An Inter-Comparison and Rigorous Analysis of UAV and Manned Airborne Hyperspectral Imagers

Transcription

1 Geological Remote Sensing Group Annual General Meeting and Conference October 2018 London, England An Inter-Comparison and Rigorous Analysis of UAV and Manned Airborne Hyperspectral Imagers George Leblanc 1, Raymond Soffer 1, Gabriela Ifimov 1, J. Pablo Arroyo-Mora 1, and Margaret Kalacska 2 1 Flight Research Laboratory, National Research Council of Canada, Ottawa, ON K1A-0R6, Canada 2 Applied Remote Sensing Laboratory, Department of Geography, McGill University, 845 Rue Sherbrooke Ouest, Montréal, QC H3A 0B9, Canada

2 About NRC 3,670+ employees and 575+ volunteer and independent visitors NRC is Government of Canada s national research organization - similar to DRL in breath of research activities (Aerospace, Metrolology, Manufacturing, Nano-tech, Quantum-tech, Biologics, Astrophysics...) 500 km IRAP Research facilities

3 Flight Research Laboratory Part of NRC s Aerospace Research Center Owns and operates a fleet of fixed-wing and rotary-wing research aircraft, UAV s and an assortment of EO and atmospheric sensors Performs research for national and international industries, governments and militaries

4 Motivation Are small UAV hyperspectral sensors able to provide the necessary data quality to replace their manned aircraft counterparts? 4 NRC

5 Instrumentation and Installation Pushbroom 39.9degree FOV 0.48 mrad IFOV 1498 pixels 288 spectral channels 367 nm-1053 nm 14 bit variable Frame Rate GPS/INS u Pushbroom 34.2 degree FOV 0.33 mrad IFOV 1835 pixels 288 spectral channels 400 nm- 995 nm 12 bit variable Frame Rate GPS/INS Co-Mounted Aboard Twin Otter

6 Lab-based Measurements SHU and ICU with KVH1750 IMU µ SHU SVC1024i Field Spectrometer

7 Lab-based Measurements

8 Ground Data Validation Site Field Spectroscopy SVC HR-1024i ( nm) Calibration targets asphalt Hemispherical concrete Photos and SPN-1 Diffuse:Global Irradiance sensor grey tarp black tarp Sky Photos

9 Spatial Quality u I.T / F.T (ms) 48 / 48 7 / 11 FOV ( ) Twin Otter Altitude = 1030 m AGL Average Ground Speed = 39.6 m/s Image Pixels Cross Track Resolution (m) Along Track Spacing (m) I.T. / Frame 1.90 / / Along Track Resolution (m) Geocorrection Resampling (m) 0.5 x x 0.5 u

10 Radiance Results No Corrections vs u Grey Tarp Radiance vs u Concrete Radiance vs u Black Tarp Radiance vs u Asphalt Radiance

11 Radiance No Corrections Target Mean Radiance Standard Deviation Range Grey Tarp Black Tarp Asphalt Concrete Target Mean Ratio Standard Deviation Range Grey Tarp Black Tarp Asphalt Concrete

12 Reflectance No Corrections SVC u SVC u SVC u SVC u

13 Reflectance Post Acquisition Correction SVC u SVC u SVC u SVC u

14 Issue: Image Saturation 12 vs 14 bit vs u Aircraft Radiance vs u Aircraft Reflectance

15 Summary u is considerably more noisy than ~ 5 times as noisy u offers spatial advantages due to larger # of pixels and IT/FR Lower SNR for the u proves to be critical issue at wavelengths longer than ~800 nm Good agreement of u and in the nm region Some potential path radiance effects in u near 400nm In studies with high reflectance targets, significantly outperforms The cost of the instrument is a primary consideration for quality of measurement and confidence in the system

16 Thank you George Leblanc Team Lead: Hyperspectral and Aeromagnetics Aerospace National Research Council 1920 Research Rd Ottawa ON June 24, 2018 Mer Bleue Peatland, Ottawa 288 Spectral Bands Altitude: 15 m AGL Swath Width: ~ 8 m Acquired pixel size: XTR = 0.5 cm ATS = 1.1 cm ATR = 1.1 cm Geocorrected size: 1.0 cm x 1.0 cm Image RGB: 756 nm 689 nm 552 nm