integration of sensors for photogrammetry and remote sensing 8 th semester, ms 2005
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Integration of sensors for photogrammetry and remote sensing
8th semester, MS
2005
Overview on satellites and sensors operating in the optical spectrum
• Earth observing system (EOS)• Landsat• SPOT• NOAA• Other satellite programs
• 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
• 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:
– Return Beam Vidicon (RBV)
– Multispectral Scanner (MSS)
– Thematic Mapper (TM)
– Enhanced Thematic Mapper (ETM)
– Enhanced Thematic Mapper Plus (ETM+)
Landsat satellite program
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
• 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 : – 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
LevelRadiometric corrections
Geometric corrections
Format
0R - - HDF
1R + - HDF
1G ++
(systematic errors, projection)
HDF, GeoTIFF
Landsat 7 0R product
BandNumber
Resolution(meters)
Samples(columns)
Data Lines(rows)
Bits perSample
1-5, 7 30 6600 6000 8
6 60 3300 3000 8
8 15 13200 12000 8
Image Dimensions for a Landsat 7 0R Product
Size of the scene approx. 185 km x 180 km
Applications of Landsat images
• 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 sensorsSPOT 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 stereoimagesacross-track
Acquisition of stereoimagesalong-track, only HRS on SPOT 5
Fore-and-aft stereo data collection
Derivation of a DEM at resolution of 10 m
SPOT products• Level 1A
– radiometric corrections– average location accuracy 350m/50m (SPOT 1 - 4/SPOT 5)
• Level 1B– radiometric corrections and systematic geometric corrections– average location accuracy better than 350m/50m
• 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
• Level 2B (Precision)– images georeferenced into a given map projection using GCPs– average location accuracy better than 30 m in flat terrain
• Level 3 (Ortho)– images georeferenced into a given map projection using GCPs and orthorectified– average location accuracy better than 15m
Applications of SPOT images
monitoring urban growth
detection of a leak on a pipeline
inventorying crops, estimating yields and organizing harvesting
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
…
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 Systemhttp://eospso.gsfc.nasa.gov/
• Landsathttp://landsat.gsfc.nasa.gov/
• SPOThttp://www.spot.com/html/SICORP/_401_.php
• NOAAhttp://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
• 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
Classification algorithms
Minimum distance classifier
Parallelepiped classifierMaximum likelihood classifier
Supervised classification
– training stage (training areas)
– classification stage
Principal Component Analysis
• images from various wavelength bans
appear similar, obtained information is
almost the same (interband correlation)
• all information contained in an original
n-band data set is compressed to n1<n
bands called COMPONENTS
• principal component (PC) data values are
linear combinations of the original data
values
• total scene variance of PC1 > PC2 > PC3…
• data contained in PCs are uncorrelated
(orthogonality)B
and
2
Band 1
Axis I
Axis II