30. HYPERSPECTRAL IMAGER SURVEY AND DEVELOPMENTS
FOR SCIENTIFIC AND OPERATIONAL LAND PROCESSES
MONITORING APPLICATIONS
309
IFOV, thus, either large apertures or reduced radiometric or geometric
performance compared to the other category:
Pushbroom IS, which are sensors with electronic across-track and spectral
scan, thus, the inverse of the line frequency being equal the pixel dwell time, requiring 2-d detector arrays per wavelength range; this group will
form the emphasis of this paper—and here we have two basic sub-groups
again:
Wide-field IS, such as MERIS (Baudin et al., 1993) or ROSIS (Blechinger
et al., 1995) for global mapping, often by assembling multiple optics module aside, and
Narrow-field IS, for spot-mode observations of discrete targets, typically
addressed by an additional front optics-pointing mirror.
2.
a)
b)
This categorization has the following basic technical reasons:
The main limitation arises from the 2-d detector arrays which, at least
for the spectral range
typically are limited to less than 1024
detector elements in the spatial scanning direction
Correspondingly, the front and spectrometer optics have to provide a
planar focal plane of a certain physical extension, typically 30–50 mm
width, which excludes a priori several optics concepts
FOR SCIENTIFIC AND OPERATIONAL LAND PROCESSES
MONITORING APPLICATIONS
309
IFOV, thus, either large apertures or reduced radiometric or geometric
performance compared to the other category:
Pushbroom IS, which are sensors with electronic across-track and spectral
scan, thus, the inverse of the line frequency being equal the pixel dwell time, requiring 2-d detector arrays per wavelength range; this group will
form the emphasis of this paper—and here we have two basic sub-groups
again:
Wide-field IS, such as MERIS (Baudin et al., 1993) or ROSIS (Blechinger
et al., 1995) for global mapping, often by assembling multiple optics module aside, and
Narrow-field IS, for spot-mode observations of discrete targets, typically
addressed by an additional front optics-pointing mirror.
2.
a)
b)
This categorization has the following basic technical reasons:
The main limitation arises from the 2-d detector arrays which, at least
for the spectral range
typically are limited to less than 1024
detector elements in the spatial scanning direction
Correspondingly, the front and spectrometer optics have to provide a
planar focal plane of a certain physical extension, typically 30–50 mm
width, which excludes a priori several optics concepts