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. Prior to measurement, a spatially-dependent calibration process was done to compensate the inter-channel inconsistency in responsivity and positioning. The calibrated 8-channel probe array exhibits high-sensitivity, which enables the detection of tiny feature with superior spatial resolution. The proposed system allows for the visualization of the geometric characteristics of the flaws with an inter-spacing of more than 2 mm on a copper sample. The suggested approach has great potential in nondestructive testing of metallic sheets for the characterization of small and intricate shape flaws.