一种应用相息图对灰度图像信息进行隐藏的方法

一幅灰度图像的相息图被隐藏于一幅宿主图像中,该相息图是采用基于相息图迭代的双随机相位加密技术得到的.由于采用仅含有位相信息的相息图作为待加密灰度图像信息的载体,因而与隐藏图像同时具有振幅和相位信息的情况相比较,需要隐藏的信息量大大降低,从而可在对宿主图像影响较小的情况下,提高提取信息的质量;并可有效地提高信息提取时的光学效率,并且对二元图像信息的隐藏也同样适用.水印图像的剪切对隐藏信息提取质量的影响也被分析,模拟实验结果证明了所采用方法的有效性. 关键词： 灰度图像 相息图 信息隐藏     

基于复小波变换和自适应像素聚类的图像信息隐藏

针对大多数图像信息隐藏技术需要先验信息及训练难度大的问题,提出一种基于复小波变换和自适应像素聚类的图像信息隐藏方法.方法利用新型的无监督种群优化算法对秘密图像进行自适应的像素聚类处理,采用支持向量机选择载体图像双树复小波变换的最优小波子带,将最优小波子带作为信息隐藏的载体以保证信息隐藏的不可感知性.实验结果表明方法具有...     

一种应用相息图对灰度图像信息进行隐藏的方法

一幅灰度图像的相息图被隐藏于一幅宿主图像中，该相息图是采用基于相息图迭代的双随机相位加密技术得到的.由于采用仅含有位相信息的相息图作为待加密灰度图像信息的载体，因而与隐藏图像同时具有振幅和相位信息的情况相比较，需要隐藏的信息量大大降低，从而可在对宿主图像影响较小的情况下，提高提取信息的质量；并可有效地提高信息提取时的光学效率，并且对二元图像信息的隐藏也同样适用.水印图像的剪切对隐藏信息提取质量的影响也被分析，模拟实验结果证明了所采用方法的有效性.     

基于虚拟光学的三维空问数字水印系统

数字水印已成为数字作品版权保护的一种手段。数字水印是一种嵌入到图像、视频或者音频数据中的不可见标志，通过对水印信息的检测可以达到保护多媒体数据版权的目的。先前众多的水印算法大部分是基于二维操作的(如静止图像、视频)。基于虚拟光学信息隐藏理论提出了一种三维空间的数字水印算法。该数字水印算法能成为一种多媒体数据产权保护的有效方案。对算法的测试结果表明，该算法对于噪声叠加、剪切、有损压缩等常见的信号处理操作具有较高的鲁棒性。同时，该算法由于引入了虚拟光学信息隐藏思想，将虚拟光路的几何结构参量作为密钥，设计出了多重“锁”和多重“密钥”，大大提高了水印系统的密钥空间，仿真结果表明该算法具有良好的安全性。     

基于HVS的小波域信息隐藏方法

为了提高信息隐藏的不可感知性和鲁棒性,结合人眼视觉系统(HVS)的相关知识,提出了一种新的小波域信息隐藏算法。将载体图像的中等亮度区域设为不可用区域,不在该区域隐藏信息,同时选择在载体图像小波变换的高频系数细节子图隐藏信息,并优先选择在对角高频系数细节子图中隐藏。计算局部子块的方差值作为隐藏信息的嵌入系数,并通过计算高频子图的噪声敏感模型ωθ(i,j)决定隐藏信息的位置。充分考虑了人眼的各种视觉掩蔽效应,使得隐藏信息后的结果图像相比隐藏之前没有出现明显的降质。实验结果表明该方法能够有效提高信息隐藏的不可知性,达到了很好的隐藏效果,同时能够有效地抗击噪声、裁剪和压缩等攻击影响,具有很好的鲁棒性,在信息安全领域有较好的应用前景。     

基于级联分数傅里叶变换系统的数字水印技术

提出一种基于分数傅里叶变换和随机相位编码的光学加密数字水印技术,可成为一种信息隐藏及保护的有效方案.该数字水印技术对于噪音叠加和常见的图像处理操作具有较强的稳健性.该技术根据光学级联分数傅里叶变换系统,利用两个随机相位分布函数对水印信息编码并经过迭代分数傅里叶变换嵌入到变换域的载体图像中.在水印检测和提取过程中,两个相位分布函数作为密钥.随机相位编码技术的引入,进一步提高了数字水印系统的密钥空间.增强了系统的安全性.该数字水印技术基于光学分数傅里叶变换原理,可以利用光学变换系统方便地实现.     

基于联合变换相关器光学加密和离散余弦变换的数字水印

提出了一种以联合变换相关器和离散余弦变换为基础的数字水印方法。利用联合变换相关器光学加密系统对需要隐藏的信息进行加密,然后嵌入到宿主图像8×8分块的离散余弦变换中频系数上。与其他基于双随机相位编码的数字水印技术相比,该技术在加密阶段和解密阶段的密钥相同,省去了制作复共轭密钥的麻烦。数值仿真结果表明,这种数字水印技术具有很好的不可见性和很高的安全性,对JPEG压缩、剪切、滤波和加噪声等多种数字图像处理操作都具有很强的鲁棒性。     

基于多重光栅解码的半色调图像隐藏信息的三维显示方法研究北大核心CSCD

光栅防伪技术由于成本低、适用范围广、呈现方式多样,被广泛应用于印刷产品的防伪中。基于单重光栅防伪方法,探索了多重光栅解码下隐藏信息的三维显示方法,分析了不同加网线数、网点面积率、隐藏信息在色版中的嵌入距离差和嵌入顺序等参数对图像的隐藏和显示效果的影响。在此基础上,以隐藏和显示的三维效果的最佳参数为依据,进行了实际印刷的验证,实验结果与理论模拟获得一致的效果,证明了该方法的科学性和实用性,可用于实际印刷包装品的防伪,增强产品防伪的效果。     

基于增强型视觉密码的光学信息隐藏系统

提出了一种基于增强型视觉密码的光学信息隐藏系统.该系统可将秘密图像分解为多幅有实际意义的分享图像,然后将这些分享图像隐藏在相位密钥中,相位密钥可以制成衍射光学元件,以实体的形式保存和传输,扩展了视觉密码的应用范围.在提取过程中,只需要使用激光照射衍射光学元件,再现分享图像,然后只需要将一定数量的分享图像进行非相干叠加即可提取秘密图像,不需要额外掌握光学和密码学的知识,其简单性让任何人都可以使用.仿真实验和光学实验结果表明,该系统可应用于实际,并且具有良好的安全性.     

半色调编码计算全息图的数字水印方法

提出一种新的基于信息光学的数字水印方法。该方法将水印信息隐藏于半色调编码的计算全息图之中。通过相位复原技术将需隐藏的水印信息编码为相位函数嵌入在复波前中,其振幅定义为宿主图像,通过计算全息记录复波前并对全息图进行半色调编码完成水印信息的嵌入。水印的提取过程只需对含有水印信息的半色调图像进行光学或数字的傅里叶变换即可完成。并给出了算法有效性的理论分析和仿真实验结果。结果证明这种水印技术对于各种数字图像处理操作具有很高的稳健性,且半色调编码图的二值特性使嵌入水印具有很强的抗打印、抗复印、抗扫描的能力。     

Security analysis and improvement on a double-random phase-encoding technique based information hiding method

The security of an information hiding method using the double-random phase-encoding technique is analyzed and improved. The method encodes the hidden image with the double-random phase-encoding technique, and then embeds the real and imaginary parts of the encoded image to an enlarged host image. Recovering the hidden image from the composed image does not need the original host image, while the quality of the reconstructed image is satisfying. However, the original method is insecure in the sense of information hiding, since the composed image can be detected easily with some technical metrics. The security is improved by adding random perturbation on the encoded data. The validity of the improved method is demonstrated by numerical simulation experiments.     

Increasing the data hiding capacity and improving the security of a double-random phase-encoding technique based information hiding scheme

A double-random phase-encoding technique based information hiding scheme was analyzed and improved. By encoding the hidden image with the double-random phase-encoding technique, and embedding the encoded image into the enlarged host image to generate the composed image, the original scheme can recover the hidden image from the composed image directly (i.e., without using the original host image) with satisfying quality. For the proposed improved scheme, 3 values (other than 2 values as in the original scheme) are embedded into each 2 × 2 block within the enlarged host image, resulting in increasing the data hiding capacity around 50%, while not influence the qualities of the composed image and the reconstructed hidden image seriously. In addition, the security of the original scheme is enhanced markedly. Theoretical analysis and experimental results demonstrate the effectiveness of the improved scheme.     

Information hiding based on the optical interference principle

An information hiding method based on the optical interference principle is proposed. In this method, a secret image can be obtained by two light beams' interference. One of the beams is modulated by our assigned host image; and the other is modulated by a noise-like complex distribution, which is regard as the encrypted image. The transmission of the encrypted image can be implemented by hiding it in the host image to prevent the communication from being perceived by unauthorized person. In addition, this method can also realize simultaneous encryption and hiding for two images. A series of numerical simulation results are presented to verify the feasibility of our proposed method.     

Multiple-image hiding by information prechoosing

The information inevitably lost in multiple-image hiding is discarded in advance by the operation of prechoosing information before the hiding process; thus both fidelity and multiplexing capacity can be improved significantly. Various characters of each image provide a great many possibilities for information prechoosing. The ideal low-pass filter presented with the matched encoding and hiding procedure may be one of the simplest examples of information prechoosing for generally used images. Computer simulations demonstrate its good performance, and the security is analyzed as well.     

Optical color image hiding scheme by using Gerchberg–Saxton algorithm in fractional Fourier domain

We proposed an optical color image hiding algorithm based on Gerchberg–Saxton retrieval algorithm in fractional Fourier domain. The RGB components of the color image are converted into a scrambled image by using 3D Arnold transform before the hiding operation simultaneously and these changed images are regarded as the amplitude of fractional Fourier spectrum. Subsequently the unknown phase functions in fractional Fourier domain are calculated by the retrieval algorithm, in which the host RBG components are the part of amplitude of the input functions. The 3D Arnold transform is performed with different parameters to enhance the security of the hiding and extracting algorithm. Some numerical simulations are made to test the validity and capability of the proposed color hiding encryption algorithm.     

A method for hiding information utilizing double-random phase-encoding technique

A method for hiding information is proposed. Firstly, the image to be hidden is encoded by the doubled-random phase-encoding technique. Then, the real part of the encoded data, together with the imaginary part, is embedded into a sufficiently large host image, which has been enlarged according to some rules. The superposition weighting is adjusted to a proper value such that the composed image will not be subject to severe degradation compared to the original host image. When decryption is needed, the reconstructed hidden image can be extracted directly from the composed image without using original host image, with the result being quite satisfactory. The quality of the reconstructed hidden image and of the composed image has been analyzed as the superposition weight varies, allowing the determination of the optimum superposition weight. The optimum superposition weight is related to the average gray level value of the hiding image.     

Steganalysis of HMPD reversible data hiding scheme

Based on feature mining and pattern classification, this paper presents a steganalysis technique against reversible data hiding by histogram modification of pixel differences scheme (HMPD). HMPD reversible data hiding scheme involves the modification of pixel differences, which introduces artifacts into the pixel-difference histograms. It is found that four-way pixel difference features are sensitive for HMPD embedding algorithm. These features are used to design a specific steganalysis method for detecting HMPD reversible data hiding scheme. Support Vector Machine (SVM) classifiers are trained to discriminate stego-images from cover images and estimate the secret keys of a stego image. The experimental results show that the proposed scheme not only successfully attacks HMPD reversible data hiding scheme in various embedding levels, but also accurately estimates the secret keys.     

A novel data hiding and reversible scheme using SMN blocks in VQ-compressed images

Data hiding is a technique for embedding secret data into cover media. It is important to multimedia security and has been widely studied. Reversible data hiding methods are becoming prevalent in the area because they can reconstruct the original cover image while extracting the embedded data. In this paper, we propose a new reversible method for vector quantization (VQ) compressed images. Our method takes advantages of the relationship among the side match neighbouring (SMN) blocks to achieve reversibility. The experimental results show that the proposed method has higher compression rate and larger capacity than other existing reversible methods.