基于小型英文WORD文档的数字水印算法

针对小型英文Word文档信息量少的特点,该文提出一种文本水印嵌入方法。以文本中单词内的字符为对象,利用字符特征的变化,将有意义的水印信息置乱后依据单词内容以不同方式嵌入文本中.这样,仅几行文字的小文本亦可嵌入水印信息,该算法具备较好的文本完整性检测性能并兼具一定程度的鲁棒性。     

Fast two-layer image watermarking without referring to the original image and watermark

A fast two-layer image watermarking without referring to the original image and watermark is proposed in this study. Two layers of algorithms are employed to simultaneously hide the same watermarks in the spatial domain. More specifically, the first layer watermarking resists high-frequency destruction, while that in layer two resists low-frequency destruction. Although the image is modified through two layers of watermarking, the watermarks are still invisible. In addition, the proposed watermarking has other advantages. First, the proposed embedding technique is based on an intra-relationship within the original image rather than an inter-relationship between the original and watermarked images so that the original image is not required during the detection process. Second, the proposed watermark is composed of fixed and variable parts. The fixed part allows the detection of the watermark existence and location without referring to the original watermark. The variable part permits greater flexibility and variety of watermarks. Third, the proposed watermark is a short serial number, which allows it to be duplicated. Because of the duplication, a majority voting strategy can be employed to facilitate watermark detection. Finally, the proposed method is fast and simple. It takes only one or two seconds for either the embedding stage or the detection stage. Various experiments have been conducted to verify the above advantages of the two layer watermarking.     

一种新颖的水印密钥系统

水印技术作为一种有效的信息隐藏方法,发展得非常迅速.大部分水印系统都只具有一把私钥,而且不能公开,但是在某些应用中需要公钥来恢复水印.如何保证公钥的产生不会影响私钥的性能,是水印密钥系统的关键问题.构造了一种水印密钥系统,提出了一种新颖的公钥生成方法.无须原始数据即可利用公钥恢复嵌入的标识符.由于公钥的产生只涉及部分水印信息,从而成功地解决了公钥生成与私钥之间的矛盾.实验结果表明,该系统是安全、有效的.     

An image rectification scheme and its applications in RST invariant digital image watermarking

This paper presents an image rectification scheme that can be used by any image watermarking algorithm to provide robustness against rotation, scaling and translation (RST) transformations. Rotation and scaling transformations in the spatial domain result in cyclically translational shifts in the log-polar mapping (LPM) of the magnitude of the Fourier transform spectrum of an image. We cut a small block from the LPM domain as a matching template. A new filtering method is proposed to compute the cross-correlation between this template and the magnitude of the LPM of the image having undergone RST transformations to detect the rotation and scaling parameters. We employ the same strategy in the spatial domain to detect the translational parameters in the spatial domain. The scheme can also be used to detect image flipping. The cost of the templates is low and the templates can even be compressed. The detection accuracy for rotation, scaling and translation is also presented. We compare the matching results for the different filters and their performance by the three criteria: signal-to-noise ratio (SNR), peak-to-correlation energy (PCE), and Horner efficiency. We demonstrate that our phase-only filtering method is the only one that can be used in the LPM domain. We also introduce three applications for this rectification scheme and give their experimental results.

一种稳健的公开数字图像水印技术

提出一种稳健的公开图像水印技术。随机选取若干象素点及其邻域,通过量化象素与邻域的均值之差来隐藏水印信息。实验表明,该方法简单、高效、安全性能好,且具有较好的不可感知性,对通常的图像处理及JPEG压缩等具有极好的稳健性。     

音频信息隐藏技术及其发展方向

音频信息隐藏技术已成为近年来的研究热点之一.利用该技术可在音频文件中嵌入秘密信息以达 到“掩蔽通信”和“版权保护”等目的.本文首先介绍了音频信息隐藏的一些基本问题,如人类听觉系统模型、音 频文件格式、声音传送环境及对音频信息隐藏的基本要求等等.随后重点研究了迄今为止已出现的一些音频 信息隐藏技术的工作原理及其局限性.最后指出该研究领域未来的研究和发展方向.     

数字水印技术

数字技术与互联网络的发展对传统的版权保护手段提出了挑战,作为一个解决数字产品版权保护的新方法,数字水印技术在最近几年引起人们的极大关注,目前已提出了多种数字水印方案,本文首先介绍了数字水印的主要应用方面,而后描述了这些方案所共有的总体框架与特性,介绍了数字水印的生成、嵌入与恢复方法,最后简单分析了数字水印的研究方向与应用前景以及数字水印方法可能存在的一些问题。     

Hybrid watermarking of medical images for ROI authentication and recovery

Medical image data require strict security, confidentiality and integrity. To achieve these stringent requirements, we propose a hybrid watermarking method which embeds a robust watermark in the region of non-interest (RONI) for achieving security and confidentiality, while integrity control is achieved by inserting a fragile watermark into the region of the interest (ROI). First the information to be modified in ROI is separated and is inserted into RONI, which later is used in recovery of the original ROI. Secondly, to avoid the underflow and overflow, a location map is generated for embedding the watermark block-wise by leaving the suspected blocks. This avoids the preprocessing step of histogram modification. The image visual quality, as well as tamper localization, is evaluated. We use weighted peak signal to noise ratio for measuring image quality of watermarked images. Experimental results show that the proposed method outperforms the existing hybrid watermarking techniques.     

基于DCT和神经网络的视频版权保护算法

针对目前数字水印技术对视频版权保护和抵抗攻击时存在的一系列问题,提出了基于DCT、数字水印、神经网络和数据加密等技术的有效算法．该算法首先将原始水印信息采用Arnold变换进行置乱处理,然后运用神经网络将水印嵌入到宿主视频中,提取时利用确定的神经网络实现水印的盲提取．实验结果表明,该算法具有较好的不可见性和鲁棒性．     

子块结构信息与LSB相结合的脆弱水印

该文结合H．264／AVC视频编码特点,提出一种利用结构特征的脆弱水印算法。利用4×4DCT子块在宏块中的位置信息和该子块中最后一位非零量化系数之间的差值,通过LSB位的替换方法,将水印信息嵌入到该子块中所选的非零系数中,然后将嵌有水印的DCT量化系数通过熵编码写入比特流中进行传输。实验仿真结果表明,该算法具有较好的脆弱性,对视频的影响较小。