Abstract
Model-based approaches for decomposing polarimetric backscatter data
from boreal forest are discussed in this paper. Several model-based
decompositions are analyzed with respect for the most accurate
estimation of the volume scattering component. A novel generalized model
for description of the volume contribution is proposed when observed
backscatter from forest indicates that media does not follow azimuthal
symmetry case. The model can be adjusted to the polarimetric synthetic
aperture radar (PolSAR) data itself, taking into consideration higher
sensitivity of HH against VV backscattering term to the presence of
canopy at L-band. The model is general enough to allow a broad range of
canopies to be modeled and is shown to comply with several earlier
proposed volume scattering mechanism models. It is afterward
incorporated in the Freeman-Durden three-component decomposition,
yielding an improved modification. The performance of the proposed
modification is evaluated using multitemporal ALOS PALSAR data acquired
over Kuortane area in central Finland, representing typical mixed boreal
forestland. Several decompositions are also benchmarked in order to see
how they satisfy physical requirements when decomposing covariance
matrix into a weighted sum of individual scattering mechanism
contributions. When using experimental data, the proposed decomposition
is shown to better satisfy non-negativity constraints for the covariance
matrix eigenvalues at each decomposition step with less additional
PolSAR data averaging needed. Discussed decompositions are also
evaluated for the accuracy of initial stratification based on dominating
scattering mechanism using ground reference data.
Original language | English |
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Pages (from-to) | 3838-3848 |
Number of pages | 11 |
Journal | IEEE Transactions on Geoscience and Remote Sensing |
Volume | 49 |
Issue number | 10 |
DOIs | |
Publication status | Published - 2011 |
MoE publication type | A1 Journal article-refereed |
Keywords
- Boreal forest
- model-based decomposition
- polarimetry
- scattering mechanisms
- synthetic aperture radar (SAR)