Calibration of SAR Polarimetric Images by Means of a Covariance Matching Approach

Villa, Alberto; Iannini, Lorenzo; Giudici, Davide; Guarnieri, Andrea Monti; Tebaldini, Stefano

doi:10.1109/tgrs.2014.2326955

Cited by 27 publications

(22 citation statements)

References 22 publications

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“…The polarimetric system model in the Villa method [7] is commenced from the general system model without the symmetry assumption of the radar system given in Equation 2. The covariance matrix of the expected observation [C] inv with the distortion parameters is then represented as:…”

Section: Villa Methodsmentioning

confidence: 99%

“…With the Hessian optimizer, the final estimatesf ,δ should be the result that most closely matches the expected covariance matrix [C] inv to the data covariance matrix using covariance matching technique [7].…”

Section: Villa Methodsmentioning

confidence: 99%

“…Ainsworth et al [6] further refined the Quegan method by iteratively solving the system equations with only the weakest of constraints. Recently, a calibration method based on the covariance matching estimation technique was proposed by Villa et al [7]. It provides a calibration method with numerical optimization, which permits distortion parameters to be obtained without symmetry assumptions of the radar system.…”

Section: Introductionmentioning

confidence: 99%

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Comparative Analysis of Polarimetric SAR Calibration Methods

Jung

Park

2018

Remote Sensing

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In the diverse applications of polarimetric Synthetic Aperture Radar (SAR) systems, it is a crucial to conduct polarimetric calibration, which aims to remove the radar system distortion effects prior to utilizing polarimetric SAR observations. The objective of this study is to evaluate the performance of different polarimetric calibration methods. Two widely used methods, the Van Zyl and Quegan methods, and one recently proposed method, such as the Villa method, have been selected among various calibration methods in literature. The selected methods have basic differences in their assumptions that are applied to the polarimetric system model. In order to evaluate the calibration performances under different system parameters and ground characteristics, comparative analysis of the calibration results were conducted on synthetic polarimetric SAR data and ALOS PALSAR quad-pol mode data. Based on the experimental results, the advantages and limitations of different methods were clarified, and a simple hybrid calibration method is presented to further improve the polarimetric calibration performance.

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Section: Villa Methodsmentioning

confidence: 99%

Section: Villa Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Comparative Analysis of Polarimetric SAR Calibration Methods

Jung

Park

2018

Remote Sensing

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“…The early PolCAL methods were designed using different kinds of corner reflectors (CRs) or polarimetric active radar calibrators (PARCs) [ 11 ]. Subsequently, some particular scattering targets such as bare soil, desert, and grassland have been investigated and taken as PolCAL references [ 12 , 13 , 14 ]. Rainforest has also been studied for PolCAL in some research [ 9 , 15 ].…”

Section: Introductionmentioning

confidence: 99%

Polarimetric Calibration and Quality Assessment of the GF-3 Satellite Images

Chang

Zhao

et al. 2018

Sensors

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Abstract:The GaoFen-3 (GF-3) satellite is the first fully polarimetric synthetic aperture radar (SAR) satellite designed for civil use in China. The satellite operates in the C-band and has 12 imaging modes for various applications. Three fully polarimetric SAR (PolSAR) imaging modes are provided with a resolution of up to 8 m. Although polarimetric calibration (PolCAL) of the SAR system is periodically undertaken, there is still some residual distortion in the images. In order to assess the polarimetric accuracy of this satellite and improve the image quality, we analyzed the polarimetric distortion errors and performed a PolCAL experiment based on scattering properties and corner reflectors. The experiment indicates that the GF-3 images can meet the satellite's polarimetric accuracy requirements, i.e., a channel imbalance of 0.5 dB in amplitude and ±10 degrees in phase and a crosstalk accuracy of −35 dB. However, some images still contain residual polarimetric distortion. The experiment also shows that the residual errors of the GF-3 standard images can be diminished after further PolCAL, with a channel imbalance of 0.26 dB in amplitude and ±0.2 degrees in phase and a crosstalk accuracy of −42 dB.

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“…These assumptions, especially the former, are difficult to satisfy; therefore, the ranges of application of these algorithms are limited. In the second group, the distortion matrix (DM) induced by the effects of system distortions and FR together is estimated; examples of such algorithms include one that uses the polarimetric orientation angle (POA) in build-up areas [6] and one that uses covariance matrix matching estimation techniques (COMET) [7]. Although…”

Section: Introductionmentioning

confidence: 99%

Equivalent system model for the calibration of polarimetric SAR under Faraday rotation conditions

Zhang

Hong

2017

Sci. China Inf. Sci.

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An equivalent system model (ESM) that can be used to calibrate a SAR system affected by both the effect of system errors and the Faraday rotation (FR) is proposed. This ESM contains only systemdistortion-like parameters but includes a distortion matrix (DM) that is identical to the original, which contains the effects of both the system errors and the Faraday rotation angle (FRA). With this model, the conventional distributed-target-based (DT-based) algorithms which have not taken FR effect into account are readily applicable. The conditions on FRA for the successful application of DT-based algorithms are studied, and the results suggest that reliable estimates can be obtained for a well-designed system whose true system crosstalk level is lower than −20 dB provided that the mean FRA at the calibration site is within ±15 • and that the FRA can be suitably modeled as Gaussian. Thus, the requirements on the crosstalk level or the FRA that are commonly employed in other calibration methods designed for data affected by FR are relaxed.

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Calibration of SAR Polarimetric Images by Means of a Covariance Matching Approach

Cited by 27 publications

References 22 publications

Comparative Analysis of Polarimetric SAR Calibration Methods

Comparative Analysis of Polarimetric SAR Calibration Methods

Polarimetric Calibration and Quality Assessment of the GF-3 Satellite Images

Equivalent system model for the calibration of polarimetric SAR under Faraday rotation conditions

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