484
June 2014
PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING
M
anual
I
nterpretation
of
18 W
avelength
B
ands
of
I
magery
A total of five missions were successfully flown over the Purdue
AgronomyFarmduring the summer of 1964. Iwas hiredbyPurdue
University under a grant from the U.S. Department of Agriculture
(USDA), EconomicResearchService, andwhen I arrivedat Purdue
in September 1964 after my discharge from the U.S. Army, my
first task was to interpret the imagery obtained on these missions
to determine if it could be used to identify different crop species
and conditions. Of the 18 wavelength bands of imagery available,
all of the bands obtained by the
“optical-mechanical scanner”
had a military classification
of “confidential” because the
scanner had been developed
under military contract. As a
result, I had to have military
clearance to work with the
imagery. But since I had just
gotten out of the U.S. Army
and did have such clearance,
it was relatively easy to have
my credentials extended to
allow me to work with this
data. However, because the
scanner imagery was classified
as “confidential”, I had to keep
it in a locked cabinet, and no
one else could be in the room
when I was working with the
imagery!
T
able
1. W
avelength
B
ands
of
R
emote
M
ultispectral
D
ata
O
btained
in
1964
Wavelength Bands
Detector
Instrument
microns
0.32-0.38
0.38-0.44
0.41-0.47
0.45-0.52
0.48-0.56
0.55-0.64
0.62-0.68
0.71-0.79
0.85-0.89
0.38-0.89
0.4-0.7
0.7-0.9
1.5-1.7
2.0-2.6
3.0-4.1
4.5-5.5
1.5-5.5
8.2-14.0
Color (0.4-0.7
Infrared color (0.5-0.9)
Filtered photomultiplier
Filtered Kodak I - N spectroscopic film
Filtered Kodak I - N spectroscopic film
Filtered Kodak I - N spectroscopic film
Filtered Kodak I - N spectroscopic film
Filtered Kodak I - N spectroscopic film
Filtered Kodak I - N spectroscopic film
Filtered Kodak I - N spectroscopic film
Filtered Kodak I - N spectroscopic film
Unfiltered Kodak I - N spectroscopic film
Kodak Super XX Aerographic film and Wratten K2-Star filter
Kodak Infrared Aerographic film and Wratten 89-B filter
Filtered Indium Antimide (In Sb)
Filtered Indium Antimide (In Sb)
Filtered Indium Antimide (In Sb)
Filtered Indium Antimide (In Sb)
Unfiltered Indium Antimide (In Sb)
Filtered Mercury-doped Germanium (Hg: Ge)
Anscochrome D Color film and color correction filter
Kodak Ektachrome Infrared Aero film (or Camouflage detection film)
and Wratten 12 filter and special infrared color filter
Optical-mechanical scanner
U - M 9-lens camera
U - M 9-lens camera
U - M 9-lens camera
U - M 9-lens camera
U - M 9-lens camera
U - M 9-lens camera
U - M 9-lens camera
U - M 9-lens camera
U - M 9-lens camera
K - 17 camera (9” format)
K - 17 camera (9” format)
Optical-mechanical scanner
Optical-mechanical scanner
Optical-mechanical scanner
Optical-mechanical scanner
Optical-mechanical scanner
Optical-mechanical scanner
P-2 camera (70 mm format)
P-2 camera (70 mm format)
Manually interpreting the differences in gray tone that might
identify the various crop types and conditions using 18 differ-
ent wavelength bands of imagery proved to be challenging. The
approach used involved a graduated set of Kodak gray-scale
chips and visually comparing them to the gray tones of the dif-
ferent fields of agricultural crop types and conditions as seen
on the individual bands of imagery. Different crop types were
compared for each wavelength band of imagery and “Multispec-
tral Response Pattern” graphs prepared. These graphs showed
which wavelength bands would be useful for differentiating the
Figure 2. Multispectral response patterns for wheat and oats on imagery obtained on June 25, 1964 (from: Holmes
and Hoffer, 1966).
