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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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Segmentation of wheat grains in thermal images based on pulse coupled neural networks

Segmentation of wheat grains in thermal images based on puls...

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IEEE International Conference on image Processing (ICIP 2007)

作者： Chacon, Mario Manickavasagan, Annamalai Flores-Tapia, Daniel Thomas, Gabriel Jayas, Digvir S. DSP and Vision Laboratory Chihuhahua Institute of Technology Mexico Department of Biosystems Engineering University of Manitoba Canada Department of Electrical and Computer Engineering University of Manitoba Canada

ISBN: (纸本)9781424414369

Canada is one of the major exporters of wheat in the world. The quality of these exports is well known and factors such as lack of insect infestation are very important. The use of thermal images for subsequent analysis of temperatures profiles for grain classification and insect detection is a method under investigation. This paper presents an approach for automatic image segmentation of the wheat kernels based on the combined use of wavelet analysis and pulse coupled neural networks. It is shown that using wavelets as a preprocessing technique yields a consistent accurate segmentation in terms of the iteration number in which the network yields reliable edges of the wheat kernels. Subsequent analysis of these segmentations can determine internal qualities such as infestations.

关键词： static wavelet transform pulse coupled neural network grain segmentation thermal images

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Performance of a self-paced brain computer interface on data contaminated with eye-movement artifacts and on data recorded in a subsequent session

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Computational Intelligence and Neuroscience 2008年第unknown期2008卷 1-13页

作者： Fatourechi, Mehrdad Ward, Rabab K. Birch, Gary E. Image and Signal Processing Laboratory Department of Electrical and Computer Engineering University of British Columbia Vancouver BC V6T 1Z4 Canada Institute for Computing Information and Cognitive Systems University of British Columbia Vancouver BC V6T 1Z4 Canada Neil Squire Society Burnaby BC V5M 3Z3 Canada

The performance of a specific self-paced BCI (SBCI) is investigated using two different datasets to determine its suitability for using online: (1) data contaminated with large-amplitude eye movements, and (2) data recorded in a session subsequent to the original sessions used to design the system. No part of the data was rejected in the subsequent session. Therefore, this dataset can be regarded as a pseudo-online test set. The SBCI under investigation uses features extracted from three specific neurological phenomena. Each of these neurological phenomena belongs to a different frequency band. Since many prominent artifacts are either of mostly low-frequency (e.g., eye movements) or mostly high-frequency nature (e.g., muscle movements), it is expected that the system shows a fairly robust performance over artifact-contaminated data. analysis of the data of four participants using epochs contaminated with large-amplitude eye-movement artifacts shows that the system's performance deteriorates only slightly. Furthermore, the system's performance during the session subsequent to the original sessions remained largely the same as in the original sessions for three out of the four participants. This moderate drop in performance can be considered tolerable, since allowing artifact-contaminated data to be used as inputs makes the system available for users at ALL times.

关键词： .Brain computer Data Contaminated Eye-Movement Artifacts Subsequent Session Recorded in Subsequent SBCI contaminated with large-amplitude neurological phenomena

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A NEW GLOBAL REGISTRATION APPROACH OF MEDICAL IMAGING USING VECTOR MAPS

A NEW GLOBAL REGISTRATION APPROACH OF MEDICAL IMAGING USING ...

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IEEE International Symposium on Biomedical Imaging

作者： Hossam E. Abd El Munim Aly A. Farag Computer Vision and Image Processing (CVIP) Laboratory Department of Electrical and Computer Engineering University of Louisville Louisville KY USA

ISBN: (纸本)1424406714

In this paper, we introduce a novel global image registration approach using vector distance functions (VDF's). Edges of the source and target objects are used to represent their images. The VDF's of these edges are calculated as an implicit representation of these boundaries. An energy is formulated to measure the differences of these vectors. A variational formulation is considered to estimate the transformation parameters. Promising results in 2D and 3D are demonstrated to show the efficiency of the proposed algorithm.

关键词： Biomedical imaging image edge detection image registration Parameter estimation computer vision Mutual information Data mining Shape image processing Energy measurement

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FAST MOTION IMAGING USING REDUCED FIELD OF VIEW PARTIAL FOURIER MRI

FAST MOTION IMAGING USING REDUCED FIELD OF VIEW PARTIAL FOUR...

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IEEE International Symposium on Biomedical Imaging

作者： Harsh K. Agarwal Khaled Z. Abd-elmoniem Jerry L. Prince Image Analysis and Communication Laboratory Department of Electrical and Computer Engineering Johns Hopkins University Baltimore MD USA

Fast MR imaging techniques often exploit the redundancy present in an underlying MR image time series to compensate for k-space undersampling. When imaging motion using techniques like HARP, DENSE, and phase contrast (PC), it is the phase in static regions that is constant and therefore redundant. In this paper, we present a technique that first estimates the phase in the static portion of an undersampled MR image time series and then uses a partial Fourier reconstruction technique to combine phase in the static portion and undersampled data to reconstruct the full image time series. The technique is illustrated using a computational phantom undergoing simulated cardiac motion and imaged using the HARP protocol. Results demonstrate a gradual degradation of accuracy with loss of data due to undersampling, indicating that a 25% speedup in imaging time is possible for an image time series in which 50% of the pixels correspond to the object that do not move over time.

关键词： Magnetic resonance imaging image reconstruction Phase estimation Protocols Frequency estimation Motion analysis image motion analysis Laboratories Imaging phantoms Computational modeling

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A Geometry-Based Local Descriptor for Range Data

A Geometry-Based Local Descriptor for Range Data

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Proceedings of the Digital image Computing: Technqiues and Applications (DICTA)

作者： Fredrik Viksten Klas Nordberg Image Coding Group Department of Electrical Engineering Linköping university Sweden Computer Vision Laboratory Department of Electrical Engineering Linköping university Sweden

ISBN: (纸本)9781424431618;9780769530673

We present a novel local descriptor for range data that can describe one or more planes or lines in a local region. It is possible to recover the geometry of the described local region and extract the size, position and orientation of each local plane or line-like structure from the descriptor. This gives the descriptor a property that other popular local descriptors for range data, such as spin images or point signatures, does not have. The estimation of the descriptor is dependant on estimation of surface normals but does not depend on the specific normal estimation method used. It is shown that is possible to extract how many planar surface regions the descriptor represents and that this could be used as a point-of-interest detector.

关键词： Tensile stress Layout computer vision Geometry Data mining Digital images computer applications Application software image coding Laboratories

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Robust Object Tracking using Local Kernels and Background Information

Robust Object Tracking using Local Kernels and Background In...

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IEEE International Conference on image Processing

作者： Jaideep Jeyakar R. Venkatesh Babu K. R. Ramakrishnan Computer Vision Laboratory Department of Electrical Engineering Indian Institute of Science Bangalore India

The mean shift algorithm has been proved to be efficient for tracking 2D blobs through a video sequence. Even so, this algorithm has certain inherent disadvantages. In this paper, we propose a robust tracking algorithm which overcomes the drawbacks of global color histogram based tracking. We incorporate tracking based only on reliable colors by separating the object from its background. A fast yet robust model update is employed to overcome illumination changes. This algorithm is computationally simple enough to be executed real time and was tested on several complex video sequences. The proposed technique could be easily extended to other tracking algorithms too.

关键词： Robustness Kernel Target tracking Histograms Voting Lighting computer vision Video sequences Particle tracking Testing

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Measuring Land Development in Urban Regions using Graph Theoretical Features

Measuring Land Development in Urban Regions using Graph Theo...

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International Conference on Recent Advances in Space Technologies (RAST)

作者： Cemr Unsalan Computer Vision Research Laboratory Department of Electrical and Electronics Engineering Yeditepe University Istanbul Turkey

Inferring land use from satellite images is studied extensively. In previous studies, the focus was on classifying large regions due to the resolution of available satellite images. Nowadays, very high resolution satellite imagery (Ikonos and Quickbird) allow researchers to focus on more complex land use problems such as monitoring development in urban regions. Solutions to these complex problems may improve life standards of city residents. To this end, we focus on automatically monitoring construction zones using their very high resolution panchromatic satellite images through time. To monitor land development, we obtain sequential images of a selected region. Then, we extract features from each image in the sequence. Comparing values of these features, we expect to measure the degree of land development through time. Here, we introduce four new graph theoretical features to the existing ones. We test all our existing and new features to measure land development in 19 different urban construction zones. Our test set consists of Ikonos satellite images of these regions imaged in separate times.

关键词： Satellites image resolution Gray-scale Time measurement Spatial resolution Monitoring Cities and towns Testing Electric variables measurement computer vision

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Detecting Changes in Multispectral Satellite images using Time Dependent Angle Vegetation Indices

Detecting Changes in Multispectral Satellite Images using Ti...

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International Conference on Recent Advances in Space Technologies (RAST)

作者： Cemr Unsalan Computer Vision Research Laboratory Department of Electrical and Electronics Engineering Yeditepe University Istanbul Turkey

Change detection using satellite images is of major concern to government agencies, military, and scientists. Government agencies can monitor the construction activity on a region automatically by detecting changes. They can update maps accordingly. Forests in satellite images may be monitored automatically for any change in their condition. As for military applications, strategic plans may be updated based on the observed changes on targets. After a natural disaster, even if that region can not be reached, automatically detecting changes in the region's satellite image may provide necessary information to measure the effect of the damage. To solve all these and related problems, there exists commercially available high resolution satellite images. The problem here is automatically detecting changes using these images. In this study, we introduce a method using multispectral information to detect changes on Ikonos imagery.

关键词： Vegetation mapping Military satellites Principal component analysis image resolution Government computerized monitoring Spatial resolution computer vision Condition monitoring Remote sensing

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Editorial: Knowledge engineering, semantics, and signal processing in audio - visual information retrieval

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IEEE Transactions on Circuits and Systems for Video Technology 2007年第3期17卷 257-258页

作者： Izquierdo, Ebroul Zhang, Jian Sikora, Thomas Huang, Thomas S. Department of Electrical Engineering Queen Mary University of London London El 4NS United Kingdom Sydney Australia School of Computer Science and Engineering University of New South Wales Australia Communication Systems Group Technical University Berlin Berlin Germany ITG University of Illinois at Urbana-Champaign United States Department of Electrical and Computer Engineering Coordinated Science Laboratory United States Image Formation and Processing Group Beckman Institute for Advanced Science and Technology United States Institute's Major Research Theme Human Computer Intelligent Interaction National Academy of Engineering Chinese Academies of Engineering and Sciences China International Association of Pattern Recognition Optical Society of American United States

No abstract available

关键词： Special issues and sections Knowledge engineering Information retrieval Audio-visual systems

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