Hirdeshni Gautam Radar Image Processing and Analysisgisconference.gsd.spc.int/images/2017... ·...
Transcript of Hirdeshni Gautam Radar Image Processing and Analysisgisconference.gsd.spc.int/images/2017... ·...
Radar Data Availability for Fiji
Hirdeshni Gautam
Radar Image Processing and Analysis
Overview
• Focus:
– Space-borne Synthetic Aperture Radar (SAR)
• Brief description of SAR Imagery
• Some satellite missions
– Imagery available from these missions
SEASAT (1979)
First Space Borne Radar Mission
SAR Imagery
• It has no colour
• Each pixel records the intensity of the backscatter
• Backscatter is dependent on surface roughness
• By analysing backscatter and different polarisations we can come up with a colour composite image
Rewa Delta, (Sentinel 1) TC
Colour Composite
• Cropped
• Calibrated
• Speckle Filtered
• Terrain Corrected
• RGB, R-VV, G-VH, B-VV
Bands (Wavelengths)
• L Band – wavelength 15-30 cm
– frequency 1-2 GHz.
• S band– wavelength 8-15 cm
– frequency 2-4 GHz.
• C band radars– wavelength 4-8 cm
– frequency 4-8 GHz.
• X band– wavelength 2.5-4 cm
– frequency 8-12 GHz.
What you “see”, depends on the band
Image from http://gsp.humboldt.edu/olm_2015/Courses/GSP_216_Online/images/wavelength.png
Application :
Flood Mapping
Nadi January 2012
Application: Flood Mapping
Semi Automatic Analysis
• Speckle suppression
• Density slicing
• Deleting small areas from “water non water layer” through filter
• Raster to vector conversion
Disaster Response: Fiji Flooding 2016
http://services.gsd.spc.int/fiji
Japanese Aerospace Exploration Agency (JAXA)
• ALOS and ALOS 2
• PALSAR - Phased Array type L-band Synthetic Aperture Radar
• Frequency – 1.2 GHz
• Resolution– PALSAR – 10m
– PALSAR 2 – Spotlight mode (1 to 3 m)
Advanced Land Observation Satellite (ALOS – 2)
Public Private PartnershipGerman Space Agency and Astrium
• Twin Satellites
• acquired data to be used in generating WorldDEM
• Resolution-– SpotLight: up to 1 m
– StripMap: up to 3 m
– ScanSAR: up to 16 m
TerraSAR-X and TanDEM-X
Italian Space Agency (ASI)
COSMO-SkyMed (X Band)
• Four satellites in sun-synchronous polar orbits
• Resolution
– Spotlight modes:
• SPOTLIGHT1, military-only mode
• SPOTLIGHT2 - 1 m
– Two Stripmap modes:
• HIMAGE, 3 and 5 m
• PINGPONG, at 15 m resolution
– Two ScanSAR modes:
• WIDEREGION, 30 m
• HUGEREGION, 100 m
(Constellation of small Satellites for the Mediterranean basin Observation)
European Space Agency (ESA)
Sentinel 1
• C band
• Resolution– Strip Map Mode:
• 5 x 5 m spatial resolution
– Interferometric Wide Swath
• 5x20 m spatial resolution
– Extra-Wide Swath Mode:
• 25 x 100 m spatial resolution
– Wave-Mode:
• 5 x 20 m
Digital Globe (in partnership with MDA)
• RADARSAT 2
• RADARSAT 1 is no longer active
• Frequency Band C-Band (5.405 GHz)
• Resolution of 3m
• Polarization HH, HV, VH, VV
RADARSAT-2
German Military Satelite:SAR Lupe
• 5 satellites in tandem
• Military - reconnaissance satellite imaging
• Data not for public use
• X Band, resolution ~ 50 cm
THANK YOU