INFORMATION CONCERNING BI-SPECTRAL ACQUISITIONS AND BICOLOR VIEWING METHODS

• Document Type: CREST
• Collection: NGA Records (Formerly NIMA)
• Document Number (FOIA) /ESDN (CREST): CIA-RDP78B04767A000400050012-8
• Release Decision: RIPPUB
• Original Classification: T
• Document Page Count: 2
• Document Creation Date: December 28, 2016
• Document Release Date: April 12, 2002
• Sequence Number: 12
• Content Type: MISC

Approved For Rel
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Attachment to!
TCS-8066/6a
Information Concerning M-Sp.ctrai Acquisitions and Bicolo
Methods
25X1
Several passes of Mission are exposed in the bi-spectral 25X1
mode of acquisition. mi spectral coverage refers to a techeique
of acquiring conjugate imagery with two cameras, each using a
filter which has its peak transmission in different portions of the
visible spectrum. In this case, a red filter was used on the forward
camera and a green on the aft. In acquiring photography in this
manner, the density of images on the black and white records is
related to the filters through which they were exposed.
To exploit the advantages of bi-spectral photography, the
two black and white records can be analyzed individually with
respect to the colors which the density represents. I.E., objects
on the fwd (red filter) record which appear relatively light (low
density) on the DP compared to the same image on the aft (green
filter) record can be assumed to be reflecting in the red end of
the spectrum. However, these conclusions cannot be accepted as
absolute. The angle of the sum relative to the taking lens,
atmospheric attenuation, exposure, and reproduction characteristics
must also be considered. Even under optimum conditions, the color
of an object can only he established as being warm (red or near
rad) or cool (green or toward the blue and of the spectrum).
In order to facilitate the readout of hi-spectral information,
the photography can be viewed in a color mode referred to as
"bicolor. Bicolor is a psuedo color generated from two colors of
the spectrum instead of three, as is necessary for .'natural- color.
In order to create bicolor imagery, the black and white (DP) records
from both cameras (fwd and aft panoramic) are projected onto a
common surface, in register, through filters comparable to those used
in the taking situation (fed through red - aft through green).
Information available by this technique will be similar in scope and
value to that gained from the bi-spectral records viewed independently.
However, the bi-spectral information becomes more readily apparent
and a faster readout is possible. Red or warm tones will appear red
or some variation thereof; green or cool tones will appear predominantly
green.
Declass Review by NIMA / DoD
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The problem of employing the bicol.or methodexploitation
is that the images must be appropriately filtered and projected
in register. The geometry of the KM-4B camera is such that the
imagery must be rectified in order to be successfully registered
over areas larger than approximately 0.1 X 0.1 mm.
Although 4P1C has one prototype bicolor viewing instrument
the Ares - available, the Center is not currently prepared to
produce color prints from the bi-spectral imagery on a pre-
duttion basis for the Community.
Approved For Release 2002/06/17 : CIA-RDP78604767A0004000500
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