Giancarlo Prisco

Three-Dimensional Through-Wall Imaging Under Ambiguous Wall Parameters

A through-wall imaging problem for a 3-D geometry is considered. Scatterers are located beyond a wall represented by a dielectric slab whose features are unknown or known with some degree of uncertainty. A two-step imaging procedure is presented. First, the thickness and the dielectric permittivity of the wall are estimated by a simple procedure which takes into account that actual measurements concern the total scattered field (i.e., the field reflected by the wall plus the one scattered by the obscured scatterers). Then, the problem is cast as a linear inverse scattering problem and solved by means of a truncated-singular value decomposition algorithm. In particular, a 2-D sliced approach is employed to obtain the 3-D scene. Numerical examples are shown to assess the effectiveness of the reconstruction procedure.

A Multiarray Tomographic Approach for Through-Wall Imaging

A through-wall imaging problem for a 2-D scalar geometry is addressed. It is cast as an inverse scattering problem and tackled under the linear Born model by means of the truncated singular value decomposition inversion scheme. A multiarray-based inversion strategy is considered. In particular, first the data collected by each single array are processed to obtain different tomographic images of the same scene under test. Then, the different images are suitably combined to obtain the overall image. The inversion scheme is tested for the challenging case of objects located within a complex environment resembling a room in a building.

A Kirchhoff-Based Shape Reconstruction Algorithm for the Multimonostatic Configuration: The Realistic Case of Buried Pipes

A shape reconstruction algorithm is formulated for the multimonostatic configuration and the 2-D geometry. The imaging algorithm is based on the Kirchhoff approximation, works in the frequency domain, and exploits the singular value decomposition tool to achieve a stable solution. The effectiveness of the reconstruction algorithm is shown by processing synthetic data in the time domain generated via a finite-difference time-domain code. A performance analysis of the solution algorithm is addressed with varying host medium and measurement configurations, also by processing synthetic data for a 3-D geometry. Finally, an experimental validation of the technique is performed due to data collected by a time-domain ground-penetrating radar for buried pipe detection and localization.

Three-Dimensional Microwave Tomography by a 2-D Slice-Based Reconstruction Algorithm

This letter deals with the problem of imaging 3-D strong scatterers by means of a 2-D slice tomographic reconstruction algorithm. More in detail, the inversion algorithm is based on two steps. In the first step, 2-D slices of the object are reconstructed; then, they are superimposed and interpolated to achieve the 3-D representation of the object. The Kirchhoff approximation is exploited to develop a linear inversion scheme for reconstructing the 2-D slices for scatterers embedded in the free space. Finally, the inversion algorithm is checked against synthetic data for the interesting case of scatterers resembling the human body.

A Reconfigurative Approach for SF-GPR Prospecting

We study the impedance parameters and the energy transmitted and received by a couple of antennas working in a nonhomogeneous background. The focus is on stepped frequency ground penetrating radar (SF-GPR) prospecting. In particular, we propose a reconfiguration of the GPR system versus the frequency that accounts for the background scenario, and we show that the reconfiguration can improve the frequency behavior of the antennas significantly. Tests performed on two bow-tie antennas will be shown.

DESIGN OF A RECONFIGURABLE ANTENNA FOR GROUND PENETRATING RADAR APPLICATIONS

This paper deals with the design and numerical analysis of a reconflgurable antenna implemented according to the total geometry morphing approach. The reconflgurable antenna is designed so to resemble a reference bowtie antenna, suitable for a stepped frequency Ground Penetrating Radar (GPR) applications, with geometry variable in order to work in difierent operative conditions. In particular, the good agreement between the reference antenna and the reconflgurable one is tested within the work frequency band 0.3{ 1GHz for both the free-space and half-space geometry. Finally, a trial of the reconflgurability of the proposed solution is shown for operative conditions with antenna in contact with difierent dielectric media.

Determination of soil permittivity from GPR data and a microwave tomography approach: a preliminary study

In this paper we present a new strategy to retrieve the dielectric permittivity of the soil starting from B-Scan GPR data, gathered on a pipe buried on purpose and processed by means of a microwave tomography algorithm. The validation will be performed by making use of synthetic data, obtained from an FDTD code. The results of the proposed approach shall be compared with those achieved from the hyperbolas of the radar traces and from the Hough Transform based approach.

Intra-wall diagnostics via a microwave tomographic approach

The problem of diagnosing the internal status of a masonry structure by means of a non-destructive electromagnetic technique, based on a microwave tomographic imaging algorithm, is dealt with. The study is first developed through numerical arguments under a two-dimensional scalar geometry. Then, the microwave imaging algorithm is checked against experimental data collected in situ at the Carmine’s church belfry in Naples, Italy, by means of a ground penetrating radar system. The features of two different methods for clutter removal are also discussed.

Experimental validation of a Kirchhoff based shape reconstruction algorithm in realistic conditions: a test case for buried pipes

A two dimensional shape reconstruction algorithm is applied to experimental GPR in-situ measurement data. The reconstruction algorithm is based on the Kirchhoff approximation and is exploited to process data collected under a multimonostatic configuration by a pulsed GPR. Thus the need to pass from time domain measurements to frequency domain data suitable for the inversion algorithm is also addressed.