3
General Overview
The
FIELDSCOUT® CM1000
NDVI (Normalized
Difference Vegetation Index) Meter senses light at
wavelengths of 660 nm and 840 nm to estimate plant
health. The ambient and reflected light at each
wavelength is measured. Chlorophyll absorbs 660 nm
light and, as a result, the reflection of that wavelength
from the leaf is reduced compared to the reflected 840 nm
light. Light having a wavelength of 840 nm is unaffected
by leaf chlorophyll content and serves as an indication of
how much light is reflected due to leaf physical
characteristics such as the presence of a waxy or hairy leaf
surface.
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Lasers define the target as the trigger is pressed. At a
distance of 11.2 inches (28.4 cm), the field of view is
0.434 inches (1.10 cm) in diameter. At a distance of
72 inches (183 cm), the field of view increases to 7.4
inches (18.8 cm) in diameter.
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A NDVI value (-1 to 1) is calculated from the
measured ambient and reflected light data. [(%Near
Infrared-%Red) / (%Near In % Red)]
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The number of samples taken and a running average
of NDVI values is displayed.
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Ambient light level is displayed on a scale of 0 to 9.
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The optional data-logging system records the latitude
and longitude (if GPS is used), the sample number,
the individual NDVI reading, and the value assigned
to the ambient light level.
♦
The recorded data is downloaded to your PC using
the optional FieldScout
®
software.
♦
The data-logged files are comma-delimited text files
and can be opened and worked with in any
spreadsheet, graphing, statistical, or word processing