Detection algorithm for two air holes in underground using particle swarm optimization

We have considered the estimation algorithm using PSO for the detection of underground objects. Noting the cost functional measured scattered waves and calculated ones for the estimated parameters of the objects, we proposed the detection algorithm with PSO for an optimization problem that is minimized the functional. In order to raise a convergence of the algorithm to the optimal solution, we introduced modified update equations of PSO and a technique to narrow down estimation regions for the objects top rogressively. Furthermore, the method to maintain a variety of the swarm and the technique to avoid local minima are employed in the algorithm. For a case of two cylindrical air holes with circular cross sections, we estimate the location, radius, and relative permittivity of these holes. We also pay attention to the positional relationship between two holes in numerical calculation. Numerical results confirm the effectiveness of the proposed algorithm for the detection of the air holes in underground. Study on the numerical consideration for various buried objects remains a topic for future work.