Abstract: A pulsed eddy current (PEC) instrument acquires PEC pulse responses from different locations on a structure being inspected. The difference between the acquired PEC pulse responses and a reference PEC response is determined to obtain time-domain difference signals having a time value and a magnitude value. The time and magnitude values are stored in memory with location information. An image display is provided that is determined from the stored magnitude values, although magnitude values for difference signals whose time values do not meet a defined time condition are filtered from the display. The time condition filters from the display known conditions such as the presence of fasteners, the presence of air-gaps between layers of the structure, and excessive PEC probe lift-off from the structure and filters the display so that only information from a particular layer or depth of the inspected structure is displayed.

Abstract: A system for photoinductive imaging for flaw detection of materials and for calibrating eddy-current probes includes positioning an eddy-current probe adjacent to a specimen to be analyzed or to be used as a calibration fixture. A source of thermal energy is modulated and focused to a localized area on the specimen. Thermal energy is then scanned across at least a portion of the detection area of the eddy-probe. The resulting signal from the eddy-current probe is recorded and can depict either thermal-influenced components of the specimen or the response pattern of the eddy-current probe. The record can therefore be used to image flaws or physical holes or shapes of the specimen or calibrate the eddy-current probe.

Abstract: A system for nondestructive analysis of barrier coatings on electrically conductive materials includes imposition of a controlled known heat load to a localized area of the coating and measuring electrical conductivity of the underlying material at or near the localized area of the coating. The electrical conductivity of the material is affected by changes in temperature related to thermal conduction into the material through the coating. Thermal resistance of the coating and defects between the coating and the material can therefore be detected.

Abstract: A system for photoinductive imaging for flaw detection of materials and for calibrating eddy-current probes includes positioning an eddy-current probe adjacent to a specimen to be analyzed or to be used as a calibration fixture. A source of thermal energy is modulated and focused to a localized area on the specimen. Thermal energy is then scanned across at least a portion of the detection area of the eddy-probe. The resulting signal from the eddy-current probe is recorded and can depict either thermal-influenced components of the specimen or the response pattern of the eddy-current probe. The record can therefore be used to image flaws or physical holes or shapes of the specimen or calibrate the eddy-current probe.