Local isotropy indicator for SAR image filtering: application to Envisat/ASAR images of the Doñana Wetland
| Autor: | Martí-Cardona, Belen, Lopez, Carlos, Dolz, Jose |
|---|---|
| Přispěvatelé: | Universitat Politècnica de Catalunya. Departament de Teoria del Senyal i Comunicacions, Universitat Politècnica de Catalunya. Departament d'Enginyeria Civil i Ambiental, Universitat Politècnica de Catalunya. FLUMEN - Dinàmica Fluvial i Enginyeria Hidrològica, Universitat Politècnica de Catalunya. RSLAB - Grup de Recerca en Teledetecció |
| Jazyk: | angličtina |
| Rok vydání: | 2015 |
| Předmět: |
Engineering
Civil Enginyeria de la telecomunicació::Radiocomunicació i exploració electromagnètica::Radar [Àrees temàtiques de la UPC] Engineering Multidisciplinary Geometry Radar d'obertura sintètica Synthetic aperture radar Syntethic aperture radar Image resolution Speckle Geometrical operator SAR image filtering Engineering Ocean Texture Engineering Aerospace Engineering Biomedical Gradual edges Geometria Detectors Isotropy Computer Science Software Engineering Engineering Marine Doñana wetland Image edge detection Engineering Manufacturing Engineering Mechanical Engineering Industrial Filtering |
| Zdroj: | UPCommons. Portal del coneixement obert de la UPC Universitat Politècnica de Catalunya (UPC) Recercat. Dipósit de la Recerca de Catalunya Universitat Jaume I |
| DOI: | 10.1109/JSTARS.2014.2369133 |
| Popis: | ©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. 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. |
| Databáze: | OpenAIRE |
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