STAFF STUDY MICRODENSITOMETER MODIFICATIONS

• Document Type: CREST
• Collection: NGA Records (Formerly NIMA)
• Document Number (FOIA) /ESDN (CREST): CIA-RDP78B04770A001400070020-9
• Release Decision: RIPPUB
• Original Classification: S
• Document Page Count: 4
• Document Creation Date: December 28, 2016
• Document Release Date: February 8, 2005
• Sequence Number: 20
• Publication Date: February 10, 1969
• Content Type: STUDY

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10 February 1969
STAFF STUDY
MICRODENSITOMETER MODIFICATIONS
Declass Review by NGA.
1. PROBLEM:
To modify the existing 1032T Microdensitometer with an improved
optical system, an electronic scan controller, and additional selec-
tions of sampling frequencies.
2. FACTS BEARING ON THE PROBLEM:
a. The 1032T Microdensitometer, although sold as a trichromatic
microdensitometer, does not have the capability to perform high
resolution readouts of color film.
b. The scanning system on the microdensitometer is controlled by
microswitches which are imprecise, inefficient, and result in the pro-
duction of unwanted data requiring extra time for data reduction.
c. In order to properly sample the densities along the scan line,
the sampling frequency should be six times the highest frequency re-
corded on the film, i.e., if the film has a peak resolution of 200
lines/mm, the sampling frequency should be 1200 samples/mm. The 1032T
now has a maximum sampling frequency of 1,000 samples/mm. Although
present operational films rarely exceed 125 lines/mm in resolution,
other materials such as diazo, free radical, kalvar and some silver
halides exceed 1,000 lines/mm. The microdensitometer is therefore,
extremely limited in use with any of these new materials.
3. DISCUSSION:
a. Current Procedures - Many areas of interest imaged on black and
white film are analyzed with the microdensitometer in the scan, step-
over, scan mode. The imagery is centered on the stage and after cali-
bration, focusing, etc., microswitches are set to control the reversing
of the stage motion. When the machine is started, the stage moves
across the optical path and density readings are taken at preset
intervals. The. densities are recorded in digital form on magnetic tape.
After the scanning is completed, the data is fed into the computer for
processing. Since most of the areas scanned are smaller than the
closest settings of the microswitches, extraneous data is collected on
each scan. This data must be sifted out by the computer before any final
processing can be achieved.
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To date, very little color film has been analyzed with the
microdensitometer because the optical system contains chromatic
abberation. It is possible to focus the system for a single color,
but not simultaneously for the three colors found in tripack color
film. This precludes any meaningful analysis of the film.
In order to analyze film, or any other photographic material
which exceeds 166 lines/mm in resolution, the data points from the
scan must be taken by hand from.the analog graphic record and fed
into the computer. This process is extremely time consuming and
subject to many.e.rrors.
b. Origin of Concept The limitations of the 1032T Micro-
densitometer were discovered by the operating component (NPIC/TSSG/
APSD/ISAB/DAS) after the instrument was put into regular operation.
Attempts have been made to minimize the optics problem by inserting
different lenses into the system, but since one of the most optically
degrading factors is the glass film stage, the attempts have been
futile.
c. Proposed Program - It is proposed that a digital controller
(consisting of a set of decade switches, an up-down counter and
comparison logic) be added to the Microdensitometer. The stage scan-
ning motion could then be reversed after it had moved a programmed
distance. This distance would be variable from 10 microns to the
limits of the stage motion.
It is also proposed that the optical system be upgraded by first
building an alternate film stage which would have a very thin piece
of glass in the center. This development would minimize the aberra-
tions caused by the stage and would allow for testing of other com-
mercially available lenses. If no suitable lens or lens system can
be found on the market, a special lens system would be designed and
built. In other words, the modified stage would be contracted for,
built, and tested. Then if no suitable lens were found, a contract
for the lens design would be let. Staging the developments of the
optical system seems to be the most economical approach to the
solution.
The sampling frequency could be increased by adding an oscillator
which would be synchronized with the motor and which would control the
sampling rate.
d. Selection of Contractor - The contractor selected to add the
programmable controller and the new sampling control to the system
must have a thorough knowledge of electronics and the circuitry in
the microdensitometer. The owns the stage design
and due to the complexity of the stage, it would be impractical to go
to any other source for that development. If a new optical design is
required, only those contractors having a proven ability in optical
design and fabrication should be solicited.
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e. Coordination - The proposed task would be of no benefit to
anyone who did not possess a 1032T Microdensitometer. The only other
1032T belongs to I I so outside coordination was deemed un-
necessary. Close liaison between DED and ISAB will be maintained.
f. Alternatives - The alternatives to this proposed program are
either to live with the status quo or to undertake a specific task in
the program or to develop entirely new pieces of equipment to perform
the task. If none of the optical modifications were undertaken, NPIC
would be precluded from scanning color film simultaneously in three
colors and thereby eliminate the possibility that NPIC would delve
into color image signature analysis or extensive technical analysis
of color film. If the digital controller were not added, machine and
computer time would continue to be lost processing unneeded data. Fab-
ricating a totally new device to perform the task appears unrealistic
from both a time and a cost standpoint. An alternative to the new
sampling control is additional software that would interpolate between
the samples now recorded digitally by the microdensitometer. The cost
of designing this software and the computer time it would require, how-
ever, would exceed the cost of the hardware in the long run.
4. CONCLUSIONS:
The proposed program to modify the microdensitometer would be a
small but worthwhile investment to upgrade the capability of NPIC and
to improve the efficiency of one of the operating divisions within the
Center. The digital controller modification to the microdensitometer
would probably pay for itself within a year. The additional sampling
frequencies would provide the Center with the capability of being able
to scan very high resolution materials with the same ease that is re-
quired to scan present operational films.
Without too much investment, the 1032T Microdensitometer could be
modified so that it could be used as a tool to study color image struc-
ture, to perform image manipulations or possibly to analyze the color
signatures of imagery. By phasing this part of the modifications to
the microdensitometer, the cost of development can be held to a minimum.
5. RECOMMENDATIONS:
It is recommended that the digital controller development be pro-
cured through open bid procedures (estimated. cost -
0
It is recommended that a new sampling control be procured through
open-bid procedures (estimated cost
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It is recommended that a modified stage be purchased from
estimated cost -
I
If it is deemed necessary, after trying commercial lenses in the
system with the modified stage, it is recommended that a lens develop-
ment be purchased through open bid procedures (estimated cost -
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