Image Processing Reference
In-Depth Information
Landsat (originally called Earth Resources Technology Satellite or ERTS)
developed by National Aeronautics and Space Administration (NASA) and
operated by the United States Geological Survey (USGS)
The French earth observing series of satellites called Satellite Pour l'Observation
de la Terre (SPOT)
Indian Remote Sensing (IRS) operated by the Indian government
The U.S. Defense Meteorological Satellite Program (DMSP) series operated by
the National Oceanic and Atmospheric Administration (NOAA)
IKONOS by Space Imaging, Inc.
The ASTER imaging system mounted on the TERRA earth observing satellite
and operated by NASA
The QuickBird mission by DigitalGlobe (formerly EarthWatch, Inc.)
The first successful launch year for each of the above missions is marked in Fig. 7.1
to illustrate their operational time scale.
Although the operating principles of various imaging instruments have changed
over the years, the spectrum of applications and usability of imagery have been
largely determined by the spatial, radiometric, spectral, and temporal resolutions of
the imaging system. Image resolution character-
istics play a major role in determining the size
and properties of the features or phenomena that
can be discriminated in remotely sensed imagery.
The spatial, radiometric, spectral, and temporal
resolutions are discussed below for the digital
imaging systems and multi-spectral scanners
listed in Fig. 7.1 . Spatial, radiometric, spectral,
and temporal resolutions can each be defined in two different contexts, the users'
needs and the technical specifications of the imaging system. In the context of
users' needs, definitions depend on the purpose of the study. The definitions of
usability of imagery in
urban applications is
determined by the spatial,
radiometric, spectral, and
temporal resolutions of
the imaging system
Fig. 7.1 Time scale of operational earth observing missions most commonly used in urban
remote sensing applications
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