High-Resolution Flaw Detection Using Eddy-Current Probe Array Based on Giant Magnetoresistance Sensors

This work presents a flaw detection system consisting of an array of eddy-current (EC) probes based on giant-magnetoresistance (GMR) sensors for mapping the defects on a metal sheet. Before measurement, a spatially dependent calibration process was done to compensate for the inter-channel inconsistency in output offsets and responsivity. The calibrated 8-channel probe array exhibits high sensitivity in revealing tiny features of defects with superior spatial resolution. The proposed system allows for the visualization of the geometric characteristics of the surface defects with an inter-spacing of more than 2 mm. The suggested approach has great potential in the nondestructive testing of metallic sheets for the characterization of minor and intricately shaped flaws.