Table Of ContentRR
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Initial Radiometric Calibration of the AWiFS using
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o o Vicarious Calibration Techniques
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p p Mary Pagnutti
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Science Systems and Applications, Inc.
John C. Stennis Space Center, MS 39529
228-688-2135
mary.pagnutti@ssc.nasa.gov
JACIE Civil Commercial Imagery Evaluation Workshop
Laurel, Maryland, USA
March 14–16, 2006
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- - Selected Targets – Wiggins, MS
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cc Four selected targets of opportunity near near Perkinston, MS near Big Level, MS
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m m meters across:
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b b – Two gravel pit sand sites
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lele – Cut grass amateur golf course
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rr 0 100 200 Meters 0 200 400 Meters
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AWiFS imagery (4,3,2)
0 100 200 Meters 0 50 100 Meters
April 27, 2005
Includes material ©DigitalGlobe, Inc.
March 16, 2006 JACIE Civil Commercial Imagery Evaluation Workshop, Laurel, MD 2
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- - Selected Targets - Park Falls, WI
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mm A target of opportunity was found near an
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tsts Aerosol Robotic Network (AERONET) site
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Landsat 7 imagery (7,4,2)
August 5, 2005
Target field 150 m x 400 m
AWiFS imagery (4,3,2)
August 5, 2005
March 16, 2006 JACIE Civil Commercial Imagery Evaluation Workshop, Laurel, MD 3
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- - Ground Reflectance Measurements
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mm • ASD FieldSpec® FR spectroradiometer
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and several target areas were taken
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b b – ~50 m x 50 m area of a grassy
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bb field/golf course
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lele – ~100 m x 200 m area of a rye
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; v; v grass field
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ioio • Measurements were taken along
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– Measurements were taken at nadir
and satellite elevation angles to
account for BRDF effects
– All measurements were taken
while walking to increase spatial
averaging
– Periodic Spectralon panel
measurements were taken
• All data were acquired within
40 minutes of satellite overpass
March 16, 2006 JACIE Civil Commercial Imagery Evaluation Workshop, Laurel, MD 4
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- - SSC Calibration and Characterization
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ee of ASD FieldSpec Spectroradiometers
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m m FieldSpec FR spectroradiometers
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b b – Laboratory transfer radiometers
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lidlid • Radiometric Calibration
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e pe p – NIST-calibrated integrating sphere
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• Spectral Calibration
– Laser and pen lamp illumination of
integrating sphere
• Environmental Testing
– Temperature stability tests
performed in environmental
chamber
March 16, 2006 JACIE Civil Commercial Imagery Evaluation Workshop, Laurel, MD 5
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uu • Novel hyperspectral sun photometer is capable Percent
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ASR 27 ASD Difference Difference
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tsts Band Generated Generated ASR-ASD 1 -(asd/asr)
m m ASRs and MFRSRs by making use of the
aa 380 nm 0.588 0.5982 -0.010 -1.74%
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b b laboratory radiometric calibration of the 400 nm 0.495 0.4852 0.010 1.99%
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bb FieldSpec FR spectroradiometers 440 nm 0.366 0.3216 0.044 12.14%
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lele – Optical Depth/Transmission 520 nm 0.224 0.1988 0.025 11.25%
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; v; v – Diffuse-to-Global Ratio 610 nm 0.161 0.1563 0.005 2.91%
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lidlid 670 nm 0.108 0.1002 0.008 7.26%
aa • Sun photometer developed with fewer
tete 780 nm 0.07 0.0691 0.001 1.33%
p p limitations than current sun photometers,
riorio 870 nm 0.049 0.0508 -0.002 -3.58%
r tor to utilizing equipment already used in the field RMS 1:8 0.019
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spectroradiometers
– 99% reflectance Spectralon panels
• Measurements are made only at the time of
overpass, thus reducing the impact of a
changing atmosphere on the calculation of
optical depth
Novel Hyperspectral
Sun Photometer Setup
March 16, 2006 JACIE Civil Commercial Imagery Evaluation Workshop, Laurel, MD 6
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- - Comparison to Spectralon Panel
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uu • Verification of parameters used to generate MODTRAN at-sensor radiance estimate
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nn – Measuring the radiance of Spectralon panel with a well-calibrated
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e oe o – Use ground truth data and geometry modeling an ASD FieldSpec FR
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.. Avg. Spectralon Radiance
MODTRAN Radiance
March 16, 2006 JACIE Civil Commercial Imagery Evaluation Workshop, Laurel, MD 7
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- - Data Acquisitions – Wiggins, MS
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aa Date Camera Time (UTC) Elevation Azimuth Elevation Azimuth
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ss Mar 24, 2005 B 16:59 71.1 deg 285 deg 57.2 deg 149.8 deg
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lidlid Apr 27, 2005 B 16:50 84.5 deg 285 deg 67.7 deg 135.4 deg
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15 AWiFS 15 AWiFS
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Wiggins, MS, 3/24/05 Wiggins, MS, 4/27/05
March 16, 2006 JACIE Civil Commercial Imagery Evaluation Workshop, Laurel, MD 8
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- - Data Acquisitions – Park Falls, WI
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Park Falls, WI, 8/5/05
March 16, 2006 JACIE Civil Commercial Imagery Evaluation Workshop, Laurel, MD 9
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- - Green Band Calibration Summary
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March 16, 2006 JACIE Civil Commercial Imagery Evaluation Workshop, Laurel, MD 10
