Eddy current imaging

A laboratory eddy current imaging system has been assembled to scan a probe over a sample and to record digital eddy current images. The system is microprocessor controlled and it transmits images to a VAX 780 computer for image processing. These images have been used for probe characterization and to study the imaging process. The eddy current system has a vector response to a flaw; the signal has both magnitude and phase. Images of response magnitude, in-phase component, out-of phase component, and phase angle have been displayed. Image processing techniques have been applied to the images for data correction and to extract imformation. Two types of probes have been examined: cylindrical pot-core probes and recording head probes.