Imaging of Compact Objects Buried in Underwater Sediments Using Electrical Impedance Tomography

A detailed study is undertaken to investigate the performance and phenomenology of electrical impedance tomography for underwater applications. Experiments are performed in an aquarium tank filled with water and a sediment layer. A 64-electrode square array, appropriately scaled down in size, and a previously developed data acquisition system are used. An evaluation is conducted of the ability to detect compact objects buried at various depths in the sediment, with different horizontal separations, and at various vertical separations between the electrode array and the sediment layer. The objects include metallic and nonmetallic mine-like objects and inert ammunition projectiles, all appropriately scaled down in size. The effects of a number of other physical factors are studied, including sediment type, water turbidity and salinity, and object coating integrity and rusting.