基于特征点的抗几何攻击水印算法

利用Harris特征点并结合图像的归一化原理提出了一种新的数字水印方案。由于Harris算子的算法简单,稳健性较好,图像的特征点在经过几何攻击后仍然可以保持。而且,归一化的图像对图像的旋转不太敏感,所以首先对每一个以特征点为圆心的互不重叠的圆归一化以确定水印的嵌入点,然后把水印嵌入到原来的图像中,这样,可以很好地解决水印嵌入和检测的同步问题。实验证明,该算法能很好地抵抗如旋转,缩放,剪切等形式的几何攻击与常规信号处理攻击。     

基于特征点的图像水印嵌入方案

提出一种新的图像水印嵌入算法,用Harris算子提取宿主图像的多个特征点,以选定的个别特征点为中心,形成互不重叠方形区域,并进行小波变换。将水印信息分别嵌入到特征点对应区域的小波低频系数中。实验结果表明,该算法的水印不可感知性较好,且可抵抗多种水印攻击,其中对JPEG压缩、几何剪切等攻击的鲁棒性较突出,可应用于图像的版权保护。     

基于SVD局部数字水印算法

本文将水印嵌入和局部不易发生变化的特征点结合,首先利用多尺度Harris角点检测算法检测出图像的特征点;其次以局部最稳定的特征点为中心选取局部特征区域;最后对特征区域分块,利用奇异值分解后最大奇异值的稳定性,将水印嵌入在最大的奇异值上。实验证明,该算法不仅具有很好的不可见性,而且对一些图像攻击具有很好的鲁棒性,尤其是局部攻击。     

基于图像特征的鲁棒水印算法研究

为提高图像盲水印抗几何攻击的能力,提出了一套基于图像特征的水印嵌入方案。首先利用具有几何不变性的Harris算子检测出图像特征点,然后在每块由特征点生成的Delaunay三角网上采用一种基于小波系数显著性差异调制量化方式进行水印的嵌入和检测。该嵌入水印算法的思想是通过比较每组小波系数的显著性差异值和所有组的平均显著性差异值的方法来量化每一组块的最大小波系数。实验结果表明,该方法不仅对压缩、滤波等常见攻击具有稳健性,同时对旋转、缩放、变形等几何攻击也具有较好的稳健性。     

基于图像特征的鲁棒水印算法研究

为提高图像盲水印抗几何攻击的能力,提出了一套基于图像特征的水印嵌入方案.首先利用具有几何不变性的Harris 算子检测出图像特征点,然后在每块由特征点生成的 Delaunay 三角网上采用一种基于小波系数显著性差异调制量化方式进行水印的嵌入和检测.该嵌入水印算法的思想是通过比较每组小波系数的显著性差异值和所有组的平均显著性差异值的方法来量化每一组块的最大小波系数.实验结果表明,该方法不仅对压缩、滤波等常见攻击具有稳健性,同时对旋转、缩放、变形等几何攻击也具有较好的稳健性.     

基于图像内容的局部化数字水印算法

本文提出一种基于DWT的CBWM局部化数字水印算法，该算法是利用图像中相对稳定的特征点来标示局部水印的嵌入位置，并在与每个特征点对应的局部区域内独立地嵌入水印 。这样。当只有部分图像时，仍能通过这些特征点来定位并检测水印。该算法中，局部水印的嵌入是通过将水印嵌入到局部图像小波变换域的低频空间的特征向量中，并且嵌
入的局部水印与特征向量两者正交。实验结果轰明．该算法对裁剪等各类攻击具有很好的鲁棒性。     

基于图像特征点的公钥水印算法

对于现在公钥水印算法一些抗几何攻击能力弱的问题,提出一种基于图像特征点的公钥水印算法。通过Harris-Laplace算法提取图像的特征点,构造局部特征区域,并在这些区域内做DCT变换和水印信息的嵌入,使得嵌入水印后的图像可以更好地抗RST攻击。     

非线性尺度空间自适应均衡水印算法

针对线性尺度空间水印算法嵌入水印位置定位不够精确,嵌入强度参数选取随机,提出一种非线性尺度空间自适应均衡水印算法。利用KAZE算法提取并筛选出非线性尺度空间稳定性强的特征点,构建嵌入水印区域;将水印图像奇异值分解,构造新矩阵作为待嵌入水印载体,通过调整果蝇优化算法的适应度函数计算嵌入强度,结合DWT-SVD算法自适应完成嵌入水印过程。对受到攻击的水印图像提取特征点,合成特征区域矩阵,使用嵌入水印的逆过程,提取水印。实验结果表明,PSNR值均达到44 dB以上,平均◢NC◣值高达0.99,有效均衡了水印算法的不可见性和鲁棒性。     

一种模板和图像特征相结合的数字水印算法

针对目前基于图像特征的数字水印对非等比例缩放攻击鲁棒性不足的现状,提出了一种模板和图像特征相结合的水印算法。该算法首先利用模板信息纠正非等比例缩放的攻击,再用Harris Laplacian检测算子从载体图像中提取出稳定的特征点,然后根据特征尺度自适应确定局部特征区域,并采用圆环量化的方法将水印信息嵌入到局部特征区域中。实验表明,新算法可以保证水印的不可见性,而且对常规信号处理和几何攻击尤其是非等比例缩放具有较好的鲁棒性。     

基于图像内容的局部化自适应数字水印算法

提出一种小波域基于图像内容的局部化自适应数字水印算法．该算法利用图像中相对稳定的特征点来标示局部水印的嵌入位置，并在与每个特征点对应的局部区域(子图像)内，依据DWT域的水印嵌入策略，独立地、自适应地嵌入基于子图像内容的水印．实验结果证明，该算法对裁剪等各类攻击具有很强的鲁棒性．     

Feature based robust watermarking using image normalization

This paper presents a robust watermarking scheme based on feature point detection and image normalization. Firstly some stable feature points are detected from the original image using the proposed multiresolution feature point detection filter. Then, image normalization is applied to the disks centered at these feature points. The watermark is embedded in the subband coefficients of DFT domain of each disk separately. And the watermark detection uses the correlation between the watermark embedding coefficients and the original watermark, and does not need the original image. The proposed scheme combines the advantages of feature point detection and image normalization, which can achieve strong robustness to signal processing and geometrical distortions. The experimental results also demonstrate good performance of the proposed scheme.     

局部化数字水印算法

数字水印是一种嵌入到图象,视频或音频数据中的不可见标志,可以用于多媒体数字的版权保护,认证和标注等,为了提高在频率域嵌入水印抵抗裁剪攻击的能力,提出一种局部化的图象数字水印算法,该算法利用图象中相对稳定的特征点标示水印嵌入的位置,并在与每个特征点对应的局部区域中独立地嵌入水印,这样,当只有部分图象时,仍能通过这些特下点来定位并提取水印,此算法中,水印的嵌入是在局部图象的小波域中进行的,并采用对小波系数进行特殊量化的方法来隐藏水印比特,而水印的提取不需要原始图象参与,实验结果证明,算法对裁剪有很强的抵抗能力,同时对压缩,滤波,噪声,StirMark攻击等也有较好的鲁棒性。     

A New Digital Image Watermarking Algorithm Resilient to Desynchronization Attacks

Synchronization is crucial to design a robust image watermarking scheme. In this paper, a novel feature-based image watermarking scheme against desynchronization attacks is proposed. The robust feature points, which can survive various signal-processing and affine transformation, are extracted by using the Harris-Laplace detector. A local characteristic region (LCR) construction method based on the scale-space representation of an image is considered for watermarking. At each LCR, the digital watermark is repeatedly embedded by modulating the magnitudes of discrete Fourier transform coefficients. In watermark detection, the digital watermark can be recovered by maximum membership criterion. Simulation results show that the proposed scheme is invisible and robust against common signal processing, such as median filtering, sharpening, noise adding, JPEG compression, etc., and desynchronization attacks, such as rotation, scaling, translation, row or column removal, cropping, and random bend attack, etc.     

基于尺度不变特征点的抗几何攻击水印算法

利用基于尺度空间理论的特征点检测方法，检测出的特征点不但在大尺度缩放变换下重复率高，而且每个特征点的特征尺度随图像缩放尺度等比例变化。以特征尺度及特征点相对位置作为参考，生成一种几何变换自适应图形作为水印嵌入的区域。随着特征点相对位置的变化，自适应图形会产生相应变化，达到抗几何攻击的目的。实验表明，该算法能有效抵抗各种几何攻击，具有较好的性能。     

基于图像特征的数字水印算法研究

为了使数字水印具有更鲁棒的抗攻击能力，提出了一种基于图像特征的数字水印新算法。该算法首先利用Harris—Laplace算子提取载体图像特征点；然后结合特征尺度白适应确定局部特征区域；最后，采纳DFT中频幅值比较策略将数字水印信息重复嵌入到多个不相交的局部特征区域中。检测时，根据模糊模式识别的最大隶属度原则检测水印信息。仿真实验结果表明，该新算法不仅具有较好的透明性，而且对常规信号处理（中值滤波、边缘锐化、叠加噪声和JPEG压缩等）和去同步攻击（旋转、平移、缩放、行列去除、剪切和局部随机弯曲等）均具有较好的鲁棒性。     

Localized image watermarking based on feature points of scale-space representation

This paper proposes a novel method for content-based watermarking based on feature points of an image. At each feature point, the watermark is embedded after scale normalization according to the local characteristic scale. Characteristic scale is the maximum scale of the scale-space representation of an image at the feature point. By binding watermarking with the local characteristics of an image, resilience against affine transformations can be obtained easily. Experimental results show that the proposed method is robust against various image processing steps including affine transformations, cropping, filtering and JPEG compression.     

A robust color image watermarking using local invariant significant bitplane histogram

Desynchronization attacks that cause displacement between embedding and detection are usually difficult for watermark to survive. It is a challenging work to design a robust image watermarking scheme against desynchronization attacks, especially for color images. In this paper, we propose a robust color image watermarking approach based on local invariant significant bitplane histogram. The novelty of the proposed approach includes: 1) A fast and effective color image feature points detector is constructed, in which probability density and color invariance model are used; 2) The fully affine invariant local feature regions are built based on probability density Hessian matrix; and 3) The invariant significant bitplane histograms are introduced to embed digital watermark. The extensive experimental works are carried out on a color image set collected from Internet, and the preliminary results show that the proposed watermarking approach can survive numerous kinds of distortions, including common image processing operations and desynchronization attacks.     

一种基于小波域特征树量化的数字水印算法*

首先使用尺度交互式特征检测算法提取图像小波域逼近子图的特征点,然后构造相应的特征树,最后对特征树所有节点进行量化以嵌入二值水印信息。水印信息嵌入到图像的特征之中,对JPEG,JPEG 2000以及高斯白噪音等多种处理具有较强的鲁棒性。     

Invariant image watermarking using multi-scale Harris detector and wavelet moments

Desynchronization attack is known as one of the most difficult attacks to resist, which can desynchronize the location of the watermark and hence causes incorrect watermark detection. It is a challenging work to design a robust image watermarking scheme against desynchronization attacks. Based on multi-scale Harris detector and wavelet moment theory, we propose a new content based image watermarking algorithm with low computational complexity, good visual quality and reasonable resistance toward desynchronization attacks in this paper. Firstly, the steady image feature points are extracted from the origin host by using multi-scale Harris detector, and the local feature regions (LFRs) are constructed adaptively according to the feature scale theory. Then, the LFRs are image normalized, and significant regions are obtained from the normalized LFRs by utilizing the invariant centroid theory. Finally, the digital watermark is embedded into the LFRs by modifying wavelet moment invariants of the significant regions. By binding the watermark with the geometrically invariant image features, the watermark detection can be done without synchronization error. Experimental results show that the proposed image watermarking is not only invisible and robust against common image processing operations as sharpening, noise adding, and JPEG compression etc, but also robust against the desynchronization attacks such as rotation, translation, scaling, row or column removal, cropping, and local random bend etc.     

DWT域抗几何攻击水印算法研究

鲁棒水印面临的最大问题就是几何攻击.小波变换域不具有几何不变性,一个微弱不可察觉的几何攻击就能使小波域水印算法失效.提出了一种新的以特征点作为模板、有效抵抗几何攻击的图像水印算法.它包括:(1)根据小波变换空间各子带呈树形结构的特性,选择每棵小波树中纹理最强的方向子树的树根作为水印嵌入点;(2)根据嵌入点在低频对应位置的能量和该方向子树高频叶子结点的纹理信息确定一种自适应嵌入水印策略;(3)利用Harris-Laplace算子从含有水印的图像中提取出具有几何形变鲁棒性的特征点,将其作为模板;(4)水印检测时,先利用特征点模板通过线性变换恢复几何形变的图像.然后通过统计图像的相关性来验证水印的存在,无需原始图像.仿真实验表明,所提出的水印算法不仅具有很好的透明性,而且对常见的图像处理和几何变换具有很好的鲁棒性.