Figure 3.
Figure depicting information content relative to the number of Hyperion
bands for classifying 7 vegetation classes in Central Africa. The 7 vegetation classes
are: slash and burn agriculture, agricultural fallows (1-3 years), agricultural fallows
(>3 years), wetlands, young secondary forest, mature secondary forest, and primary
forest. About 15 hyperspecral Hyperion bands achieve 92% accuracy, beyond which
the additional bands provide little or no increase in accuracy.
Table 2. Optimal (non-redundant) hyperspectral narrow bands to study vegetation and agricultural crops
1,2,3,4,5,6
Waveband
number (#)
Waveband
center (λ)
Waveband
width (Δλ)
Importance and physical significance of waveband in vegetation and cropland
studies
A. Ultrviolet
1
375
5
fPAR, leaf water
: fraction of photosynthetically active radiation (fPAR), leaf water content
B. Blue bands
2
405
5
Nitrogen, Senescing:
sensitivity to changes in leaf nitrogen. reflectance changes due to
pigments is moderate to low. Sensitive to senescing (yellow and yellow green leaves).
3
490
5
Carotenoid, Light use efficiency (LUE), Stress in vegetation:
Sensitive to
s
enescing
and loss of chlorophyll\browning, ripening, crop yield, and soil background effects
C. Green bands
4
515
5
Pigments (Carotenoid, Chlorophyll, anthocyanins), Nitrogen, Vigor
: positive
change in reflectance per unit change in wavelength of this visible spectrum is maximum
around this green waveband
5
531
1
Light use efficiency (LUE), Xanophyll cycle, Stress in vegetation, pest and disease:
Senescing and loss of chlorophyll\browning, ripening, crop yield, and soil background
effects
6
550
5
Chlorophyll
: Total chlorophyll; Chlorophyll/carotenoid ratio, vegetation nutritional and
fertility level; vegetation discrimination; vegetation classification
7
570
5
Pigments (Anthrocyanins, Chlorophyll), Nitrogen
: negative change in reflectance
per unit change in wavelength is maximum as a result of sensitivity to vegetation vigor,
pigment, and N.
D. Red bands
8
682
5
Biophysical quantities and yield
: leaf area index, wet and dry biomass, plant height,
grain yield, crop type, crop discrimination
E. Red-edge bands
9
705
5
Stress and chlorophyll
: Nitrogen stress, crop stress, crop growth stage studies
10
720
5
Stress and chlorophyll
: Nitrogen stress, crop stress, crop growth stage studies
11
700-740
700-740
Chlorophyll, senescing, stress, drought:
first-order derivative index over 700-740 nm
has applications in vegetation studies (e.g., blue-shift during stress and red-shift during
healthy growth)
“Eliminating the redundant
bands, and establish optimal
bands, is an important step in
hyperspectral data analysis.
Overall, ~15 to 20, but no
more than about 28 HNBs
provide optimal information
in study of vegetation or
crop characterization and
classification”
PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING
August 2014
701
