Multitemporal C- and L-band polarimetric signatures of crops

Skriver, Henning; Svendsen, M.T.; Thomsen, Anne Belinda

doi:10.1109/36.789639

Cited by 121 publications

(81 citation statements)

References 21 publications

(42 reference statements)

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“…For NDVIs higher than 0.4, Δ˚ saturates below 0.1 dB.˚− 1 whatever the crop type, the radar frequency and the polarization. The variation of angular response along with crop growth confirms and generalizes the observations that were made in previous studies [22,50].…”

Section: −3supporting

confidence: 80%

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Monitoring Wheat and Rapeseed by Using Synchronous Optical and Radar Satellite Data—From Temporal Signatures to Crop Parameters Estimation

Fieuzal¹,

Baup²,

Marais-Sicre³

2013

ARS

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This paper investigates the sensitivity of multi-temporal SAR data acquired at different frequencies (X-, C-and L-bands), polarizations (HH, VV, VH and HV) and incidence angles (from 24˚ to 53˚) during the growing season of two winter crops (rapeseed and wheat). This study was part of a multi-sensor crop-monitoring experiment that was performed from February to November 2010 (MCM'10). During the experiment, dense series of satellite data were acquired in microwave, optical and thermal domains (more than 150 images were provided by TerraSAR-X, Radarsat-2 Alos, Formosat-2, Spot-4/5 and Landsat-5/7) were synchronous with ground measurements over an agricultural area located in southwestern France, near Toulouse. An angular normalization of radar signals is first performed for each crop type at X-and C-bands by using a dense temporal satellite series and the complementarity provided by microwave and optical data. The results show that the angular sensitivity of radar backscatter decreases with the increase of the vegetation index (from 0.4 dB.˚− 1 over bare soils to 0.05 dB.˚− 1 for fully vegetated fields). Lower angular sensitivity is observed at X-band (compared to C-band), and for the cross-polarized signal. Analyses of the temporal signatures of the radar backscatter show a well-marked signal dynamic at X-, C-and L-bands, depending on the crops and theirs associated phenological stages. During the stems elongation of wheat while the NDVI increases of 0.2, a dynamic of 10 dB is observed at X-band and at C-band with VV polarization. Interesting behaviors are also observed during the crop senescence with an increase of several dB (depending on the sensor configuration), while the NDVI decreases of 0.5. Over rapeseed, cross-polarized backscatters offer promising dynamic of 6 dB during the seed development, while the NDVI saturates at maximum values. The use of radar signals, in complement of optical, for crop parameters monitoring is achieved in terms of leaf area index and crop height estimations. Over rapeseed, best correlations between crop parameters and radar signals are obtained at C-band, by combining co-and cross-polarized backscatters (R 2 > 0.61). Over wheat, best results are achieved by using X-band data (R 2 > 0.64).

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Section: −3supporting

confidence: 80%

“…Previous studies have shown the strong influence of incidence angle on backscattering coefficients during particular crop stages for contrasted soil conditions [16,22,24,50].…”

Section: Angular Normalization Of Sar Backscattersmentioning

confidence: 99%

Monitoring Wheat and Rapeseed by Using Synchronous Optical and Radar Satellite Data—From Temporal Signatures to Crop Parameters Estimation

Fieuzal¹,

Baup²,

Marais-Sicre³

2013

ARS

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“…Single-date multi-polarization SAR data also has the potential to identify crops based on the variation in their scattering signatures in different polarizations. Various authors have reported of achieving significant classification accuracies for crops and other landuse classes using dual and quad polarimetric data from airborne as well as spaceborne SARs [1,6,7,23,24,26]. Although there is a consensus that full-polarimetric imaging modes provide higher classification accuracies than dual polarimetric modes, opinions vary regarding the classification accuracies obtained by different modes of dual polarimetric SARs, including hybrid-dual polarimetric imaging modes.…”

Section: Introductionmentioning

confidence: 99%

Assessment of L-Band Sar Data at Different Polarization Combinations for Crop and Other Landuse Classification

Haldar¹,

Das²,

Mohan³

et al. 2012

PIER B

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Abstract-In the present study evaluation of L-band SAR data at different polarization combinations in linear, circular as well as hybrid polarimetric imaging modes for crop and other landuse classifications has been carried out. Full-polarimetric radar data contains all the scattering information for any arbitrary polarization state, hence data of any combination of transmit and receive polarizations can be synthesized, mathematically from full-polarimetric data. Circular and various modes of hybrid polarimetric data (where the transmitter polarization is either circular or orientated at 45 • , called π/4 and the receivers are at horizontal and vertical polarizations with respect to the radar line of sight) were synthesized (simulated) from ALOS-PALSAR fullpolarimetric data of 14th December 2008 over central state farm central latitude and longitude 29 • 15 N/75 • 43 E and bounds for northwest corner is 29 • 24 N/75 • 37 E and southeast corner is 29 • 07 N/75 • 48 E in Hisar, Haryana (India) Supervised classification was conducted for crops and few other landuse classes based on ground truth measurements using maximum-likelihood distance measures derived from the complex Wishart distribution of SAR data at various polarization combinations. It has been observed that linear fullpolarimetric data showed maximum classification accuracy (92%) followed by circular-full (89%) and circular-dual polarimetric data (87%), which was followed by hybrid polarimetric data (73-75%) and then linear dual polarimetric data (63-71%). Among the linear dual polarimetric data, co-polarization complex data showed better classification accuracy than the cross-polarization data. Also multidate single polarization SAR data over central state farm during rabi (winter) season was analyzed and it was observed that single date fullpolarimetric SAR data produced equally good classification result as the multi-date single polarization SAR data.

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“…From Section IV-C we have that connection filter resulting in MLE is chosen from the set of possible connection filters iff (26) The overall most likely connection filter is the filter where the neighboring CMs result in the overall highest probability (26), and these values are found by solving the log likelihood equation . To be able to solve this equation, we need to introduce a constraint.…”

Section: Bias Of the Mean CM Estimatementioning

confidence: 99%

Restoration of polarimetric SAR images using simulated annealing

Schou

Skriver²

2001

IEEE Trans. Geosci. Remote Sensing

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Abstract-Filtering synthethic aperture radar (SAR) images ideally results in better estimates of the parameters characterizing the distributed targets in the images while preserving the structures of the nondistributed targets. However, these objectives are normally conflicting, often leading to a filtering approach favoring one of the objectives. An algorithm for estimating the radar cross-section (RCS) for intensity SAR images has previously been proposed in the literature based on Markov random fields and the stochastic optimization method simulated annealing. A new version of the algorithm is presented applicable to multilook polarimetric SAR images, resulting in an estimate of the mean covariance matrix rather than the RCS. Small windows are applied in the filtering, and due to the iterative nature of the approach, reasonable estimates of the polarimetric quantities characterizing the distributed targets are obtained while at the same time preserving most of the structures in the image. The algorithm is evaluated using multilook polarimetric L-band data from the Danish airborne EMISAR system, and the impact of the algorithm on the unsupervised -classification is demonstrated.

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Multitemporal C- and L-band polarimetric signatures of crops

Cited by 121 publications

References 21 publications

Monitoring Wheat and Rapeseed by Using Synchronous Optical and Radar Satellite Data—From Temporal Signatures to Crop Parameters Estimation

Monitoring Wheat and Rapeseed by Using Synchronous Optical and Radar Satellite Data—From Temporal Signatures to Crop Parameters Estimation

Assessment of L-Band Sar Data at Different Polarization Combinations for Crop and Other Landuse Classification

Restoration of polarimetric SAR images using simulated annealing

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