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TitlePolarimetric RADARSAT-2 wetland classification using the Touzi decomposition: case of the Lac Saint-Pierre Ramsar wetland
AuthorGosselin, G; Touzi, R; Cavayas, F
SourceCanadian Journal of Remote Sensing vol. 36, no. 6, 2013 p. 491-506,
Alt SeriesEarth Sciences Sector, Contribution Series 20120407
PublisherInforma UK Limited
Mediapaper; on-line; digital
File formatpdf
AreaSaint-Pierre Lake
Lat/Long WENS -73.2500 -73.1667 46.4167 46.0000
SubjectsNature and Environment; remote sensing; environmental impacts; wetlands; Touzi decomposition; Radarsat-2; RAMSAR; incoherent target-scattering decomposition (ICTD); ecosystem monitoring; wetland classification
Illustrationslocation maps; tables; graphs; diagrams; satellite images
ProgramRemote Sensing Science, Methodology
Released2014 06 04
AbstractWetlands play a key role in regional and global environments and are linked to climate change, water quality, and hydrological and carbon cycles. They also contribute to wildlife habitat and biodiversity and can act as indicators of overall environmental health. Unfortunately, wetlands continue to be under threat. There is an immediate need for improved mapping and monitoring of wetlands to better manage and protect these sensitive areas. Recently, the Touzi decomposition was introduced and proved very promising for wetland characterization using polarimetric airborne (Convair-580) SAR data. The purpose of this study is to assess the Touzi incoherent target-scattering decomposition (ICTD) for wetland classification using polarimetric Radarsat-2 (RS2) data collected over the RAMSAR wetland site in Lac Saint-Pierre, Canada. In particular, the sensitivity of the ICTD parameters to seasonal evolution of marsh and swamp
scattering is discussed and demonstrated. The intent is to show that the dominant scattering type magnitude ((alpha) s1) and phase ( (omega)s1), and the dominant (n1) and lowest scattering eigenvalues (n3), lead to an effective characterization of the various backscattering mechanisms of the wetland plant species. The ICTD parameters form the basis of a new hierarchical classification that is efficient for wetland classification. The use of multitemporal information obtained from multidate RS2 acquisitions between April and September allows an accurate wetland classification. The RS2 polarimetric classification is then compared with a supervised maximum-likelihood classification using a pair of Landsat-5 images.