Classification of Tropical Vegetation Using Multifrequency Partial SAR Polarimetry

Abstract

International audienceThis letter presents a case study addressing the comparison between different synthetic aperture radar (SAR) partial polarimetric options for tropical-vegetation cartography. These options include compact polarization (CP), dual polarization (DP), and alternating polarization (AP). They are all derived from fully polarimetric (FP) SAR data acquired by the airborne SAR (AIRSAR) sensor over the French Polynesian Tubuai Island. The classification approach is based on the support vector machine algorithm and is further validated by several ground surveys. For a single frequency band, FP data give significantly better results than any other partial polarimetric configuration. Among the partial polarimetric architectures, the CP mode performs best. In addition, the DP mode shows better performance than the AP mode, highlighting the value of the polarimetric differential phase. The combination of different frequency bands (P-, L-, and C-bands) holds the most significant improvement: The multifrequency diversity adds generally more information than the multipolarization diversity. A noticeable result is the major contribution of the C-band at VV polarization (the only polarization available at C-band with the AIRSAR data set used in this letter) to the classification performance, due to its ability to discriminate between Pinus and Falcata

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“…Quad-polarization data (also called fully polarimetric data) have the most abundant information on observed targets compared with single-or dual-polarization data and there are also plentiful analytical methods for quad-polarization data such as eigenvalue analysis (Cloude and Pottier 1997) and model-based decomposition (Freeman andDurden 1998, Lee andPottier 2009). On the other hand, the richness of quad-polarization data comes at the expense of swath widths (Crisp 2004, Lardeux et al 2011). There is a certain trade-off relation between quad-and single-polarization data.…”

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