US5339256A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Expert system for analyzing eddy current measurements
Assignee: United States Department of Energy
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Filing: 1991-11-27
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Granted: 1994-08-16
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Expires: 2011-11-27
Abstract
Abstract A method and apparatus (called DODGER) analyzes eddy current data for heat exchanger tubes or any other metallic object. DODGER uses an expert system to analyze eddy current data by reasoning with uncertainty and pattern recognition. The expert system permits DODGER to analyze eddy current data intelligently, and obviate operator uncertainty by analyzing the data in a uniform and consistent manner.
Inventors
- 👤 Arthur J. Levy
- 👤 Jane E. Oppenlander
- 👤 David M. Brudnoy
- 👤 James M. Englund
- 👤 Kent C. Loomis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 21:38
CPC Classifications
G; G06; G06N; G06N5/00; G06N5/04; G01; G01N; G01N27/00; G01N27/72; G01N27/82; G01N27/90; G01N27/9046; Y; Y10; Y10S; Y10S706/00; Y10S706/902; Y10S706/911
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
181 words
A computer-based method of analyzing eddy current signals to provide information about flaws in a metallic object, using an expert system, wherein said eddy current signals are obtained prior to using said expert system by passing an eddy current probe along said metallic object, detecting any change in current by a change in electrical impedance, and recording said change in electrical impedance as electrical signal data on a storage device, comprising the steps of: a) retrieving said electrical signal data for one said metallic object from said storage device for analysis; b) calibrating said expert system; c) associating calibration information with said data; d) displaying said data as graphical data patterns; e) analyzing said graphical data patterns in a consistent and uniform manner, wherein said analyzing includes applying a rule base and a knowledge base, said knowledge base including reasoning with uncertainty and pattern recognition to interpret said electrical signal data; and wherein said pattern recognition comprises obtaining geometric parameters from said graphical data patterns and storing said parameters in said knowledge base; and f) presenting a diagnosis of said flaws.
Claim 2
Dependent Claim
181 words
A computer-based method of analyzing eddy current signals to provide information about flaws in a metallic object, using an expert system, wherein said eddy current signals are obtained prior to using said expert system by passing an eddy current probe along said metallic object, detecting any change in current by a change in electrical impedance, and recording said change in electrical impedance as electrical signal data on a storage device, comprising the steps of: a) retrieving said electrical signal data for one said metallic object from said storage device for analysis; b) calibrating said expert system; c) associating calibration information with said data; d) displaying said data as graphical data patterns; e) analyzing said graphical data patterns in a consistent and uniform manner, wherein said analyzing includes applying a rule base and a knowledge base, said knowledge base including reasoning with uncertainty and pattern recognition to interpret said electrical signal data; and wherein said pattern recognition comprises obtaining geometric parameters from said graphical data patterns and storing said parameters in said knowledge base; and f) presenting a diagnosis of said flaws.
Claim 3
Dependent Claim
17 words
The method of claim 1, wherein said analysis step includes analysis of hypotheses suggested by an operator.
Claim 4
Dependent Claim
19 words
The method of claim 1, wherein said calibration step includes signal mixing calibration, depth calibration, signal rotation and normalization.
Claim 5
Dependent Claim
30 words
The method of claim 1, wherein said analysis step includes using fuzzy set representation to analyze said geometric parameters stored in said knowledge base obtained from said graphical data patterns.
Claim 6
Dependent Claim
17 words
The method of claim 1, wherein said analysis step includes recognizing conflicts in said electrical signal data.
Claim 7
Dependent Claim
18 words
The method of claim 1, wherein said analysis step includes distinguishing between lack of knowledge and conflicting evidence.
Claim 8
Dependent Claim
26 words
The method of claim 1, wherein said analysis step includes weighting a set of rules in order to control contribution of those rules to said diagnosis.
Claim 9
Dependent Claim
18 words
The method of claim 1, wherein said pattern recognization step includes classifying said patterns according to curvature functions.
Claim 10
Dependent Claim
23 words
The method of claim 1, wherein said pattern recognition step includes removing noise from said patterns including endpoint noise and small loop noise.
Claim 11
Dependent Claim
28 words
The method of claim 1, wherein said geometric parameters obtained in said pattern recognition step include but are not limited to phase vectors, amplitude and width of lobes.
Claim 12
Dependent Claim
14 words
The method of claim 1 wherein said metallic object is a heat exchanger tube.
Claim 13
Dependent Claim
16 words
The method of claim 1 wherein said analysis step includes operator interaction with said expert system.
Claim 14
Dependent Claim
22 words
The method of claim 1 wherein said calibration step includes selecting a calibration standard and identifying features of interest on said standard.
Claim 15
Dependent Claim
18 words
The method of claim 1 wherein said analysis step further comprises generating a belief value for said diagnosis.
Claim 16
Dependent Claim
26 words
The method of claim 14 wherein said generating step uses an optimally chosen minimal amount of data to achieve a belief in a most likely diagnosis.
Claim 17
Dependent Claim
33 words
The method of claim 15 wherein said generating step further comprises automatically and dynamically selecting a next frequency signal for analysis in order to minimize said data used in said most likely diagnosis.
Claim 18
Dependent Claim
34 words
The method of claim 14 wherein said generating step further comprises automatically and dynamically determining when a sufficient amount of said data has been analyzed to generate an optimal belief value in said diagnosis.
Claim 19
Dependent Claim
40 words
The method of claim 17 wherein said determining step further comprises: 1) pursuing a most believable and plausible hypothesis based on said data; and 2) pursuing said hypothesis whose belief value increases most as a new frequency signal is analyzed.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-08-15 | 1998-02-14 | 1998-08-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-08-15 | 2002-02-14 | 2002-08-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-08-15 | 2006-02-14 | 2006-08-16 | $7700.00 | Window Closed / Lapsed |