Three-dimensional ground-penetrating radar imaging through multilayered subsurface

Most of existing ground-penetrating radar (GPR) imaging algorithms are only capable of imaging of targets under a single-layer subsurface. In this paper, a generalized three-dimensional (3-D) fast imaging algorithm for GPR imaging of targets buried under multilayered subsurface is presented. The exploding reflection model is employed to simplify the imaging algorithm, and then the layered media dyadic Green's function is expanded in spectral form to facilitate the easy implementation of the imaging algorithm with fast Fourier transform. The wave propagation effects through multilayered subsurface are efficiently taken into account and are properly compensated for in the imaging formulation through the multilayer media dyadic Green's function. The linearization of the inversion scheme and utilization of fast Fourier transform resolve the time-consuming challenge in 3-D GPR imaging and make the imaging algorithm suitable in several applications concerning the diagnostics of a large probed region. Representative numerical and experimental examples are presented to show the effectiveness and efficiency of the proposed algorithm for 3-D GPR imaging through multilayered media.