Title: Aucun titre de diapositive
1 Analysis of forest
parameters and agricultural field structure from
high resolution PolInSAR X band data Franck
Garestier (1), Kostas Papathanassiou (2), Irena
Hajnsek (2), Pascale Dubois-Fernandez (1)
Xavier Dupuis (1) (1) ONERA, BA 701, Ecole de
l Air, 13661 Salon AIR, France (2) DLR,
Microwave and Radar Institute, 8230 Wessling,
Germany
2Plan of the presentation
- Presentation of the RITAS data
- Ground truth campaigns (during and after
acquisition) - Pine forest
- Random Volume over Ground model
- Assumptions and correction of the data
- Mean extinction coefficient estimation
- Wheat type fields
- Signature of oriented volume observation
- Conclusion
3Presentation of the data
- Campaign Radar Imagerie Thématique
Agricole et Sols - Team
INRA, CETP, BRGM, CEMAGREF and ONERA - Date acquisition in March 2002 by
R.A.M.S.E.S. system - Data X band
mono-pass PolInSAR - Size of the resolution cell 0.9 m x
0.9 m - Swath 800 m
- Mean incidence angle 30
4Ground truth campaigns
INRA test site orchards specie, height,
biomass, maturity, water content soils
roughness, hygrometry
during the
acquisition The entire data vegetation
specie, height, tree density, maturity
buildings height after the
acquisition
optic
radar
I.N.R.A. test site, Avignon, France
Montfavet
5- Presentation of the RITAS data
- Ground truth campaigns (during and after
acquisition) - Pine forest
- Random Volume over Ground model
- Assumptions and correction of the data
- Mean extinction coefficient estimation
- Wheat type fields
- Signature of oriented volume observation
- Conclusion
6Pine forest Random Volume over Ground
model Cloude Papathanassiou
2001
18 m
Representation of Pauli basis polarimetric
HHVV HV HH-VV
Polarimetric DEM HH HV VV
7Pine forest interferometric coherence
Interferometric coherence for a
polarization straight line in the complex
plane Ground to volume ratio with
and the coherency matrixes of canopy and
soil Interferometric coherence of the volume
only contribution depends on and
Im
Re
Complex plane
8Pine forest limitation of the data
antennas
High rate switch dysfunction during the
flight problem in V emission
decorrelation on the whole images
Decorrelation on VH and VV channel (small loss
of coherence for VV)
9Pine forest dual (lite) pol
Im
The slight loss of coherence in VV
channel should induce a bias in parameter
extraction overestimation of the
forest height use of only two
polarisations HH and HV
degradation of the estimation (compared to
Quad-pol mode) interferometric coherence
associated to HV
HH HV VV
Re
Complex plane
10Pine forest canopy decorrelation
Im
range axis
resolution cell
gHV
gHH
Re
Complex plane
Interferometric phase of the ground remains
unchanged
The roughness of the canopy induces a scalar
decorrelation of decorrelation coefficient
only applied on the volume contribution
Radial correction ( 0,07)
Impossible to extract and
simultaneously
Assumption on to estimate forest height
11Pine forest coherences and heights
slight underestimation of the forest height
6 m vertical separation (9)
0
1
Coherence of HH and HV channels
Mono-pass acquisition high coherences
0.9 lt lt 0.95 (Coherence observed
on bare surfaces 0.98)
Phase standard deviation -
phase estimation accuracy 3 -
forest structure
12Pine forest volume height
18 m height pine forest without underlying
topography
2 1,8 1,6 1,4 1,2 1 0,8 0,6 0,4
(dB/m)
0 10
20
30
0 10
20
30
Height (m) histogram of the estimated ground level
Forest height (m) histograms for different
extinction values
Height retrieved with high extinction
Dual-pol mode reduces the accuracy of
estimation
13Pine forest extinction estimation
18 m height pine forest without underlying
topography
Mean forest height (m)
Mean forest height error (m)
Mean extinction coefficient (dB/m)
Mean extinction coefficient error (dB/m)
Mean extinction coefficient of a sparse pine
forest at X band
A large interval of mean extinction
coefficient gives a satisfying inversion. Accurac
y of 0.5 dB/m
14- Presentation of the RITAS data
- Ground truth campaigns (during and after
acquisition) - Pine forest
- Random Volume over Ground model
- Assumptions and correction of the data
- Mean extinction coefficient estimation
- Wheat type fields
- Signature of oriented volume observation
- Conclusion
15Wheat type fields orientation effect
Bare soil surface
HH HV VV
INRA 8 wheat orchards
Representation of Pauli basis polarimetric
HHVV HV HH-VV
16Conclusion
Pine forest Phase centers corresponding to
HH and HV separated wave
penetration in the canopy of a sparse pine forest
at X band determination of a high mean
extinction coefficient using RVoG model
forest height estimation low sensitivity to mean
extinction coefficient (HV phase center
close to the top of the canopy) Wheat type
fields observation of an orientation effect
due to the vertical structure