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A NEW METHOD FOR MEASURING LONG-TERMCREEP DEFORMATION IN A SMALL REGION

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Acta Metallurgica Sinica(English Letters) 1998年第6期11卷 442-448页

作者： J.M.Gong S.T.Tu J.Xia X.Ling Nanjing Univ of Chemical Technology Nanjing China

Creep deformation localization is generally found in structures at high temperamture,typically in weldments. As the heat affected zone (HAZ) in a weldment is very narrow, deformation in HAZ region can hardly be measured by conventional displacement gauge. A new method for measuring long-term local creep deformation was developed by quartz optical fiber and technique of digital image analysis. The creep deformations of base metal, weld metal and HAZ in weldments are thereby determined with crossweld specimens.

关键词： creep deformation weldment quartz optical fiber image analysis

Critical review of the use and scientific basis of forensic gait analysis

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Forensic Sciences Research 2018年第3期3卷 183-193页

作者： Nina M.van Mastrigt Kevin Celie Arjan L.Mieremet Arnout C.C.Ruifrok Zeno Geradts Department of Digital Technology and Biometry Netherlands Forensic InstituteThe HagueThe Netherlands Intelligent Information Systems University of AmsterdamAmsterdamThe Netherlands

This review summarizes the scientific basis of forensic gait analysis and evaluates its use in the Netherlands,United Kingdom and Denmark,following recent critique on the admission of gait evidence in Canada.A useful forensic feature is(1)measurable,(2)consistent within and(3)different between individuals.Reviewing the academic literature,this article found that(1)forensic gait features can be quantified or observed from surveillance video,but research into accuracy,validity and reliability of these methods is needed;(2)gait is variable within individuals under differing and constant circumstances,with speed having major influence;(3)the discriminative strength of gait features needs more research,although clearly variation exists between individuals.Nevertheless,forensic gait analysis has contributed to several criminal trials in Europe in the past 15 years.The admission of gait evidence differs between courts.The methods are mainly observer-based:multiple gait analysts(independently)assess gait features on video footage of a perpetrator and suspect.Using gait feature databases,likelihood ratios of the hypotheses that the observed individuals have the same or another identity can be calculated.Automated gait recognition algorithms calculate a difference measure between video clips,which is compared with a threshold value derived from a video gait recognition database to indicate likelihood.However,only partly automated algorithms have been used in practice.We argue that the scientific basis of forensic gait analysis is limited.However,gait feature databases enable its use in court for supportive evidence with relatively low evidential value.The recommendations made in this review are(1)to expand knowledge on inter-and intra-subject gait variabilities,discriminative strength and interdependency of gait features,method accuracies,gait feature databases and likelihood ratio estimations;(2)to compare automated and observer-based gait recognition methods;to design(3)an international standard method with known validit

关键词： Forensic science forensic gait analysis validation biometric characteristics image analysis video analysis survey gait recognition

Automatic Visual Leakage Detection and Localization from Pipelines in Chemical Process Plants Using Machine Vision Techniques

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Engineering 2021年第6期7卷 758-776页

作者： Mina Fahimipirehgalin Emanuel Trunzer Matthias Odenweller Birgit Vogel-Heuser Institute of Automation and Information Systems Technical University of MunichGarching 85748Germany Evonik Technology and Infrastructure GmbH Hanau 63450Germany

Liquid leakage from pipelines is a critical issue in large-scale process plants.Damage in pipelines affects the normal operation of the plant and increases maintenance costs.Furthermore,it causes unsafe and hazardous situations for operators.Therefore,the detection and localization of leakages is a crucial task for maintenance and condition monitoring.Recently,the use of infrared(IR)cameras was found to be a promising approach for leakage detection in large-scale plants.IR cameras can capture leaking liquid if it has a higher(or lower)temperature than its surroundings.In this paper,a method based on IR video data and machine vision techniques is proposed to detect and localize liquid leakages in a chemical process plant.Since the proposed method is a vision-based method and does not consider the physical properties of the leaking liquid,it is applicable for any type of liquid leakage(i.e.,water,oil,etc.).In this method,subsequent frames are subtracted and divided into blocks.Then,principle component analysis is performed in each block to extract features from the blocks.All subtracted frames within the blocks are individually transferred to feature vectors,which are used as a basis for classifying the blocks.The k-nearest neighbor algorithm is used to classify the blocks as normal(without leakage)or anomalous(with leakage).Finally,the positions of the leakages are determined in each anomalous block.In order to evaluate the approach,two datasets with two different formats,consisting of video footage of a laboratory demonstrator plant captured by an IR camera,are considered.The results show that the proposed method is a promising approach to detect and localize leakages from pipelines using IR videos.The proposed method has high accuracy and a reasonable detection time for leakage detection.The possibility of extending the proposed method to a real industrial plant and the limitations of this method are discussed at the end.

关键词： Leakage detection and localization image analysis image pre-processing Principle component analysis k-nearest neighbor classification

A Novel Gaussian Extrapolation Approach for 2D Gel Electrophoresis Saturated Protein Spots

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Genomics, Proteomics & Bioinformatics 2012年第6期10卷 336-344页

作者： Massimo Natale Alfonso Caiazzo Enrico M. Bucci Elisa Ficarra Department of Control and Computer Engineering Politecnico di Torino BioDigitalValley S.r.l. WIAS Berlin Istituto di Biostrutture e Bioimmagini

analysis of images obtained from two-dimensional gel electrophoresis （2D-GE） is a topic of utmost importance in bioinformatics research, since commercial and academic software available currently has proven to be neither completely effective nor fully automatic, often requiring manual revision and refinement of computer generated matches. In this work, we present an effective technique for the detection and the reconstruction of over-saturated protein spots. Firstly, the algorithm reveals overexposed areas, where spots may be truncated, and plateau regions caused by smeared and overlapping spots. Next, it reconstructs the correct distribution of pixel values in these overexposed areas and plateau regions, using a two-dimensional least-squares fitting based on a generalized Gaussian distribution. Pixel correction in saturated and smeared spots allows more accurate quantification, providing more reliable image analysis results. The method is validated for processing.highly exposed 2D-GE images, comparing reconstructed spots with the corresponding non-saturated image, demonstrating that the algorithm enables correct spot quantification.

关键词： image analysis Two-dimensional gel electrophoresis Proteomics Software tools

Linear camera calibration and pose estimation from vanishing points

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Chinese Optics Letters 2012年第B6期10卷 83-87页

作者：储珺王丽冯瑞娜张桂梅 Software College of Nanehang Hangkong University Nanchang 330063 China Aviation Manufacturing Engineering College of Nanchang Hangkong University Nanchang 330063 China Aircraft Engineering College of Nanchang Hangkong University Nanchang 330063 China

In order to broaden the scope of application and ensure the calibration precision, a new method of linear calibration by making fully use of vanishing point attributes is proposed. The method dose not need any rigorous restrictions, and solves the self-calibration problem with only five vanishing points in two digital images, which are arbitrarily taken by a handheld digital camera. Furthermore, another approach for camera＇s pose estimation is also put forward without any strict controlled motions. The experimental results of both computer simulation and real images show that the calibration algorithm is effective, feasible, and robust.

关键词： 100.2000 Digital image processing 100.2960 image analysis 100.6890 Three-dimensional image processing

MAP-based infrared image expansion

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Chinese Optics Letters 2005年第8期3卷 451-454页

作者：张楠金伟其苏秉华刘扬阳陈华 Department of Optical Engineering School of Information Science and Technology Beijing Institute of Technology

image expansion plays a very important role in image analysis. Common methods of image expansion, such as the zero-order hold method, may generate a visual mosaic to the expanded image, linear and cubic spline interpolation may blur the image data at peripheral regions. Since infrared images have the characteristics of low contrast and low signal-to-noise ratio （SNR）, the expanded images derived from common methods are not satisfactory. As shown in the analysis of the course from images with low resolution to those with high resolution, the expansion of image is found to be an ill-posed inverse problem. An image interpolation algorithm based on MAP estimation under Bayesian framework is proposed in this paper, which can effectively preserve the discontinuities in the original image. Experimental results demonstrate that the expanded images by this method are visually and quantitatively （analyzed by using the criteria of mean squared error （MSE） and mean absolute error （MAE）） superior to the images expanded by common methods of linear interpolation. Even in expansion of infrared images, this method can also give good results. An analysis about choosing regularization parameter a in this algorithm is given.

关键词： image analysis Infrared imaging Interpolation Inverse problems Signal to noise ratio

Drag Coefficient of a Non-Convex Polygonal Plate during Free Fall

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Journal of Flow Control, Measurement & Visualization 2023年第1期11卷 1-13页

作者： Yoshihiro Kubota Yuhei Endo Department of Mechanical Engineering Toyo University Kawagoe Japan Graduate School of Science and Engineering Toyo University Kawagoe Japan

Waterside creatures or aquatic organisms use a fin or web to generate a thrust force. These fins or webs have a non-convex section, referred to as a non-convex shape. We investigate the drag force acting on a non-convex plate during unsteady motion. We perform the experiment in a water tank during free fall. We fabricate the non-convex plate by cutting isosceles triangles from the side of a convex hexagonal plate. The base angle of the triangle is between 0° to 45°. The base angle is 0 indicates the convex hexagonal thin plate. We estimate the drag coefficient with the force balance acting on the model based on the image analysis technique. The results indicate that increasing the base angle by more than 30° increased the drag coefficient. The drag coefficient during unsteady motion changed with the growth of the vortex behind the model. The vortex has small vortices in the shear layer, which is related to the Kelvin-Helmholtz instabilities.

关键词： Drag Coefficients Freefall image analysis Non-Convex Polygonal Plate Unsteady Motion Vortex Formation

Air-coupled ultrasonic infrared thermography for inspecting impact damages in CFRP composite

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Chinese Optics Letters 2012年第B6期10卷 13-15页

作者：陈大鹏曾智张存林陶宁张峥 School of Material Science and Engineering Beihang University Beijing 100191 China Institute of Physics and Electronic Engineering Chongqing Normal University Chongqing 400047 China Beijing Key Laboratory for Terahertz Spectroscopy and Imaging Key Laboratory of Terahertz Optoelectronics Ministry of Education Department of Physics Capital Normal University Beijing 100048 China

Ultrasonic thermography or thermosonics is proved to be an effective non-destructive testing （NDT） method for inspecting carbon-fiber-reinforced polymer （CFRP） composites; however, the potential dam- ages for the structure cannot be ignored, because of the contact vibration between the ultrasonic horn and the specimen. This work aims at developing a new excitation method for ultrasonic thermography--air- coupled ultrasonic excitation. CFRP laminates with impact damages are tested by air-coupled ultrasonic thermography, and the theoretical model of heat conduction is given. Results demonstrate good excitation performance for impact damages detection in CFRP composites. Moreover, the conventional ultrasonic thermography results are shown, and the prospect of air-coupled ultrasonic thermo^raphv is discussed.

关键词： 040.6808 Thermal (uncooled) IR detectors, arrays and imaging 100.2960 image analysis 100.3010 image reconstruction techniques

Progressive refinement for robust image registration

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Chinese Optics Letters 2005年第7期3卷 392-394页

作者：宋利周源华周军 Institute of image Communication and Information Processing Shanghai Jiao Tong University Shanghai 200030Received September 30 2004

A new image registration algorithm with robust cost function and progressive refinement estimation is developed on the basis of direct method (DM). The robustness lies in M-estimation to avert larger local noise and outliers. Moreover, the progressive refinement model estimation under the multi-resolution framework, where the initial parameter values of coarse level are estimated by Mellin transformation, is adopted so as to get global optimization and reduce search space. Experiments show that the proposed algorithm greatly extends the scope of the conventional DM of image registration.

关键词： Global optimization image analysis Mathematical transformations Pattern recognition Sensor data fusion