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TitleTemporal filters for mapping phragmites with C-HH SAR data / Filtres temporels pour cartographier les phragmites à partir de données RSO en bande C-HH
AuthorWhite, L; Brisco, B; Murnaghan, K; Pasher, J; Duffe, J
SourceCanadian Journal of Remote Sensing 2020 p. 1-10, Open Access logo Open Access
Alt SeriesNatural Resources Canada, Contribution Series 20200393
PublisherTaylor & Francis Inc.
Mediapaper; on-line; digital
File formatpdf; html
NTS31D/13; 31E/04; 41A/16; 41H/01
AreaGeorgian Bay Islands National Park of Canada
Lat/Long WENS -80.1992 -79.7775 45.1547 44.7731
Subjectsgeophysics; Science and Technology; Nature and Environment; remote sensing; satellite imagery; radar methods; software; vegetation; wetlands; surface waters; Phragmites australis; GAMMA; RADARSAT Constellation Mission (RCM); Data processing
Illustrationslocation maps; tables; satellite images; flow diagrams; time series
Released2020 08 18
AbstractWe compared traditional spatial filters and multi-temporal filters to remove speckle from synthetic aperture radar (SAR) data for mapping Phragmites australis. SAR constellations, with more rapid revisit capability, allow one to generate stacks of SAR data and to use multi-temporal filters for speckle reduction. GAMMA software offers multi-temporal filters for SAR processing, two of which we compared to the traditional Enhanced Lee and the Lee filters. We evaluated the filters using three criteria: (1) visual inspection, (2) signal level ratio, and (3) the equivalent number of looks (ENL). The results of this study show that multi-temporal filters were able to reduce speckle from areas of surface water and land, as well as to improve the detection of Phragmites patches due to preserving the resolution and texture which helped in the detection of the patch boundaries. The signal level ratio was approximately 1.0 with the GAMMA Multi-temporal filter and approximately 0.9 with the other filters. The enhanced Lee and the two multi-temporal filters produced an equal ENL of about 6. However, due to small patch sizes and backscatter similarity with cattails and other cover types Phragmites patches were difficult to separate from other types of flooded vegetation with C-HH intensity only.

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