APPLICATION OF A THREE-DIMENSIONAL TWO-WAY PARABOLIC EQUATION MODEL FOR RECONSTRUCTING IMAGES OF UNDERWATER TARGETS

A three-dimensional, two-way parabolic equation model developed for solving three-dimensional backscattering problems in previous work is applied incorporating a focus-marching procedure to study the image reconstructions for underwater targets. Intensive numerical simulations are performed in this paper. Targets in the water are formed by objects with simple shapes. The "experimental data" of the return signals from targets are simulated by the backscattered sound calculated at a short distance from the source. These simulated return signals are processed by reversing their phases, and numerically propagated back to the place of the targets. It is due to the conjugating process that the target image may be reconstructed with less deformation at a distance near the target surface. This realistic study demonstrates an encouraging technique that may be utilized for studying underwater target imaging in many sonar applications.