Complex part inspection with eddy current sensors

A method of defect detection, the method comprising:

• scanning a sensor array having a plurality of sense elements over a test object;
• during the scanning recording a spatial position of the sensor array;
• collecting measurements from each of the plurality of sense elements of the sensor array as a function of the spatial position;
• and
• operating a processor to correlate as a function of spatial position, the measurements from a subset of sense elements with each defect signature in a signature library,
• wherein each defect signature in the signature library comprises, on a first number of channels, a defect response as a function of spatial position, the first number being two or more, and
• the subset of sense elements has the first number of sense elements,
• wherein the processor generates a correlation value based on the correlating,
• the processor determines a defect is present when the correlation value exceeds a threshold, and
• the processor outputs a signal indicating a presence of the defect.

A system for defect detection, the system comprising:

• at least one processor;
• a sensor array having a plurality of sense elements;
• an encoder to record a spatial position of the sensor array;
• an instrument configured to collect measurements from each of the plurality of sense elements of the sensor array as a function of the spatial position obtained from the encoder;
• and
• at least one non-transitory computer-readable storage medium having stored thereon
• a signature library, the signature library comprising a plurality of defect signatures obtained at a plurality of liftoffs, each defect signature having, on a first number of channels, a defect response as a function of spatial position, the first number being two or more, and
• a plurality of software modules, each comprising instructions executable by the at least one processor, including
• a correlation module to correlate, as a function of spatial position, the measurements from a subset of sense elements with each defect signature in the signature library, and generate a correlation value, wherein the subset of sense elements has the first number of sense elements,
• a detection module to determine a defect is present when the correlation value exceeds a threshold, and
• an output module to output a signal indicating a presence of the defect.