2,001 research outputs found
Remembering Matteo Pastorino [In Memoriam]
No full textRecounts the career and contributions of (Matteo Pastorino)
Advanced Inversion Techniques for Ground Penetrating Radar
No full textGround Penetrating Radar (GPR) systems arenowadays standard inspection tools in several application areas, such as subsurface prospecting, civil engineering and cultural heritage monitoring. Usually, the raw output of GPR isprovided as a B-scan, which has to be further processed inorder to extract the needed information about the inspectedscene. In this framework, inversescattering-based approachesare gaining an ever-increasing interest, thanks to their capabil-ities of directly providing images of the physical and dielectricproperties of the investigated areas. In this paper, some advances in the development of such inversion techniques in theGPR field are revised and discussed.</jats:p
Experimental validation of a novel Gauss-Newton inversion method for microwave tomographic imaging
No full textMicrowave imaging systems are acquiring an ever growing importance. In order to tackle the nonlinearity and illposedness of the underlying inverse scattering problems, several inversion approaches have been formulated in the scientific community. In this framework, an efficient Gauss-Newton method, based on a regularization in Banach spaces, has been recently developed and numerically tested. In this paper, an experimental validation of the approach using real data is provided
A two-step multifrequency imaging technique for ground penetrating radar
No full textIn the present paper, a combined method for ground penetrating radar imaging is presented. The proposed technique has a first step in which the electric field scattered by the buried structure is estimated and a qualitative reconstruction is obtained, and a second quantitative inversion step for reconstructing the dielectric properties of the buried targets. The full-wave multifrequency inexact-Newton inversion approach used in the second step uses the information about the target position extracted by the qualitative procedure and takes the scattered field data estimated by a time-domain filtering method. Numerical simulations are presented to prove the effectiveness of the proposed technique
Electromagnetic biomedical imaging in Banach spaces: A numerical case study
No full textThis paper reports the results of the application of a microwave imaging method developed in Banach spaces to a model of human head in presence of a hemorrhagic brain stroke. The approach is based on the integral equations of the inverse scattering problem. A Gauss-Newton scheme is adopted as a solving procedure. Being developed in Banach spaces, the method turns out to be quite efficient in reducing the over-smoothing effects usually associated to
Hilbert-space reconstructions. Numerical simulations are reported involving a realistic model of human head
banach spaces and multifrequency processing
No full textThe reconstruction of the distributions of the dielectric properties of unknown targets by using interrogating microwaves is a topic that has been widely investigated by the scientific community in the last years (M. Pastorino, Microwave imaging, John Wiley, 2010). In this framework, the present authors have developed an approach based on an inexact Newton method (C. Estatico et al., IEEE Trans. Antennas Propag., 60, 2012, pp. 3373-3381), which has been found to be quite efficient in finding a regularized solution of the associated electromagnetic inverse scattering problem with a spatial resolution beyond the Rayleigh limit (since it is developed in the spatial domain)
Electron heating in subpicosecond laser interaction with overdense and near-critical plasmas
No full textn this work we investigate electron heating induced by intense laser interaction with micrometric flat solid
foils in the context of laser-driven ion acceleration. We propose a simple law to predict the electron temperature in
a wider range of laser parameters with respect to commonly used existing models. An extensive two-dimensional
(2D) and 3D numerical campaign shows that electron heating is due to the combined actions of j×B
and Brunel effect. Electron temperature can be well described with a simple function of pulse intensity and angle of incidence,
with parameters dependent on pulse polarization. We then combine our model for the electron temperature with
an existing model for laser-ion acceleration, using recent experimental results as a benchmark. We also discuss
an exploratory attempt to model electron temperature for multilayered foam-attached targets, which have been
proven recently to be an attractive target concept for laser-driven ion acceleration
Full-waveform inversion of Ground Penetrating Radar data for target characterization in multilayer environments
No full textIn the last decades, ever growing efforts have been devoted to the development of techniques for extracting information from Ground Penetrating Radar (GPR) measurements. In particular, the processed data are used to retrieve two different kinds of features. The first kind includes the socalled qualitative properties of buried targets, which are typically related to the location and/or the shape of the objects. The second kind of features is related to the quantitative dielectric characterization of the underground targets. Both strengths and weaknesses of qualitative and quantitative approaches are well known in the scientific community. Despite the more complex mathematical structure of quantitative techniques, their use is attracting an increasing attention in
multiple geophysical and engineering applications. In this contribution, the full dielectric characterization of the region of interest is retrieved by a
quantitative inversion approach that works in the mathematical framework of Lebesgue spaces with variable exponents. The most important parameter of this algorithm is represented by the map of the exponent function inside the investigation domain. Here, different strategies for obtaining and refining this map in an adaptive fashion iteration-by-iteration are proposed. Numerical results are presented to check the effectiveness of the inversion approach
A through-the-wall imaging procedure based on a Lebesgue-space inversion method
No full textA novel through-the-wall imaging method is presented in this paper. The approach is based on a linearized scattering
model, which is inverted by means of an efficient algorithm performing a regularization in the framework of Lebesgue
spaces. Some preliminary numerical results are reported for assessing the capabilities of the approach
Effect of data noise on LSTM-FC scattered-field processing for microwave imaging
No full textA strategy to mitigate model error in microwave imaging by introducing a neural-network-based preprocessing of the scattered field is considered in this paper. In particular, the approach consists of a long short-term memory (LSTM) cell combined with fully-connected (FC) neural layers. Such a network, which works in the time domain, aims at extracting the scattered field contributions as they were measured by a canonical two-dimensional setup with line-source antennas and ideal probing elements. The extracted data are then given in input to a quantitative tomographic technique formulated in the mathematical context of Lebesgue spaces with variable exponents. Here, the effect of input data noise on the whole imaging procedure is evaluated for the first time. Results obtained on simulated data involving circular dielectric cylinders are presented to assess the processing error and the imaging performance against the signal-to-noise ratio
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