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In polarimetrie filters, the adjacent pixels in the same neighborhood are regarded as possessing similar scattering mechanism, and these pixels in the continuous window are usually selected to do the averaging process when filtering the central pixel. Considering the different similarity between each neighbor pixel and the central pixel, the averaging process is given by a new definition and used...
Polarimetric Synthetic Aperture Radar (PolSAR) images are an important source of information. Speckle noise gives SAR images a granular appearance that makes interpretation and analysis hard tasks. A major issue is the assessment of information content in these kind of images, and how it is affected by usual processing techniques. We study this problem from the classification accuracy viewpoint. Our...
SAR remote sensing has been expected as an efficient rice crop monitoring tool due to its flexible operability with wide swath. Though many researchers have intensively analysed the backscatter, there still exist non-negligible mysteries to extract physical parameters. To solve the problems, it is essential to conduct theoretical characterization of experimentally obtained radar backscatter from rice...
A simple target scattering model is developed integrating the shape factor and geometric randomness that are less influenced by the SAR configuration, dielectric properties of crop, and the underlying soil conditions, to describe the shape and statistical distribution of the targets, respectively. 47 fully polarimetric RADARSAT-2 images in FQ1W, FQ6W, FQ10W, FQ15W and FQ19W modes with different incidence...
Poyang Lake is the largest freshwater lake in China and one of the most important wetlands in the world. Vegetation, an important component of wetland ecosystems, is one of the main sources of the carbon in the atmosphere. The backscatter coefficients (HH, HV and VV), the Pope biophysical indices, the polarimetric parameters from Freeman-Durden decomposition, Cloude-Pottier decomposition, TSVM decomposition...
We propose to test model-based polarimetric decomposition techniques for robustness to variations in the underlying in-scene scattering mechanisms. The accuracy and robustness of the decomposition results are determined from simulated data sets. The simulation input parameters, e.g. volume scattering model, polarimetric signal-to-noise, etc., are known and thus provide the “ground truth” for comparison...
We challenge the often-made claim that fully polarimetric synthetic aperture radars (SARs) are beneficial for discriminating between mineral oil films and biogenic slicks. We conjecture that the results obtained from previous analyses of spaceborne polarimetric SAR data, which seem to show differences in the scattering mechanism between radar scattering from mineral oil films and biogenic slicks,...
In this paper, the recent advancement of PolSAR filtering is reviewed. Speckle filtering is a necessary procedure for most of PolSAR applications, to reduce speckle noise level and to form incoherent scattering by averaging coherency or covariance matrices of neighboring pixels. In this paper, we addressed several important but often ignored issues associated with PolSAR speckle filtering, and the...
Change detection in large urban areas is an application with increasing relevance. In this domain, Polarimetric SAR (PolSAR) sensors are receiving more attention recently. The enhanced polarimetric information provides useful features which can describe multi-temporal changes. In this work, we aim at introducing an approach for unsupervised change detection with focus on built-up areas that relies...
Classification is one of the most important applications and also key technology of Polarimetric SAR image interpretation, which mainly includes feature extraction and optimization of classifiers. For high resolution Polarimetric SAR images, the fine description and accurate classification becomes increasingly complex and difficult with a single feature or classifier. Thus, the selective ensemble...
We extend previous work in sparsity-regularized radar imaging to the case of multiple, coupled polarization channels. We demonstrate the ability to extract key canonical polarization signatures while emphasizing spatial sparsity and removing channel crosstalk. When the crosstalk is known, measured data can be decoupled prior to sparse imaging. However, the proposed incorporation of channel crosstalk...
The log-cumulants of the second and third order are widely used to determine the statistical model of PolSAR data. However, same values of these statistics could result from both the product model and the mixture model, which represent two different physical scenarios. In other words, there is an ambiguity between the texture and the mixture according to these statistics. In this work, the log-cumulant...
This paper proposes a new formulation for POLSAR incoherent target decomposition, which models the POLSAR image as a result of a two-stage process, i.e. assembly of coherent scatterers followed by spatial distribution of incoherent atom scatterers. This assembly-distribution forward model is described by a triple matrix multiplication while its inverse problem, the new target decomposition problem,...
A sensitivity of L-band SAR to an inundated area was examined for an application of rapid flood mapping. Based on a theoretical scattering model, an intensive comparison by using the various real spaceborne and airborne L-band SAR data obtained by ALOS-2 was conducted. A proposed time series approach plays an important role to improve an accuracy of flooding area extraction.
SAR remote sensing has been expected as an efficient rice crop monitoring tool due to its flexible operability with wide swath. Though many researchers have intensively analysed the backscatter, there still exist non-negligible mysteries to extract physical parameters. To solve the problems, it is essential to conduct theoretical characterization of experimentally obtained radar backscatter from rice...
This paper uses RADARSAT-2 quad Polarimetric Synthetic Aperture Radar (PolSAR) and TerraSAR-X dual polarimetric SAR data to monitor agriculture crop growth stages. Two RADARSAT-2 Fine Quad Wide (FQW) beam modes FQ2W and FQ10W, each of which has 5 sets of data, and 13 sets of Stripmap TerraSAR-X data were used in the study. Both RADARSAT-2 and TerraSAR-X PolSAR data were acquired in summer 2012 outside...
Scattering matrices (SVV, SHH, SVH, SHV) are calculated from numerical 3D solutions of Maxwell equations (NMM3D). Using the simulated scattering matrices, we compute the polarimetric speckle and the coherency matrix for Pol-SAR applications. Results from NMM3D are examined by the comparison with theoretical distributions, including amplitude, phase difference, and amplitude ratio. Surface roughness...
In this paper, the scattering model, also known as random walk model, is studied with the objective to obtain a physical explanation for the texture of polarimetric SAR data. Statistical analysis of the simulated data shows that both the fluctuation of the scatterer number and the mixture of different scatterers can give non-Gaussian distributed data. The mixture of scatterers will lead to extremely...
Rice is the staple food in many countries and monitoring the area of rice fields is demanded. The backscatter behavior of rice as function of time is so unique that it can be used to distinguish rice from other crops. In this paper, scattering matrix decomposition models were adopted to identify rice paddy fields from multi-temporal polarimetric SAR images. A series of Radarsat-2 polarimetric SAR...
Many research studies have investigated the retrieval of surface parameters for bare soils. This study attempts to take into account agricultural fields with crop residues and low vegetation cover. An adaptive two-component decomposition (ATCD) method is developed in this paper to invert surface parameters in these fields. The study area is located in Southwestern Ontario, Canada where two wheat fields...
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