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BACKGROUND TO IMAGING SPECTROSCOPY
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The technique of imaging spectroscopy represents a further
step in the continuing development of new ways to obtain more accurate
information on the physical properties of the Earth's surface from remote
platforms. The technique was originally developed to obtain chemical
information of inaccessible planetary surfaces in the solar system but is now
becoming of increasing importance in many application areas in Earth
observation.
Most natural Earth surface materials have diagnostic absorption features in the 400 nm to 2500 nm range of the reflected solar spectrum. Since these diagnostic features are typically of a very narrow spectral appearance, surface materials can only be identified directly, if the spectrum is sampled at sufficiently high resolution.
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During the last few years a new generation of airborne optical
remote sensing systems (such
as AVIRIS - Airborne Visible and Infrared Imaging Spectrometer) has evolved under the name of "imaging spectrometers".
The new sensors can provide image data with detailed spectral resolution up
to as many as 200 spectral bands. These are powerful tools for Earth sensing because the data captured can be used in surface
differentiation by evaluation of spectral signatures. The ultimate goal in
imaging spectrometry is to produce laboratory-like reflectance spectra for
each pixel in the image.
The spectral information collected from imaging spectrometers can be used in a wide range of disciplines such as agricultural science environmental science, atmospheric science and oceanography.
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