Image Processing Reference
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Fig. 7.2 Historical trend of increasing spatial resolution of imaging instruments most commonly
used in urban remote sensing applications. The DMSP Operational Linescan System (OLS) is not
included in this figure due to its relatively low spatial resolution at 2.7 km low spatial resolution
(smooth mode) and at 550 m high spatial resolution (fine mode) (Dickinson et al. 1974 ). The
thermal infrared (TIR) band of Landsat Multispectral Scanner (MSS) is not included in the figure
due to its limited use in urban analysis
the end of 1999 and 2000, respectively, are currently operational. IKONOS and
QuickBird provide images at 1 m and 0.61 cm spatial resolution in panchromatic
mode and 4 and 2.5 m spatial resolution in V/NIR mode respectively. The OrbView-3
satellite system was launched in 2003 and has similar sensor specifications as the
IKONOS system. A new IRS mission (CartoSat) designed for cartographic applica-
tions was launched on 5 May, 2005 and will provide panchromatic imagery at 2.5 m.
Urban remote sensing applications have substantially benefited from the high
spatial resolution characteristics of commercial satellite image data and the ensuing
ability to monitor smaller features of interest in complex urban environments (Donnay
et al. 2001 ). The trend of increasing spatial resolution of imaging sensors since the
1970s is illustrated in Fig. 7.2 and includes all satellite imaging systems of pertinence.
Radiometric Resolution
The radiometric resolution (or radiometric precision) of remote sensing data is
determined by the detector or film sensitivity and noise level, as well as the quan-
titative manner in which analog radiance measurements are digitized and stored as
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