3D interferometric ISAR imaging of noncooperative targets Martorella, Marco; Stagliano, Daniele; Salvetti, Federica ...
IEEE transactions on aerospace and electronic systems,
2014-October, 2014-10-00, 20141001, Letnik:
50, Številka:
4
Journal Article
Recenzirano
Inverse synthetic aperture radar (ISAR) images are frequently used in target classification and recognition applications. Nevertheless, the interpretation of ISAR images remains problematic for ...several reasons. One of these is the fact that the image plane cannot be defined by the user but instead depends on the target's own motions and on its relative position with respect to the radar. In order to overcome the problem of interpreting two-dimensional (2D) ISAR images, a method for three-dimensional (3D) reconstruction of moving targets is presented. This method is based on the use of a dual interferometric ISAR system. The interferometric phases measured from two orthogonal baselines are used to jointly estimate the target's effective rotation vector and the heights of the scattering centers with respect to the image plane. The scattering center extraction from the ISAR image is performed by applying a multichannel CLEAN technique. Finally, a 3D image of the moving target is reconstructed from the 3D spatial coordinates of the scattering centers. The effectiveness and robustness of the proposed algorithm is first proven theoretically and then tested against several radar-target scenarios as well as in the presence of noise.
Three-dimensional ISAR imaging: a review Martorella, Marco; Salvetti, Federica; Staglianò, Daniele ...
Journal of engineering (Stevenage, England),
October 2019, Letnik:
2019, Številka:
20
Journal Article
Recenzirano
Odprti dostop
Three-dimensional (3D) inverse synthetic aperture radar (ISAR) imaging has been proven feasible by combining traditional ISAR imaging and interferometry. Such technique, namely inteferometric ISAR ...(In-ISAR), allows for the main target scattering centres to be mapped into a 3D spatial domain as point clouds. Specifically, the use of an In-ISAR system can overcome the main geometrical interpretation issues imposed by the monostatic acquisition geometry as the problem of cross-range scaling and unknown image projection plane (IPP). However, some issues remain such as scatterer scintillation, shadowing effects, poor SNR etc., which limit the effectiveness of 3D imaging. A solution to such unsolved issues can be found in the use of multiple 3D views, which can be obtained exploiting either multi-temporal or multi-perspective configurations or a combination of both. This study aims to review the main concepts to produce multi-view 3D ISAR images by using In-ISAR systems also presenting real data collected with a multi-static In-ISAR system.
Three-dimensional (3D) inverse synthetic aperture radar (ISAR) imaging has been proven feasible by combining traditional ISAR imaging and interferometry. Such technique, namely Inteferometric ISAR ...(InISAR), allows for the main target scattering centers to be mapped into a 3-D spatial domain, therefore forming 3-D images under the form of 3-D point clouds. 3-D InISAR overcomes some main limitations of traditional 2-D ISAR imaging, such as the problem of cross-range scaling and unknown image projection plane. Despite the great advantage of 3-D imaging over traditional 2-D imaging, some issues remain, such as scatterer scintillation, shadowing effects, poor SNR, etc., which limit the effectiveness of 3-D imaging. A solution to these issues can be found in the use of multiple 3-D views, which can be obtained exploiting either multitemporal or multiperspective configurations or a combination of both. This paper proposes this concept and develops the image fusion algorithms that are necessary to produce multiview 3-D ISAR images. The effectiveness of the proposed technique is tested by using real data collected with a multistatic InISAR system.
This study reports on a novel technique for the estimation of the target total rotational velocity of a non-cooperative target. The technique makes use of the second-order local polynomial Fourier ...transform to estimate the hitherto unknown component of the velocity vector in the radar line-of-sight direction, and three-dimensional (3D) interferometric inverse synthetic aperture radar (ISAR) imaging the target. The aspect-independent 3D size and shape of a target – an important metric for automatic target recognition – can thus be estimated. Cross-range focus in the component 2D ISAR images is also improved in the process. Results obtained from extensive simulations demonstrate the feasibility of the proposed approach.
Rating and quantification of cerebral white matter hyperintensities on magnetic resonance imaging (MRI) are important tasks in various clinical and scientific settings. As manual evaluation is time ...consuming and imprecise, much effort has been made to automate the quantification of white matter hyperintensities. There is rarely any report that attempts to study the similarity/dissimilarity of white matter hyperintensity patterns that have different sizes, shapes and spatial localizations on the MRI. This paper proposes an original computational neuroscience framework for such a conceptual study with a standpoint that the prior knowledge about white matter hyperintensities can be accumulated and utilized to enable a reliable inference of the rating of a new white matter hyperintensity observation. This computational approach for rating inference of white matter hyperintensities, which appears to be the first study, can be utilized as a computerized rating-assisting tool and can be very economical for diagnostic evaluation of brain tissue lesions.
InISAR imaging has proven an effective tool to produce 3D target reconstruction. 3D target reconstruction solves the problems related to the ISAR image interpretation, due to the unknown target's ...projection onto the image projection plane. Nevertheless, problems related to shadowing are not solved as scatterers that are not visible cannot be detected and located in a 3D coordinate system. To overcome this problem, a multistatic InISAR system is introduced. A method for multistatic 3D target reconstruction that is based on an incoherent technique is proposed and analysed.
It has recently been demonstrated that Interferometric ISAR is able to reconstruct 3D point-like target images. However, such 3D reconstructions are generally composed of a small amount of points as ...the number of scatterers that can be accurately extracted from the received signal and placed in a 3D space is limited by the SNR associated to each of them. This lack of information may cause difficulties for targets identification and classification. To overcome this issue, a 3D reconstruction method based on the use of multi-temporal and multistatic data that makes use of an incoherent 3D image fusion technique is presented in this paper.
We report on a new technique for the estimation of the total rotational velocity of a non-cooperative target using a single interferometric ISAR system. It uses 3D interferometric ISAR techniques to ...obtain a first estimate of the scatterers' positions and effective rotation vector. Then the second-order local polynomial Fourier transform (LPFT) is applied to estimate the second component of the total rotation vector, and therefore the total vector itself. The true three-dimensional size and shape of a target - an important metric for automatic target recognition - can thus be estimated. Cross-range resolution in the 2D ISAR images is also improved in the process.
Inference of white matter hyperintensities of the brain on magnetic resonance imaging data can be a useful and economical tool for the pre-screening of mental diseases and their associated disorders. ...We present in this paper an improved computational model for the grouping of similar patterns of white matter hyperintensities. Experimental results have shown that the use of the proposed model can improve the inference system.
Summary Background Our previous study in patients with cerebellar ataxias of different causes showed significant benefit of riluzole after 8 weeks. We aimed to confirm these results in patients with ...spinocerebellar ataxia or Friedreich's ataxia in a 1-year trial. Methods Patients with spinocerebellar ataxia or Friedreich's ataxia (2:1 ratio) from three Italian neurogenetic units were enrolled in this multicentre, double-blind, placebo-controlled trial, and randomly assigned to riluzole (50 mg orally, twice daily) or placebo for 12 months. The randomisation list was computer-generated and a centralised randomisation system was implemented. Participants and assessing neurologists were masked to treatment allocation. The primary endpoint was the proportion of patients with improved Scale for the Assessment and Rating of Ataxia (SARA) score (a drop of at least one point) at 12 months. An intention-to-treat analysis was done. This trial is registered at ClinicalTrials.gov , number NCT01104649. Findings Between May 22, 2010, and Feb 25, 2013, 60 patients were enrolled. Two patients in the riluzole group and three in the placebo group withdrew their consent before receiving treatment, so the intention-to-treat analysis was done on 55 patients (19 with spinocerebellar ataxia and nine with Friedreich's ataxia in the riluzole group, and 19 with spinocerebellar ataxia and eight with Friedreich's ataxia in the placebo group). The proportion with decreased SARA score was 14 (50%) of 28 patients in the riluzole group versus three (11%) of 27 in the placebo group (OR 8·00, 95% CI 1·95–32·83; p=0·002). No severe adverse events were recorded. In the riluzole group, two patients had an increase in liver enzymes (less than two times above normal limits). In two participants in the riluzole group and two participants in the placebo group, sporadic mild adverse events were reported. Interpretation Our findings lend support to the idea that riluzole could be a treatment for cerebellar ataxia. Longer studies and disease-specific trials are needed to confirm whether these findings can be applied in clinical practice. Funding Agenzia Italiana del Farmaco.
PDF
