3D Imaging of Buried Dielectric Targets with a Tomographic Microwave Approach Applied to GPR Synthetic Data

Alessandro Galli,Ilaria Catapano,Gianluca Gennarelli,Elena Pettinelli,Francesco Soldovieri,Davide Comite

doi:10.1155/2013/610389

Abstract

Effective diagnostics with ground penetrating radar (GPR) is strongly dependent on the amount and quality of available data as well as on the efficiency of the adopted imaging procedure. In this frame, the aim of the present work is to investigate the capability of a typical GPR system placed at a ground interface to derive three-dimensional (3D) information on the features of buried dielectric targets (location, dimension, and shape). The scatterers can have size comparable to the resolution limits and can be placed in the shallow subsurface in the antenna near field. Referring to canonical multimonostatic configurations, the forward scattering problem is analyzed first, obtaining a variety of synthetic GPR traces and radargrams by means of a customized implementation of an electromagnetic CAD tool. By employing these numerical data, a full 3D frequency-domain microwave tomographic approach, specifically designed for the inversion problem at hand, is applied to tackle the imaging process. The method is tested here by considering various scatterers, with different shapes and dielectric contrasts. The selected tomographic results illustrate the aptitude of the proposed approach to recover the fundamental features of the targets even with critical GPR settings.

Highlights

In a large variety of civil, forensic, geophysical, and planetary applications, ground penetrating radar (GPR) is used in standard configurations close to a ground interface with the aim of locating and imaging shallow-buried targets [1,2,3,4]
The depth slices of the reconstructed contrast functions in color-plot form are shown in Figure 6 for the cube and in Figure 7 for the sphere. These figures present 20 planar color plots corresponding to z values which regularly increase moving from the interface towards the bottom of the ground medium, with a spatial
A full 3D imaging has been attempted for dielectric targets, which can have dimensions comparable to the typical wavelengths of the signals and are buried in the shallow subsurface in near-field conditions

Summary

Introduction

In a large variety of civil, forensic, geophysical, and planetary applications, ground penetrating radar (GPR) is used in standard configurations close to a ground interface with the aim of locating and imaging shallow-buried targets [1,2,3,4]. The reliability of the reconstructed images to provide information on the geometrical and physical features of the targets (i.e., location, size, shape, and contrast) depends both on the amount and quality of the data available with GPR systems [1,2,3,4,5,6,7,8,9] and on the adopted imaging procedures, mostly based on the solution of inverse scattering problems [1,2,3,4, 10,11,12,13,14,15,16,17,18,19,20,21] In this context, the study presented here is focused on the assessment of the GPR technique to provide valid imaging performance, referring to the critical problem of reconstructing targets buried in shallow subsurface.

Objectives

Results

Conclusion