一种基于DCT的模糊聚类自适应水印算法

在DCT域提出了基于模糊和人类视觉系统的新颖的数字水印算法，该算法将图像块按照亮度和纹理进行分类，可以自适应地根据图像特点嵌入水印。水印为二值图像，根据块分类以不同的嵌入强度嵌入到所选择块的中频系数中。该方法允许在一定的视觉距离下嵌入更为鲁棒的水印，达到鲁棒性和不可见性的良好折衷。仿真结果显示了该方法可以抵抗如压缩，加噪等常用攻击。     

基于整数小波变换的灰度图像水印技术

数字水印技术通过在媒体图像中隐藏信号来达到保护媒体版权的作用。论文提出一种针对灰度图像水印的,基于整数小波提升算法的水印技术。该方法在对原始图像分块的基础上进行整数小波提升变换,然后对灰度水印图像置乱,再进行位平面分解,最后将每一个位面的水印信息都嵌入到原始图像的小波变换系数中。实验结果表明,该方法能较好地抵抗剪切和JPEG压缩攻击,对于滤波及噪声干扰也有一定的鲁棒性。     

Perceptually adaptive spread transform image watermarking scheme using Hadamard transform

The present paper proposes a digital image watermarking scheme using the characteristics of the human visual system (HVS), spread transform technique and statistical information measure. Spread transform (ST) scheme is implemented using the transform coefficients of both the host and the watermark signal. Watermark embedding strength is adaptively adjusted using frequency sensitivity, luminance, contrast and entropy masking of HVS model. The choice of Hadamard transform as watermark embedding domain offers several advantages, such as low loss in image information (higher image fidelity), greater reliability of watermark detection and higher data hiding capacity at high degree of compression. Performance of the proposed method is compared with a number of recently reported watermarking schemes based on spread spectrum (SS) and quantization index modulation (QIM).     

基于DWT-SVD域的彩色图像自适应水印算法

为了保护数字彩色图像版权,提出了一种结合离散小波变换(DWT)和矩阵奇异值分解(SVD)的彩色图像自适应水印算法。其主要设计思想是:先将原RGB彩色图像的各颜色分量进行小波分解;再将得到的中、低频带的小波系数与原水印图像分别进行奇异值分解,水印信息的奇异值重复嵌入到三通道中、低频带的小波系数奇异值中,且利用临界视觉阈值与奇异值之间的关系对水印嵌入强度作自适应调节,从而达到增强水印鲁棒性和确保水印透明性的目的。本算法适用于二值及灰度水印,在二值水印的提取过程中需设定一个提取阈值,以保证提取水印的完整性。仿真结果说明本算法对水印系统的透明性与鲁棒性作了较好的协调,是一种较稳健的算法。     

一种基于混合变换域的双重扩频盲水印算法

为权衡水印技术的鲁棒性和对篡改敏感性的冲突,本文提出了在载体图像中嵌入鲁棒水印和全脆弱水印的双重数字水印方案。首先对水印图像进行了置乱和加密,并对得到的加密水印进行了扩频处理。接着在混合变换域内实现了对加密扩频水印的嵌入:先对图像载体进行小波变换和离散余弦变换,通过修改各块的部分余弦系数的差值实现水印信息的嵌入。提取时实现了盲水印提取。实验结果表明,该算法具有很强的安全性和不可见性,对抗噪声和剪切攻击具有良好的鲁棒性。     

脊波域的图像数字水印算法研究

提出一种将混沌置乱加密后的水印信息嵌入到图像脊波变换域的算法。将图像分块后进行有限脊波变换,选择出图像纹理块的脊波域最大能量方向上的系数嵌入水印,水印提取只需要记录嵌入位置序列即可。实验结果表明,算法对噪声、压缩、不规则剪切、对比度等攻击有较强的鲁棒性。     

A new watermarking scheme for colour image using QR decomposition and ternary coding

At present, the binary images are often used as the original watermark images of many watermarking methods, but partial methods cannot be easily extended to colour image watermarking methods. For resolving this problem, we propose a new watermarking method using ternary coding and QR decomposition for colour image. In the procedure of embedding watermark, the colour image watermark is coded to ternary information; the colour host image is also separated into image blocks of sized 3?×?3, and these image blocks are further decomposed via QR decomposition; then, one ternary watermark is embedded into one orthogonal matrix Q of QR decomposition by the proposed rules. In the procedure of extracting watermark, the proposed method uses the blind-manner to extract the embedded ternary information. The novelty of this scheme lies in the proposed ternary coding for watermark image, which can improve the imperceptibility, embedded watermark capacity and real-time feature of the watermarking scheme. The results of simulation show the presented technique is better than other compared schemes with respect to imperceptibility, embedded watermark capacity and real-time feature under the similar robustness.

     

提升方案小波和DCT下的图像盲水印算法

在研究HVS对图像掩蔽特性的基础上,提出一种基于提升方案小波和DCT的彩色图像盲水印算法．首先将宿主图像亮度分量进行基于提升方案的小波分解,然后对其较低频子带进行基于分块的DCT分解,最后将二值图像的水印信息嵌人到各分块DCT域的中频系数中．文中算法结合HVS的掩蔽特性,使得水印信息的嵌人能量具有自适应的特性,从而保证了所嵌人的水印在不可见性的前提下,对常见的一些图像处理操作具有很强的鲁棒性．实验结果验证了文中算法的有效性．     

一种基于奇异值分解的自适应水印算法

变换域水印算法对压缩、噪音和滤波等攻击具有较好的鲁棒性,但水印算法对仿射变换攻击的抵抗力较差,提出了基于奇异值分解的自适应水印算法,首先根据人眼视觉模型,利用小波变换的能量特性做水印容量自适应分析,然后分块嵌入具有不同能量因子的水印,既保证了水印的嵌入量又增强了其鲁棒性.最后采用能量统计技术对提取的水印作误差校正,有效地解决了提取水印对角线明显失真的问题.仿真试验表明,算法不仅对剪切、滤波和噪声等攻击有较强的鲁棒性,对各种仿射变换也有非常好的抵抗力.     

Fractal and neural networks based watermark identification

Transform techniques generally are more robust than spatial techniques for watermark embedding. In this paper, a color image watermarking algorithm based on fractal and neural networks in Discrete Cosine Transform (DCT) domain is proposed. We apply fractal image coding technique to obtain the characteristic data of a gray-level image watermark signal and encrypt the characteristic data by a symmetric encryption before they are embedded. We then use neural networks and Human Visual System (HVS) to embed the watermark in the DCT domain. A Just Noticeable Difference (JND) threshold controller is designed to ensure the strength of the embedded data adapting to the host image itself entirely. Aiming at misjudging problem of the extracting process, maximum membership principle criterion is selected for identifying the watermark. And the CIELab color space is chosen to guarantee the stability of the results. The simulation results show that the algorithm is robust for common digital image processing methods as attacks and that the quality of the image is retained.     

Partially compressed-encrypted domain robust JPEG image watermarking

Digital media is often handled in a compressed and encrypted form in Digital Asset Management Systems. And watermarking of the compressed encrypted media items in the compressed-encrypted domain itself is required sometimes for copyright violation detection or other purposes. In this paper, we propose a robust image watermarking technique for partially compressed-encrypted JPEG images. However, arbitrary embedding of a watermark in a partially compressed encrypted image can cause drastic degradation of the quality as the underlying change may result in random decrypted values. In addition, due to the encryption the compression efficiency may become very low. Thus the challenge is to design a watermarking technique that provides good watermarked image quality and at the same time gives good compression efficiency. While the proposed technique embeds watermark in the partially compressed-encrypted domain, the extraction of watermark can be done in the encrypted or decrypted domains. The experiments show that the watermarked image quality is good and the reduction in compression efficiency is low. The proposed watermarking technique is robust to common signal processing attacks. The watermark detection performance of the proposed scheme is better than the existing encrypted domain watermarking techniques.     

New watermarking algorithm utilizing quaternion Fourier transform with advanced scrambling and secure encryption

Digital watermarking technology, as a powerful tool for copyright protection and content authentication of multimedia works, has received increasing attention, and the current image watermarking technology has developed significantly. Generally, embedding a watermark is done in grayscale images, mainly due to the fact that grayscale images are easier to process than color images, and grayscale images only contain brightness information and color-free information, in which an embedded watermark will not produce new color components. In real life, however, color images are more common than grayscale image information. To improve the security of the watermark information and the ability to embed the location and improve the security of the algorithm against a variety of attacks, this paper proposes an algorithm based on quaternion Fourier transform (QFT) with chaotic encryption and Arnold scrambling. Geometric Algebra (GA) can process color images in the form of vectors, and each component of Red,Green and Blue (RGB) should be processed separately. We utilized quaternion (which is a subalgebra of GA) and effectively completed color image processing by utilizing Fourier transform. After utilizing QFT, each component was made more secure by scrambling the pixels of the watermark and performing encryption utilizing chaotic sequencing. Different types of results utilizing Mean Square Error (MSE),Peak Signal to Noise Ratio (PSNR),Structure Similiarity Index Metric (SSIM), etc. were computed to verify the performance of our proposed algorithm and show that the robustness and security are high by utilizing our method.

     

高稳健性图像水印算法

提出了一个以8位灰度图像作为水印的DCT域水印算法。首先对以往的基于人眼视觉掩蔽特性(HVS)的块分类方法进行了改进，使其能更充分地挖掘载体图像的信息隐藏能力。在图像水印的嵌入方法上，将水印图像进行DCT变换，然后将DCT系数的低频分量嵌入到拉伸因子较大的块中。同时，对水印图像的DCT系数进行调整，使得各频率的能量基本相当，间接地提高了提取的水印图像的信噪比。实验结果表明，所提出的水印算法对多种攻击具有较好的稳健性，尤其对JPEG压缩、旋转和剪切攻击。其稳健性更明显。     

基于HVS和关系的DCT域彩色图像水印方案

提出了一种基于人类视觉系统和关系的离散余弦变换域水印技术。首先对二值水印图像进行混沌加密和Arnold置乱处理;其次对载体彩色图像的每一分量进行8×8分块的离散余弦变换;最后根据每一分块的亮度和纹理掩蔽特性和水印图像的像素取值来自适应调整选定位置的离散余弦变换系数的大小关系以嵌入水印。实验表明,提出的算法具有较好的透明性和抵抗攻击的能力,且在红色分量嵌入的水印比在蓝色或绿色分量嵌入的水印对滤波、有损压缩攻击等具有更好的鲁棒性。与同类算法相比,提出的算法具有更好的性能。     

基于内容的空域图像水印算法研究

In this paper,a novel space domain watermarking scheme based on image content is presented.The proposed method can use the human visual system(HVS) to adaptively embed a watermark in an image by decomposing the host image,selecting streak blocks,modifying the intensities of the block.Experimental results show that the watermarking scheme proposed in this paper is invisible and robust to cropping,and also has good robustness to compression,filtering,noise adding,image enhancement,and rnosaie.     

基于GHM和FCM的自适应图像水印算法

提出一种基于GHM多小波变换域上的模糊自适应水印算法。利用多小波系数块的能量、重要系数对小波块进行分类,结合图像自身的局部特性,在多小波系数中的两个相关的细节子图像中自适应地嵌入一幅二值水印图像;为了增强水印的鲁棒性,采用冗余嵌入方法;水印的提取不需要原始图像。实验结果证明,该算法对剪切、JPEG压缩、锐化等多种图像处理具有很好的鲁棒性。     

A new robust reference logo watermarking scheme

In this paper, a new yet simple reference logo watermarking scheme based on fractional Fourier transform (FrFT) and singular value decomposition (SVD) is proposed. The core idea of the proposed scheme is to segment host image into non-overlapping blocks by the means of Hilbert space filling curve and a reference image is formed by considering Human visual system (HVS). First, reference image is transformed into FrFT domain and embedding is done by modifying singular values of the reference image using singular values of watermark. After embedding, modified reference image is segmented into blocks and these modified blocks are mapped into their original places for constructing watermarked image. For extraction, a reliable watermark extraction scheme is proposed. The experimental results demonstrate better visual imperceptibility and resiliency of the proposed scheme against intentional or un-intentional variety of attacks.     

Visible watermarking based on importance and just noticeable distortion of image regions

Visible watermarking is the process of embedding data (watermark) into a multimedia object (video/image) such that the embedded watermark is perceptible to a human observer. Many times, visible watermarks occlude important portion of multimedia objects. This paper introduces a visible watermarking algorithm to embed a binary logo watermark at N non-overlapping positions in an image such that important portions of the image are not occluded. The important portions are found through visual saliency computation or available human eye fixation density maps. In the proposed visible watermarking, just noticeable distortion is used to adaptively filter the watermark embedding energy based on the image content. A mathematical model in terms of information-content-weighted-structural-similarity-index and visual importance is proposed to find optimal watermark embedding strength. We tested the algorithm on several color images of different sizes and on several binary watermarks of different sizes and found the results to be very promising as per the requirements in visible watermarking. When compared to the state-of-the-art, we also found that the proposed technique does better in not hiding the details of any test image.     

基于数字水印和加密技术的Internet音乐保护

提出了一种基于数字水印和加密技术的Internet音乐保护方法,并针对两种适用于Internet在线传输的音乐格式：压缩音乐和MIDI,提出了两种快速和鲁棒性强的数字水印加入方法,以保护Internet在线音乐的知识产权。对于压缩音乐,采用部分解压来加入水印且加入方法与音乐内容紧密相关;对于MIDI,水印被加在一些虚拟音符中,这些虚拟音符随机地隐藏在MIDI音符中。     

基于SVD和Radon变换的抗旋转攻击盲水印算法

为了提高传统基于奇异值变换（SVD）的数字水印抗几何攻击能力,提出一种在小波变换域将Radon变换和奇异值变换相结合的抗旋转攻击鲁棒性水印算法。将宿主图像进行小波变换,对变换后的低频子带进行奇异值分解,将经过仿射变换置乱后的二值水印图像嵌入到奇异值中。在水印嵌入操作上采用了奇偶量化嵌入算法从而实现了二值水印图像在水印检测时的盲提取;同时在水印检测之前,利用Radon变换检测算法对待检测图像进行几何校正,然后提取水印信息。实验结果表明,该算法对于噪声感染、滤波、JPEG压缩等常规信号处理的鲁棒性优于传统的基于SVD的数字水印算法,同时对于旋转几何变换具有很好的鲁棒性。