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This paper deals with microwave tomography for brain stroke imaging using state-of-the-art numerical modeling and massively parallel computing. Iterative microwave tomographic imaging requires the solution of an inverse problem based on a minimization algorithm (e.g. gradient or Newton-like methods) with successive solutions of a direct problem. The solution direct requests an accurate modeling of...
In this paper, we present quantitative image reconstructions (i.e. permittivity and conductivity profiles) from synthetic and experimental data. First, we perform the qualitative imaging for localizing the target in order to determine the investigation domain. Second, we solve the inverse-scattering problem via an iterative algorithm based on a Conjugate Gradient (CG) method.
In this paper, we present the results of image reconstructions of foreign object debris (FOD) based on 2D algorithms in the W-band (75–110 GHz). To test the feasibility of using 2D reconstruction algorithms, we first studied the relevance of two-dimensional assumption in the working frequency band for different typical debris. Thanks to the short wavelength (2.7 to 4 mm), most debris can be considered...
For sake of simplicity and execution speed, many imaging algorithms are based on two-dimensional approaches. We present a study on the relevance and validity domain of two-dimensional approaches to detect debris on airport runways in W-band (75–110 GHz), taking into account polarization (both 2D-TM and 2D-TE). The study deals, first with objects in free-space, and second placed on runway in far field...
This paper presents a comparison study between a simple time-reversal algorithm (designed at LEAT) and the SEABED algorithm (designed at Kyoto University) with their application to multiple-target experiments. Data are collected with an eight element ultra-wideband antenna linear array connected to an eight port vector network analyzer, working in a frequency bandwidth starting from 1.5 GHz up to...
A shape-gradient optimization based on contour deformations by means of Level Set method is used for reconstructing 2-D and 3-D perfectly conducting objects electromagnetic imaging. A frequency hopping technique is applied during the inverse scattering procedure for first locating the objects and reconstruct them roughly, then with higher frequencies to allow finer details to be retrieved. The numerical...
This paper presents detection and imaging capabilities of a simple time-reversal focusing algorithm, applied to experimental data that are obtained under various radar scene configurations (single- or multiple-target in free-space or through-the-wall). Data are collected with the ultra-wideband surface penetrating radar SIMIS (synthetic-impulse microwave imaging system, designed in LEAT) which operates...
Comparison of different techniques for short-range UWB radar imaging has been performed based on experimental data. To acquire experimental data, a video-impulse radar with a specially developed antenna system with a single transmitter antenna and an array of receiver antennas has been used. Topology of the receiver array was made in such a way that the footprint of the receiver array does not have...
The development of SIMIS (Synthetic Impulse Microwave Imaging System), a microwave array of eight ultra-wideband Vivaldi-type ETSA antennas, employed to image unknown targets situated in an anechoic chamber, is presented. Real scattering data, collected via an RF multiplexer interfaced to a vector network analyzer, is imaged using the Time Reversal Method. The imaging algorithm is applied to the scattered...
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