Electricity: measuring and testing – Magnetic – With compensation for test variable
Reexamination Certificate
2011-08-30
2011-08-30
Nguyen, Ha Tran T (Department: 2858)
Electricity: measuring and testing
Magnetic
With compensation for test variable
C324S227000, C324S233000, C324S237000, C702S038000
Reexamination Certificate
active
08008913
ABSTRACT:
Variations in the lift-off separation between a probe and the surface of a structure to be tested often mask the detection of defects in the structure. A method and apparatus for automatically classifying and compensating for variations in the lift-off is described. A reference signal at a known lift-off may be weighted by a corresponding calculated ratio parameter and subtracted from a test signal to compensate for lift-off. A number of reference signals are preferably obtained and the largest magnitude gradient for each reference signal is preferably determined. The largest magnitude gradient for subsequent test signals is also obtained and the corresponding reference signal with the closest largest magnitude gradient to the test signal is identified and the corresponding reference signal is selected in the related compensation procedure. Such a method has been found to restore the signal such that lift-off is removed and defects are easily identified.
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German Patent Application No. 102008002883.5-52, German Search Report and Written Opinion, Apr. 14, 2011.
Hansen John
Qiao Xiaoyu
Chan Emily Y
Conklin Mark A.
GE Inspection Technologies, Ltd
Global Patent Operation
Nguyen Ha Tran T
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