Land Cover Classification in Amazon using Alos Palsar Full Polarimetric Data

The ALOS PALSAR sensor can provide full polarimetric SAR data (HH, HV and VV) but the full polarimetric mode is only available experimentally. Here, several supervised classifiers have been studied to determine how much the use of full polarized (HH, VV and HV, no phase information) PALSAR data information can improve, or not, the overall classification accuracy in comparison with the standard products, which, for PALSAR instrument, is the HH (like JERS-1) or the dual polarization product HH-HV. The study area, Tapajos National Forest at the south of Santarem City, in the Brazilian Amazon, Para State, has being object of intensive scientific observation for more than 15 years. Several types of supervised classifiers are tested for having, as much as possible, an assessment rather independent of the classifier type. Initial results indicate that, no phase considered, the dual polarization product HH-HV is the better channels combination for mapping the set of tropical classes composed by the primary forest, secondary forest, bare soil, agriculture and degraded forest. Also, it was observed that one year regeneration areas are not discriminated in any PALSAR combination, which indicates the utility of maintaining the complementary use of optical images when possible, because, in the optical combination, the 'one year regeneration' class still shows different from secondary forest. Region based classification, particularly one developed to take in account as much as possible the radar statistical behavior, generally presented better performance.