the most promising technique to protect the copyright of digital multimedia contents (Cox et al., 2001). Most of the proposed watermarking schemes are symmetric, in which keys for watermark detecting are identical to those for watermark embedding. Therefore, symmet-ric watermarking s…     

基于多小波变换的数字水印嵌入方法

提出了一种基于多小波变换的数字水印算法,将二值水印嵌入到宿主图像的多小波变换域中。首先将对应于相同位置的多小波系数形成向量序列,然后采用均值量化方法嵌入数字水印。实验结果表明,该水印算法在多种攻击下都具有较好的鲁棒性。     

基于三维模型网格子集属性的数字水印算法

提出了一种基于三维模型网格子集的新型盲水印算法。算法以三维模型网格中的网格子集为载体,提取三维模型的三角形面片数据,根据三角形相似四元组（TSQ）法计出边长比和宽高比,通过阈值控制定位嵌入基元,最后根据水印信息值修改网格子属性ID嵌入水印。水印提取过程则通过对嵌入基元定位后,查询属性ID值计算完成。实验结果表明:该算法对于几何变换和剪切、噪声攻击等都具有较好的鲁棒性。     

A new semi-fragile watermarking algorithm for image authentication

1 Introduction1 With the rapid development of Internet, digital multimedia can be easily shared via computer networks and conveniently processed for queries in databases. At the same time, the powerful multimedia manipulation software has made it possible to edit and alter the media’s content seamlessly, which breeds the demand of a secure authentication system to verify authentication. Digital watermarking has been proposed as a possible solution for data and tamper detection. An authentica…     

基于稳健信息隐藏的脆弱水印

Block-wise fragile watermarks can be used to reveal maliciously tampered areas in multimedia products. However a forged content containing a cloned fragile watermark can be constructed by using a series of watermarked data. To defeat this type of counterfeit attack, a novel fragile watermarking technique is proposed in which different pseudo-random data are selected for different host products, and the generated fragile watermark is dependent upon the selected information. While inserting the fragile watermark, the     

基于神经网络和多小波变换的数字水印算法

基于图像多小波域低频系数子块的相似性,利用神经网络的学习特性,提出了新的盲数字水印算法.将宿主图像变化为多小波域,把水印加入到宿主图像多小波变化后的低频系数中.通过后向传播算法的神经网络训练出宿主图像与嵌入的水印信号之间的关系特征,利用神经网络具有学习和自适应的特性,训练后的神经网络能够完全恢复嵌入到宿主图像中的水印信息.仿真实验表明,该算法针对各种攻击具有很好的鲁棒性,特别是在水印检测时不需要原始图像.     

基于语音权重的关系数据库水印算法研究

阐述了水印关系数据库在数据阻盗版中的需要,明确了对水印技术提出挑战的关系型数据的特点。创造性地提出了一个新型的方法,为关系型数据库产生水印,根据分配的权重不同,把语音信号嵌入到数据库中作为水印。实验结果表明在各种不同的攻击下该方案是健壮的。该方法更加直接,并支持简单的水印识别。     

一种新的中文文本数字水印加密方法

目前数字水印的研究主要集中在于图像、音频、视频等方面,文本水印技术尚未成熟。本文根据汉字的结构特点,在不改变文本内容。有较好视觉性能的前提下,通过合并汉字、西文字母替换、标点符号替换等方法,实现中文文本的数字水印加密。该水印方法简便,视觉性能好,具有较好的应用前景。     

Adaptive audio watermarking based on SNR in localized regions

In this paper, a novel localized audio watermarking scheme based on signal to noise ratio （SNR） to determine a scaling parameter a is proposed. The basic idea is to embed watermark in selected high inflexion regions, and the intensity of embedded watermarks are modified by adaptively adjusting a. As these high inflexion local regions usually correspond to music edges like sound of percussion instruments, explosion or transition of mixed music, which represent the music rhythm or tempo and are very important to human auditory perception, the embedded watermark is especially expected to escape the distortions caused by time domain synchronization attacks. Taking advantage of localization and SNR, the method shows strong robustness against common problems in audio signal processing, random cropping, time scale modification, etc.     

一个小波域数字水印算法

提出了一个新的DWT域数字水印算法。该算法利用双密钥调制方法,在载体图像的低频子带嵌入置乱水印,水印提取不需要原始图像。实验结果表明水印具有良好的鲁棒性和不可见性。     

一种基于有限脊波变换的数字图像水印算法

提出了一种基于有限脊波变换域实现图像水印的方法。其优点是良好的稳健性和层次性的检测方法。这种算法充分利用有限脊波变换的特点,把原始图像和水印分解成多频段的图像来嵌入水印。检测时,把加了水印的图像分解,通过计算处理每一层取得所有的有关信息。     

一种基于视觉感知模型的小波域图像盲水印方案

提出了一种基于视觉感知模型的小波域图像盲水印方案.该水印方案充分利用了人类的视觉感知特性,根据人眼对图像不同局部特征敏感程度的不同,自适应地调节水印的嵌入强度.水印的嵌入强度由图像的视觉临界差异决定,水印的提取不需要载体图像.仿真实验表明,该水印方案具有很强的抗攻击能力,并且水印的嵌入不影响图像的视觉质量.     

数字作品的保护神——数字水印技术

作为信息隐藏技术的一个分支 ,数字水印技术在现代数字媒体的版权保护、电子票据防伪、信息隐藏标识等领域发挥着重要作用。因此 ,数字水印在数据安全中占有不可替代的地位     

Watermarking on 3D mesh based on spherical wavelet transform

In this paper we propose a robust watermarking algorithm for 3D mesh. The algorithm is based on spherical wavelet transform. Our basic idea is to decompose the original mesh into a series of details at different scales by using spherical wavelet transform; the watermark is then embedded into the different levels of details. The embedding process includes: global sphere parameterization, spherical uniform sampling, spherical wavelet forward transform, embedding watermark, spherical wavelet inverse transform, and at last resampling the mesh watermarked to recover the topological connectivity of the original model. Experiments showed that our algorithm can improve the capacity of the watermark and the robustness of watermarking against attacks.     

Watermarking on 3D mesh based on spherical wavelet transform

INTRODUCTIONTherapidgrowthofdigitalmediaoverInternetprovideseverybodywiththefacilityofeasyaccess,copy,editanddistributionofdigitalcontentssuchaselectronicdocuments,images,soundsandvideos.Thereisurgentdemandfortechniquestoprotectthecopyrightoftheoriginaldigitaldataandtopreventunauthorizedduplicationortampering.Digitalwatermarkingordatahidingisonesolutionforthecopyrightprotectionofdigitaldata.Digitalwatermarkingisaprocessbywhichauser-specifiedsignal(watermark)ishiddenorembeddedintoanothersi…     

一种基于数字水印和DES加密的印章图像认证算法

电子印章在电子政务中的应用越来越普遍,保证印章图像的权威性,使公文接收者接收到印章图像后,能确认印章拥有者的身份是电子印章系统必要的技术。本文针对印章图像的特点提出一种基于数字水印的印章图像认证算法,该算法主要采用基于量化索引调制方法QIM水印算法完成印章图像认证和DES加密保证水印信息的隐秘性,在实现中得到了很好的效果,能够满足电子印章系统的安全需求。     

基于混沌映射、小波变换和RSA加密的数字水印算法

本文提出了一种新的公开算法的数字水印算法。该算法首先应用Logistic映射构造了一个原始图像的子图,其次把DWT变换作用在这个子图上得到两个子带LH1和HL1,然后对这两个子带进行RSA加密并把水印嵌入在这两个被加密的子带上,接着解密这两个子带并通过IDWT变换重构子图,最后按构成子图的顺序把每一个8×8像素的小块放回到原图中相应位置,从而得到了一个嵌入了水印信息的图像。实验结果表明,通过该算法嵌入的水印具有较好的鲁棒性、安全性和不可感知性。     

一种新的基于小波变换的基音检测算法

1IntroductionPitch periodis ani mportant parameterinthe analys-is and synthesis of speech signals.Pitch period infor-mation is used in various applications such as(1)speaker identification and verification,(2)pitch syn-chronous speech analysis and synthesis,(3)linguisticand phonetic knowledge acquisition and(4)voice dis-ease diagnostics.However the task of esti mating thepitchis very difficult since(1)the human vocal tract isvery flexible andits characteristics varyfrompersontoperson,(2)the pi…     

Misalignment analysis of journal bearing influenced by asymmetric deflection, based on a simple stepped shaft model

The effects of journal misalignment on a journal bearing caused by an asymmetric rotor structure are presented in this study.A new model considering the asymmetric deflection is applied.Also,the thermo-hydrodynamic of the oil film in the journal bearing and straightforward elasticity theory are considered in the analysis.Based on the structure stiffness equivalent characteristic,a simple stepped shaft can reflect the entire complex structure model.The existing lubrication model,which does not consider this angle component,is not very precise for journal bearings.Film pressure,misalignment angle,velocity field,oil leakage,and temperature field were calculated and compared in the journal bearing analysis.The results indicate that bearing performances are greatly affected by misalignment caused by the asymmetric structure.A simple stepped shaft can effectively represent a misaligned journal bearing in a rotor-bearing system.     

基于空换时技术的分数域时频分析快速算法

提出一种以空间换取时间的方案,能有效提高分数域时频分析的运算效率。鉴于该算法对时间域进行切割,将导致时频分布在衔接处出现边界效应,文章还提出错位平滑技术,有效将各时间段的时频分布进行无缝拼接。