NEW STRUCTURE OF EDDY-CURRENT TRANSDUCER AND ALGORITHM FOR MEASURING METAL ELECTRICAL AND MAGNETIC-PROPERTIES

This paper describes a new structure for eddy-current transducers whic h improves sensitivity while maintaining high lateral resolution. We h ave developed an analytical model to allow a model-based inversion fro m transducers signals to estimate thick and homogeneous plates electri cal conductivity, magnetic permeability and/or lift-off. The inversion procedure is described and shows the possibility of a precise simulta neous estimation of the three parameters. Experiments were conducted w ith magnetic and non magnetic metals.