Evaluation of an Electrical Impedance Tomography Model for Underwater Object Detection

Underwater detection and localization measurement systems gained more importance in recent years. E.g., partly buried objects like high-voltage power cables must be identified and localized reliably. The concept of Electrical Impedance Tomography (EIT) focuses on the current flow between sets of two source electrodes. Changes in the transmission medium's conductivity based on inhomogeneous objects lead to impedance variances that influence the current flow and therefore the measured electric potentials. By activating multiple sets of source electrodes iteratively, an characterization of the environment in a dedicated observation area is created. Multiphysics simulations are able to model these potential measurements. But the quality of the model is still an open question. In this work, we model a 3-dimensional EIT array of 20 electrodes overall, divided in distinct sets of ten source and measurement electrodes each. We derive the theoretical background and simulate the current flow, which is analyzed to determine the resulting electric potential at the measurement electrodes without and with a copper cylinder in the observation area. The cylinder is able to influence the simulation results and leads to significant object position indications based on the changes of the measured potentials. Also, the model depicts the increasing distance between cylinder and EIT array correctly, since the influence on the potential measurements is decreasing.