DigitalGlobe Proprietary and Business Confidential
Workshop on Geologic Remote Sensing
WV-3 and SWIR 26 February 2014 Bill Baugh Staff R&D Scientist DG Labs HQ
DigitalGlobe Proprietary and Business Confidential
DigitalGlobe Proprietary and Business Confidential
Agenda Introduction: Geologic Remote Sensing Theory 1. 2. 3. 4.
Light-mater interaction Reflectance verses radiance Spectral signatures WV-3 Sensor and SWIR
Applications 1. 2. 3.
RGB display of SWIR bands. Mineral Indices: Cuprite, Nevada USA Rooftop classification: Los Angeles, California, USA
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2
Mt Everest, Nepal
Mt Everest | Digital Elevation Model | 0.5 m | WorldView 2 | Wireframe
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3
Mt Everest, Nepal
Mt Everest | Digital Elevation Model | 0.5 m | WorldView 2 | 2m | False Color IR Drape
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4
Mt Everest, Nepal
Mt Everest | Digital Elevation Model | 0.5 m | WorldView 2 | 2m | False Color IR Drape
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5
Mt Everest, Nepal
Mt Everest Summit | Digital Elevation Model | 0.5 m | WorldView 2 | 2m | False Color IR Drape
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6
Mt Everest, Nepal Sediments
Qomolangma detachment Metamorphic Rocks
Lhotse
Everest
Changtse
Graphic: Searle, et al., 2003 Mt Everest Summit | Digital Elevation Model | 0.5 m | WorldView 2 | 2m | False Color IR Drape
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7
Why Reflectance? radiance vs reflectance Radiance is what a satellite measures. It is ‘how much energy’.
- Things look different when they are brightly or dimly lit. - This is radiance.
DigitalGlobe Proprietary and Business Confidential
8
Why Reflectance? radiance vs reflectance Reflectance is a constant, predictable property of the material.
“Percent of light that is reflected!”
- Reflectance is a ratio. OUT/IN = reflectance - This is reflectance.
50% Out
In
50% Out In
DigitalGlobe Proprietary and Business Confidential
9
Why Reflectance? radiance vs reflectance The fine print: -
Reflectance has a lot of moving parts Sun-Earth distance. Sun-Target-Sensor geometry. Atmospheric effects. Calibration. BRDF etc, etc.
The bottom line. We need reflectance for: • Change detection • Material identification • Vegetation studies • Consistency • Balanced colors DigitalGlobe Proprietary and Business Confidential
10
Light-Matter Interaction The Options 1. Reflect 2. Absorbed as heat
“Spectral scientist wants both”
Water Molecule | Light-Matter interaction
DigitalGlobe Proprietary and Business Confidential
Exploitation
Fe3+
OH-
SO4/OH-
What can we do with it?
Concentration • Band depth
Reflectance (offset)
Mineral Identification • Band position • Absorption shape
Alunite
400
Jarosite
900
1400 Wavelength (nm)
1900
2400 * Offset for Clarity
Alunite and Jarosite differ only by Al / Fe: Alunite (KAl3(OH)6(SO4)2) Jarosite (KFe3(OH)6(SO4)2)
DigitalGlobe Proprietary and Business Confidential
WV-3 and SWIR (Short Wave Infrared) Visible (V) Picture
Near Infrared (NIR) Veg
Iron
Short Wave Infrared (SWIR) Man made
Rocks
Landsat 8 (30 m)
ASTER (15/30 m)
WV 3 only
WV 2 - 3 (1.2 / 3.7)
300
500
700
900
1100 1300 1500 1700 1900 2100 2300 2500 DigitalGlobe Proprietary. ©DigitalGlobe. All rights reserved.
13
“this work assumes reflectance data”
Sensor Introduction
AVIRIS: • Imaging Spectrometer: 224 bands VNIR-SWIR. • Pixels vary: 2 to 20 m. • Used to generate WV3 simulated spectra.
ASTER • Multispectral: 10 bands VNIR - SWIR. • Pixels: 15, 30 m. • SWIR failed.
Landsat (8) • •
Multispectral: 8 bands VNIR - SWIR. Pixels: 30 m.
WorldView 3 • • •
Multispectral: 16 bands VNIR-SWIR. Pixels: 1.2, 3.7 m. CAVIS instrument for atmospheric retrievals.
Expected launch: mid-2014 DigitalGlobe Proprietary. ©DigitalGlobe. All rights reserved.
CAVIS → Reflectance Atmospheric Retrievals on WorldView3 CAVIS Band Names Desert Clouds Aerosol-1 Green Aerosol-2 Water-1 Water-2 Water-3 NDVI-SWIR Cirrus Snow Aerosol-3 Aerosol-3
CAVIS retrieves atmospheric Aerosol and Water Vapor at the same time as the image, making reflectance calculations easier.
Expected launch: mid-2014 DigitalGlobe Proprietary. ©DigitalGlobe. All rights reserved.
15
Applications!
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16
Blue SWIR-4
Exploitation
Green SWIR-5
Red SWIR-7
Reflectance
3-Band RGB Display The Main Idea Bracket the “alunite” absorption feature with Red, Green, and Blue display bands. High Red + High Blue (and Low Green) makes magenta.
Alunite Silica 1500
True Color: R, G, B
WV3: S7, S5, S4
1700
1900 2100 Wavelength (nm)
2300
In General When you know the absorption feature, bracket it with red, green, and blue display bands to make it stand out in magenta.
Cuprite, Nevada USA| AVIRIS| 3.7 m | WorldView 2 and 3 Simulations
DigitalGlobe Proprietary and Business Confidential
Exploitation 3-Band RGB Display
To Do 1. 2. 3. 4. 5. 6. 7. 8.
Open Cuprite image in ENVI. Select “RGB Color” in Available Bands List. Select “R” Button, and click on “SWIR-7” band. Repeat for “G” and “SWIR-5”. Repeat for “B” and “SWIR-4”. Click on “Load RGB”. Optional – Stretch under “Enhance” menu, try “[Image] Linear 2%”. Optional – Show Spectrum, right click in image and select “Z profile (spectrum)”.
DigitalGlobe Proprietary and Business Confidential
Exploitation Panchromatic
Cuprite, Nevada USA | AVIRIS| 3.7 m | WorldView 1 Panchromatic Simulation
DigitalGlobe Proprietary. ©DigitalGlobe. All rights reserved.
Exploitation True Color
Cuprite, Nevada USA | AVIRIS| 3.7 m | WorldView 2 Color Simulation
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Exploitation Mineral Indices
Cuprite, Nevada USA | AVIRIS| 3.7 m | WorldView 3 SWIR Mineral Index Simulation
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Exploitation Mineral Indices
ASTER Index: “Alunite Kaolinite Pyrophyllite” (S3+S6)/S5 Grayscale
DigitalGlobe Proprietary and Business Confidential
Exploitation Mineral Indices
ASTER Index: “Alunite Kaolinite Pyrophyllite” (S3+S6)/S5 Threshold Vector
DigitalGlobe Proprietary and Business Confidential
Exploitation
ASTER Index: “Alunite Kaolinite Pyrophyllite” (S3+S6)/S5 Threshold Vector at “2.7”
Mineral Indices Index =
𝑆𝑊𝐼𝑅 3+𝑆𝑊𝐼𝑅 6 𝑆𝑊𝐼𝑅 5
Index Values Calculated Alunite = 3.79 Jarosite = 2.26 Alunite
Reflectance
Jarosite
SWIR-5 A = 0.28 J = 0.58
SWIR-6 A = 0.34 J = 0.50
SWIR-3 A = 0.72 J = 0.81
WV-3 Mineral Spectra 1500
1700
1900 2100 Wavelength (nm)
2300
For this index • Alunite greater than jarosite • Alunite greater than threshold (2.7) • Alunite “selected” correctly DigitalGlobe Proprietary and Business Confidential
Exploitation Mineral Indices To Do 1. 2. 3. 4. 5. 6. 7. 8.
Open Cuprite image in ENVI. Select “Band Math” from “Basic Tools” menu. Select “Restore” Button, and navigate to file “mineral_indices_workshop.exp”. Select the first one “Alunite-Clay”, click “OK”. Pair the variable to the bands (i.e. click “B11”, then select “SWIR-3 (11)” from Available Bands List. Repeat for remaining variables, choose a filename, click “OK”. Repeat Band Math for two more expressions – “Carbonate” and “Mica”. In Available Bands List, use RGB Color and display: R = Alunite, G = Mica, B = Carbonate. DigitalGlobe Proprietary and Business Confidential
Roof Type Classification
Boulder, Colorado USA | AVIRIS | 10.8 m | WorldView 3 Simulation
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26
Spectral reflectance of roofs AVIRIS resampled to WV2, WV3 response
1 0.9 0.8 0.7 0.6
Steel Red Tile
0.5
Painted AL 0.4
Fiberglass
0.3 0.2 0.1
WV 2 & 3
WV 3 new bands
0 0.4
0.6
0.8
1
Boulder, Colorado USA | AVIRIS| 10.8 m | Roof Spectra
1.2
1.4
1.6
1.8
2
2.2
2.4
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27
Exploitation Spectral Matching To Do
1.
2. 3. 4. 5. 6. 7. 8.
Open two items in ENVI: a. “LA_Basin_mosaic_ss_rfl_WV3_ss” b. “Roofs_spectral_library.sli” Select “Classification” -> “Supervised” -> “Spectral Angle Mapper”. Select file “LA_Basin_mosaic_ss_rfl_WV3_ss”, then “OK”. Select “Import” -> “from Spectral Library file…”. Select “Roofs_spectral_library.sli”, then “OK”. In “Input Spectral Library”, click “Select All Items”, then “OK”. In “Endmember Collection”, click “Select All”, then “Apply”. In “Spectral Angle Mapper Parameters”: a. change “Maximum Angle (radians)” from “0.100” to “0.150”. b. Enter (use “Choose”) filename “yourname_roofs_sam” c. Enter 2nd filename (“Choose”) “yourname_roofs_sam_rule” d. Click “OK” DigitalGlobe Proprietary and Business Confidential
Exploitation Spectral Matching To Display 1.
2. 3. 4. 5. 6.
In “Available Bands List” : a. Select “Yourname_roofs_sam” b. Click “Load Band” Then load RGB image from “LA_Basin_mosaic_ss_rfl_WV3_ss” into a new window. Right click in either window, select “Link Displays”, and “OK”. Right click in either window, select “Cursor Location/Value”. Browse, and see roof category in “Cursor Location/Value”. Optional – use GoogleEarth for “ground truth”.
DigitalGlobe Proprietary and Business Confidential
Exploitation Spectral Matching True Color: R, G, B
Los Angeles area, California USA | AVIRIS| 3.4 m | WV-3 Roof Spectral Classification
Rooftop spectral classification
DigitalGlobe Proprietary and Business Confidential
Summary Introduction: Geologic Remote Sensing Theory 1. 2. 3. 4.
Light-mater interaction Reflectance verses radiance Spectral signatures WV-3 Sensor and SWIR
Applications 1. 2. 3.
RGB display of SWIR bands. Mineral Indices: Cuprite, Nevada USA Rooftop classification: Los Angeles, California, USA
DigitalGlobe Proprietary and Business Confidential
31
WV-3 and SWIR 26 February 2014 Bill Baugh Staff R&D Scientist DG Labs HQ
DigitalGlobe Proprietary and Business Confidential
DigitalGlobe Proprietary and Business Confidential
Agenda Introduction: Geologic Remote Sensing Theory 1. 2. 3. 4.
Light-mater interaction Reflectance verses radiance Spectral signatures WV-3 Sensor and SWIR
Applications 1. 2. 3.
RGB display of SWIR bands. Mineral Indices: Cuprite, Nevada USA Rooftop classification: Los Angeles, California, USA
DigitalGlobe Proprietary and Business Confidential
2
Mt Everest, Nepal
Mt Everest | Digital Elevation Model | 0.5 m | WorldView 2 | Wireframe
DigitalGlobe Proprietary. ©DigitalGlobe. All rights reserved.
3
Mt Everest, Nepal
Mt Everest | Digital Elevation Model | 0.5 m | WorldView 2 | 2m | False Color IR Drape
DigitalGlobe Proprietary. ©DigitalGlobe. All rights reserved.
4
Mt Everest, Nepal
Mt Everest | Digital Elevation Model | 0.5 m | WorldView 2 | 2m | False Color IR Drape
DigitalGlobe Proprietary. ©DigitalGlobe. All rights reserved.
5
Mt Everest, Nepal
Mt Everest Summit | Digital Elevation Model | 0.5 m | WorldView 2 | 2m | False Color IR Drape
DigitalGlobe Proprietary. ©DigitalGlobe. All rights reserved.
6
Mt Everest, Nepal Sediments
Qomolangma detachment Metamorphic Rocks
Lhotse
Everest
Changtse
Graphic: Searle, et al., 2003 Mt Everest Summit | Digital Elevation Model | 0.5 m | WorldView 2 | 2m | False Color IR Drape
DigitalGlobe Proprietary. ©DigitalGlobe. All rights reserved.
7
Why Reflectance? radiance vs reflectance Radiance is what a satellite measures. It is ‘how much energy’.
- Things look different when they are brightly or dimly lit. - This is radiance.
DigitalGlobe Proprietary and Business Confidential
8
Why Reflectance? radiance vs reflectance Reflectance is a constant, predictable property of the material.
“Percent of light that is reflected!”
- Reflectance is a ratio. OUT/IN = reflectance - This is reflectance.
50% Out
In
50% Out In
DigitalGlobe Proprietary and Business Confidential
9
Why Reflectance? radiance vs reflectance The fine print: -
Reflectance has a lot of moving parts Sun-Earth distance. Sun-Target-Sensor geometry. Atmospheric effects. Calibration. BRDF etc, etc.
The bottom line. We need reflectance for: • Change detection • Material identification • Vegetation studies • Consistency • Balanced colors DigitalGlobe Proprietary and Business Confidential
10
Light-Matter Interaction The Options 1. Reflect 2. Absorbed as heat
“Spectral scientist wants both”
Water Molecule | Light-Matter interaction
DigitalGlobe Proprietary and Business Confidential
Exploitation
Fe3+
OH-
SO4/OH-
What can we do with it?
Concentration • Band depth
Reflectance (offset)
Mineral Identification • Band position • Absorption shape
Alunite
400
Jarosite
900
1400 Wavelength (nm)
1900
2400 * Offset for Clarity
Alunite and Jarosite differ only by Al / Fe: Alunite (KAl3(OH)6(SO4)2) Jarosite (KFe3(OH)6(SO4)2)
DigitalGlobe Proprietary and Business Confidential
WV-3 and SWIR (Short Wave Infrared) Visible (V) Picture
Near Infrared (NIR) Veg
Iron
Short Wave Infrared (SWIR) Man made
Rocks
Landsat 8 (30 m)
ASTER (15/30 m)
WV 3 only
WV 2 - 3 (1.2 / 3.7)
300
500
700
900
1100 1300 1500 1700 1900 2100 2300 2500 DigitalGlobe Proprietary. ©DigitalGlobe. All rights reserved.
13
“this work assumes reflectance data”
Sensor Introduction
AVIRIS: • Imaging Spectrometer: 224 bands VNIR-SWIR. • Pixels vary: 2 to 20 m. • Used to generate WV3 simulated spectra.
ASTER • Multispectral: 10 bands VNIR - SWIR. • Pixels: 15, 30 m. • SWIR failed.
Landsat (8) • •
Multispectral: 8 bands VNIR - SWIR. Pixels: 30 m.
WorldView 3 • • •
Multispectral: 16 bands VNIR-SWIR. Pixels: 1.2, 3.7 m. CAVIS instrument for atmospheric retrievals.
Expected launch: mid-2014 DigitalGlobe Proprietary. ©DigitalGlobe. All rights reserved.
CAVIS → Reflectance Atmospheric Retrievals on WorldView3 CAVIS Band Names Desert Clouds Aerosol-1 Green Aerosol-2 Water-1 Water-2 Water-3 NDVI-SWIR Cirrus Snow Aerosol-3 Aerosol-3
CAVIS retrieves atmospheric Aerosol and Water Vapor at the same time as the image, making reflectance calculations easier.
Expected launch: mid-2014 DigitalGlobe Proprietary. ©DigitalGlobe. All rights reserved.
15
Applications!
DigitalGlobe Proprietary and Business Confidential
16
Blue SWIR-4
Exploitation
Green SWIR-5
Red SWIR-7
Reflectance
3-Band RGB Display The Main Idea Bracket the “alunite” absorption feature with Red, Green, and Blue display bands. High Red + High Blue (and Low Green) makes magenta.
Alunite Silica 1500
True Color: R, G, B
WV3: S7, S5, S4
1700
1900 2100 Wavelength (nm)
2300
In General When you know the absorption feature, bracket it with red, green, and blue display bands to make it stand out in magenta.
Cuprite, Nevada USA| AVIRIS| 3.7 m | WorldView 2 and 3 Simulations
DigitalGlobe Proprietary and Business Confidential
Exploitation 3-Band RGB Display
To Do 1. 2. 3. 4. 5. 6. 7. 8.
Open Cuprite image in ENVI. Select “RGB Color” in Available Bands List. Select “R” Button, and click on “SWIR-7” band. Repeat for “G” and “SWIR-5”. Repeat for “B” and “SWIR-4”. Click on “Load RGB”. Optional – Stretch under “Enhance” menu, try “[Image] Linear 2%”. Optional – Show Spectrum, right click in image and select “Z profile (spectrum)”.
DigitalGlobe Proprietary and Business Confidential
Exploitation Panchromatic
Cuprite, Nevada USA | AVIRIS| 3.7 m | WorldView 1 Panchromatic Simulation
DigitalGlobe Proprietary. ©DigitalGlobe. All rights reserved.
Exploitation True Color
Cuprite, Nevada USA | AVIRIS| 3.7 m | WorldView 2 Color Simulation
DigitalGlobe Proprietary. ©DigitalGlobe. All rights reserved.
Exploitation Mineral Indices
Cuprite, Nevada USA | AVIRIS| 3.7 m | WorldView 3 SWIR Mineral Index Simulation
DigitalGlobe Proprietary. ©DigitalGlobe. All rights reserved.
Exploitation Mineral Indices
ASTER Index: “Alunite Kaolinite Pyrophyllite” (S3+S6)/S5 Grayscale
DigitalGlobe Proprietary and Business Confidential
Exploitation Mineral Indices
ASTER Index: “Alunite Kaolinite Pyrophyllite” (S3+S6)/S5 Threshold Vector
DigitalGlobe Proprietary and Business Confidential
Exploitation
ASTER Index: “Alunite Kaolinite Pyrophyllite” (S3+S6)/S5 Threshold Vector at “2.7”
Mineral Indices Index =
𝑆𝑊𝐼𝑅 3+𝑆𝑊𝐼𝑅 6 𝑆𝑊𝐼𝑅 5
Index Values Calculated Alunite = 3.79 Jarosite = 2.26 Alunite
Reflectance
Jarosite
SWIR-5 A = 0.28 J = 0.58
SWIR-6 A = 0.34 J = 0.50
SWIR-3 A = 0.72 J = 0.81
WV-3 Mineral Spectra 1500
1700
1900 2100 Wavelength (nm)
2300
For this index • Alunite greater than jarosite • Alunite greater than threshold (2.7) • Alunite “selected” correctly DigitalGlobe Proprietary and Business Confidential
Exploitation Mineral Indices To Do 1. 2. 3. 4. 5. 6. 7. 8.
Open Cuprite image in ENVI. Select “Band Math” from “Basic Tools” menu. Select “Restore” Button, and navigate to file “mineral_indices_workshop.exp”. Select the first one “Alunite-Clay”, click “OK”. Pair the variable to the bands (i.e. click “B11”, then select “SWIR-3 (11)” from Available Bands List. Repeat for remaining variables, choose a filename, click “OK”. Repeat Band Math for two more expressions – “Carbonate” and “Mica”. In Available Bands List, use RGB Color and display: R = Alunite, G = Mica, B = Carbonate. DigitalGlobe Proprietary and Business Confidential
Roof Type Classification
Boulder, Colorado USA | AVIRIS | 10.8 m | WorldView 3 Simulation
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26
Spectral reflectance of roofs AVIRIS resampled to WV2, WV3 response
1 0.9 0.8 0.7 0.6
Steel Red Tile
0.5
Painted AL 0.4
Fiberglass
0.3 0.2 0.1
WV 2 & 3
WV 3 new bands
0 0.4
0.6
0.8
1
Boulder, Colorado USA | AVIRIS| 10.8 m | Roof Spectra
1.2
1.4
1.6
1.8
2
2.2
2.4
DigitalGlobe Proprietary. ©DigitalGlobe. All rights reserved.
27
Exploitation Spectral Matching To Do
1.
2. 3. 4. 5. 6. 7. 8.
Open two items in ENVI: a. “LA_Basin_mosaic_ss_rfl_WV3_ss” b. “Roofs_spectral_library.sli” Select “Classification” -> “Supervised” -> “Spectral Angle Mapper”. Select file “LA_Basin_mosaic_ss_rfl_WV3_ss”, then “OK”. Select “Import” -> “from Spectral Library file…”. Select “Roofs_spectral_library.sli”, then “OK”. In “Input Spectral Library”, click “Select All Items”, then “OK”. In “Endmember Collection”, click “Select All”, then “Apply”. In “Spectral Angle Mapper Parameters”: a. change “Maximum Angle (radians)” from “0.100” to “0.150”. b. Enter (use “Choose”) filename “yourname_roofs_sam” c. Enter 2nd filename (“Choose”) “yourname_roofs_sam_rule” d. Click “OK” DigitalGlobe Proprietary and Business Confidential
Exploitation Spectral Matching To Display 1.
2. 3. 4. 5. 6.
In “Available Bands List” : a. Select “Yourname_roofs_sam” b. Click “Load Band” Then load RGB image from “LA_Basin_mosaic_ss_rfl_WV3_ss” into a new window. Right click in either window, select “Link Displays”, and “OK”. Right click in either window, select “Cursor Location/Value”. Browse, and see roof category in “Cursor Location/Value”. Optional – use GoogleEarth for “ground truth”.
DigitalGlobe Proprietary and Business Confidential
Exploitation Spectral Matching True Color: R, G, B
Los Angeles area, California USA | AVIRIS| 3.4 m | WV-3 Roof Spectral Classification
Rooftop spectral classification
DigitalGlobe Proprietary and Business Confidential
Summary Introduction: Geologic Remote Sensing Theory 1. 2. 3. 4.
Light-mater interaction Reflectance verses radiance Spectral signatures WV-3 Sensor and SWIR
Applications 1. 2. 3.
RGB display of SWIR bands. Mineral Indices: Cuprite, Nevada USA Rooftop classification: Los Angeles, California, USA
DigitalGlobe Proprietary and Business Confidential
31
