基于计算全息的Contourlet域数字水印算法

目的提出一种基于计算全息的contourlet域数字水印算法。方法首先,利用共轭对称延拓傅里叶计算全息方法,将原始二值水印图像生成全息水印图像;然后,将原始图像进行二级contourlet变换,得到8个中频方向子带系数;最后,将全息水印嵌入在其中频系数中。结果该方法可以有效抵抗高斯滤波、中值滤波和均值滤波以及打印-扫描攻击,同时,对噪声攻击、裁切攻击和JPEG压缩攻击也有很强的抵抗能力。在水印提取时无需原始图像,属于盲水印算法。结论该算法可以广泛应用于数字图像的版权保护中。     

基于QR码与混沌加密的Contourlet域彩色图像盲水印算法

目的针对现行数字水印算法中抗几何攻击能力弱以及嵌入水印信息容量差的问题,提出一种Contourlet变换下QR码与混沌加密相结合的彩色图像水印算法。方法采用QR码作为水印图像,利用Logistic混沌序列对其进行加密,再将加密的水印图像嵌入到二级Contourlet变换的低通子带中,利用系数间的大小关系,修改系数完成水印嵌入与提取。结果通过实验结果可知,水印的嵌入对载体图像影响较小,PSNR值高达42.764,经过旋转、剪切及常规攻击后,提取出的水印均可正确解码。结论该算法具有良好的安全性、不可见性,对于各类攻击具有较优的鲁棒性。水印信息容量高于普通图像,水印提取方式为盲提取,能够更好地满足各类数字作品版权保护的实际需要。     

多尺寸普适的抗印刷扫描水印算法

目的为了赋予固定尺寸水印自适应不同尺寸宿主图像的尺寸普适性,提出一种多尺寸普适的抗印刷扫描水印算法。方法对宿主图像进行裁剪、分层、分块获得图块,计算每个图块的最大奇异值,取最大奇异值前九的图块组成拼接图像,结合水印嵌入算法在拼接图像中抽取获得待嵌图像,将制成全息图的水印嵌入待嵌图像的DWT域内。结果实验表明,将固定尺寸水印嵌入不同尺寸宿主图像后,随着宿主图像尺寸的增加,水印图像的不可见性明显提高,并且经历模拟印刷扫描可顺利提取水印。结论该算法不仅可以赋予固定尺寸水印适应不同尺寸宿主图像的普适性,且提升了水印嵌入后的不可见性,对印刷扫描具有较好的鲁棒性,为数字水印在印刷防伪领域的应用研究提供了新思路。     

基于归一化的全息水印技术

提出了一种结合了归一化技术和全息技术的数字水印技术。首先,利用归一化技术对图像作归一化运算,同时利用全息技术将水印二值图处理为全息图;其次,取归一化后图像分块离散余弦变换的中频系数,对中频系数所组成的矩阵作离散小波变换;最后将全息图嵌入到离散小波变换的低频分量中。由于图像归一化技术具有抗仿射变换的性能,同时全息技术具有很强的抗裁切的性能,所以此数字水印技术具有很强的抗仿射变换的性能,可以广泛的用于数字作品的版权保护。     

基于二值离散运算的自适应数字图像水印算法

论文提出了一种在小波变换域内基于二值离散运算的自适应数字图像水印算法.算法利用人眼视觉掩盖特性,根据要嵌入的伪随机数水印长度自适应地选择原始图像小波逼近子图中纹理信息丰富的图像子块,通过对这些图像子块系数的二值离散修改实现水印的嵌入,水印检测无需原始图像.由于水印的嵌入与检测是基于二值离散运算,所嵌入的水印具有很理想的鲁棒性,能免疫于常规图像处理方法的有限攻击.同时,嵌入的水印具有理想的隐蔽效果,完全满足水印不可觉察性要求.     

A Robust Image Watermarking Scheme Using Z-Transform,Discrete Wavelet Transform and Bidiagonal Singular Value Decomposition

Watermarking is a widely used solution to the problems of authentication and copyright protection of digital media especially for images, videos, and audio data. Chaos is one of the emerging techniques adopted in image watermarking schemes due to its intrinsic cryptographic properties. This paper proposes a new chaotic hybrid watermarking method combining Discrete Wavelet Transform (DWT), Z-transform (ZT) and Bidiagonal Singular Value Decomposition (BSVD). The original image is decomposed into 3-level DWT, and then, ZT is applied on the HH3 and HL3 sub-bands. The watermark image is encrypted using Arnold Cat Map. BSVD for the watermark and transformed original image were computed, and the watermark was embedded by modifying singular values of the host image with the singular values of the watermark image. Robustness of the proposed scheme was examined using standard test images and assessed against common signal processing and geometric attacks. Experiments indicated that the proposed method is transparent and highly robust.     

基于倍福PLC的779型条盒包装机烟包制动系统的改造

目的 为解决FOCKE-FX 779型条盒包装机因故障引起的设备快速停机,复位启动后因烟包制动系统不稳定而造成的烟包擦碰、夹烟问题,设计一套基于倍福PLC的烟包挡块机构,辅助原机制动系统完成烟包的准确定位.方法 通过设计电气控制逻辑,在倍福PLC中完成控制程序编写,将原机制动气囊正压空气接通信号和烟包堆垛到位信号关联到挡块机构的控制电磁阀,实现烟包挡块机构与烟包制动系统的控制一致性,同时保证挡块机构按照设定控制次数7次,配合原制动气囊对烟包进行制动,增强制动系统的稳定性.结果 改造后的烟包制动系统稳定性得到明显提升,消除了因烟包定位不准出现擦碰而带来的产品质量隐患,779型条盒包装机的总停机率由5.08％降低到2.27％,设备"产质耗"指标得到明显改善.结论 烟包挡块机构工作稳定,功能可靠,后期免维护性强,满足了生产设备稳定性需求,能为同类型问题的处理提供参考和借鉴.     

SVD-based digital image watermarking using adaptive generated watermark

In this paper, an evolutionary-based algorithm for digital image watermarking is proposed. Robustness and imperceptibility are two important properties of digital image watermarking which conflict with each other. A singular value decomposition (SVD)-based intelligent algorithm is applied to make a trade-off between robustness and imperceptibility. In the proposed algorithm, first, the original image is divided into 8×8 blocks. Then some special blocks are transformed into discrete cosine transform (DCT) domain. SVD decomposition of DCT coefficients of special blocks is the next stage of the method. Finally, a binary watermark image is embedded into the singular values by a quantisation method. The major property of the proposed method is the generation of a binary watermark image using genetic algorithm to solve the optimisation problem between robustness and imperceptibility. So the watermark could be variable and image adaptive. The simulation results show improvement in robustness of the proposed method against several attacks such as noise contamination, filtering, joint photographic experts group (JPEG) compression and some geometrical attacks like cropping, rotation and rescaling in comparison with a recently similar existing work.     

基于YCoCg-R颜色空间与离散余弦变换的自适应彩色图像水印算法

目的为了解决当前彩色图像水印技术的水印容量和不可感知性不佳等问题,设计基于YC_oC_g-R颜色空间和离散余弦变换的自适应图像水印算法。方法首先,将载体图像从RGB空间转换到YC_oC_g-R空间,计算Y,C_o,C_g这3个颜色分量;随后,引入离散余弦变换DCT对Y分量进行处理,获取相应的DCT系数;引入模糊聚类分析,将DCT低频系数视为局部特征,利用SVM机制对DCT低频系数进行训练分类,确定出适合嵌入水印的DCT系数;设计水印嵌入机制,将水印数据隐藏到合适的DCT低频系数中;借助可逆DCT方法,将Y分量从频域变换到空域;联合初始的C_o与C_g分量,将其变换到RGB空间,输出水印图像;最后,通过相应的水印提取方法,复原初始水印信息。结果测试数据表明,与当前水印方法相比,所提技术具有更高的不可感知性与水印容量,其水印图像的PSNR值为43.67 dB,且其允许的水印容量可超过1 bits,在多种攻击下,复原水印的质量更高,相关系数NC均超过了0.92。结论所提技术能够较好地将水印信息隐藏在载体图像中,具有较高的鲁棒性和安全性。     

Dual plane multiple spatial watermarking with self-encryption

Watermarking has established itself as a promising solution in the context of digital image copyright protection. Frequency domain watermarking is mainly preferred due to associated robustness and perceptual issues but requires a large amount of computation. On the other hand spatial domain watermarking is much faster but lacks when robustness is concerned. In this paper a block based spatial domain watermarking technique for color images is proposed that is fast and robust. Two-way embedding introduced in the paper provides capability to previously estimate perceptual degradation in host image due to watermark embedding. Multiple watermarking in two component images is used to achieve better imperceptibility and better robustness. Self-encryption introduced aims to remove dependency over external secret key however optional encryption with random secret keys is proposed for providing better security. Proposed embedding technique is an effort to achieve proper balance between robustness and quality degradation of image. Experiments suggest proposed method is robust against processing attacks such as spatial filtering transformations image enhancement and loss compression.     

基于奇异值分解的Contourlet域水印算法

目的提高数字水印算法抗信号处理攻击能力,提升水印鲁棒性。方法提出一种基于Contourlet变换和奇异值分解(SVD)相结合的水印算法。对水印图像进行多次Arnold置乱处理,实现置乱加密;选择Contourlet域变换系数的方向子带作为水印嵌入区域;在Contourlet系数构建矩阵中进行SVD分解,并结合人类视觉系统进行嵌入强度的自适应选择。结果实验结果得出图像的峰值信噪比为54.1279 d B,表明所述算法具有很好的透明性、隐蔽性。结论所述图像数字水印算法具有很好的鲁棒性、不可见性以及抵抗各种攻击的能力,对数字产品的版权保护具有促进作用。     

基于NSCT_SVD_DE的自适应大容量水印算法

目的针对NSCT_SVD水印算法水印容量较小的问题,提出一种基于视觉区域特性和菱形编码的自适应大容量水印算法。方法对图像进行NSCT变换,对NSCT域低频系数矩阵进行8×8分块,选取每一块中最大的奇异值。根据人眼对图像亮度、纹理及平滑的敏感程度不同,选择在不同的分块嵌入不同大小的水印信息。结果实验表明,在6幅标准512×512像素的灰度图像中嵌入水印后的PSNR保持在39左右,具有较好的不可感知性,水印容量比DWT_SVD水印算法提升了约41.41倍,比NSCT_SVD水印算法提升了约20.95倍。对常见的中值滤波、高斯滤波、椒盐噪声、旋转和JEPG压缩等攻击具有较好的鲁棒性。结论该水印算法在满足不可见性和鲁棒性的前提下,增加了水印容量,具有一定的实用价值。     

一种强鲁棒性的彩色图像数字水印技术

目的提出了一种彩色图像数字水印技术,解决数字水印在大数据量水印、不可见性和鲁棒性之间的关系。方法该算法对彩色QR码水印和彩色载体图像分别进行RGB三通道分解,彩色水印单通图像进行混沌加密;对彩色载体单通道图像进行Contourlet变换;按对应通道将水印嵌入到载体图像低频经奇异值分解后的对角矩阵。结果该算法在水印嵌入和提取仿真实验结果为PSNR50 d B;鲁棒性仿真实验结果表明,该算法在抵抗任意旋转攻击和基本图像处理操作的攻击下,提取出来的彩色QR码颜色未失真,并且均能够成功解码和自动识别。结论该算法具有较强的鲁棒性和较好的不可见性,能够很好地将彩色水印嵌入彩色图像,可应用到实际的数字版权保护中。     

Robust Image Watermarking Using LWT and Stochastic Gradient Firefly Algorithm

Watermarking of digital images is required in diversified applications ranging from medical imaging to commercial images used over the web. Usually, the copyright information is embossed over the image in the form of a logo at the corner or diagonal text in the background. However, this form of visible watermarking is not suitable for a large class of applications. In all such cases, a hidden watermark is embedded inside the original image as proof of ownership. A large number of techniques and algorithms are proposed by researchers for invisible watermarking. In this paper, we focus on issues that are critical for security aspects in the most common domains like digital photography copyrighting, online image stores, etc. The requirements of this class of application include robustness (resistance to attack), blindness (direct extraction without original image), high embedding capacity, high Peak Signal to Noise Ratio (PSNR), and high Structural Similarity Matrix (SSIM). Most of these requirements are conflicting, which means that an attempt to maximize one requirement harms the other. In this paper, a blind type of image watermarking scheme is proposed using Lifting Wavelet Transform (LWT) as the baseline. Using this technique, custom binary watermarks in the form of a binary string can be embedded. Hu’s Invariant moments’ coefficients are used as a key to extract the watermark. A Stochastic variant of the Firefly algorithm (FA) is used for the optimization of the technique. Under a prespecified size of embedding data, high PSNR and SSIM are obtained using the Stochastic Gradient variant of the Firefly technique. The simulation is done using Matrix Laboratory (MATLAB) tool and it is shown that the proposed technique outperforms the benchmark techniques of watermarking considering PSNR and SSIM as quality metrics.     

一种基于YC-rC-b颜色空间和视觉特性的彩色图像水印技术

根据图像离散余弦变换频谱图特征及结合人眼对亮度和颜色的对比度敏感视觉特性,提出了一种人眼感知图像最小误差即JND阈值的计算方法,通过计算出的JND阈值,提出了一种基于YCrCb颜色空间的彩色图像水印技术方案。方案依据JND阈值筛选彩色图像的3个分量亮度图变换域频谱系数来进行水印的嵌入和提取。从水印技术方案上看,JND阈值的引入使得水印的嵌入达到最大;嵌入算法使得水印嵌入的位置具有随机性,有力地保证了水印信息的安全性。仿真实验和攻击测试表明:含水印图经压缩攻击后的图像与原始图像基本一样,提取的水印信息与原始水印基本相同;攻击后的含水印图具有较好的透明性和较高的鲁棒性。提出的基于YCrCb颜色空间和人眼视觉特性的彩色图像水印技术方案,是一种可行的、较好的彩色图像技术。     

Robust watermarking technique for digital images utilizing the invariant relation of vector quantization indices

Abstract

The digital property of multimedia has received significant attention in recent years. Robust watermarking of digital images and video for copyright protection is an important and challenging topic. In this paper, a watermarking method is presented which is based on vector quantization (VQ). In the proposed method, the watermark is related to the codebook that is permuted by an owner-specific random sequence. Also, the extraction of the watermark does not require the existence of the original image. The proposed method exploits the relation of VQ indices to provide the property of invisibility and robustness for various attacks. The experimental results in this work demonstrate the effectiveness of the proposed method.     

一种用于印刷图像防伪的水印算法设计与实现

阐述了基于DCT变换域的数字水印理论和算法,并根据相关理论模型,提出了一种在离散傅里叶变换中实现的、可用于印刷品防伪的数字水印嵌入算法。研究表明与传统的LSB算法和Patchwork算法相比,该算法有较好的抗攻击能力。给出了系统的水印嵌入算法和水印提取流程设计的过程。实践证明,基于DCT变换域的数字水印算法能确保水印的不可见性,并保持较好的鲁棒性,实现了印刷图像载体数字版权的保护,并可检测出用此算法嵌入印刷图像中的不可见标记。最后通过实验验证了此算法的可行性、可靠性和有效性,为印刷品版权保护提供参考和借鉴。     

基于Logistic混沌加密的NSCT-SVD抖动调制盲水印算法

目的提出一种既安全又具高稳健性的盲水印算法。方法首先通过Logistic映射混沌置乱对图像加密,然后对载体图像进行三层非采样Contourlet变换(NSCT),提取低频部分进行8×8分块,最后对低频带的子块进行奇异值分解(SVD),将混沌变换的水印图像嵌入在进行抖动调制的奇异值中。结果该算法解决了奇异值分解引起的False positive问题即虚警率,在提取水印的算法过程中没有用到原载体图像,实现了水印的嵌入及盲检测。实验结果显示,该算法提高了水印的防伪性,耐常见攻击的抵抗能力也较强。结论该算法满足了数字水印技术要求的隐蔽性和稳健性,并且可以对数字产品起到版权保护的作用。     

An adaptive compressed MPEG-2 video watermarking scheme

Digital watermarking is becoming more and more important for protecting the authenticity of multimedia objects as they become easier to copy, exchange, and modify. Several watermarking schemes have been proposed in recent years, but most of them deal with still images, only some being extended over to the temporal domain for video watermarking. But again most of those approaches are applied to uncompressed video processing domain. In the subject paper, a new compressed video watermarking procedure is proposed. The developed method embeds several binary images, decomposed from a single watermark image, into different scenes of a video sequence. The spatial spread spectrum watermark is embedded directly into the compressed bit streams by modifying discrete cosine transform (DCT) coefficients. In order to embed the watermark with minimum loss in image fidelity, a visual mask based on local image characteristics is incorporated. Extensive experimental simulations demonstrate that the proposed watermarking scheme is substantially more effective and robust against spatial attacks such as scaling, rotation, frame averaging, and filtering, besides temporal attacks like frame dropping and temporal shifting.     

A new semi-blind watermarking algorithm using ordered Hadamard transform

An efficient and fast watermarking algorithm based on ordered Hadamard transform (HT) is proposed. Since it uses a few information of watermark image in secret key, it is categorised as a semi-blind method. In our algorithm, both host and watermark images are decomposed into non-overlapping blocks. Next, they are mapped into transform domain as Hadamard coefficients. Then, several high frequency AC components of host image are substituted with watermark coefficients without using any strength factor. Not employing this factor guarantees the embedded image to be retrieved with primary quality. Moreover, using HT offers several advantages of fastness, higher image fidelity, greater reliability of watermark detection and higher data hiding capacity. The experimental results show that our method keeps the quality of host image and is robust to common attacks. Compared to frequency domain and hybrid methods, it has advantages of shorter processing time, acceptable robustness and ease of hardware implementation.