Non conducting object detection using low frequency electric field imaging: Possible application to anomaly detection in insulating materials

This paper deals with the detection of non conducting objects by 2D-scanning of electric field variations. The principle relies on the measurement of the perturbations of a low frequency excitation electric field induced by the polarization of the object to be detected. These perturbations are measured thanks to an electric sensor and the excitation field is provided by a pair of electrodes. Finite elements method simulations are shown which illustrate the expected response of the system. The experimental setup is based on a horizontal planar (x-y) scanning table and on a synchronous detector locked at the excitation frequency. Images of the in-phase component of the vertical (z-axis) component of the electric field are obtained for two objects. These resulting images are discussed, allowing to expect further reconstruction of the non conducting objects shapes.