Contourlet-based image adaptive watermarking

In the contourlet transform (CT), the Laplacian pyramid (LP) decomposes an image into a low-frequency (LF) subband and a high-frequency (HF) subband. The LF subband is created by filtering the original image with 2-D low-pass filter. However, the HF subband is created by subtracting the synthesized LF subband from the original image but not by 2-D high-pass filtering the original image. In this paper, we propose a contourlet-based image adaptive watermarking (CIAW) scheme, in which the watermark is embedded into the contourlet coefficients of the largest detail subbands of the image. The transform structure of the LP makes the embedded watermark spread out into all subbands likely in which the LF subbands are included when we reconstruct the watermarked image based on the watermarked contourlet coefficients. Since both the LF subbands and the HF subbands contain watermarking components, our watermarking scheme is expected to be robust against both the LF image processing and the HF image processing attacks. The corresponding watermarking detection algorithm is proposed to decide whether the watermark is present or not by exploiting the unique transform structure of LP. With the new proposed concept of spread watermark, the watermark is detected by computing the correlation between the spread watermark and the watermarked image in all contourlet subbands fully. The proposed CIAW scheme is particularly superior to the conventional watermarking schemes when the watermarked image is attacked by some image processing methods, which destroy the HF subbands, thanks to the watermarking components preserved in the LF subbands. Experimental results show the validity of CIAW in terms of both the watermarking invisibility and the watermarking robustness. In addition, the comparison experiments prove the high-efficiency of CIAW again.     

A robust color image watermarking algorithm against rotation attacks

A robust digital watermarking algorithm is proposed based on quaternion wavelet transform (QWT) and discrete cosine transform (DCT) for copyright protection of color images. The luminance component Y of a host color image in YIQ space is decomposed by QWT, and then the coefficients of four low-frequency subbands are transformed by DCT. An original binary watermark scrambled by Arnold map and iterated sine chaotic system is embedded into the mid-frequency DCT coefficients of the subbands. In order to improve the performance of the proposed algorithm against rotation attacks, a rotation detection scheme is implemented before watermark extracting. The experimental results demonstrate that the proposed watermarking scheme shows strong robustness not only against common image processing attacks but also against arbitrary rotation attacks.     

基于混沌加密的dwt域数字水印算法

提出了一种将二维混沌系统应用到水印图像预处理中,对水印图像进行混沌加密。然后对载体图像进行三级小波分解,选择在水平和垂直子带中根据分块能量的大小,选择能量块较大的块系数嵌入水印,该算法在水印提取过程中需要原始载体图像。实验结果表明:该算法嵌入的数字水印具有很好的隐蔽性,同时对叠加噪声、平滑滤波等攻击具有很好的鲁棒性。     

一种基于小波变换与奇异分解的图像水印算法

提出一种基于离散小波变换(Discrete Wavelet Transform,DWT)与奇异值分解(Singular Value Decomposition,SVD)相结合的数字水印算法。该算法将原始图像的小波子图进行奇异值分解,将灰度水印图像进行Arnold变换以及扰乱加密,再进行分块离散余弦变换(Discrete Cosine Transform,DCT),将变换后的系数分类嵌入到相应的奇异值中。实验仿真表明,这种方法能抗大多数图像处理攻击,具有良好的鲁棒性。     

一种有效抵抗裁剪攻击的小波域盲水印算法

该文提出了一种有效抵抗裁剪攻击的小波域盲水印算法,能从小的图像块上检测出水印。首先将图像进行小波变换,选择两个所需要的子带,利用相邻特征平均值和奇偶判决法在两个子带上各自重复内嵌一半水印,在水印检测过程中不需要原始图像。实验结果表明,该算法具有较好的透明性,对各种攻击有较强的鲁棒性,尤其是明显增强了小波域水印在面临裁剪攻击和联合攻击时的鲁棒性。     

一种基于特征的自适应水印算法

基于图像多尺度空间理论和扩频机制以及视觉感知模型的特性,给出一种基于特征的数字图像水印算法。算法采用尺度不变特征变换算子提取图像的局部不变特征区域,根据信噪比特点自适应选取水印嵌入强度因子,将一幅二值水印图像嵌入到原始图像中,实现了数字水印的不可感知性和鲁棒性。仿真结果表明,该算法对添加噪声、压缩、旋转等常见的图像处理攻击具有较强的鲁棒性。     

结合置乱与扩频的数字水印算法

提出了一种使用置乱技术置乱水印图像，然后将Gold码用于水印结构设计的扩频数字水印算法。通过置乱技术提高了抽取数字水印的视觉效果，并可以在一定程度上弥补数字水印在嵌入、传输和抽取过程中的损耗。利用Gold码具有较多独立码的特性，以多位二进制信息为单位对置乱后的二值图像水印进行扩频调制，然后将调制信号自适应地加入到载体图像离散余弦变换域的低频分量系数中。应用Gold码使得算法可以采用较长的扩频序列，相应提高了鲁棒性。这种结合置乱和扩频的水印算法对于抵抗各种噪声、滤波和压缩等合法攻击以及其他非法攻击都具有很好的鲁棒性。     

抗攻击的图像水印技术综述

文章简要地探讨了抗各种攻击图像水印技术,包括一些基本概念:水印概念、水印的嵌入和提取过程、水印的分类和衡量水印的基本指标。文章把几何攻击分为图像变换攻击和剪裁攻击,图像处理攻击分为噪声攻击、滤波攻击、JPEG攻击和打印扫描拍照攻击。此外,文章探讨了图像水印抗击几何攻击和抗图像处理攻击从传统到最新的技术和方法。     

基于视觉系统特征的分层数字水印技术

在分析人类视觉系统(HVS)特征的基础上,提出了一种新型的分层数字水印技术.利用HVS对不同区域、不同局部特征的噪声敏感性不同,设置相应的区域水印权重和局部水印权重,将水印按照设置的分层权重嵌入到静态小波变换(SWT)后的细节子带中.利用所提出的新型多分辨率检测器,通过与传统的水印方法比较表明,该方法具有较好透明性和盲检测性;对于常见的压缩、中值滤波等图像处理攻击,该方法表现了很好的稳健性.     

一种基于曲波变换的数字水印算法

提出了一种基于曲波变换的数字水印算法,该算法将水印信息嵌入到曲波变换的粗尺度系数矩阵中,考虑到水印鲁棒性和不可见性的要求,选择合理的嵌入强度,使得加水印图像的不可见性更好。由于选择了代表图像大多数能量的低频系数嵌入,在抵抗JPEG压缩、噪声攻击、中值滤波等攻击性能方面较理想,因此文中算法具有较强的鲁棒性,能满足水印系统不可见性和鲁棒性的要求。     

基于自适应频带选择的数字水印技术

如何选择水印的隐藏区域是水印算法中的关键问题。该文提出了一种自适应DCT域水印算法,利用了人眼视觉系统(HVS)和图像局部特性自适应地选择水印隐藏区域,有效地实现了水印的稳定性和不可见性的折衷。与其它水印算法比较,该文提出的自适应算法适合于具有不同总体特性和局部特性的图像。实验结果表明该算法具有很好的感知质量,水印稳健性好,可以抵制各种图像处理操作诸如加性白噪声(AWGN),JPEG压缩以及裁剪,中值滤波,缩放等。     

一种基于离散余弦变换与奇异值分解的数字图像水印算法

结合奇异值分解（SVD）和离散余弦变换（OCT）的特点,提出了一种基于离散余弦交换与奇异值分解的数字图像水印算法.该算法能够很好地解决透明性和鲁棒性之间的矛盾.算法中采用经过置乱变换的灰度图作为水印,不仅增加了嵌入的信息量,而且提高了水印的安全性.实验结果表明,该算法不仅具有较好的透明性,而且对常见攻击如：叠加噪声、JPEG压缩、滤波以及几何攻击等具有较好的鲁棒性.     

基于人类视觉系统和DCT中频水印算法

数字水印技术作为数字产品版权保护的一项新技术，已得到广泛的应用。一个适用的数字水印算法应该既能保证图像良好的可视性，又要具有很好的鲁棒性。而基于DCT域的数字水印技术已成为当前的一个研究热点。文中提出的算法是结合人类视觉系统（HVS）特性通过改变中频段DCT相邻系数实现水印的嵌入。实验结果表明，该算法具有很好的视觉效果，检测出的水印效果较好，对JPEG有损压缩、剪裁、噪声干扰、模糊等操作具有较强的鲁棒性。     

一种嵌入可读水印的自适应盲水印算法

本文提出了一种基于DWT的嵌入可读水印的自适应盲水印算法,通过分析图像经离散小波变换后细节子带系数的特性,把细节子带系数的均值和方差作为水印信息的一部分来自适应地修改图像小波分解后某些细节子带的系数值,在满足水印不可感知性的条件下自适应地嵌入水印信息,实现了水印不可感知性和鲁棒性之间的折衷.同时,水印的提取无须求助于原图像,很好的实现了水印的盲检测.这里的水印是一幅有实际意义的二值图像.实验结果和攻击测试表明,本文提出的算法对JPEG/JPEG2000压缩、添加噪声、剪切、像素移位等多种攻击有较强的鲁棒性,同时对直方图均衡化、对比度调整和高斯滤波等图像处理操作也具有一定的抵抗能力.     

SIFT特征区域Contourlet域遥感图像水印算法

针对现有遥感图像数字水印算法多为基于图像全局的水印算法,抵抗旋转、缩放、行列剪切以及联合几何攻击能力较差的问题,提出一种基于SIFT特征区域的Contourlet域遥感图像数字水印新方法。算法选取二值数字图像作为水印图像,将二值水印图像置乱预处理后,对其进行行扫描形成一维向量作为待嵌入的水印信息;然后,在宿主遥感图像中提取SIFT特征点,筛选特征点,并依据特征点确定水印嵌入的特征区域;最后,规范所选特征区域,对其进行归一化后实施Contourlet变换,利用奇偶量化方法将水印信息嵌入所选的变换系数内。实验结果表明算法对JEPG压缩、噪声以及滤波等常规信号处理具有较好的鲁棒性,同时能够更好地抵抗旋转、缩放、平移及其联合等几何攻击。      

Using Deep learning for image watermarking attack

Digital image watermarking has justified its suitability for copyright protection and copy control of digital images. In the past years, various watermarking schemes were proposed to enhance the fidelity and the robustness of watermarked images against different types of attacks such as additive noise, filtering, and geometric attacks. It is highly important to guarantee a sufficient level of robustness of watermarked images against such type of attacks. Recently, Deep learning and neural networks achieved noticeable development and improvement, especially in image processing, segmentation, and classification. Therefore, in this paper, we studied the effect of a Fully Convolutional Neural Network (FCNN), as a denoising attack, on watermarked images. This deep architecture improves the training process and denoising performance, through which the encoder–decoder remove the noise while preserving the detailed structure of the image. FCNNDA outperforms the other types of attacks because it destroys the watermarks while preserving a good quality of the attacked images. Spread Transform Dither Modulation (STDM) and Spread Spectrum (SS) are used as watermarking schemes to embed the watermarks in the images using several scenarios. This evaluation shows that such type of denoising attack preserves the image quality while breaking the robustness of all evaluated watermarked schemes. It could also be considered a deleterious attack.     

基于LAB色彩空间的自适应数字水印算法

文章针对彩色图像提出了一种基于LAB色彩空间的自适应数字水印算法。算法将预处理置乱后的水印嵌入LAB色彩空间的亮度L分量,在嵌入过程中根据人类视觉对LAB空间色差的要求自适应地调整嵌入强度因子,以达到平衡水印图像的鲁棒性和不可见性。实验结果表明该算法对常用的图像处理,如压缩、低通滤波、加噪、剪切、旋转和缩放等攻击具有较好的鲁棒性和不可见性。     

基于DWT域图像数字水印技术

提出了一种基于DWT域的自适应盲检测数字水印算法,将二值水印图像自适应地嵌入到经小波变换后的原始图像的逼近子图上。实验结果显示,不论是视觉主观还是客观计算上,此算法得到的水印图像都具有很好的不可见性,对常见图像攻击和处理后的水印检测情况证明此算法所得的水印图像具有很强的鲁棒性。     

Robust image watermarking based on multiband wavelets and empirical mode decomposition.

In this paper, we propose a blind image watermarking algorithm based on the multiband wavelet transformation and the empirical mode decomposition. Unlike the watermark algorithms based on the traditional two-band wavelet transform, where the watermark bits are embedded directly on the wavelet coefficients, in the proposed scheme, we embed the watermark bits in the mean trend of some middle-frequency subimages in the wavelet domain. We further select appropriate dilation factor and filters in the multiband wavelet transform to achieve better performance in terms of perceptually invisibility and the robustness of the watermark. The experimental results show that the proposed blind watermarking scheme is robust against JPEG compression, Gaussian noise, salt and pepper noise, median filtering, and ConvFilter attacks. The comparison analysis demonstrate that our scheme has better performance than the watermarking schemes reported recently.     

基于约瑟夫环和DCT系数的盲水印算法

提出了基于约瑟夫环和DCT系数的盲水印算法。该算法首先使用约瑟夫环对水印信息进行置乱,使水印不可见性及抗攻击能力增强,再利用DCT系数量化,及对量化值进行奇偶性检验,实现了水印的嵌入及提取。增加了水印容量,从而提高了算法的鲁棒性。结果表明,该算法对压缩、中值滤波、高斯噪声等攻击,具有很好的鲁棒性,并且安全性强。