Spectral Unmixing Applied to Desert Soils for the - Naval ...

Collins et al. (1997) was able to successfully use the characteristic spectrum of desert
varnish to not only detect targets such as military vehicles and fox holes, but tank tracks
on the desert varnish itself (Colins et al., 1997). Use of the differences in restrahlen
emissivity between the desert varnish and other materials provided a useful visualization
of vehicle traffic and target location (Figure 6) (Collins et al., 1997).
Figure 6. The above image from Collins et al. (1997) shows the results of using
principal component analysis achieved using LWIR hyperspectral SEBASS
data for their target detection and terrain classification study.
Hyperspectral imagery have also proved useful for several environmental
applications. One in particular that applies to this research is the use of hyperspectral
data to identify plant stress during a study conducted in 2004 (Smith et al., 2004).
Observed spectral changes consisted of decreased reflectance in plants that were
undergoing stress in the near infrared range between 0.72 and 0.73 µm (720 and 730 nm)
(Smith et al., 2004). Characteristic changes in reflectance related to stress can be seen in
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