Adaptive,scalable and robust watermarking for wavelet-based progressive image transmission

Abstract

Image watermarking refers to the process of embedding an authentication message, called watermark, into the host image to uniquely identify the ownership. In this paper, an adaptive, scalable, blind and robust wavelet-based watermarking approach is proposed. The proposed approach enables scalable watermark detection and provides robustness against progressive wavelet image compression. A multiresolution decomposition of the binary watermark is inserted into the selected coefficients of the wavelet-decomposed image that represent the high activity regions of the image. The watermark insertion is started from the lowest frequency sub-band of the decomposed image and each decomposed watermark sub-band is inserted into its counterpart sub-band of the decomposed image. In the lowest frequency sub-band, coefficients with maximum local variance and in the higher frequency sub-bands, coefficients with maximum magnitude are selected. The watermarked test images are transparent according to the human vision system characteristics and do not show any perceptual degradation. The experimental results very efficiently prove the robustness of the approach against progressive wavelet image coding even at very low bit rates. The watermark extraction process is completely blind and multiple spatial resolutions of the watermark are progressively detectable from the compressed watermarked image. This approach is a suitable candidate for providing efficient authentication for progressive image transmission applications especially over heterogeneous networks, such as the Internet.     

数字全息水印在印刷半色调图像中的应用

在印刷半色调图像中嵌入特定信息可用于印刷品的保护和认证。设计了一种新颖的应用于非数字形式印刷半色调图像中的信息隐藏算法,将原始水印信息制成菲涅耳全息图,以此作为水印信息,利用离散小波变换算法嵌入到宿主图像中,以实现信息隐藏。该算法利用全息图独特的不可撕毁性来增强水印的鲁棒性。实验结果表明,该算法对图像半色调化攻击具有较好的鲁棒性。     

Watermarking in halftone images with mixed halftone techniques

Ordered dithering and error diffusion are the two most popular processes to produce halftone results for printing industry. Ordered dithering inherently has the benefit of efficiency. On the other hand, error diffusion has high quality and reasonable complexity. In this article, we propose a watermarking that adopts the ordered dithering to produce the referenced halftone image, then applying the noise‐balanced error diffusion to embed the watermark. A low computational complexity, low memory demand, and good embedded image quality are achieved with the proposed technique. From the experimental results, this technique can guard against the cropping and print‐and‐scan two major degradation processes in halftone images. © 2008 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 17, 303–314, 2007     

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。     

Fragility and Robustness of Binary-Phase-Only-Filter-Based Fragile/Semifragile Digital Image Watermarking

In the fragile/semifragile digital image watermarking for image authentication, fragility or sensitivity of the embedded watermark to malicious attacks is an important problem. On the other hand, robustness to some incidental manipulations, such as JPEG compression, is required for the semifragile watermark. Recently, a binary-phase-only-fllter (BPOF)-based watermarking technique has been proposed for image authentication, where the authors embedded a watermark upon the BPOF of the Fourier spectrum of an image into the corresponding magnitude. Then, they performed image authentication by calculating the correlation between the extracted watermark and the phase information computed from the watermarked image. In this paper, we propose to use the identical ratio (IR) between the extracted watermark and the computed BPOF to detect watermark and measure the degree of authenticity. The IR is simpler, computationally efficient, and yields better watermark-detection performance when compared to the correlation-based calculation. In addition, it is found that the technique works better for fragile watermarking when compared to the semifragile watermarking. Furthermore, to accommodate semifragile watermarking, we propose to use the low-frequency ranges for watermark embedding and detection, which improves the required fragility and robustness. The performance of the improved algorithm is verified via experimental results.     

New scheme of digital watermarking using an adaptive embedding strength applied on multiresolution filed by 9/7 wavelet

Digital image watermarking is still a new field for research. In fact, digital watermarking is the best tool for the copyright protection and the authentication of the digital data. Researches are interested in the tradeoff that exists between the insertion capacity, the imperceptibility, and the robustness. The embedding function has a great influence on these characteristics. Channel coding techniques are used to reduce the error probability of the hidden watermark. On the other hand, the watermark strength is adapted according to human visual perception. In this article, we present a new scheme to achieve the embedding function in the framework of a robust and nonblind watermarking in multiresolution field by 9/7 wavelet of Daubechies. Indeed, we replace the constant embedding strength by a variable coefficient based on the logarithmic function. This coefficient is adaptive according to the magnitude of the wavelet transform magnitude that will be watermarked. This adaptive scheme reduces the computational error and enhances the robustness and the imperceptibility. Experimental results are presented to show that our scheme gives a better correlation and an improved PSNR. They demonstrate that the detection is enhanced. © 2007 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 16, 249–257, 2006     

Digital image watermarking based on VSS in BTC domain

Abstract

An image watermarking model based on visual secret sharing (VSS) is proposed for protection of ownership. In the embedding phase, the watermark is first divided by VSS into two parts: a hiding watermark and a secret watermark. Then only the hiding watermark is embedded into the original image and the secret watermark is reserved for watermark extracting by the owner. In the extracting phase, the hiding watermark is extracted from the watermarked image first and then directly superimposed on the secret watermark to recover the watermark information.     

Digital watermarking based on fractal image coding

Abstract

With advances in computer network and multimedia technology, digital media are rapidly proliferating, and thus the issue of copyright protection for electronic publishing is receiving great attention. To achieve the goal of copyright protection, the digital watermarks are used to identify the owner of a certain image, so as to prevent illegal copying. Digital watermarking is the technique that embeds an invisible signal including owner identification and copy control information into multimedia data such as audio, video, and images. A new digital watermark approach based on fractal image coding is proposed in this paper. We present a way to use the fractal code as a means of embedding a watermark into image. The proposed approach has been shown to be resistant to general attacks, like StirMark. Moreover, someone who owns the decryption key can simply extract the digital watermark from the watermarked image without resorting to the original image.     

基于 DWT-SVD 和 QR 码的抗几何攻击数字水印技术

目的为了抵御QR码数字水印图像的几何攻击,提出一种基于奇异值分解和离散小波变换的数字水印技术。方法利用QR码编码规则,将文本信息编码生成宿主图像;将宿主图像进行对数极坐标变换,然后进行一级小波分解,利用奇异值分解原理在其低频分块中嵌入置乱后的水印图像,形成含水印的QR码图像。结果实验结果表明,该算法可以使QR码水印图像抵抗旋转、缩放、平移(RST)等几何攻击。结论算法有良好的鲁棒性和不可见性,能够作为一个可行的版权保护和认证的工具。     

基于DCT域的数字盲水印技术

提出一种鲁棒性较好的DCT域数字盲水印方案。该方案将汉明编码应用于二值水印图像,同时,采用混沌调制序列伪随机选取嵌入区域,提高水印算法的安全性。通过分析DCT中频特定系数关系,实现水印的盲提取。实验结果表明,该算法对于常见的图像攻击具有较好的鲁棒性,是一种有效的盲水印。     

印刷品水印图像的半色调算法比较

对Bayer抖动、误差扩散和绿噪声3种半色调算法进行了分析比较。利用离散小波变换将水印信息嵌入宿主图像,采用峰值信噪比对3种算法生成的半色调图像质量进行客观评价;用归一化相关系数衡量半色调图像提取的水印质量;以Matlab程序运行时间判断3种算法的计算效率;同时,结合人眼视觉对半色调图像质量进行主观评价。综合各种评价,结果表明:误差扩散是最适合小波水印图像的半色调算法。     

Watermarking in halftone images with noise balance strategy

Two novel and robust methods for embedding watermarks into error‐diffused halftone images are presented in this study. The first method is referred to as Dither‐Referenced Error Diffusion (DREDF), where the proposed Average Ordered Dithering (AOD) is adopted to produce the referenced halftone image. The Noise‐ Balanced Error diffusion (NBEDF) is then applied to embed the watermark. The other method is referred to as Parity‐Matched Error Diffusion (PMEDF). This approach achieves good image quality and capacity as high as 6.25 to 25%. Since the two techniques are blind, the decoder does not need any priori knowledge of the original halftone image or watermark. The capacity of the two approaches is also flexible to accommodate all kinds of applications. As the experimental results demonstrated, both techniques are able to guard against degradation due to cropping, tampering, and the print‐and‐scan process in error‐diffused halftone images. Moreover, both methods have features of low computational complexity, low memory demand, and good image quality. © 2010 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 20, 202–214, 2010.     

一种基于 Contourlet 变换的彩色图像全息水印算法

提出了一种结合了全息水印加密技术和 Contourlet 变换技术的彩色图像水印算法。 算法首先将 RGB 模式的水印载体图像转换至 YCrCb 颜色空间,选取亮度分量作为水印载体通道,对其进行多层 Contourlet 分解,得到细节子带图像;而后对二值水印图像进行傅里叶全息加密,将加密后的图像嵌入至载体图像的 Contourlet变换系数中。 仿真实验结果表明,该水印算法具有良好的不可见性,对于常见的几何变换及多种攻击具有良好的鲁棒性。     

数字水印技术在印刷品防伪中的应用

在许多打印和出版应用中,需要在半色调图像中嵌入数据用于作品的版权保护和认证.介绍了一种新颖的半色调图像中数据隐藏的算法,该算法利用DCT域数据分类法进行数字水印信息的嵌入.实验结果显示:该算法能够抵抗打印/扫描攻击,鲁棒性较好.     

基于SIFT变换和DWT-SVD的自适应图像水印算法

目的由于传统的自适应水印技术无法实现水印嵌入区域依据图像自身的特征而改变,且抵抗几何攻击的能力较弱,提出一种基于SIFT特征提取,结合DWT-SVD的水印嵌入方法。方法首先对图像进行SIFT特征提取,然后利用RANSAC算法选取出鲁棒性较好的特征点,通过特征点选取合适大小的水印区域,最后结合DWT-SVD算法将水印嵌入原始图像中。结果采用SIFT变换结合DWT-SVD算法嵌入的水印,含水印图像的视觉效果较好。含水印图像在没有受到攻击时,可以无损地提取出水印;在受到攻击时,提取出的水印品质较好,NC值均高于0.96,且算法的时间复杂度和空间复杂度均较小。结论实验证明,此方案在面对任意角度的旋转攻击,以及常规图像处理攻击有很好的鲁棒性,可以达到保护数字产品的目的。     

基于小波变换的傅里叶加密印刷水印算法研究

在研究傅里叶加密全息技术、数字水印技术和小波理论的基础上,提出了一种基于小波变换的傅里叶加密印刷水印算法。利用该算法重建水印,有效地抑制了载体图像的低频分量对水印产生的噪声的影响;使能量分布在图像的所有像素上,具有良好的抗裁切能力;算法采用密钥加强了水印的安全性。实验表明:嵌入水印的图像一次印刷可检测,二次扫描印刷提取的水印脆弱,可以抵抗基本的图像处理操作。     

Watermark Embedding for Direct Binary Searched Halftone Images by Adopting Visual Cryptography

In this paper, two methods are proposed to embed visual watermark into direct binary search (DBS) halftone images, which are called Adjusted Direct Binary Search (ADBS) and Dual Adjusted Direct Binary Search (DADBS). DADBS is an improved version of ADBS. By using the proposed methods, the visual watermark will be embedded into two halftone images separately, thus, the watermark can be revealed when these two halftone images are overlaid. Experimental results show that both methods can achieve excellent image visual quality and decoded visual patterns.     

强鲁棒性全息水印算法

提出了一种强鲁棒性变换域全息水印算法。首先将RGB模式彩色载体图像分离通道,分块后运用DCT转换到变换域,将奇异值分解与傅里叶全息技术结合起来,改善了传统全息水印抗滤波差及不可旋转的缺点。计算机仿真结果表明:该算法能够满足人眼对含水印图像的质量要求,重建的水印与原水印图像相似度高;该算法能够抵抗常见的多种攻击并兼顾了水印安全性与不可见性,在版权保护与信息隐藏的实际应用中具有重要意义。     

基于LWT-QR分解和Laplacian Pyramid的水印算法

目的为了提高数字水印的鲁棒性和不可见性,提出一种基于Laplacian Pyramid和LWT-QR分解的水印算法。方法首先对宿主图像进行2层Laplacian Pyramid分解,取其第2层Laplacian残差图像进行一层LWT分解,取其低频子带进行大小为4×4的无重叠分块处理。然后,基于提升小波系数的相关属性,再对每个选中的低频子块进行QR分解,取分解后R矩阵的第1行为目标进行水印的嵌入,同时对水印进行Arnold置乱,置乱后的水印图像嵌入到R矩阵的第1行元素中。结果嵌入水印后图像的PSNR能够达到45 d B,而且该方案对常见的信号处理攻击有较好的鲁棒性,NC均值在0.9以上。结论理论分析和大量的实验数据表明,该方案能够很好地改善图像操作过程中的鲁棒性和不可见性。     

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。