Novel Approach To The Classification Of Ultrasonic Nde Signals
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Novel Approach To The Classification Of Ultrasonic Nde Signals
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Author : Daewon Kim
language : en
Publisher:
Release Date : 200?
Novel Approach To The Classification Of Ultrasonic Nde Signals written by Daewon Kim and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 200? with Non-destructive testing categories.
Ultrasonic inspection methods are widely used for detecting flaws in materials. The signal analysis step plays a crucial part in the data interpretation process. A number of signal processing methods have been proposed to classify ultrasonic flaw signals. One of the more popular methods involves the extraction of an appropriate set of features followed by the use of a neural network for the classification of the signals in the feature space. This thesis describes an alternative approach which uses the least mean square (LMS) method to determine the coordinates of the ultrasonic probe followed by the use of a synthetic aperture focusing technique (SAFT). The method is employed for classifying nondestructive evaluation (NDE) signals from steam generator tubes in a nuclear power plant. The movement of the probe inside the tube is modeled using spherical and cylindrical coordinate systems. The mean square error (MSE) between the model prediction and the experimentally measured distance between the probe and the tube wall is minimized using the steepest descent algorithm to obtain estimates of the probe canting angle and its location. The information is used in conjunction with the synthetic aperture focusing technique to estimate the location of the ultrasonic reflector. An alternate approach employing a model based deconvolution has been described to facilitate comparison of results. The method uses the space alternating generalized expectation maximization (SAGE) algorithm in conjunction with the Newton-Raphson method to estimate the time of flight. Results using these schemes for the classification of ultrasonic signals from cracks and deposits within steam generator tubes are presented.
Ultrasonic Nde Signal Classification With Wiener Filtering Deconvolution
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Author : Xiaoming Yu
language : en
Publisher:
Release Date : 2000
Ultrasonic Nde Signal Classification With Wiener Filtering Deconvolution written by Xiaoming Yu and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2000 with categories.
This thesis presents a method for discriminating different types of ultrasonic flaws signals collected from steam generator using pulse-echo reflection techniques. The proposed method uses various signal processing, image processing techniques to extract features from ultrasonic signals. Then several pattern recognition techniques are used to get the optimum classification results. The training and testing with these features shows that a better performance than previous effort is achieved. In ultrasonic area, it is often desired to deconvolve the impulse of transducers from the A-scans to recover the impulse response (IR) from real flaws. The duration of the deconvolved IR should be shorter than what we observe in A-scans. The longer duration in the A-scan often hides some information such as the exact location of flaw, which might make classification more difficult. To overcome this problem, Wiener filtering deconvolution technique is introduced in this project to get better resolution in time domain and get more possible features other than those from the original signals.
Evaluation Of Various Preprocessing Techniques For Classification Of Ultrasonic Ndt Signals
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Author : Kavi Ram Shahani
language : en
Publisher:
Release Date : 1992
Evaluation Of Various Preprocessing Techniques For Classification Of Ultrasonic Ndt Signals written by Kavi Ram Shahani and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1992 with categories.
Automated Compensation And Classification Algorithms For Array Probe Eddy Current Nondestructive Evaluation
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Author : Pradeep Kumar Jella
language : en
Publisher:
Release Date : 2004
Automated Compensation And Classification Algorithms For Array Probe Eddy Current Nondestructive Evaluation written by Pradeep Kumar Jella and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2004 with Eddy currents (Electric) categories.
Ultrasonic And Advanced Methods For Nondestructive Testing And Material Characterization
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Author : Chi-hau Chen
language : en
Publisher: World Scientific
Release Date : 2007
Ultrasonic And Advanced Methods For Nondestructive Testing And Material Characterization written by Chi-hau Chen and has been published by World Scientific this book supported file pdf, txt, epub, kindle and other format this book has been release on 2007 with Medical categories.
Ultrasonic methods have been very popular in nondestructive testing and characterization of materials. This book deals with both industrial ultrasound and medical ultrasound. The advantages of ultrasound include flexibility, low cost, in-line operation, and providing data in both signal and image formats for further analysis. The book devotes 11 chapters to ultrasonic methods. However, ultrasonic methods can be much less effective with some applications. So the book also has 14 chapters catering to other or advanced methods for nondestructive testing or material characterization. Topics like structural health monitoring, Terahertz methods, X-ray and thermography methods are presented. Besides different sensors for nondestructive testing, the book places much emphasis on signal/image processing and pattern recognition of the signals acquired.
Ultrasonic Nde Signal Classification On Steam Generator Tubes
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Author : Rongzhi Xing
language : en
Publisher:
Release Date : 2000
Ultrasonic Nde Signal Classification On Steam Generator Tubes written by Rongzhi Xing and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2000 with categories.
This thesis presents a method for discriminating two different types of ultrasonic defect signals (cracks and deposits) collected from steam generator tubing using pulse-echo reflection techniques. The proposed method uses various signal processing and image processing techniques, such as the fast Fourier transform, deconvolution, the wavelet transform and binary morphology, to extract features from ultrasonic signals. Then several pattern recognition techniques, such as the K-mean clustering algorithm, univariate decision tree, oblique tree, and feed-forward back-propagation neural network are used to classify the flaws. Training and testing with these features results in improved performance in comparison with previous research projects concerning this data. In the feature extraction steps, a Wiener filter was used to get the impulse response of the defects. Then features from the time and frequency domains were extracted. A 1-D wavelet transform was also used to get multi-resolution representation of A-scans. Features from different decomposition levels were extracted. Image processing and binary morphology were also used to get features from 2-D images of defects. Useful features such as image area and image moments were extracted. An oblique tree and a feed-forward back-propagation neural network were shown to perform well in this project. Based on the features we obtained thus far, a feed-forward back-propagation neural network gives the best performance.
Ultrasonic Nondestructive Evaluation Systems
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Author : Pietro Burrascano
language : en
Publisher: Springer
Release Date : 2014-12-04
Ultrasonic Nondestructive Evaluation Systems written by Pietro Burrascano and has been published by Springer this book supported file pdf, txt, epub, kindle and other format this book has been release on 2014-12-04 with Technology & Engineering categories.
This book deals with a number of fundamental issues related to the practical implementation of ultrasonic NDT techniques in an industrial environment. The book discusses advanced academic research results and their application to industrial procedures. The text covers the choice and generation of the signals energizing the system to probe position optimization, from quality assessment evaluation to tomographic inversion. With a focus to deepen a number of fundamental aspects involved in the specific objective of designing and developing an ultrasonic imaging system for nondestructive testing, aimed to automatically classify the entire production of an industrial production line, targeted to the field of precision mechanics. The contents of this book is the result of the common effort of six University Research Groups that focused their research activities for two years on this specific objective, working in direct conjunction with primary industrial firms, in a research project funded by the Italian government as a Strategic Research Project.
Review Of Progress In Quantitative Nondestructive Evaluation
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Author : Donald O. Thompson
language : en
Publisher: Springer Science & Business Media
Release Date : 2013-11-11
Review Of Progress In Quantitative Nondestructive Evaluation written by Donald O. Thompson and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013-11-11 with Technology & Engineering categories.
This volume (Parts A and B) contains the edited papers presented at the annual Review of Progress in Quantitative Nondestructive Evaluation held at the University of California - San Diego, La Jolla, CA, on August 1-5, 1988. The Review was organized by the Center for NDE at Iowa State University and the Ames Laboratory of the U. S. Department of Energy in cooperation with the Air Force Materials Laboratory, the Office of Basic Energy Sciences, USDOE, the Office of Naval Research, the NASA-Langley Research Center, and The Metallurgical Society (TMS). Yith a total of over 450 participants from the US and nine foreign countries who presented a record 325 papers, this conference has grown into the largest, most significant gathering of NDE researchers and engineers anywhere in the Yest. The meeting was divided into 36 sessions with as many as four sessions running concurrently. All stages of NDE development from basic research investigations to early engineering applications and all methods of inspection science from ultrasonics to x-ray tomography were covered. Following a pattern now familiar to regular attendees of the Review and readers of the Proceedings, the editors have organized the papers in the Proceedings according to topical subject headings rather than the original order of presentation. This rearrangement yields a more user friendly reference work. Part A of the Proceedings treats NDE technique development whereas Part B is organized around the theme of materials.
Ultrasonic Signal Processing And Classification Using Principal Component Analysis
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Author : Robert A. Volesky
language : en
Publisher:
Release Date : 2001
Ultrasonic Signal Processing And Classification Using Principal Component Analysis written by Robert A. Volesky and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2001 with categories.
In ultrasonic signal processing, discriminatory information exists in the variations in a neighborhood of signals. Principal component analysis (PCA) is a method to measure the variances in the signals and to transform the signals to a lower dimensional space for classification. PCA is a multivariate analysis technique that reduces the dimensionality of the data set by transforming the data to a new set of variables that are aligned with the directions of greatest variability of the original data set. This technique may be applied to Nondestructive Evaluation (NDE) for signal classification purposes. A neural network-based signal classification system is proposed for the interpretation of ultrasonic signals obtained from inspection of welds, where signals have to be classified as resulting from porosity, slag, lack of fusion, or cracks in the weld region. Standard techniques rely on differences in individual A-scans to classify the signals. Ultrasonic NDE classification is performed using PCA derived features. These features may be used to quantify the variance in NDE signals and determine how the ultrasonic signals vary based upon the class. Classification of the signals is performed using features based on the eigenvalues, eigenvectors, and principal components of the covariance matrix generated from ultrasonic signals. Rigorous preprocessing of the signals is required in this classification consisting of time gating, normalization, and signal alignment. Additionally, PCA is computed on transform domain signals including the Fourier transform, Wavelet transform, and Cosine transform. The results indicate that PCA may be useful to significantly reduce the feature vector's dimensionality while maintaining high classification performance.
Dissertation Abstracts International
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Author :
language : en
Publisher:
Release Date : 2003
Dissertation Abstracts International written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2003 with Dissertations, Academic categories.