Manuela Maffongelli

Impact of Background Noise on Dielectric Reconstructions Obtained by a Prototype of Microwave Axial Tomograph

This paper investigates the influence of noise on a microwave axial tomograph developed by some of the authors for the inspection of dielectric objects. In particular, the impact of the measurement environment is considered and the images obtained from data measured in a controlled and an uncontrolled environment are presented and compared. Moreover, the effects of interference signals are considered. Accordingly, several experimental results are reported and discussed in terms of proper error parameters.

A Microwave Tomographic System for Wood Characterization in the Forest Products Industry

Abstract Nondestructive testing and evaluation techniques able to extract information about the internal structure of the samples under test are very important in the wood industry. Microwave imaging systems have been considered for a long time promising apparatuses for this task. In this framework, approaches exploiting the full scattering phenomena for creating images of the distributions of the dielectric properties of the targets have been developed in the last few years. In this paper, a prototype of microwave tomographic system is presented and several experimental validation confirming its suitability for the use in the wood and forest product industry are reported.

Preliminary test of a prototype of microwave axial tomograph for medical applications

An existing prototype of microwave imaging tomograph, previously designed by the present Authors for non destructive testing (NDT) applications, has been adapted in order to deal with biomedical targets. The developed system allows collecting multi-view multi-frequency data. An efficient inversion procedure is used to retrieve the distributions of the dielectric properties from the measured field samples. Some numerical simulations aimed at validating the proposed system and preliminary measurement results obtained by using a breast phantom are presented in this paper.

Reconstruction of Metallic Inclusions Inside Dielectric Targets by Means of a Microwave Tomographic System

Experimental results concerning the inspection at microwave frequencies of wood material with metallic inclusions are reported. They have been obtained by inverting samples of the scattered electromagnetic field collected by a prototype of an imaging system. The system is able to acquire multi-illumination multiview data in a tomographic arrangement. The retrieved maps of the dielectric permittivity and electric conductivity of the cross sections of unknown targets are obtained by applying the distorted-wave Born approximation to the electric field integral equation governing the scattering phenomenon.

Experimental evaluation of a prototype of a microwave imaging system

This paper investigates the effects of noise and interferences on the reconstruction quality of the dielectric parameter distributions provided by a prototype of a microwave tomograph. In particular, the reconstructions obtained starting from electric field measurements collected in a standard environment and in an anechoic chamber are compared in order to evaluate the impact of reflections of the interrogating electromagnetic waves from the objects surrounding the tomograph and the consequences of standard interferers, such as UMTS signals.

Imaging of dielectric targets with metallic inclusions by means of a prototype of microwave axial tomograph

Microwave systems are becoming powerful tools for imaging applications. In fact, when designed by taking into account the full scattering phenomena, they are able to directly provide information about the physical properties of the target under test. In this paper, the possibility of detecting metallic inclusions inside dielectric objects is assessed by using a prototype of a microwave axial tomograph, which is able to create images of the dielectric permittivity and of the electric conductivity of the inspected target.