Method and apparatus for a multi-channel multi-frequency data acquisition system for nondestructive eddy current inspection testing
First Claim
1. An eddy current inspection apparatus for detecting flaws in a conductive surface comprising:
- a plurality of spatially correlated eddy current probe means;
means for driving select probe means of the plurality with a plurality of select frequencies;
means for automatically scanning in a vicinity of the surface to synchronously acquire discrete scan responsive measurement signals from each of the plurality of probe means;
means for responsively multiplexing each measurement signal onto a predetermined number of independent data channels in order to collect a corresponding plurality of measurement signals for parallel processing;
means for demodulating each measurement signal of the plurality against a reference frequency in order to obtain a corresponding pair of basis components for image processing;
means for converting each component pair into digital format;
automated means for storing the digitized components; and
means for automated parallel image processing of the digital components.
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Abstract
The invention discloses an inspection system for detecting near surface flaws or defects in conductors using nondestructive eddy current testing suitable for industrial application. The system provides a method and apparatus for acquiring real time, synchronized, discrete eddy current measurement signals from a plurality of sufficiently disposed, spatially correlated eddy current probes then processing and formatting said measurement signals automatically over parallel data channels to accommodate digital processing techniques in order to produce on eddy current image. Utilizing digital image processing provides a capability for improving flaw detection limits while simultaneously enhancing image resolution.
144 Citations
12 Claims
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1. An eddy current inspection apparatus for detecting flaws in a conductive surface comprising:
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a plurality of spatially correlated eddy current probe means; means for driving select probe means of the plurality with a plurality of select frequencies; means for automatically scanning in a vicinity of the surface to synchronously acquire discrete scan responsive measurement signals from each of the plurality of probe means; means for responsively multiplexing each measurement signal onto a predetermined number of independent data channels in order to collect a corresponding plurality of measurement signals for parallel processing; means for demodulating each measurement signal of the plurality against a reference frequency in order to obtain a corresponding pair of basis components for image processing; means for converting each component pair into digital format; automated means for storing the digitized components; and means for automated parallel image processing of the digital components. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An eddy current inspection apparatus for detecting flaws in a conductive surface comprising:
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a plurality of spatially correlated eddy current probes comprising at least one drive element in cooperation with a plurality of sense elements operating in reflectance mode; means for driving select probe drive elements with a plurality of select frequencies; means for automatically scanning in a vicinity of the surface to synchronously acquire discrete scan responsive measurement signals from each probe sense element of the plurality; means for responsively multiplexing measurement signals onto a predetermined number of independent data channels in order to collect a corresponding plurality of measurement signals for parallel processing; means for demodulating each signal of the plurality against a reference frequency in order to obtain a corresponding pair of basis components for image processing; means for converting each component pair into digital format; automated means for storing the digital components; and means for automated parallel image processing of the digital components. - View Dependent Claims (8, 9, 10, 11, 12)
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Specification