DEVELOPMENT OBJECTIVIES MODULATED- LIGHT FILM VIEWING SYSTEM

• Document Type: CREST
• Collection: NGA Records (Formerly NIMA)
• Document Number (FOIA) /ESDN (CREST): CIA-RDP78B04747A001100060018-5
• Release Decision: RIPPUB
• Original Classification: K
• Document Page Count: 4
• Document Creation Date: December 28, 2016
• Document Release Date: December 5, 2001
• Sequence Number: 18
• Publication Date: March 23, 1964
• Content Type: SUMMARY

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23 March 1964
DEVELOPMENT OBJECTIVES
MODULATED-LIGHT FILM VIEWING SYSTEM
1. INTRODUCTION.
These objectives propose a feasibility study which would investigate con-
s stems and develop the concept(s) most adaptable
topts for ds of-mecttvie y This would include: (1) contact or 1:1 view-
ing kinds of dirrect viewing.
ing as is now done on basic light tables by means of transmitted light, and
for instance, by a
(2) high-magnification, macroscopic viewing afforded
mounted on the same basic table.
STATIN2 L BACKGROUND.
In the history of photo interpretation, one of the most necessary and basic
pieces of viewing equipment has been the direct-viewer light table.
In general format, the viewers are box-like, rectangular in shape, and
have either a 10" x 20" or a. 10" x 40" viewing surface (opal gla.ss)vevinlye
illuminated from underneath by fluorescent tubes with continuously. Bleh-
intensity. Film spools and winding gear are located at either 99 nd e na.dod most
sized tables are placed on support tables, specially designed,
often to view roll-film positives.
The P.I. uses the 9" x 18" table primarily for contact viewing the
standard format films (which range to 9" x 18"): his technique involves first
scanning the exposure by naked eye and then studying details with a 7X or 12X
tube magnifier. So that the seated P.I. could lean into his work ra.there hanal: p have to lean over it, the table was designed to rotate and tilt on
and away
its most familiar working position is at an angle 450 from
d natural horizontal position
from the seated P.I.
The 9" x 40" light table is more often use
(with a. long side nearest the P.I.) for larger format and highar-re solution films.
Viewing is frequently augmented by a stereomicroscope capable of 7X-60X
magnifications.
The illumination system in current models fulfills its basic purpose as
a light source. However, a. more sophisticated, modulating- g syst
be of direct benefit to the intelligence
lvedrforlthelhuman visualtsywould not only
stem b t also
reduce the physiological strains
enhance the display of photographic information for more effective exploitation.
For example: with current, standard fluorescent illumination of trans-light
parencies, there is no means of masking extraneous light or of attenuating light
under thin densities and providing adequate brightness under heavy nu
At contact scale, when the P.I. searches for details in dense regions
a
either
transparency, his eye is affected (the iris closes down) by
surrounding the transparency or passing through adjacent, thin-density image
areas. Particularly trying visual situations are presented by snow, clouds
and shadows, and occasionally by haze.
DECLASS REVIEW bg NIMA/DOD
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In addition, a direct-viewer used with a. microscope for detecting
magnified details often proves inadequate in total illumination level.
3. SCOPE.
Envisioned is a direct-viewer light table built around a modulating
illumination system capable of automatically and continuously responding to
film densities and spatial frequencies and regulating light accordingly.
The effect would be similar to that of a printer. STATINTL
A11 concepts with potential application show be considered: some which
were visualized in the course of the original project idea are:
3.1. CRT scanning systems.
3.2. Light-beam scanning systems.
3.3. UV-IR quenching systems.
3.4. Photochromic filter or masking systems.
3.5. Phototropic filter or masking systems.
3.6. Various combinations of the above systems.
3.7. It would be ideal if one concept -- or at least compatible systems --
were applicable to both direct-viewing uses of the light table. On the other
hand, it might prove sensible to develop two entirely different principles and,
consequently, independent systems.
3.8. Further but secondary considerations should be given to rear-projection
viewers and the potential incorporation of light-modulating principles in such
equipment.
3.9. Proposals will be evaluated on the basis of the following:
3.9.1. Performance - the degree to which the contractor can assure the
customer of meeting the stated requirements.
3.9.2. Simplicity - an approach which implies fewer contingencies, broad
application and reasonable economy.
To a certain extent these factors are mutually exclusive; however, each is
so important that concurrent development of the most promising proposal for
each category is a distinct possibility.
4. REQUIREMENTS-
4.1. Physical Configuration. It is desired that this modulated light
system be suitable for packaging in a mode similar to the conventional
10" x 20" or 10" x 40" roll-film viewers. If this is not feasible, then the
proposal should include a description of appropriate packaging which will be
evaluated for its relative merits as a design concept.
4.1.1. Viewing Area. The entire 10" x 20" or 10"? x 40" viewing areas
should be illuminated by the modulating system; however, consideration will
be given to systems which utilize auxiliary illumination on either end and
confine the modulated illumination to the central portion. The minimum
acceptable size for the area. of the modulated illumination is 9" x 9".
4.1.2. Controls. Controls must be kept to a minimum and should be
mounted directly on the viewer. If a separate control console is unavoidable,
then it would be acceptable.
4.1.2.1. Modulated Illumination. Controls should be provided for adjust-
ing the degree of modulation in terms of intensity and/or spatial frequency.
There should be a control for setting the unmodula.ted levels of intensity and
controls for setting the size and position of the area of modulated illumination.
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Illumination. If auxiliary illumination is required
4.1.2.2. Auxiliary
it should be to cover the entire specified viewing ra,illumination. lAdmeans e should abeab e
and completely isolated from the modulated auxiliary source and illuminat-
provided for instantaneously extinguishing the
ing it to a. preset level.
4.1.3. Physical Interference. Physical obstructions which come beaeen
the operator and his work and which would inhibit viewing or effic
not acceptable.
4.2. Illumination Characteristics.
4.2.1. Brightness. Minimum acceptable level of brightness for the entire
illuminated area is 1000 foot-lamberts: a. level of 2000 foot-lamberts is
desired.
4.2.1.1. Brightness Modulation. Brightness modulation shall be arffunction
of density and spatial frequency. Brightness shall be inversely p p
to transmittance and directly proportional to the spatial frequency of the
transparency being viewed. These modulations shall be variable in range,
allowing for individual operator preference and for the requirements of magnified
viewing (5X - 6ox).
4.2.1.2. Response Time. Since the viewer is to be used for scanning, the
response time of the modulation system must be such that no visually perceptible
effects such as flicker or smear are produced. size-reduction of the
4.2.1.3. Reduced Field. If possible, masking or s
illuminated area should result in a pr p?o ionate
effects easeasn maximum int edsity. those produc by
4.2.1.4. Spurious Effects. No spurious
uni-directional scan, are acceptable. On the other hand, speci&.l,effects, available
o _
at the operator's option, are acceptable.
brightnesshattessation.
4.2.2. Color Tempera.u be ? aC~eociab.ly changed byshall
5500?K range and shall not pp shall be executed in two,
4.3. Development Plan. This development independent, successive phaOute feasiility study ofdbophrpha.ses~f No?fundse?
Contract award shall constitute however, until the
phase,
will be approved for the operational prototype
customer has given assent on thbSS of ltoytermanateawathoutdpursait
demonstrations. It is the customer's prerogative
of the prototype phase if he is not satisfie with the
detailed documentation loflthe.
e
hi
q
s r
4.3.1. Feasibility Study. T
ustsprecedenthe nprototypeaphase dboa.rding.
study program, which should include minve
Successful beard stration
This requires production of a prototype
4,s3.2. O Op edberational Prototype. with both l:l direct viewing and
system which can be evaluated opera.tiona.lYsha.ll include detailed descriptions
5X - 60X magnified viewing. The prototype
of all aspects of the systems as well as maintenance and operating instructions.
5. SECONDARY REQUIREMENTS.
These requirements should be considered if they do not compromise those
stated in Section 4: variable in
5.1. Masking. The modulated light area should be continuously
size. Size should be independently variable in X and Y; identical change in
X and Y would be acceptable. Increase in intensity -- in correct proportion
to reduction in area. -- is desired.
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The modulated light a.reai once re uce ,size, This should trans-
5.2. Translation.
position within its or g joy-stick) or
be movable to any desired p either manually (by a
lation should be optionally controlled --
osition of the viewing microscope)? possible by a
automatically (by the p ial optical effects made p
5.3. Enhancement. Other spec
modulating light source should be considered
Rear-Projection Viewers. If a ssmilar lihavemaamagnificationl~range
which
5?4?
could be applied to rear-projection viewer ,
-0X and a screen size of 30 x 30"", there is interest in establis ing
of 5X 5
its feasibility.
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