Color image processing by using binary quaternion-moment-preservingthresholding technique

This paper presents a new moment-preserving thresholding technique, called the binary quaternion-moment-preserving (BQMP) thresholding, for color image data. Based on representing color data by the quaternions, the statistical parameters of color data can be expressed through the definition of quaternion moments. Analytical formulas of the BQMP thresholding can thus be determined by using the algebra of the quaternions. The computation time for the BQMP thresholding is of order of the data size. By using the BQMP thresholding, quaternion-moment-based operators are designed for the application of color image processing, such as color image compression, multiclass clustering of color data, and subpixel color edge detection. The experimental results show that the proposed operator for color image compression can have output picture quality acceptable to human eyes. In addition, the proposed edge operator can detect the color edge at the subpixel level. Therefore, the proposed BQMP thresholding can be used as a tool for color image processing.     

Robust image watermarking using a chirp detection-based technique

A new robust image watermarking algorithm that embeds multiple watermark bits in the host image is proposed. Linear chirps are embedded as watermark messages, where the slopes of the chirp on the time-frequency (TF) plane represent watermark messages, such that each slope corresponds to a unique message. The Hough-Radon transform (HRT) is a widely used tool to detect directional elements that satisfy a parametric constraint in images. Since linear chirps are localised as a straight line in the TF plane, the HRT is used to detect the watermark messages at the receiver. The HRT acts as an error correcting scheme and robustly estimates the slope of the chirps in the presence of any attacks. It is found that the HRT based detector is able to detect the watermark message accurately when the bit error rate is less than 20%. The robustness of the proposed scheme has been evaluated using the checkmark benchmark attacks.     

RII: Renovating the irregular illumination of digital image archives

Digitization is critical for preserving valuable culture archives such as texts and images. Considering the physical characters of digital cameras or scanners and the artificial negligence, some distortions such as under-exposure or over-exposure often appear in the digital form of archives. These distortions decrease the quality of the digital pieces and lead to disputation in some circumstances. Several methods have been used to deal with these illumination problems. These existing methods mainly focus on how to mitigate the under-exposure phenomenon in text-only or text-photo images. Over-exposure cases in which brightness comes from different orientations are not considered. Hence, we propose a novel system for renovating irregular illumination (RII) to handle the over-exposure problem as well as under-exposure distortion. Experimental results show that the processing outcomes of RII can guarantee accurate restoration of the transformed digital pieces. In particular, RII can be extended to improve the uneven light distribution problem for complicated and colorful images.     

Watermarking-based image authentication with recovery capability using halftoning technique

In this paper two watermarking algorithms for image content authentication with localization and recovery capability of the tampered regions are proposed. In both algorithms, a halftone version of the original gray-scale image is used as an approximated version of the host image (image digest) which is then embedded as a watermark sequence into given transform domains of the host image. In the first algorithm, the Integer Wavelet Transform (IWT) is used for watermark embedding which is denominated WIA-IWT (Watermarking-based Image Authentication using IWT), while in the second one, the Discrete Cosine Transform (DCT) domain is used for this purpose, we call this algorithm WIA-DCT (Watermarking-based Image Authentication using DCT). In the authentication stage the tampered regions are detected using the Structural Similarity index (SSIM) criterion, which are then recovered using the extracted halftone image. In the recovery stage, a Multilayer Perceptron (MLP) neural network is used to carry out an inverse halftoning process to improve the recovered image quality. The experimental results demonstrate the robustness of both algorithms against content preserved modifications, such as JPEG compression, as well as an effective authentication and recovery capability. Also the proposed algorithms are compared with some previously proposed content authentication algorithms with recovery capability to show the better performance of the proposed algorithms.     

Information mining in remote sensing image archives: system evaluation

We present an algorithmic protocol for the evaluation of a content-based remote sensing image information mining system. In order to provide users fast access to the content of large image databases, the system is composed of two main modules. The first includes computationally intensive algorithms for off-line data ingestion in the archive, image feature extraction, and indexing. The second module consists of a graphical man-machine interface that manages the information fusion for interactive interpretation and the image information mining functions. According to the system architecture, the proposed evaluation methodology aims to determine the objective technical quality of the system and includes subjective human factors as well. Since the query performance of a content-based image retrieval system mainly depends on the datasets stored in the archive, we first analyze the complexity of image data. Then, we determine the accuracy of the interactive training that can be considered as a supervised Bayesian classification of the entire archive. Based on the stochastic nature of user-defined cover types, the system retrieves images using probabilistic measurements. The information quality of the queried results is measured by target and misclassified images, precision and recall, and the probability to forget and to overretrieve images. Since the queried images are the result of a number of interactions between user and system, we analyze the man-machine communication dialogue and the system operation, too. Finally, we compare the objective component of the evaluation protocol with the users' degree of satisfaction to point out the significance of the computed measurements.     

Adaptive region growing technique using polynomial functions for image approximation

This paper presents an approximation algorithm for two-dimensional signals (e.g., images) using polynomial functions. The proposed algorithm is based on an adaptive segmentation of the original signal into adjacent regions and on the approximation of the signal in each region by a two-dimensional polynomial function. The segmentation is obtained by an adaptive region growing technique which allows perfect adaptation between the chosen approximation and the inner structure of the signal. Results of this technique are presented in the context of image coding applications.     

湖北数字气象档案管理RFID应用系统设计与应用

系统的硬件电路以51单片机为控制核心,使用RFID读卡器模块读取档案元数据信息并将其传至单片机,基于HTTP标准协议接口能够将气象档案RFID元数据传输至数字气象档案管理RFID应用系统。系统采用B/S模式,后台数据库使用ORACLE数据库管理软件,通过JAVA高级编程语言实现了具有气象档案储位管理、档案查询、档案销毁既安全管理模块的数字气象档案管理RFID应用系统软件。结果表明该系统能够实现气象档案的定位、查询及管理,具有较高的安全可靠性。     

Anti-phishing technique based on dynamic image captcha using multi secret sharing scheme

With the cutting-edge improvement of web, online abuses have been increasing rapidly. Phishing is the most widely recognized abuses performed by digital crooks nowadays. It is an activity to steal private data (for example, client names, passwords and Visa data) in an electronic correspondence. It is a sort of fraud with the end goal of monetary benefit and other fake exercises. It utilizes phony websites that resemble genuine ones. Phishing messages might contain links to sites that are contaminated with malware. In this paper, “an anti-phishing approach using multi secret sharing scheme” is implemented as an answer to this problem. Here, Dynamic Image CAPTCHA based verification using multi secret sharing is performed. Image CAPTCHA is divided into two pieces called shares. Multiple secret pictures are revealed by overlapping the same set of shares at different angles. In the proposed approach, shares are of different modes i.e., user’s share is imprinted on a physical transparency while server’s share is in digital mode. By using the proposed approach, websites and end clients can cross confirm their identity.     

Processing of an optical image obtained under adverse meteorological conditions

A method for processing of a digital image distorted by the atmosphere and the circuit noise is presented. The method consists of two consequent steps: estimation and compensation of the background and nonlinear transformation of the absolute value of the spatial spectrum. The results of processing of real photographs and a series of coherent images with constant foreshortening are presented.     

红外动态图像生成技术

利用热传导方程,从理论上探讨了基于光纤面阵红外图像生成的机制,分析了光纤端面吸收膜表面处红外辐射的时间常数随吸收膜材料的发射率、光纤材料热传导系数、光纤材料比定压热容、光纤材料密度,以及激发光的功率和脉宽的变化规律.提出了一种被动式红外动态图像生成技术,其空间分辨率只受可见光图像的分辨率和光纤面阵总的像束数影响.为实验装置的设计提供了理论依据.应用该原理制作的图像转换装置所得到的红外图像可用于对红外成像仪器和设备进行动态性能检测和标定,以及红外成像仿真实验.     

一种改进的图像匹配技术

图像匹配技术具有广泛应用,寻求高效率、高精度、健壮性好以及复杂度低的图像匹配算法是当下计算机视觉中的研究重点之一.本文对各种特征点提取和匹配算法进行了对比分析,在此之上提出了一种改进的特征提取以及图像匹配算法,提高了匹配算法的鲁棒性.     

立体图像编码中的子空间投影技术

描述的子空间投影技术（SPT）是一种把视差补偿（DC）和二维低阶近似相结合的立体图像编码方法。这种算法可以随着立体对交叉相关特性的改变而局部自适应。在视差估计失败的遮挡区域,由低阶近似提供比较理想的投影图像,并通过零阶项对立体对的光学度变化进行补偿。实验结果表明,SPT方法其峰值信噪比（PSNR）高于像块尺寸固定的视差补偿算法。     

A novel fingerprint image compression technique using wavelets packets and pyramid lattice vector quantization

A novel compression algorithm for fingerprint images is introduced. Using wavelet packets and lattice vector quantization , a new vector quantization scheme based on an accurate model for the distribution of the wavelet coefficients is presented. The model is based on the generalized Gaussian distribution. We also discuss a new method for determining the largest radius of the lattice used and its scaling factor , for both uniform and piecewise-uniform pyramidal lattices. The proposed algorithms aim at achieving the best rate-distortion function by adapting to the characteristics of the subimages. In the proposed optimization algorithm, no assumptions about the lattice parameters are made, and no training and multi-quantizing are required. We also show that the wedge region problem encountered with sharply distributed random sources is resolved in the proposed algorithm. The proposed algorithms adapt to variability in input images and to specified bit rates. Compared to other available image compression algorithms, the proposed algorithms result in higher quality reconstructed images for identical bit rates.     

Spatial-domain image hiding using image differencing

A method to embed a secret image into a cover image is proposed. The method is based on the similarity among the grey values of consecutive image pixels as well as the human visual system's variation insensitivity from smooth to contrastive. A stego-image is produced by replacing the grey values of a differencing result obtained from the cover image with those of a differencing result obtained from the secret image. The process preserves the secret image with no loss and produces the stego-image with low degradation. Moreover, a pseudorandom mechanism is used to achieve cryptography. It is found from experiment that the peak values of signal-to-noise ratios of the method are high and that the resulting stego-images are imperceptible. Even when the size of the secret image is about a half of the cover image     

A practical adaptive image compression technique using visualcriteria for still-picture transmission with electronic mail

An efficient image compression/decompression technique for complex scenes is presented. An image is first decorrelated by a full two-dimensional DCT (discrete cosine transform). The resulting coefficient map is weighted using properties of the human visual system and finally encoded with a novel multiresolution encoder. The result is converted into printable ASCII for transmission by electronic mail     

城建档案图文综合管理的设计与实现

介绍了适合中小城市城建档案馆现代化管理需要，实现档案数据、文字及图纸一体化管理的“城建档案图文综合管理系统”的设计思想、开发过程和所使用的主要技术。     

织物图像增强技术的研究

对具有不同特性的织物数字图像利用二维离散傅立叶变换进行图像增强和图像复原等操作,能有效地改善图像的 质量,突出所需要的细节,为织物密度的自动测量提供最佳质量的图像.研究了二维离散快速傅立叶变换算法,以及利用该 算法在频率域中进行图像增强和图像复原的新方法.实验结果分析表明,利用提出的方法可以较好地改善织物图像的质量.     

Bayesian technique for image classifying registration

In this paper, we address a complex image registration issue arising while the dependencies between intensities of images to be registered are not spatially homogeneous. Such a situation is frequently encountered in medical imaging when a pathology present in one of the images modifies locally intensity dependencies observed on normal tissues. Usual image registration models, which are based on a single global intensity similarity criterion, fail to register such images, as they are blind to local deviations of intensity dependencies. Such a limitation is also encountered in contrast-enhanced images where there exist multiple pixel classes having different properties of contrast agent absorption. In this paper, we propose a new model in which the similarity criterion is adapted locally to images by classification of image intensity dependencies. Defined in a Bayesian framework, the similarity criterion is a mixture of probability distributions describing dependencies on two classes. The model also includes a class map which locates pixels of the two classes and weighs the two mixture components. The registration problem is formulated both as an energy minimization problem and as a maximum a posteriori estimation problem. It is solved using a gradient descent algorithm. In the problem formulation and resolution, the image deformation and the class map are estimated simultaneously, leading to an original combination of registration and classification that we call image classifying registration. Whenever sufficient information about class location is available in applications, the registration can also be performed on its own by fixing a given class map. Finally, we illustrate the interest of our model on two real applications from medical imaging: template-based segmentation of contrast-enhanced images and lesion detection in mammograms. We also conduct an evaluation of our model on simulated medical data and show its ability to take into account spatial variations of intensity dependencies while keeping a good registration accuracy.     

An energy efficient image compression scheme for wireless multimedia sensor network using curve fitting technique

Wireless Networks - Wireless multimedia sensor network (WMSN) comprising of miniature sensor nodes is capable of processing multimedia data traffic such as still images and video from the...     

A technique for determining the normalized impedance of slots inthe image plane of the image NRDG

This paper presents a method for determining the normalized impedance of a transverse slot in the image plane of the image nonradiative dielectric guide using measurements of the standing wave. The method overcomes the problem of distortion caused by the scattered evanescent fields that are present in the vicinity of the slot. The measurement equipment, its optimum parameters, and aspects necessary for accurate measurements are also discussed. Moreover, the finite-difference time-domain technique is employed to determine the normalized slot impedance, and good agreement is obtained with measured results, confirming the reliability of the method