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17th World Conference on Non-Destructive Testing

作者： Clemente Ibarra-Castanedo Ermanno Grinzato Sergio Marinetti Paolo Bison Marc Genest Marc Grenier Jean-Marc Piau Abdelhakim Bendada Xavier Maldague Computer Vision and Systems Laboratory Department of Electrical and Computer EngineeringUniversité LavalQuebec CityCanada GIK 7P4 Istituto per le Tecnologie della Costruzione-Consiglio Nazionale delle Ricerche (ITC-CNR) Corso Stati Uniti4-35127PadovaItaly. Institute for Aerospace Research (IAR) National Research Council Canada (NRC)1200 Montreal RoadBldg.M-14Room 130OttawaONCanadaK1A 0R6 Computer Vision and Systems Laboratory Department of Electrical and Computer EngineeringUniversité LavalQuebec CityCanada 1IK 7P4 Computer Vision and Systems Laboratory Department of Electrical and Computer EngineeringUniversité LavalQuebec CityCanada G1K 7P4

＜正＞The use NonDestructive Testing and Evaluation （NDT＆E） techniques for the inspection of aerospace materials has progressively increase in the last few decades as commercial and military aircrafts exceed their initial design life. Aerospace components are typically made of aluminium,honeycomb structures, composites or fibre metal laminates （FML）,which are affected by different types of anomalies,namely:delaminations,disbonds,water ingress,node failure and core *** causes are either material contamination introduced during manufacture,***,solvents,moisture,oils,etc.;or by damages caused during in-flight operation,*** *** thermography techniques have proven to be an effective way to detect and,in many cases,to quantify the degree of surface and subsurface damage on such components. Several configurations have been proposed to achieve an active thermography inspection ranging from passive inspection,*** applying any external stimulation,to active approaches,in which an external source of energy is used to produce a thermal contrast between the non-defective and the defective material. The thermal stimulation can be delivered to the specimen surface by optical, mechanical,electromagnetic or other *** physics and the practical considerations behind these approaches are different in all cases,and the selection of one or another will depend on the specific application and the availability of the *** this paper,a review of recent developments on the thermographic inspection of aerospace materials is *** guidelines,supported with examples on real and academic specimens,are provided to illustrate the most suitable technique to be considered for some conventional applications.

关键词： Infrared thermography Fibre metal laminates Honeycomb structures Composites Aluminium

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Robust adaptive control of a twin-roaor Aircraft

Robust adaptive control of a twin-roaor Aircraft

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IEEE Conference on Decision and Control

作者： P. Krishnamurthy F. Khorrami Q. Lam IntelliTech MicroSystems Inc. Bowie MD USA Control/Robotics Research Laboratory (CRRL) Department of Electrical and Computer Engineering Polytechnic University Brooklyn NY USA Orbital Sciences Corporation Dalles VA USA

We propose robust adaptive control designs for a twin-rotor aircraft with specific focus on attaining good disturbance attenuation properties to facilitate operation in a shipboard environment wherein the aircraft is subject to severe aerodynamic disturbances including ship airwake, deck vortices, and rotor downwash especially during ship roll and pitch motions. Furthermore, the controllers can operate on their own or can gracefully co-exist with a baseline controller in a control augmentation fashion thus minimizing flight software change impact. The performance of the proposed controllers was validated through extensive simulation studies.

关键词： Robust control Adaptive control Aircraft Aerospace control Aerodynamics Marine vehicles Three-term control Error correction Motion control Attenuation

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A Comparative Study of Classification Techniques for Knowledge-Assisted Image Analysis

A Comparative Study of Classification Techniques for Knowled...

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International Workshop on Image Analysis for Multimedia Interactive Services, WIAMIS

作者： G. T. Papadopoulos K. Chandramouli V. Mezaris I. Kompatsiaris E. Izquierdo M. G. Strintzis Informatics and Telematics Institute Centre for Research and Technology Hellas Thessaloniki Greece Information Processing Laboratory Electrical & Computer Engineering Department Aristotle University of Thessaloniki Thessaloniki Greece Multimedia and Vision Research Group Queen Mary University of London London UK

In this paper, four individual approaches to region classification for knowledge-assisted semantic image analysis are presented and comparatively evaluated. All of the examined approaches realize knowledge-assisted analysis via implicit knowledge acquisition, i.e. are based on machine learning techniques such as support vector machines (SVMs), self organizing maps (SOMs), genetic algorithm (GA)and particle swarm optimization (PSO). Under all examined approaches, each image is initially segmented and suitable low-level descriptors are extracted for every resulting segment. Then, each of the aforementioned classifiers is applied to associate every region with a predefined high-level semantic concept. An appropriate evaluation framework has been employed for the comparative evaluation of the above algorithms under varying experimental conditions.

关键词： Image analysis Image segmentation Algorithm design and analysis Knowledge acquisition Machine learning Support vector machines Support vector machine classification Self organizing feature maps Genetic algorithms Particle swarm optimization

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A wearable, self-calibrating, wireless sensor network for body motion processing

A wearable, self-calibrating, wireless sensor network for bo...

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IEEE International Conference on robotics and Automation (ICRA)

作者： Kwang Yong Lim Francis Young Koon Goh Wei Dong Kim Doang Nguyen I-Ming Chen Song Huat Yeo Henry Been Lirn Duh Chung Gon Kim Robotics Research Centre School of Mechanical and Aerospace Engineering Nanyang Technological University Singapore Interactive and Digital Media Institute Department of Electrical and Computer Engineering National University of Singapore Singapore The Biomechanics Laboratory National Institute of Education Nanyang Technological University Singapore

A novel self-calibrating sensing technology using miniature linear encoders and inertial/magnetic measurement unit (IMU) provides the accuracy, fast response and robustness required by many body motion processing applications. Our sensor unit consists of an accelerometer, a 3-axis magnetic sensor, 2 gyroscopes and a miniature linear encoder. The fusion of data from the sensors is accomplished by extracting the gravity related term from the accelerometer and consistently calibrating the gyroscopes and linear encoder when the sensor unit is under static conditions. Using the fused sensors, we developed a complete motion processing system that consists of a gateway where the human kinematics modeling is embedded. A time divided multiple access wireless architecture is adopted to synchronize the sensor network at 100 Hz. Experimental results show that the combination of the IMU and linear encoder produces a low RMS error of 3.5deg and correlation coefficient of 99.01%. A video showing the capture a performer's upper body motion is also realized.

关键词： Wireless sensor networks Magnetic sensors Sensor fusion Accelerometers Gyroscopes Magnetic variables measurement Robustness Wearable sensors Data mining Gravity

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Fractional-Order Signal Processing using a Polymer-Electrolyte Transistor

Fractional-Order Signal Processing using a Polymer-Electroly...

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51st Midwest Symposium on Circuits and Systems (MWSCAS 2008), vol.2

作者： Robert L. Ewing Hoda S. Abdel-Aty-Zohdy Michael C. Hollenbeck Kenneth S. Stevens Information Directorate US Air Force Research Laboratory OH USA Microelectronics System Design Laboratory Department of Electrical and Systems Engineering Oakland University Rochester MI USA Department of Electrical and Computer Engineering University of Utah Salt Lake UT USA

Fractional-order systems have applications in the areas of Flight Control, robotics, Missile Guidance, Control of Structural Vibrations of Space Platforms and Sensor Technology. Fractional-order transfer functions can characterize complex nonlinear dynamics with many fewer parameters than integer-order functions. This paper addresses the use of a polymer-electrolyte transistor (PET) for use in implementating fractional-order algorithms for signal processing. The PET's advantage over the conventional RC and RL circuits is that it can be both functionally scaled and varied for dynamic fractional-order parameter controllability.

关键词： Fractional-Order Signal Processing Polymer-electrolyte transistor Acid/base chemistry Diffusion Electrokinetic flow

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Optimal Protraction of a Three-Joint Robot Leg

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IFAC Proceedings Volumes 2008年第2期41卷 1703-1710页

作者： Mustafa Suphi Erden Kemal Leblebicioğlu BioMechanical Engineering Intelligent Mechanical Systems Group Delft university of Technology Delft 2628 CD The Netherlands (Tel: +31 (0)15 27 86794 Department of Electrical & Electronics Engineering Computer Vision and Intelligent Systems Research Laboratory Middle East Technical University Ankara 06531 Turkey (Tel: +90 (0)312 210 4558

In this paper protraction movement, namely stepping ahead, of a three joint robot leg is optimized for energy efficiency for any given pair of initial-final tip point positions. For the optimization a modified version of gradient descent based optimal control algorithm with Hamiltonian formulation is used. The objective function is modified in steps to jump over the infeasible and inefficient local optimums. The results of 79 optimizations are used to construct a radial basis function neural network (RBFNN) in order to interpolate between the optimized trajectories. The results are presented and discussed in the paper.

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Tracking ground targets with measurements obtained from a single monocular camera mounted on an unmanned aerial vehicle

Tracking ground targets with measurements obtained from a si...

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IEEE International Conference on robotics and Automation (ICRA)

作者： Dustin Deneault Dale Schinstock Chris Lewis Graduate Research Assistant for the Autonomous Vehicle Systems Laboratory Kansas State University USA Department of Mechanical and Nuclear Engineering Kansas State University USA Department of Electrical and Computer Engineering Kansas State University USA

In this paper, a novel method is presented for tracking ground targets from an unmanned aerial vehicle (UAV) outfitted with a single monocular camera. The loss of observability resulting from the use of a single monocular camera is dealt with by constraining the target vehicle to follow ground terrain. An unscented Kalman filter (UKF) provides a simultaneous localization and mapping solution for the estimation of aircraft states and feature locations, which define the target's local environment. Another filter, a loosely coupled Kalman filter for the target states, receives 3D measurements of target position with estimated covariance obtained by an unscented transformation (UT). The UT uses the mean and covariance from the camera measurements and from the UKF estimated aircraft states and feature locations to determine the estimated target mean and covariance. Simulation results confirm the concepts developed.

关键词： Target tracking Cameras Unmanned aerial vehicles State estimation Aircraft Observability Land vehicles Road vehicles Simultaneous localization and mapping Filters

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Flagellar swimming for medical micro robots: Theory, experiments and application

Flagellar swimming for medical micro robots: Theory, experim...

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IEEE/RAS-EMBS International Conference on Biomedical robotics and Biomechatronics (BioRob)

作者： Gabor Kosa Peter Jakab Nobuhiko Hata Ferenc Jolesz Zipi Neubach Moshe Shoham Menashe Zaaroor Gabor Szekely Computer Vision Laboratory Department of Information Technology and Electrical Engineering ETH Zurich Switzerland Harvard Medical School Boston MA USA Division of MRI and Image Guided Therapy Program at Department of Radiology Brigham and Women's Hospital Boston MA USA Faculty of Mechanical Engineering Technion-Israel Institute of Technology Haifa Israel Department of Neurosurgery Rambam Medical Center Haifa Israel

Flagellar swimming is one of the swimming methods used by micro-organisms to advance in aquatic environment. The undulating motion of the flagella was successfully imitated to create propulsion for a medical swimming micro robot. The influence of a head section on the performance of such a robot is shown analytically. Swimming experiments demonstrate forward and backward swimming of a novel magnetically driven swimming tail. We intend to use the flagellar swimming tail in a three tail configuration for neurosurgical intervention in the ventricular system.

关键词： Medical robotics Tail Medical diagnostic imaging Propulsion Magnetosphere Neurosurgery Intestines computer vision Laboratories Information technology

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Using a patient image archive to diagnose retinopathy

Using a patient image archive to diagnose retinopathy

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Annual International Conference of the IEEE engineering in Medicine and Biology Society (EMBC)

作者： Kenneth W. Tobin Michael D. Abramoff Edward Chaum Luca Giancardo V. Priya Govindasamy Thomas P. Karnowski Matthew T.S. Tennant Stephen Swainson Image Science and Machine Vision Group Oak Ridge National Laboratory Oak Ridge TN USA Department of Electrical and Computer Engineering University of Iowa Iowa IA USA Department of Ophthalmology and Visual Sciences University of Iowa Hospitals and Clinics Iowa IA USA Tennessee Health Science Center Hamilton Eye Institute Memphis TN USA Oak Ridge National Laboratory Oak Ridge TN USA Department of Ophthalmology University of Alberta Edmonton Canada Faculty of Medicine University of Alberta AB Canada

Diabetes has become an epidemic that is expected to impact 365 Million people worldwide by 2025. Consequently, diabetic retinopathy is the leading cause of blindness in the industrialized world today. If detected early, treatments can preserve vision and significantly reduce debilitating blindness. Through this research we are developing and testing a method for automating the diagnosis of retinopathy in a screening environment using a patient archive and digital fundus imagery. We present an overview of our content-based image retrieval (CBIR) approach and provide performance results for a dataset of 98 images from a study in Canada when compared to an archive of 1,355 patients from a study in the Netherlands. An aggregate performance of 89% correct diagnosis is achieved, demonstrating the potential of automated, web-based diagnosis for a broad range of imagery collected under different conditions and with different cameras.

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A combined integral transform asymptotic expansion method for the characterization of interface flaws through pulsed infrared thermography1

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Quantitative InfraRed Thermography Journal 2007年第1期4卷 3-23页

作者： Bendada, Abdelhakim Ibarra-Castanedo, Clemente Maldague, Xavier Computer Vision and Systems Laboratory Department of Electrical and Computer Engineering Université Laval Quebec City G1K7P4 Canada

This work is devoted to the non-destructive evaluation of materials using stimulated infrared thermography. The proposed approach provides simple analytical solutions to evaluate the lateral extent, and the thickness of a plane flaw in a three-dimensional (3D) heat transfer configuration. It is based on the application of a Laplace transform on the time variable t, then a double Fourier transform on the space variables x and y. Reduction of the models is obtained through an asymptotic expansion method. This mathematical formalism leads to the construction of explicit relationships that are very convenient for quantitative inversion. An experimental validation of the inversion procedures is performed on calibrated carbon-epoxy laminates. A particular attention is dedicated in the second part of this work to the experimental analysis of the impact of the definition of the experimental thermal contrast and the sane (i.e., non-defective) area on the inverted parameters. The analysis is carried out through a comparison between two classical definitions of the thermal contrast and a new method, the DAC contrast, developed recently by our team. The impact of a hyper parameter of the inversion procedures (i.e., the Laplace variable) is also analyzed. Both analyses are illustrated through an experiment aiming to estimate the depths of some calibrated flaws in a CFRP laminate. © 2007 Taylor & Francis Group, LLC. All rights reserved.

关键词： 3D heat transfer DAC thermal contrast Flaw characterization Infrared thermography Mathematical perturbations Non destructive evaluation Thermal quadrupoles

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