Microwave Imaging of Multiple Dielectric Objects by Fdtd and Apso

An imaging approach to clear detection of two-dimensional geometries is proposed in this paper. The imaging reconstruction of multiple dielectric objects is retrieved by finite difference time domain (FDTD) method and the asynchronous particle swarm optimization (APSO) to determine the shape, location and permittivity of each dielectric object. The forward problem is solved based on the subgrid FDTD method by using EM pulse to illuminate the dielectric object. In order to reduce the number of the unknown parameters for the imaging problem, the shape function of the object is interpolated in terms of the cubic spline. The inverse problem is resolved by an optimization approach, and the global searching scheme APSO is then employed to search the parameter space. Numerical results demonstrate that, even when the initial guess is far away from the exact one, good reconstruction can be obtained.