Eddy Current Imaging for Material Surface Mapping

Abstract

For most nondestructive inspections, quantitative evaluations have to be performed to correlate the measured signals and the desired material properties. In some applications, the relationship between the signals and the material parameters is simple and straightforward. An analytic mathematical function can be easily constructed and solved to describe the interaction. The inverse function also can be readily determined to transform the measured data into the desired information. In some cases, such as defect characterizations, the interaction between the sensing field and the test object is often too complicated for such an approach. Advanced signal analysis techniques with complex assumptions, approximations, and computations are required to interpret the signals. Such an intricate approach is frequently time consuming and beyond general comprehension. Alternative methods that enable the direct correlation of the signals with the test piece are being sought. Imaging techniques which provide a unique capability of correlating NDE signals with component geometry, are gaining in popularity.