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Local Isotropy Indicator for SAR Image Filtering: Application to Envisat/ASAR Images of the Doñana Wetland (November 2014)

Marti-Cardona, B, López-Martínez, C and Dolz-Ripollés, J (2014) Local Isotropy Indicator for SAR Image Filtering: Application to Envisat/ASAR Images of the Doñana Wetland (November 2014) IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 8 (4). pp. 1614-1622.

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Abstract

This paper explores a geometrical and computationally simple operator, named Ds, for local isotropy assessment on SAR images. It is assumed that isotropic intensity distributions in natural areas, either textured or nontextured, correspond to a single cover class. Ds is used to measure isotropy in processing neighborhoods and decide if they can be considered as belonging to a unique cover class. The speckle statistical properties are used to determine suitable Ds thresholds for discriminating heterogeneous targets from isotropic cover types at different window sizes. An assessment of Ds as an edge detector showed sensitivities similar to those of the ratio edge operator for straight, sharp boundaries, centered in the processing window, but significantly better sensitivity for detecting heterogeneities during the window expansion in multiresolution filtering. Furthermore, Ds presents the advantage versus the ratio edge coefficient of being rotationally invariant, and its computation indicates the direction of the main intensity gradient in the processing window. The Ds operator is used in a multiresolution fashion for filtering ASAR scenes of the Doñana wetland. The intensities in isotropic areas are averaged in order to flatten fluctuations within cover types and facilitate a subsequent land cover classification. The results show high degree of smoothing within textured cover classes, plus effective spatial adaptation to gradients and irregular boundaries, substantiating the usefulness of this operator for filtering SAR data of natural areas with the purpose of classification.

Item Type: Article
Subjects : Civil & Environmental Engineering
Divisions : Faculty of Engineering and Physical Sciences > Civil and Environmental Engineering
Authors :
AuthorsEmailORCID
Marti-Cardona, BUNSPECIFIEDUNSPECIFIED
López-Martínez, CUNSPECIFIEDUNSPECIFIED
Dolz-Ripollés, JUNSPECIFIEDUNSPECIFIED
Date : 26 November 2014
Identification Number : 10.1109/JSTARS.2014.2369133
Copyright Disclaimer : © 2014 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.
Uncontrolled Keywords : —Doñana wetland, geometrical operator, gradual edges, isotropy, SAR image filtering, texture.
Depositing User : Symplectic Elements
Date Deposited : 03 Aug 2016 14:13
Last Modified : 03 Aug 2016 14:13
URI: http://epubs.surrey.ac.uk/id/eprint/811374

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