Transcript Passive Remote Sensing - National Cheng Kung University

Chapter 9
Passive Remote Sensing
Introduction to Remote Sensing
Instructor: Dr. Cheng-Chien Liu
Department of Earth Sciences
National Cheng-Kung University
Last updated: 16 December 2004
Introduction
 Optical range  0.3 m m~14 m m
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Landsat series
SPOT series
High spatial resolution
High spectral resolution
Landsat satellite program overview
 Earth Resources Technology Satellite
(ERTS) 1967
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ERTS-1, 1972~1978
Nimbus weather satellite  modified
Experimental system  test feasibility
Open skies principle
 Landsat-2, 1975 (ERTS-2)
Landsat satellite program overview
(cont.)
 Table 6.1: Characteristics of Landsat
1~6
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Return Beam Vidicon (RBV) camera systems
Multispectral Scanner system (MSS)
Thematic Mapper (TM)
Enhanced Thematic Mapper (ETM)
 Table 6.2: Sensors used on Landsat 1~6
missions
Orbit characteristic of Landsat-1, -2,
and –3
 Fig 6.1: Landsat –1, -2, and –3 observatory
configuration
• 3m x 1.5m, 4m width of solar panels, 815 kg, 900 km
• Inclination = 90
• To= 103 min/orbit
 Fig 6.2: Typical Landsat-1, -2 and –3 daily
orbit pattern
• Successive orbits are about 2760km
• Swath: 185km
• Orbital procession  18 days for coverage repetition
20 times of global coverage per year
Orbit characteristic of Landsat-1, -2,
and –3 (cont.)
 Sun-synchronous orbit
• 9:42 am  early morning skies are generally
clearer than later in the day
• Pros: repeatable sun illumination conditions on
the same day in every year
• Cons: variable sun illumination conditions
with different locations and seasons 
variations in atmospheric conditions
Sensors onboard Landsat-1, -2 and –
3
 3-Channel RBV
• 185km x 185 km
• Ground resolution: 80m
• Spectral bands: 1: 0.475 mm~0.575 mm (green)
2:0.580 mm~0.680 mm (red)
3: 0.690 mm~0.830 mm (NIR)
• Expose  photosensitive surface  scan  video
signal
• Pros:
Greater cartographic fidelity
Reseau grid  geometric correction in the recording process
Sensors onboard Landsat-1, -2 and –
3 (cont.)
 3-Channel RBV (cont.)
• Landsat-1: malfunction  only 1690 scenes
• Landsat-2  only for engineering evaluation
 only occasionally RBV imagery was
obtained.
• Landsat-3
Single broad band (0.505~0.75 u mm)
2.6 times of resolution improved: 30m  double f
Two-camera side-by-side configuration with side-lap and
end-lap. (Fig 6.5)
Fig 6.6: Landsat-3 RBV image
Sensors onboard Landsat-1, -2 and –
3 (cont.)
 4 Channel MSS
• 185km x 185km
• Ground resolution: 79m
• Spectral band:
Band 4: 0.5 mm ~ 0.6 mm (green)
Band 5: 0.6 mm ~ 0.7 mm (red)
Band 6: 0.7 mm ~ 0.8 mm (NIR)
Band 7: 0.8 mm ~ 0.9 mm (NIR)
Band 8: 10.4~12.6 um  Landsat-3, failed
Band 4~7  band 1~4 in Landsat-4, -5
Fig 6.7: Comparison of spectral bands
Sensors onboard Landsat-1, -2 and –
3 (cont.)
 4 Channel MSS (cont.)
• Fig 6.8: Landsat MSS operating configuration
Small TFOV  use an oscillating scan mirror
• A-to-D converter (6 bits)
Pixel width: 56m x 79m  set by the pixel sampling rate (Fig 6.9)
Each Landsat MSS scene  185km x 185km
 2340 scan lines, 3240 pixels per line, 4 bands
 Enormous data
Fig 6.10: Full-frame, band 5, Landsat MSS scene
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Parallelogram  earth’s rotation
15 steps
Tick marks  Lat. Long.
Annotation block
• Color composite: band 4 (b), band 5 (g), band 7(r)
(Fig 6.7)
Sensors onboard Landsat-1, -2 and –
3 (cont.)
 Data distribution
• Experiment  transitional  operational
• NASA
NOAA
NASA
USGS
EOSAT
USGS
Landsat-1,-2,-3 Landsat-4,-5,-6 Landsat-7
Department of Interior Department of Commerce Department of Defense
• Data receiving station
• Data reprocessing
• Data catalogue
Orbit characteristics of Landsat-4
and -5
 Fig 6.20: Sun-synchronous orbit of
Landsat-4 and –5
• Altitude: 900  705km
Retrievable by the space shuttle
Ground resolutions
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Inclination 98.20 T=99min  14.5 orbit/day
9:45 am
Fig 6.21: adjacent orbit space = 2752km
16-day repeat cycle
8-day phase between Landsat-4 and –5 (Fig 6.22)
Sensors onboard Landsat-4 and -5
 Fig 6.23: Landsat-4 and –5 observatory
configuration
• MSS, TM
• 2000 kg, 1.5x2.3m solar panels x 4 on one side
• High gain antenna  Tracking and Data Relay
Satellite system (TDRSS)
• Direct transmission  X-band and S-band
MSS: 15 Mbps
TM: 85 Mbps
Sensors onboard Landsat-4 and –5
(cont.)
 MSS
• Same as previous except for larger TFOV for keeping
the same ground resolution (79m  82m)
• Renumber bands
 TM
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7 bands (Table 6.3)
DN: 6  8 bits
Ground resolution: 30m (thermal band: 120m)
Geometric correction  Space Oblique Mercator
(SOM) cartographic projection
Sensors onboard Landsat-4 and –5
(cont.)
 TM (cont.)
• Bi-directional scan  the rate of oscillation of mirror
dwelling time  geometric integrity signal-to-noise
• Detector:
MSS: 6x4=24
TM: 16x6+4x1=100
• Fig 6.14: Thematic Mapper optical path and
projection of IFOV on earth surface
• Fig 6.15: Schematic of TM scan line correction
process
Landsat-6 planned mission
 A failed mission
 Enhanced Thematic Mapper (ETM)
• TM+ panchromatic band (0.5~0.9 mm) with
15m resolution  pan sharpening
• Monolithic detector design  coregister
• Set 9-bit A-to-D converter to a high or low gain
8-bit setting from the ground.
Low reflectance  water  high gain
Bright region  deserts  low gain
Landsat-7
 Launch: 1999
 Web site: http://landsat.gsfc.nasa.gov
 Landsat 7 handbook
 Landsat 7 in orbit
 Depiction of Landsat 7
Landsat-7 (cont.)
 Landsat 7 Orbit
• Orbital paths
• Swath
• Swath pattern
 Landsat data
• http://landsat.gsfc.nasa.gov/main/data.html
Landsat-7 (cont.)
 Payload
• Enhanced Thematic Mapper Plus (ETM+)
Dual mode solar calibrator
Data transmission
 TDRSS or stored on board.
GPS  subsequent geometric processing of the data
• High Resolution Multi-spectral Stereo Imager
(HRMSI)
5m panchromatic band
10m ETM bands 1~4
Pointable  revisit time (<3 days) Stereo imaging.
00~380 cross-track and 00~300 along-track
Landsat-7 (cont.)
 Application
• Monitoring Temperate Forests
• Mapping Volcanic Surface Deposits
• Three Dimensional Land Surface Simulations
Landsat TM Image interpretation
 Pros:
• Spectral and radiometric resolution
• Ground resolution
 Fig 6.26: MSS vs TM
 Fig 6.27: All seven TM bands for a
summertime image of an urban fringe area
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Lake, river, ponds: b1,2 > b3 > b4=b5=b7=0
Road urban streets: b4  min
Agricultural crops: b4  max
Golf courses
Landsat TM Image interpretation
(cont.)
 Fig 6.27 (cont.)
• Glacial ice movement: upper right  lower left
Drumlins, scoured bedrock hills
Band 7  resample from 120m to 30m
 Plate 12 + Table 6.5: TM band color
combinations
• (a): normal color  mapping of water sediment
patterns
• (b): color infrared  mapping urban features and
vegetation types
• (c)(d): false color
Landsat TM Image interpretation
(cont.)
 Fig 6.28: Landsat TM band 6 (thermal
infrared) image
• Correlation with field observations  6 gray
levels  6T
 Plate 13: color-composite Landsat TM
image
• Extremely hot  blackbody radiation 
thermal infrared
• TM bands 3, 4 and 7
Landsat TM Image interpretation
(cont.)
 Fig 6.29: Landsat TM band 5 (midinfrared) image
• Timber clear-cutting
 Fig 6.30: Landsat TM band 3, 4 and 5
composite
• Extensive deforestation.
 Fig 6.31: Landsat TM band 4 image
map
• 13 individual TM scenes + mosaic
SPOT Satellite Program
 Background
• French+Sweden+Belgium
• 1978
• Commercially oriented program
 SPOT-1
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French Guiana, Ariane Rocket
1986
Linear array sensor+pushbroom scanning+pointable
Full-scene stereoscopic imaging
SPOT Satellite Program (cont.)
 SPOT-2
• 1990
 SPOT-3
• 1993
Orbit characteristics of SPOT-1, -2
and -3
 Orbit
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Circular, near-polar, sun-synchronous orbit
Altitude: 832km
Inclination: 98.70
Descend across the equator at 10:30AM
Repeat: 26 days
Fig 6.21: SPOT revisit pattern at latitude 450
and 00
At equator: 7 viewing opportunities exist
At 450: 11 viewing opportunities exist
Sensors onboard SPOT-1, -2
and -3
 Configuration (Fig 6.34)
• 223.5m, 1750 kg, solar panel: 15.6m
• Modular design
 High Resolution Visible (HRV) imaging
system
• 2-mode
10m-resolution panchromatic mode (0.51~0.73mm)
20m-resolution color-infrared mode. (0.5~0.59mm,
0.61~0.68mm, 0.79~0.89mm)
Sensors onboard SPOT-1, -2 and –3
(cont.)
 HRV (cont.)
• Pushbroom scanning
No moving part (mirror)  lifespan
Dwell time 
Geometric error 
• 4-CCD subarray
6000-element subarray  panchromatic mode, 10m
Three 3000-element subarrays  multi-spectral mode, 20m
8-bit, 25 Mbps
• Twin-HRV instruments
IFOV (for each instrument)  4.130
Swath: 60km  2 - 3km = 117km (Fig 3.36)
TFOV (for each instrument)  270=0.6045 (Fig 3.35)
Sensors onboard SPOT-1, -2 and –3
(cont.)
 HRV (cont.)
• Data streams
Although 2-mode can be operated simultaneously, only one mode data
can be transmitted  limitation of data stream
• Stereoscopic imaging
Off-nadir viewing capability (Fig 6.37)
Frequency  revisit schedule (Fig 6.33)
Base-height ratio  latitude
 0.75 at equator, 0.5 at 450
• Control
Ground control station  Toulouse, France  observation sequence
Receiving station  Tordouse or Kiruna, Sweden
 Tape recorded onboard
 Transmitted within 2600km-radius around the station
SPOT HRV image interpretation
 Fig 6.38: SPOT-1 panchromatic image
• 10m-resolution
Cf: Landsat MSS 80m
Cf: Landsat TM 30m (Fig 6.26)
Cf: Landsat ETM 15m (Fig 6.32)
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Fig 6.39: SPOT-1 panchromatic image
Plate14: merge of multispectral & panchromatic data
Fig 6.40: SPOT-1 panchromatic image stereopair
Plate 15: Perspective view of Alps
SPOT stereopair + parallax calculation
Plate 23
• Fig 6.41: before and after the earthquake
SPOT –4 and –5
 SPOT –4
• Launched 1998
• Vegetation Monitoring Instrument (VMI)
Swath: 2000km  daily global coverage
Resolution: 1km
Spectral band: b(0.43~0.47mm), g(0.5~0.59mm),
r(0.61~0.68mm), N-IR(0.79~0.89mm), mid-IR(1.58~1.75mm)
SPOT –4 and –5 (cont.)
 SPOT – 5
• Launched 2002
• Vegetation Monitoring Instrument (VMI)
Swath: 2000km  daily global coverage
Resolution: 1km
Spectral band: b(0.43~0.47mm), g(0.5~0.59mm),
r(0.61~0.68mm), N-IR(0.79~0.89mm), mid-IR(1.58~1.75mm)
Earth Observing System
 Mission to Planet Earth (MTPE)
• Aims: providing the observations,
understanding, and modeling capabilities
needed assess the impacts of natural events and
human-induced activities on the earth’s
environment
• Data and information system: acquire, archive
and distribute the data and information
collected about the earth
• Further international understanding of the
earth as a system
Earth Observing System (cont.)
 EOS (Table 6.19)
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ASTER
CERES
MISR
MODIS
MOPITT
 MODIS (Table 6.20)
• Table 6.20
• Terra: 2000
• Aqua: 2002
 ASTER (Table 6.21)
Hign-resolution satellite system
 CORONA
• 1960 – 1972, declassified in 1995
• KH-1 ~ KH-4B ~ KH-5
Camera + film
Band and resolution
• Web site: http://earthexplorer.usgs.gov
• Impacts
Hign-resolution satellite system (cont.)
 IKONOS
• 1999 by Space imaging
• Bands and resolution
1m-resolution
 0.45 – 0.90 mm
4m-resolution
 0.45 – 0.52 mm
 0.52 – 0.60 mm
 0.63 – 0.69 mm
 0.76 – 0.90 mm
• Orbit: sun-synchronous
• Repeat coverage: 1.5 (1m) ~ 3 (4m) days
Hign-resolution satellite system (cont.)
 OrbView–3 and –4
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http://www.orbimage.com
OrbView-2: SeaWiFS
Will be launched soon!
Similar bands and resolution as IKONOS
 OrbView–4
• 200 spectral channels in the range 0.45 – 2.5 m
m at 8m resolution
Hign-resolution satellite system (cont.)
 QuickBird
• 2001 by EarthWatch Inc.
• Bands and resolution
61cm-resolution
 0.45 – 0.89 mm
2.44m-resolution
 0.45 – 0.52 mm
 0.52 – 0.60 mm
 0.63 – 0.69 mm
 0.76 – 0.89 mm
Hyperspectral satellite system (cont.)
 Earth Observing 1 (EO-1)
• NASA + USGS
21 November 2000
One-year technology validation/demonstration mission
Landsat Data Continuity Mission (LDCM)
• Hyperion
• ALI