Non-destructive evaluation of small defects using an eddy current microcoil sensor array

EC sensors are widely used for non-destructive defect detection and characterization. Microsensor arrays permit to increase the rapidity and the reliability of the detection as well as to get richer data, in order to facilitate the defect characterization. In this paper, a multicoil sensor array is used in a predefined transmission-reception scheme and the EC signals are parametrized in the complex plan. Then parameters are selected and processed in order to estimate the dimensions of each defect. The mean quadratic error is inferior to 70 m in length and 30 m in depth for surface breaking submillimetric defects.