| definition |
-
Surface directional radiances and reflectances were measured
with a Modular Multiband Radiometer (MMR), in six of the
spectral bands nominally corresponding to the Thematic Mapper
bands, and the seventh band was in the middle infrared
region. The spectral regions, nominal band-widths and the uses
of the bands are as follows:
Band Wavelength Primary
(micrometer) Application
---- ------------ ------------------------------------------------
1 0.45 - 0.52 Water bodies, land use, soil, and vegetation
analyses.
2 0.52 - 0.62 Green reflectance of healthy vegetation.
3 0.63 - 0.69 Vegetation discrimination, soil and geological
boundary delineations.
4 0.75 - 0.88 Amount of vegetation biomass, crop identification,
emphasizes soil-crop and land-water contrasts.
5 1.15 - 1.30 Crop drought and plant vigor investigations,
hydrologic discrimination between clouds,
snow, and ice.
6 1.50 - 1.85 Crop drought and plant vigor investigations,
hydrologic discrimination between clouds,
snow, and ice.
7 2.08 - 2.35 Discrimination of geologic rock formations, and
zones of hydrothermal alteration in rocks.
The Barnes Modular Multiband Radiometer (MMR) was designed to
acquire multispectral radiance data over the visible, near
infrared, middle infrared and thermal regions of the
electromagnetic spectrum. It produces analog voltage responses
to scene radiance in 8 spectral bands. Voltages from thermistors
attached to the instrument chopper and detectors are recorded to
provide a means of compensating for thermal effects on sensor
response and for calculation of target surface temperatures. The
8 bands are approximately 0.45 '-' 0.52,0.52 0.60, 0.63-0.69,
0.76-0.90, 1.15-1.30, 1.55-1.75, 2.08-2.35, 10.4-12.5 um. Bands
1-4 have silicon detectors and bands 5-7 have lead sulfide
detectors. The MMR's dimensions are 26.4 cm by 20.5 cm by 22.2
cm and the device weighs 6.4 kg. The MMR is battery
powered. Data logging was via a microprocessor-based Omnidata
Polycorder where analog to digital conversions take place.
The NASA Bell UH-1B helicopter optical remote sensing system
supported a data acquisition system consisting of a bore-sighted
MMR; a color video camera; and two 35 mm flight research cameras
loaded with color film (one with a 1 inch focal length and the
other with a 6 inch focal length). Controller units for all the
optical devices are rack-mounted inside the helicopter and are
wired such that a single switch closure triggers all
devices. The switch closure also activates an audible tone which
is recorded on one of the two audio tracks of a Beta-format
video recording system. The other audio track of the VCR was
used to record cabin intercom conversations among the helicopter
crew. If one desires to examine site conditions in greater
detail, the higher resolution 35 mm still photography can be
reviewed.
Additional information available at
"http://forest.gsfc.nasa.gov/html/fedmac/helo/helo_mmr.html"
[Summary provided by NASA]
|
