A temporal domain audio watermarking technique

Audio watermarking techniques can be used to embed extra information into audio signals. The goal is to hide prespecified data carrying some information into the audio stream such that it is not audible to the human ear (i.e., transparent) and is, at the same time, resistant to removal attacks (i.e., robust). In the currently known watermarking systems, the above challenges are not always adequately resolved. We present an alternative audio watermarking technique that mitigates these and other related shortcomings. The system is referred to as modified audio signal keying (MASK). In MASK, the short-time envelope of the audio signal is modified in such a way that the change is imperceptible to the human listener. The MASK system can easily be tailored for a wide range of applications. Moreover, informal experimental results show that it has a good robustness and audibility behavior.     

Digital watermarking algorithm in SWT domain based on robust local feature

Aiming at the challenging work to design a robust digital audio watermarking algorithm against desynchronization attacks,a new second generation digital audio watermarking in stationary wavelet transform (SWT) domain based on robust local audio feature was proposed.First,the first-order smooth gradient response of the low-pass sub-band coefficient was calculated using Gaussian filter.Then,the short-term energy was utilized to adaptively determine local feature audio segments for embedding.Finally,the watermark information was embedded into local feature audio segments with spread transform dither modulation.The experimental results show that the proposed approach has not only good transparency,but also has strong robustness against common audio processing such as MP3 compression and good robustness against the desynchronization attacks such as pitch-scale modification et al.A SWT domain audio feature point extraction method based on smooth gradient is proposed,which effectively solves the drawbacks of poor stability and uneven distribution of audio feature points,and improves the resistance of digital audio watermarks to amplitude-scale modification,pitch-scale modification,random cropping,and jittering attacks.     

Screen-shooting resistant image watermarking based on lightweight neural network in frequency domain

Currently, digital mobile devices, especially smartphones, can be used to acquire information conveniently through photograph taking. To protect information security in this case, we propose an efficient screen-shooting resistant watermarking scheme via deep neural network (DNN) in the frequency domain to achieve additional information embedding and source tracing. Specifically, we enhance the imperceptibility of watermarked images and the robustness against various attacks in real scene by computing the residual watermark message and encoding it with the original image using a lightweight neural network in the DCT domain. In addition, a noise layer is designed to simulate the photometric and radiometric effects of screen-shooting transfer. During the training process, the enhancing network is used to highlight the coding features of distorted images and improve the accuracy of extracted watermark message. Experimental results demonstrate that our scheme not only effectively ensures the balance between the imperceptibility of watermark embedding and the robustness of watermark extraction, but also significantly improves computational efficiency compared with some state-of-the-art schemes.     

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。     

一种DCT域的闭环数字水印技术

本文提出了一种DCT域的闭环数字水印技术，水印的嵌入是一个闭环过程。水印嵌入的初始强度由视觉系统结合JPEG量化表确定，并根据性能分析的结果不断调整水印的嵌入，如果性能分析结果满足某种检测要求或者水印的嵌入已经影响了图像的显示质量，相应调整水印嵌入的强度，以实现水印的最佳嵌入。本文证明了所提出的闭环水印过程具有收敛性，还对检测过程中的似然函数的分布规律进行了分析，得到正确检测率和错误检测概率的表达式，可作为闭环系统的判决条件。实验结果证明这种闭环水印技术比传统DCT域的水印技术性能好。     

一种基于小波变换的灰度数字水印嵌入技术

根据图像小波变换后小波系数的特点,提出了一种新的数字水印嵌入技术。该方法所嵌入的不再是传统的数值序列和二值图像,而是把一幅64×64×8bit的图像作为水印信息嵌入到图像中。实验证明,该水印具有较好的透明性和较好的顽健性。     

Convergence analysis of alias-free subband adaptive filters based on a frequency domain technique

Convergence analysis of alias-free subband adaptive filters (SADFs) is presented based on a frequency-domain technique where instead of analyzing the adaptive algorithms in the time-domain, the averaging method and the ordinary differential equation (ODE) method are applied to the frequency-domain expressions of the adaptive algorithms converted by the discrete Fourier transform. As an alias-free SADF algorithm, the SADF proposed by Pradhan and Reddy is known. In this paper, this technique is first applied to the Pradhan's SADF. The stability of the Pradhan's SADF is verified in the frequency domain, and a simple formula to evaluate the mean square error (MSE) of the algorithm is theoretically derived. By using a slight modification, the technique can be applied to the two-band delayless subband adaptive filter (DLSADF) with the Hadamard transform. The stability condition and the MSE of the DLSADF with the Hadamard transform are also obtained. Simulation results of both algorithms show the validity of the theoretical results.     

一种基于DWT-DCT变换域的全息水印技术

在研究傅里叶全息技术基础上,提出了一种结合离 散小波变换和离散波变换(DWT-DCT)变换的彩色图像数字水印算法,使得水印 拥有强鲁棒性和不可见性。首先,对水印信息进行傅里叶变换,并生成全息水印图; 其次,将载体图 像在RGB空间内的蓝色B分量进行小波分解,对其低频部分进行DCT;最后, 将水印全息图嵌入其高频系数 中。实验结果发现,以k=0.05的强度嵌入水印后,含水印图像的峰值 信噪比(PSNR)达到47,能有效抵抗 信号处理和裁切攻击,同时提取出的水印和原始水印的相似性(NC值)能保持在0. 75以上,说明本文水印 算法有较强的鲁棒性和不可见性。本文算法能够抵抗裁切、滤波、噪声和JPEG压缩攻击,可 用于数字图像版权保护方面。     

基于DWT的视频数字水印算法

介绍了视频数字水印技术的特点和目前所采用的主要算法,针对MPEG-2视频基于小波变换的特性,提出了一种数字水印的设计方案,将伪随机序列嵌入到对亮度分量进行DWT分解后的低频和高频系数上,详述了水印的嵌入和检测过程,最后给出了结果分析.     

一种基于分数傅立叶域图象盲水印方案

利用分数傅立叶变换级次的任意性,提出了一种基于分数傅立叶域图象水印方案。对载体图像进行p级的二维离散分数傅立叶变换,将原始水印图像用LSB算法,嵌入到载体图像的p级分数域的低频系数矩阵中,再进行逆变换得到水印图像。提高了水印安全性,缓解了水印的不可见性与鲁棒性之间的矛盾。仿真试验结果表明该水印具有良好的不可见性和抗噪声攻击性。     

Realisation and robustness evaluation of a blind spatial domain watermarking technique

A blind digital image watermarking scheme based on spatial domain is presented and investigated in this paper. The watermark has been embedded in intermediate significant bit planes besides the least significant bit plane at the address locations determined by pseudorandom address vector (PAV). The watermark embedding using PAV makes it difficult for an adversary to locate the watermark and hence adds to security of the system. The scheme has been evaluated to ascertain the spatial locations that are robust to various image processing and geometric attacks JPEG compression, additive white Gaussian noise, salt and pepper noise, filtering and rotation. The experimental results obtained, reveal an interesting fact, that, for all the above mentioned attacks, other than rotation, higher the bit plane in which watermark is embedded more robust the system. Further, the perceptual quality of the watermarked images obtained in the proposed system has been compared with some state-of-art watermarking techniques. The proposed technique outperforms the techniques under comparison, even if compared with the worst case peak signal-to-noise ratio obtained in our scheme.     

基于Zig-Zag扫描与FCM的多小波域水印算法

提出了一种安全性高,可自适应嵌入的多小波域水印算法。该算法对水印图像进行Zig-Zag扫描后,对形成的一维向量进行相邻像素异或运算并自换位,从而使置乱达到更好的效果,同时根据模糊C均值聚类(FCM)对二层小波变换的中频区域进行分析,自适应地嵌入水印。仿真实验证明,算法对高斯噪声、中值滤波、椒盐噪声、压缩、剪切攻击具有很好的抗攻击能力,并且兼顾了不可见性,实现水印的盲提取。     

一种基于纠错编码的小波域数字图像水印技术

提出一种基于纠错编码的小波域数字水印算法,该算法在检测时不需要原始图像,实现了盲检.算法中对水印图像进行了置乱和混沌加密处理,提高了抗几何攻击的能力和安全性,纠错编码的引入使水印抗攻击能力明显增强.实验结果表明该算法较好地保持了图像质量,对一般的信号处理,如剪切、JPEG压缩、噪声等有很好的鲁棒性.     

基于小波域扩频水印算法及实现

为了达到数字产品产权保护的目的,在此提出了一种基于小波域的扩频水印算法。该算法采用二值图像作为水印,首先对原始载体图像进行DWT一级分解,然后用2个不相关的伪随机序列分别代表水印信息中的0和1,嵌入到小波分解后的LH,HL和HH三个子图上,最后’进行逆向小波变换生成嵌入水印后的图像。通过在开发工具Matlab下的模拟实验,得出了该算法对滤波、噪声和剪切等攻击显示出较强的鲁棒性,取得了隐蔽性和鲁棒性的良好折衷。     

一种结合空间域和DCT域的数字水印新算法

本文基于人类视觉系统（HVS）的特性，提出了一种结合空间域和DCT变换域的数字水印新算法。该算法在空间域对原始图像做预处理，采用逐级扩大搜索范围的方法，使原始图像的纹理区域得到突出。在DCT域，提取预处理图像中，满足一定条件的系数的位置信息，以此确定水印嵌入原始图像的合适位置，从而证了数字水印的感知透明性。大量的仿真实验证明了该算法的顽健性和有效性。     

改进的基于离散小波变换的数字水印技术

提出一种基于离散小波变换静止图像的数字水印技术，探讨了增强数字水印鲁棒性的方法，首先是新的伪随机序列的生成方法，其次是基于马尔可夫随机场（MRF）提出了自适应的水印嵌入手段，最后提出了提高数字水印对几何变换鲁棒性的基于图像配准技术的数字水印提取技术。     

基于DCT域的鲁棒水印技术研究

随着多媒体数字产品的广泛传播与应用,各种非法复制、篡改情况导致数字产品的信息安全成为当前社会各界的关注热点,借助于鲁棒数字水印技术,向作品中加入难以察觉、可区分的水印信息,可有效保护数字产品版权及其完整性.     

A noise-robust frequency domain technique for estimating planarroto-translations

This work presents a new method for estimating planar roto-translations that operates in the frequency domain and as such, is not based on features. Since the proposed technique uses all the image information, it is very robust against noise, it can be very accurate; estimation errors on the rotational angle varies from a few hundredths to a few tenths of a degree, depending on the noise level. Experimental evidence of this performance is presented, and the mathematical reasons behind these characteristics are explained in depth. Another remarkable feature of the algorithm consists in that it works in Cartesian coordinates, bypassing the need to transform from the Cartesian to the polar domain, which, typically, is a numerically delicate and computationally onerous task. The proposed technique can become an effective tool for unsupervised estimation of roto-translations by means of implementations based on FFT algorithms     

两种鲁棒数字水印技术

为有效地解决多媒体产品版权保护问题,本文提出了两种基于静止图像小波变换域位平面分解的鲁棒数字水印算法,即将水印信息嵌入小波域低频逼近系数高位位平面,有效地提高了水印信息的鲁棒性。实验结果证明,该算法具有较好的鲁棒性,并可保证水印的不可见性。     

A robust spread spectrum based image watermarking in ridgelet domain

A new robust method of spread spectrum based image watermarking is proposed in this article. Spread spectrum technique and scrambling are used for increasing robustness and invisibility of the algorithm. Our suggested method is carried out using ridgelet transform as an efficient transform for representing images with line singularities. In embedding part, the host image is partitioned into non-overlapping blocks and ridgelet transform is applied to each single block. In this way, a curved edge is divided into some straight edges so that ridgelet transform shows optimal performance even for complicated images with curve edges. To embed the watermark bits, the best directions of ridgelet coefficients are selected with respect to their variance intensity. In extraction part, a computationally efficient detection method is used for detecting watermark logo blindly from distorted watermarked image. To achieve more robust algorithm firstly, we find the best place to insert the watermark bits and secondly, we encode the scrambled watermark bits by pseudo random sequences with an authentication key. Robustness of our proposed method is tested against different kinds of attacks. According to the experimental results, proposed method shows much improved performance in comparison to other published works.