Transcript Document

Integration of sensors for
photogrammetry and remote sensing
8th semester, MS
2005
Overview on satellites and sensors
operating in the optical spectrum
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Earth observing system (EOS)
Landsat
SPOT
NOAA
Other satellite programs
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Exercise: supervised classification of a Landsat TM
image
NASA’s ESE
• 1991: NASA started the Earth Science Enterprise
(ESE), a program studying the Earth as an
environmental system
• ESE consists of:
– Earth observing system (EOS)
– Advanced processing network for processing, storing, and
distributing data
– Teams of scientists all over the world who will study the data
Earth observing system (EOS)
• consists of a series of satellites equipped with different sensors
for long-term global observations of the land surface, biosphere,
solid Earth, atmosphere, and oceans
EOS Terra
• launched on December 18, 1999
• five onboard sensors
– ASTER: Advanced Spaceborne Thermal Emission and
Reflection Radiometer
– CERES: Clouds and Earth's Radiant Energy System
– MISR: Multi-angle Imaging Spectroradiometer
– MODIS: Moderate-resolution Imaging Spectroradiometer
– MOPITT: Measurements of Pollution in the Troposphere
Landsat satellite program
• program has been running since 1970’s
• provides repetitive acquisition of high resolution multispectral
data of the Earth's surface on a global basis
• integral component of NASA's Earth Sciences Enterprise
• 7 missions until 2005
• five different types of sensors:
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Return Beam Vidicon (RBV)
Multispectral Scanner (MSS)
Thematic Mapper (TM)
Enhanced Thematic Mapper (ETM)
Enhanced Thematic Mapper Plus (ETM+)
Landsat missions
Landsat sensors
Goals of Landsat 7 mission
• provide timely, high quality visible and IR images of all landmass
and near-coastal areas on the Earth
• continually refreshing an existing Landsat database
• data will be consistent with currently archived data in terms of
acquisition geometry, calibration, coverage and spectral
characteristics to allow comparison for global and regional
change detection and characterization
• support government, international and commercial communities
• improved access to International Ground Station data
Landsat 7 data distribution system
Landsat 7 orbit
• circular
• Sun-synchronous (between 10:00 AM
and 10:15 AM on the Equator)
• near polar
• repetitive (16-day Earth coverage
cycle )
• nominal altitude of 705 km at the
Equator
• velocity 7.5 km/sec, each orbit takes
nearly 99 min
• just over 14 orbits per day
Landsat 7 swath pattern
ETM+ design
• nadir-viewing, eight-band
multispectral scanning
radiometer
• silicon detectors for bands
1-4 and 8 (panchromatic)
are located in the the
Primary Focal Plane
• detectors for bands 5, 7,
and 6 are located in the
Cold Focal Plane
• 32 detectors for band 8, 16
detectors for bands 1-5
and 7, and 8 detectors for
band 6
Landsat 7 image acquisition
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scenes placed the standard worldwide reference system
the WRS indexes orbits (paths) and scene centers (rows) into a global
grid system comprising 233 paths by 248 rows
• the ETM+ does not acquire data continually, acquisitions are
scheduled in advanced using a Long Term Acquisition Plan
(LTAP)
• LTAP aspects :
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seasonality of vegetation, niche-science communities
predicted vs. nominal cloud-cover
sun angle
missed opportunities for previous acquisitions
quality (cloud-cover) of previous acquisitions
scene clustering
system constraints (duty cycle, ground station locations, recorder capacity,
etc.)
Landsat 7 image products
Program philosophy: to provide raw data
Level
Radiometric
corrections
Geometric
corrections
Format
0R
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HDF
1R
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HDF
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(systematic errors,
projection)
HDF, GeoTIFF
1G
Landsat 7 0R product
Image Dimensions for a Landsat 7 0R Product
Band
Number
Resolution
(meters)
Samples
(columns)
Data Lines
(rows)
Bits per
Sample
1-5, 7
30
6600
6000
8
6
60
3300
3000
8
8
15
13200
12000
8
Size of the scene approx. 185 km x 180 km
Applications of Landsat images
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middle and small scale mapping
forest monitoring
mapping volcanic surface deposits
monitoring of natural disasters (floods, fires, slides)
SPOT satellite program
• SPOT = Système Pour l’Observation de la Terre
• program started from an initiative of the French government in
1978, Sweden and Belgium joined before the launch of the first
series of satellites
• first system that employed pushbroom scanning techniques and
off-nadir viewing (stereoscopic coverage)
SPOT program – general features
SPOT sensors
SPOT 1, 2, 3 high resolution visible (HRV) imaging system
SPOT 4 high resolution visible and infrared (HRVIR) imaging system
SPOT 5 high resolution geometric (HRG) and high resolution stereoscopic
(HRS) imaging system
Acquisition of stereoimages
across-track
Acquisition of stereoimages
along-track, only HRS on SPOT 5
Fore-and-aft stereo data collection
Derivation of a DEM at resolution of 10 m
SPOT products
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Level 1A
– radiometric corrections
– average location accuracy 350m/50m (SPOT 1 - 4/SPOT 5)
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Level 1B
– radiometric corrections and systematic geometric corrections
– average location accuracy better than 350m/50m
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Level 2A
– images rectified to UTM/WGS8 system without GCPs, a global DEM used
for SPOT 5 images
– average location accuracy better than 350m/50m
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Level 2B (Precision)
– images georeferenced into a given map projection using GCPs
– average location accuracy better than 30 m in flat terrain
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Level 3 (Ortho)
– images georeferenced into a given map projection using GCPs and
orthorectified
– average location accuracy better than 15m
Applications of SPOT images
inventorying crops,
estimating yields and
organizing harvesting
monitoring urban growth
detection of a leak
on a pipeline
Environmental satellites NOAA
• series of polar orbit satellites launched from 1978
• altitude approx. 830 km
• collect global data on
– cloud cover
– surface conditions such as ice, snow, and vegetation
– atmospheric temperatures, moisture, aerosol, and ozone
distributions
Sensors on NOAA satellites
• Advanced Very high Resolution radiometer (AVHRR)
– six channels detecting visible, near IR, and thermal IR channels
– nominal spatial resolution of 1.1 km at nadir
• High Resolution Infrared Radiation Sounder (HIRS)
– one visible channel, seven shortwave IR channels, and 12
longwave IR channels
– nominal spatial resolution at nadir of 20.3km and 18.9 km
• Advanced microwave sounding units (AMSU)
– provide measurements for calculating global atmospheric
temperature and humidity profiles, vertical water vapor profiles
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Among others: Search and Rescue Instruments
» program for receiving emergency signals
NOAA’s imagery applications
Sea surface temperature
map produced from the
AVHRR measurements
Cloud covers, storms.
The image with an
original resolution of
1.1km was produced from
a composite of channels
1, 2, and 4 from of the
AVHRR instrument.
Ozone profiles and maps
of total ozone values
Links
• Earth Observing System
http://eospso.gsfc.nasa.gov/
• Landsat
http://landsat.gsfc.nasa.gov/
• SPOT
http://www.spot.com/html/SICORP/_401_.php
• NOAA
http://www.oso.noaa.gov/poes/
Literature:
Lillesand,T.,M., Kiefer, R., W.: remote sensing and image
interpretation, Wiley & Sons, 2000 (2004)
Digital Image Processing
• Data Acquisition
• Image Rectification and Restoration
– geometric and radiometric corrections, noise elimination
• Image Enhancement
– contrast, filtering, edge enhancement, ...
• Image Classification
– supervised, unsupervised
• Data Merging and GIS Integration
• Image Transmission and Compression
Classification
• automatically categorisation of all pixels in an image into land
cover classes
• basic idea: in multispectral images different features types show
different combinations of digital numbers
• supervised classification
• unsupervised
– classification stage
– determining land cover identity of clusters
Classification algorithms
Supervised classification
– training stage (training areas)
– classification stage
Minimum distance classifier
Maximum likelihood classifier
Parallelepiped classifier
Principal Component Analysis
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images from various wavelength bans
appear similar, obtained information is
almost the same (interband correlation)
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all information contained in an original
bands called COMPONENTS
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principal component (PC) data values are
Band 2
n-band data set is compressed to n1<n
linear combinations of the original data
values
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total scene variance of PC1 > PC2 > PC3…
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data contained in PCs are uncorrelated
(orthogonality)
Band 1