自适应数字水印嵌入算法

研究基于小波变换域的数字水印的嵌入对策和检测方法，实现了数字水印自适应地嵌入列原始图像离散小波变换域的中频子带图像中。使用该算法嵌入的数字水印具有很好的隐蔽性，视觉上感觉不到对原始图像的影响，嵌入的数字水印具有理想的鲁棒性，常规的图像处理方法对其影响很小，实验证明了该算法的有效性和安全性。     

数字水印研究中常用的测试指标(下)

数字水印作为数字媒体版权保护的有效手段。受到极大关注，钽却没有一个良好的衡量手段来对数字水印算法作出合理的评测，本文总结了目前比较流行的数字水印算法衡量手段以及几种有效的数字水印的攻击手段，旨在帮助全面评测水印算法的性能，进而帮助改进数字水印算法，使数字水印算法具有更好的隐形性、稳健性、安全性，以促进数字水印走向实用化。     

数字水印研究中常用的测试指标(上)

数字水印作为数字媒体版权保护的有效手段，受到极大关注，但却没有一个良好的衡量手段来对数字水印算法作出合理的评测。本文总结了目前比较流行的数字水印算法衡量手段以及几种有效的数字水印的攻击手段，旨在帮助全面评测水印算法的性能，进而帮助改进数字水印算法，使数字水印算法具有更好的隐形性、稳健性、安全性，以促进数字水印走向实用化。     

一种基于纠错编码的小波域数字图像水印技术

提出了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，故可实现盲检。算法中对水印图像进行了置乱和混沌加密处理，因而可提高其抗几何攻击的能力，同时可提高安全性，且其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，该算法能较好的保持图像质量，并对一般的信号处理（如剪切、IPEG压缩、噪声等）具有很好的鲁棒性。     

基于离散余弦变换的数字水印算法研究与实现

讨论了基于离散余弦变换的数字水印算法原理及其具体步骤，并通过仿真实验实现了数字水印的嵌入和提取，验证了算法的可行性。     

数字水印技术

本文对数字水印技术及其所涉及的问题进行了论述。文章详细地介绍了数字水印的特性及其各种分类方法，并对数字图像水印嵌入与检测的多种算法以及各种算法的优缺点进行了论述。     

基于DCT域的图像数字水印技术

采用了DCT离散余弦变换的算法，对图像这种多媒体数字作品进行了数字水印的嵌入和检测研究。并且使用了MATLAB来介绍了一种DCT域的图像数字水印嵌入和提取的实例，在最后对嵌入水印的图像进行了攻击实验，验证了该算法的鲁棒性和不可见性。     

基于扩频CDMA的数字盲水印算法

数字水印技术要求所构造的算法，具有很强的鲁棒性（抗攻击能力）。在数字水印技术中引入扩频技术，提高了数字水印的鲁棒性，但同时却使嵌入信息量减小了。丈中在引入CDMA技术，进一步增强鲁棒性，同时也使嵌入的信息量得到了提高。仿真实验表明：所提出的算法具有很强的鲁棒性、透明性，而且误码率较小，在很强的干扰下，仍能提取出水印。     

基于小波变换的数字水印算法

提出了基于小波变换域的数字水印的嵌入对策和检测方法，实现了数字水印自适应地嵌入到原始图像DWT变换域的中频子带图像中。水印的检测是分级渐进地进行的，从而提高了检测效率。文中实现了伪随机序列的水印，仿真实验结果证明了该算法的有效性、安全性。     

数字水印的应用及需求分析

给出了一个完整的数字图像水印通信系统模型，对其中各个功能模块进行了分析。从应用的角度给出了数字水印的分类方法，给出了包括数字版权保护，数字指纹在内的数字水印技术的几个典型应用，在这些应用环境下对水印算法的具体要求进行了详细的分析。研究具体的数字水印技术的应用及其环境，分析其对数字水印技术的要求，对设计相应的数字水印算法将具有一定指导作用。     

Self Embedding Watermarking Using Halftoning Technique

This paper proposes a self-embedding watermarking scheme for digital images. It exploits a digital halftoning technique to transform the host image to a halftone image, in which the content features of the host image are well preserved. This halftone image is utilized as an approximate or compressed version of the host image and further adopted as a watermark. Unlike most available self-embedding watermarking techniques, in which watermark embedding, tamper detection and image recovery are block-wise-based, our scheme is a pixel-wise and block-wise composite scheme. That is, the watermark is pixel-wise permuted and embedded in the least-significant-bit plane of the host image, while in tamper detection and image recovery, a block-wise strategy is employed. This pixel-wise and block-wise complementary mechanism can overcome a common disadvantage of previous block-wise-based self-embedding watermarking techniques. Our scheme can be used for tamper detection and alteration location. Moreover, the tampered area can be approximately recovered using the extracted watermark. Experimental results demonstrate the effectiveness of the proposed scheme.     

基于ICA的数字水印的方法

数字水印是现在多媒体信号处理研究的一个热点,已经有许多关于数字水印嵌入和提取的方法.增强数字水印的鲁棒性是数字水印问题的关键.本文将独立分量分析用于数字水印,即把承载图像和水印图像在空间域直接混叠,并利用独立分量分析(ICA)的方法提取数字水印,得到了很好的结果.计算机实验结果表明这是一种鲁棒性极强的新方法.     

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…     

A Novel Audio Watermarking Algorithm for Copyright Protection of Digital Audio

Digital watermark technology is now drawing attention as a new method of protecting digital content from unauthorized copying. This paper presents a novel audio watermarking algorithm to protect against unauthorized copying of digital audio. The proposed watermarking scheme includes a psychoacoustic model of MPEG audio coding to ensure that the watermarking does not affect the quality of the original sound. After embedding the watermark, our scheme extracts copyright information without access to the original signal by using a whitening procedure for linear prediction filtering before correlation. Experimental results show that our watermarking scheme is robust against common signal processing attacks and it introduces no audible distortion after watermark insertion.     

Watermarking on Colored Images

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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 feature-based digital watermarking scheme for halftone image

It is a challenging work to design a robust halftone image watermarking scheme against desynchronization attacks. In this paper, we propose a feature-based digital watermarking method for halftone images with low computational complexity, good visual quality and reasonable resistance toward desynchronization attacks. Firstly, the feature points are extracted from host halftone image by using multi-scale Harris–Laplace detector, and the local feature regions (LFRs) are constructed according to the feature scale theory. Secondly, discrete Fourier transform (DFT) is performed on the LFRs, and the embedding positions (DFT coefficients) are selected adaptively according to the magnitude spectrum information. Finally, the digital watermark is embedded into the LFRs by quantizing the magnitudes of the selected DFT coefficients. By binding the watermark with the geometrically invariant halftone image features, the watermark detection can be done without synchronization error. Simulation results show that the proposed scheme is invisible and robust against common signals processing such as median filtering, sharpening, noise adding, and JPEG compression, etc., and desynchronization attacks such as rotation, scaling, translation (RST), cropping, local random bend, and print-scan, etc.     

A novel robust logo watermarking scheme using fractional M-band wavelet transform

Digital watermarking, means of hiding/inserting a message, which can be an image, audio, video or text within the digital media. This hidden/inserting message can be later being extracted or detected for a variety of purposes. In this paper, a novel multi-resolution logo watermarking scheme using fractional M-band wavelet transform (Fr-M-band-WT) is proposed. The watermark is embedded in the multiresolution Fr-M-band-WT coefficients of low frequency bands of the host image using singular value decomposition (SVD). A multi-resolution nature of Fr-M-band-WT is exploited in the process of edge detection. Experimental results of the proposed logo watermarking scheme are compared with the previously available watermarking algorithms, fractional Fourier transform (FrFT), fractional wavelet transform (FrWT). Further, the proposed watermark extraction scheme is also tested on different attacks. The results after being investigated the proposed watermarking scheme shows a significant improvement as compared to other existing methods.     

一种基于图像特征点的数字水印嵌入方法

如何有效抵抗去同步攻击是数字图像水印研究领域的热点问题之一.本文提出了一种可有效抵抗去同步攻击的图像水印新算法.该算法首先利用Harris-Laplace算子从载体图像中提取尺度空间特征点;再结合特征尺度自适应确定局部特征区域;最后,采纳DFT中频幅值量化策略将水印重复嵌入到多个不相交的局部特征区域中.检测时,利用特征点实现水印的重同步,无须求助于原始图像.仿真结果表明,本文算法不仅具有较好的透明性,而且对常规信号处理和去同步攻击均具有较好的鲁棒性.     

A feature-based robust digital image watermarking scheme

A robust digital image watermarking scheme that combines image feature extraction and image normalization is proposed. The goal is to resist both geometric distortion and signal processing attacks. We adopt a feature extraction method called Mexican hat wavelet scale interaction. The extracted feature points can survive a variety of attacks and be used as reference points for both watermark embedding and detection. The normalized image of an image (object) is nearly invariant with respect to rotations. As a result, the watermark detection task can be much simplified when it is applied to the normalized image. However, because image normalization is sensitive to image local variation, we apply image normalization to nonoverlapped image disks separately. The disks are centered at the extracted feature points. Several copies of a 16-bit watermark sequence are embedded in the original image to improve the robustness of watermarks. Simulation results show that our scheme can survive low-quality JPEG compression, color reduction, sharpening, Gaussian filtering, median filtering, row or column removal, shearing, rotation, local warping, cropping, and linear geometric transformations.