Digital information encrypted in an image using binary encoding

This paper proposes a new type of encoding methods to encrypt hidden (covert) information in host images. The encrypted information can be plot, fax, word, or network data, and it must be encoded with binary codes. All the pixels in an encoded (overt) image modulated from a host image are classified into three groups. The first group of pixels is called identification codes, used to judge whether the overt image is encoded by a method proposed in this paper or not. The second group of pixels is called type codes, used to judge the encoding type. The third group of pixels is called information codes, used to decode the encoded information. Applying the proposed encoding methods is quite convenient, and host images are not needed for decoding. Decoding covert information from overt images is rather difficult for un-authorized persons, whereas it is very easy for designers or authorized persons. Therefore, the proposed methods are very useful.     

Hybrid encoding method by assembling the magic-matrix scrambling method and the binary encoding method in image hiding

The magic-matrix scrambling method and the binary encoding method are combined to form a hybrid encoding method for hiding digital covert images. For this hybrid encoding method, a covert image is encoded into a host image to form an overt image. First, the magic-matrix scrambling method is used to rearrange all the pixels of the covert image by using a specified magic matrix modified from a magic square to form a scrambled matrix. Then, all the pixels of the scrambled matrix are denoted by binary data. Finally, the binary data are encoded into the host image to form the overt image. The pixels of the overt image contain nine groups of codes used for decoding the covert image, i.e. identification codes, covert-image dimension codes, scrambling-time codes, magic-square dimension codes, corner codes, shifting codes, arrangement codes, graylevel codes, and information codes. The overt image and the host image look almost the same for eyes. Furthermore, the covert image can be decoded directly from the overt image without using the host image. The most important feature is that the decoded covert image is identical to the original covert image, i.e. there is no distortion in the decoding work.     

Encrypting image by assembling the fractal-image addition method and the binary encoding method

The fractal-image addition method and the binary encoding method are assembled to form a hybrid method for encrypting a digital covert image. For this hybrid method, a host image is used to create an overt image with the information of the covert image. First, the fractal-image addition method is used to add some fractal images and the covert image to form an image-mixing matrix. Then, all the pixel values of the image-mixing matrix are transferred into binary data. Finally, the binary data are encoded into the host image to create an overt image. The pixels of the overt image contain eight groups of codes used for reconstructing the covert image. The eight groups of codes are identification codes, row amount codes, covert-image dimension codes, fractal-image amount codes, starting-pixel codes, character amount codes, character codes, and information codes. The overt image and the host image look almost the same for eyes. Furthermore, the covert image can be directly reconstructed from the overt image without using the host image. The most important feature is that the reconstructed covert image is identical to the original covert image, i.e. there is no distortion in the decoding work.     

基于图像内容视觉感知的图像质量客观评价方法

图像质量客观评价在图像和视频传输、编解码以及服务质量中起着非常重要的作用.然而现有的方法往往没有考虑图像内容特征及其视觉感知,使得其质量客观评价与主观感知结果存在一定的差距.基于此,本文结合图像内容的复杂性特征和人眼的掩蔽特性、对比敏感度特性以及亮度感知的非线性特性,提出了一种基于人眼对图像内容感知的图像质量客观评价方法.该方法首先结合亮度感知的非线性模型将图像进行转换,得到人眼感知强度图;再分别以人眼对比敏感度值和图像局部平均对比度值作为权重因子对强度求和,以求和的数据信息作为人眼感知图像的内容,并构建图像感知模型;最后以此模型分别模拟人眼感知参考图像和失真图像,并计算二者的强度差,以强度差为评价分数的基础构建图像质量客观评价模型.采用LIVE,TID2008和CSIQ三个数据库中的共47幅参考图像和1549幅测试图像进行仿真实验,且与SSIM,VSNR,FSIM和PSNRHVS等典型的图像质量客观评价模型进行对比分析,同时探讨影响图像质量评价的因素.结果表明:所提方法的评价分数与主观评价分数的Pearson线性相关性系数和Spearman秩相关系数值比SSIM的评价结果均有一定程度的提高,提高幅度分别平均为9.5402%和3.2852%,比PSNRHVS和VSNR提高幅度更大.综合以上表明:所提方法是一种有效可行的图像质量客观评价方法;同时,在图像质量客观评价中,考虑人眼对图像内容的感知和复杂度的分析有助于提高图像质量主客观评价的一致性,评价精度可得到进一步的提高.     

A distortion compensation method for a conical holographic stereogram

An image processing technique to display a distortion-free reconstructed image from a rainbow type conical holographic stereogram is proposed. The method consists of forming a new set of 2D images from the original set by applying an image process. The image processing method is made through ray tracing equations. The results show that the performance of the proposed method is good as it removes distortion of the image.     

用空间图像融合技术进行三维重建的研究

研究了从多个空间角度获得的三维物体图像的融全处理技术,并用于构成计算机三维重建时所需的表面纹理图。从光学成像系统获得的图像仅仅是三维物体在像平面上的投影,不能直接作为三维重建时的纹理图使用,必须消除由透视关系、几何投影关系等造成的畸变才能得到物体表面真实的纹理图。给出了反透视变换和逆几何投影变换所需的关系式,并将其用于真实物体三维重建时的表方理图的处理,得到了很好的结果。     

A New Quantum Gray-Scale Image Encoding Scheme

In this paper, a new quantum images encoding scheme is proposed. The proposed scheme mainly consists of four different encoding algorithms. The idea behind of the scheme is a binary key generated randomly for each pixel of the original image. Afterwards, the employed encoding algorithm is selected corresponding to the qubit pair of the generated randomized binary key. The security analysis of the proposed scheme proved its enhancement through both randomization of the generated binary image key and altering the gray-scale value of the image pixels using the qubits of randomized binary key. The simulation of the proposed scheme assures that the final encoded image could not be recognized visually. Moreover, the histogram diagram of encoded image is flatter than the original one. The Shannon entropies of the final encoded images are significantly higher than the original one, which indicates that the attacker can not gain any information about the encoded images.     

Double-image self-encoding and hiding based on phase-truncated Fourier transforms and phase retrieval

We propose a method to encrypt two covert images into an overt image based on phase-truncated Fourier transforms and phase retrieval. In this method, the two original images are self-encoded in the manner that one of the two images is directly separated into two phase masks (PMs) and used as keys for encryption, and then multiplied by a PM which is generated by using phase retrieval algorithm. At last, the whole encryption process is completed by a Fourier transform operation. In the decryption process, the image without a separation and the two PMs used as keys for encryption are all treated as encoded data. The cryptosystem is asymmetric which means the keys for encryption are different from those for decryption. Numerical simulations are presented to show the viability and good performance of the proposed method.     

一种多视点视频自动颜色校正系统

针对多视点视频系统中视点间图像颜色不一致的问题,提出了一种多视点视频自动颜色校正系统。通过求取目标图像和源图像间的颜色校正矩阵,判断其是否满足全局校正的要求;对不满足要求的图像,通过图像分割和K-L变换(Karhunen-Loeve transform),建立起目标图像和源图像中各分割区域间的局部映射关系,并通过感兴趣区域匹配,来实现对源图像的校正,最后通过视频跟踪技术实现对视频图像的校正。以标准的多视点测试图像集为例,通过将新方法与直方图匹配、全局一维线性校正算法等进行比较,表明新方法能消除匹配失真的影响,且具有较好的颜色校正效果。研究结果表明该系统可以很好地揭示图像间的颜色变化关系,并且具有很好的内容自适应性,是一种有效的多视点视频图像系统颜色校正方法。     

A blind image detection method for information hiding with double random-phase encoding

In this paper, a blind image detection method based on a statistical hypothesis test for information hiding with double random-phase encoding (DRPE) is proposed. This method aims to establish a quantitative criterion which is used to judge whether there is secret information embedded in the detected image. The main process can be described as follows: at the beginning, we decompose the detected gray-scale image into 8 bit planes considering it has 256 gray levels, and suppose that a secret image has been hidden in the detected image after it was encrypted by DRPE, thus the lower bit planes of the detected image exhibit strong randomness. Then, we divide the bit plane to be tested into many windows, and establish a statistical variable to measure the relativity between pixels in every window. Finally, judge whether the secret image exists in the detected image by operating the t test on all statistical variables. Numerical simulation shows that the accuracy is quite satisfactory, when we need to distinguish the images carrying secret information from a large amount of images.     

Fourier频率域随机谱隐秘信息加载与增量补偿系统

提出一种基于光学原理的Fourier频率域随机谱隐秘信息加载与增量补偿系统,并给出一种隐秘信息的加载方式,可实现光学图像信息隐藏.宿主图像经过随机相位调制后进行Fourier变换得到频率域的随机谱,在此随机谱上加载隐秘信息,同时,系统对由隐秘信息的加入所产生的影响进行补偿.利用该系统所得到的载体图像未经正确的密钥-随机相位-调制时,隐秘信息将弥散在载体图像的Fourier频率域空间,具有较好的不可检测性.此外,即使攻击者知道隐秘信息的存在甚至知道隐藏方法,但在不知道密钥的情况下,依然无法破解隐秘信息的内容     

像素随机映射的快速算法及在LSB隐藏技术中的应用

提出一种像素随机映射的快速方法, 将该方法与像素字节低位隐藏信息的LSB(Least Significant Bit)技术相结合, 讨论了将RGB彩色图像作为载体隐匿真彩色图像、灰度图像、二值图像及全息信息的方法. 研究结果表明, 该方法加密及解密效率高, 载体图像具有较好的抗破译及抗剪切能力. 根据隐藏信息的性质合理使用LSB技术, 能在基本不影响载体图像质量的情况下较好地隐匿多种信息.     

图像融合方法在细胞图像处理中的应用

图像融合作为一项先进技术被引入到生物细胞图像处理中，可实现图像的信息融合，完成图像配准，提高图像置信度，改善检测性能和空间分辨能力，最大限度地发掘细胞图像的信息资源，本文采用像素级的图像融合方法，将细胞荧光图像和透射图像信息融为一体，操作简便，能准确地判断细胞内部荧光位置，有利于分析其生物机理和含义。     

基于变换矩阵的BGA X-ray图像倾斜识别

针对基于X-Ray的焊球阵列封装(BGA)焊接缺陷检测中,现有的图像处理算法无法有效处理PCB意外倾斜的问题,提出了一种自动判断BGA焊点X射线图像倾斜程度并进行校正的方法。首先根据BGA焊点阵列排布的特性恢复出原始图像中的结构信息,然后使用广义逆矩阵求解出理想正视图像与实际倾斜图像之间的变换矩阵,最后对倾斜图像进行逆变换以得到理想正视图像,并使用变换矩阵估计出PCB的倾斜程度。实验针对正视与倾斜的BGA焊点的X射线图像,运用所提方法,准确判别出图像的倾斜程度,并进行了校正。此方法既可以作为一种图像质量评价算法,在BGA X-Ray缺陷检测中判断图像是否为需要的正视图像;也可以作为一种图像自动校正算法,提升基于X射线的自动检测系统的适应性。     

Determination of optimal parameters for detecting the existence of secret information hidden by the double random-phase encoding technique

A new method based on statistical hypothesis detection for information hidden using the double random-phase encoding technique is introduced. According to this method, a series of windows are opened on the lowest bit-plane of image, and an exclusive OR (XOR) operation is performed between different pixels in every window. The results of XOR operation are then analyzed. Using this method, we can judge whether an image contains secret information encrypted by the double random-phase encoding technique. The result of the judgment may be influenced by two parameters, namely the size of the window and the threshold value. A further study is also made to determine the optimal parameters.     

Shield analysis and non-rigid match in positioning the actual interferogram on the tooth flank based on oblique incidence interferometry

When the oblique incidence interferometry is used to measure the form deviation of the tooth flank, because of the anamorphic distortion and image foreshortening, the collected interference fringe pattern (IFP) cannot be positioned on the tooth flank directly. Therefore a simulation tooth image (STI) is employed as a bridge to connect the collected IFP and the tooth flank. The exiting method is good enough to deal with the IFP of spur gear tooth flank, but it is inappropriate for the IFP of helical gear. This paper focuses on two improvements for positioning the IFP of helical gear on the tooth flank: (1) in the process of generating the STI, a mathematical model of helical tooth flank is proposed to judge the shielded situation of tooth flank; (2) in the process of matching the STI with the collected IFP, a non-rigid matching method is proposed to determine the relationship of the two images. The results of an experimental application are given to verify the feasibility and accuracy.     

一种基于特征分析的偏振图像融合方法

偏振成像探测能反映出传统光学成像所无法反映的物体的信息,为了克服计算偏振参量图像丢失细节信息的不足,在已有偏振图像融合方法的基础上,提出一种基于综合图像特征的融合方法。相较于已有算法突出图像的某一方面特征,该算法提取图像的灰度特征、纹理特征和形状特征,据此确定融合权值,对图像进行融合,能够较好地反映目标的细节信息,融合后的图像相较于普通光强图像,方差、信息熵分别提高了12.6%、17.5%,平均梯度从0.59提高到1.83。针对该方法用到的特征维数较高的问题,提供了一种简化算法,耗时从3054降至1337。     

基于FPGA的图像畸变矫正算法研究

在机器视觉中需要对采集到的带有畸变的图像进行矫正。为了提高对畸变图像校正的实时性，针对使用FPGA实现图像畸变矫正算法时，存在的在线计算逆向映射坐标复杂和片上ROM容量不够问题，压缩了逆向映射表，并在FPGA上利用插值方法在线重建了逆向映射表。通过查找重建的逆向映射表来获取逆向映射坐标，从而降低了FPGA的在线计算量和片上ROM的容量需求。MATLAB仿真结果显示，当压缩参数n分别取4、8、16时都能够对畸变图像进行较好的矫正，并且图像信息不会丢失。仿真结果验证了算法的有效性，该算法可用于基于FPGA的图像畸变矫正。     

Multifactor authentication reinforces optical security

A new optical method to obtain multifactor image encoding and authentication is proposed. The encoded complex-amplitude image function fulfills the general requirements of invisible content, extreme difficulty in copying or counterfeiting, and real-time automatic verification. This optical technique is attractive for high-security purposes that require multifactor reliable authentication. A demonstration using a combination of biometric images and key codes is provided. Retina images, which are very effective for authentication, are used as biometric signals. To the best of our knowledge, this is the first report on combined multiple signal encoding and simultaneous AND authentications for optical security reinforcement.     

一种可见光成像的目标检测跟踪方法

在末制导成像阶段目标占据视场的大部分面积,形状信息丰富,这时对目标体上某一固定点的稳定跟踪成为最主要的需求。针对图像灰度过于集中目标难于提取的问题,在图像预处理阶段提出了依据概率统计的图像灰度均衡的方法;为解决图像边角点的快速检测问题,提出了图像二维投影和滑动卷积相结合的方法;最终为实现快速稳定的跟踪,提出了依据角点匹配的形心跟踪方法。根据此算法的特点研制了FPGA+DSP的硬件平台,充分利用FPGA的并行流水特性和DSP的逻辑运算特点,能快速检测到目标形心和进行稳定地跟踪,验证了方法的有效性和实用性。此方法应用在某课题上,跟踪效果良好,为试验的圆满成功提供了保障。