Post on 11-Jun-2020
koichi.iribe@dlr.de 27-Junuary-2009
Estimation of Ground Topography in Forested Terrain by means of Pol-InSAR Koichi Iribe1, Carlos Lopez-Martinez2, Kostas Papathanassiou1, Irena Hajnsek1
1 Microwaves and Radar Institute German Aerospace Center DLR2 Technical University of Catalonia UPC
Slide 2
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Slide 3
Sweden
Finland
Norway
Denmark
0°
10°E
10°E 20°E
20°E
30°E
55°N55°N
60°N60°N
65°N
65°N
70°N
70°N
Remningstorp
Brattåker
Vidsel
Västra Götaland
Västerbotten
BioSAR CampaignTime: 8th of March to 3rd of May 2007.Main objective: Estimation of the forest biomass in order to support carbon modelling using longer wavelength (L- and P-band).Observation system: DLR E-SAR (Airborne).Test site: Remningstorp, Southern Sweden (58˚28΄N, 13˚38΄E).
Topography: Fairly flat with small variations ranging between 108m and 140m above sea level.Tree property:
Predom. Spruce but also pine stands.Homogenous and managed standsBiomass level: up to 300t/haForest heights: up to 25 - 30m
In this presentation, P- and L-band polarimetric and interferometric repeat pass datasets are employed.
Slide 4
Landscape of Test Site.
Slide 5
Remningstorp Test Site in P- & L-band Radar Image and LIDAR ImageBlack area represents minimum height or no data.LIDAR Digital Terrain Model (DTM) is used for the validation.
108m
140m
azim
uth
range
LIDAR Digital Terrain Model (Projected onto P-band SLC image)
L-band Pauli decomposed image
Double bounceVolume scattering
Single bounce
Double bounceVolume scattering
Single bounce
P-band Pauli decomposed image
Slide 6
P-band Track ConfigurationQuad-pol 70MHz P-band images acquired in a repeat-pass PolInSAR mode.Dataset acquired in May is employed.6 tracks, 14 interferometric pairs. (exclude 0m baseline pair)
Slide 7
P-band HH Pol. Interferometric Coherence ΓHH
10m Baseline. 30m Baseline. 50m Baseline.0
1
Slide 8
Distribution of Interferometric Coherence ΓHH
10m Baseline.
30m Baseline.
50m Baseline.
Bare Area.Forested Area.
Slide 9
P-band HH Pol. Interferometric Phase φP
10m Baseline. 30m Baseline. 50m Baseline.-π
π
Slide 10
Differential Phase betweenφP and Topographic Phase φLIDAR
10m Baseline. 30m Baseline. 50m Baseline.-π
π
Slide 11
Differential Phase, φP – φLIDAR
10m Baseline.
30m Baseline.
50m Baseline.
Bare Area.Forested Area.
Slide 12
Differential Height, P-band InSAR DEM – LIDAR DTM
10m Baseline.
30m Baseline.
50m Baseline.
Bare Area.Forested Area.
0.01< kz <0.08
0.04< kz <0.23
0.08< kz <0.38
Slide 13
Differential Height, φo Height – LIDAR DTM
10m Baseline.
30m Baseline.
50m Baseline.
Bare Area.Forested Area.
0.01< kz <0.08
0.04< kz <0.23
0.08< kz <0.38
Slide 14
Estimated Pbandφo Height using Multi-Baseline Data
Bare Area.Forested Area.
P-band, 10m (2 pairs), 20m (2 pairs), 30m (3 pairs), 40m (2 pairs), 50m (1 pair), 60m (2 pairs), 70m (2 pairs) baseline data.Baseline length weighting combination, higher for longer length.
Smaller variance for both bare area and forested area.Bias from vegetation is less.Even bare area, which shows low coherence, shows small variance.
Slide 15
108m
140mLIDAR Digital Terrain Model
(DTM)P-band Pauli decomposed
image
Estimated P-bandφoHeight using Multi-Baseline Data
azim
uth
range
Double bounceVolume scattering
Single bounce
Estimated P-band φo Height using 14 baseline data
Slide 16
L-band HH Pol. Interferometric Coherence ΓHH
8m Baseline. 16m Baseline. 24m Baseline.0
1
Slide 17
Distribution of Interferometric Coherence ΓHH
8m Baseline.
16m Baseline.
24m Baseline.
Bare Area.Forested Area.
Slide 18
L-band HH Pol. Interferometric Phase φL
8m Baseline. 16m Baseline. 24m Baseline.-π
π
Slide 19
Differential Phase betweenφL and Topographic Phase φLIDAR
8m Baseline. 16m Baseline. 24m Baseline.-π
π
Slide 20
Differential Phase, φL – φLIDAR
8m Baseline, HH Pol.
8m Baseline, VV Pol.
8m Baseline, XX Pol.
Bare Area.Forested Area.
Slide 21
Differential Height, L-band InSAR DEM – LIDAR DTM
8m Baseline, HH Pol.
8m Baseline, VV Pol.
8m Baseline, XX Pol.
Bare Area.Forested Area.
0.01< kz <0.28
0.01< kz <0.28
0.01< kz <0.28
Slide 22
Differential Height, φo Height – LIDAR DTM
8m Baseline, Single-Baseline.
Bare Area.Forested Area.
8m Baseline, 2-Baseline.
0.01< kz <0.28
8m Baseline, 5-Baseline.
Slide 23
108m
140mLIDAR Digital Terrain Model
(DTM)L-band Pauli decomposed
image
Estimated L-bandφoHeight using Multi-Baseline Data
azim
uth
range
Estimated L-band φo Height using multi-baseline data.
Double bounceVolume scattering
Single bounce
Slide 24
Summary and Future Work
P-bandEstimated ground topography φo by means of PolInSAR shows,
Less bias and smaller variance.Improvement by using multi-baseline dataset.
L-bandGround topography φo was estimated using shorter baseline (8m) which show still useful interferometric phase quality.
Less bias but still larger variance.Improvement by using multi-baseline dataset.
Investigation of residual motion error of platform.Quantitative analysis.
Slide 25
Slide 26
Differential Height, φo Height – LIDAR DTM
8m Baseline, Single-Baseline.
Bare Area.Forested Area.
8m Baseline, Multi-Baseline.
Combined with 5 baseline data with 8m length.
Slide 27
Discrimination of Forested Area and Bare Area
*
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From view point of SNR, forested area and bare area are discriminated.High SNR is associated as forest area, low SNR is as bare area.
0
100
SNR image.
Index of forested area.
Index of bare area.
Slide 28
Utilization of CSs for phi_0 estimation (1/2)
CS candidates with low SLC CSs with high coherence (not interferometric coherence)
Phase error map acquired using CSs [rad]
Slide 29
Histogram of height difference
Before the removal of phase error
Histogram of height difference
After the removal of phase error
Utilization of CSs for phi_0 estimation (2/2)