HIGH PRECISION STEREO COMPARATOR STUDY MONTHLY NARRATIVE REPORT FOR PERIOD ENDING AUGUST 6, 1965

• Document Type: CREST
• Collection: NGA Records (Formerly NIMA)
• Document Number (FOIA) /ESDN (CREST): CIA-RDP78B04747A000200040015-0
• Release Decision: RIPPUB
• Original Classification: K
• Document Page Count: 6
• Document Creation Date: December 28, 2016
• Document Release Date: March 20, 2001
• Sequence Number: 15
• Publication Date: August 6, 1965
• Content Type: REPORT

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HIGH PRECISION STEREO COMPARATOR STUDY
MONTHLY NARRATIVE REPORT
For Period Ending August 6; 1965
Declass Review By
NIMA/DOD
1. Current Status of Work
During the reporting period a project group was formed consisting
of optical, mechanical and electronic engineers and work is now
proceeding in four general areas: Optical Design, Mechanical Design,
Correlation Techniques, and Metering Techniques.
A. tical'
A review of the optical system requirements has been started,
beginning with the illumination requi'remere;. A recheck of this
calculation has confirmed the estimates of the brightness require-
ment contained in. the proposal. Because of numdrous advantages
to be gained by using a single optical system for both the corre-
lator and the visual-observation system, a study was conducted of
the practicality of using a flying spot scanner as the input to
.both systems. In this technique there is the additional advantage
that the operator's console and the two film stages can be physically
independent of each other, since the presentation to the operator
would be on two CRT's. Unfortunately, the very high resolution
requirements of the visual observation system were found to rule
out this approach. Although the resolution might be achievable in
the scanning system itself, the scanning rate would have to be so
slow as to be unacceptable to the operator, and extreme image
smearing would occur for even slow film motion.
B. Mechanical
Work has been started on the general configuration problem,
With particular attention being given to ease of access for
loading and unloading, and convenience of viewing the overall
frame area. At present the project group is in accord with the
specification requirement that the film transport mechanism be
isolated from the X-Y measurement stage. A configuration is being
considered in which the film supply and take-up spools would track
one axis of the measurement stage, and guides would be provided so
that the entire transport could track the second axis. These some
guides would then provide for withdrawal of the transport mechan-
ism for loading and unloading.
Work on the design of the X-Y measurement stage itself has been
postponed pending the completion of a newly designed air bearing
system having a 10" x lO travel range. While it is recognized
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that this range does, not meet the requirements of the High
Precision Stereo Comparator, in other respects (straightness
of travel, orthogonality, etc.) the specifications set for the
10" x 10" stage, developed on a company-sponsored program, are
compatible with those of the Stereo Comparator. it is felt
that the experience gained in evaluating the performance of the
14" x 10" stage will therefore be of direct benefit to the Stereo
Comparator, since it will establish the validity of the Sd sign
P% -r' A Tl K ITI principles used.
During the reporting period a visit was made to tthe id s6aT TIINTL
facility at
r e measurements
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te with
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pro ems asso
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the perfsxmanc e of
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STATINTL were made by personnel
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Number 5 Measuring Machine. Over an 1
although the
exhibited straightness of travel within ? .3 mic ,
guaranteed value is + 1 micron. This, however, is attributed to
the use of sliding bearings, which would make the desired least
increment of motion extremely difficult to achieve.. Nevertheless,
the project group does not feel justified in arbitrarily excluding
all but air bearing designs, and continuing thought will be given
to the capabilities of such companies as STATINTL
C. Correlation
Three separate correlation techniques will be evaluated during the
.study program. The first uses an optical matching technique.
order to implement it in a form suitable for the Stereo Comparator,
it is necessary to scan one transparency and present it on the
face of a CRT suitably positioned with respect to the second trans-
parency. The correlation error signal then consists of the distri-
bution of light in a plane determined by the geometrical configura-
tion of the two images. In order to separate the correlation signal
.,from the background noise experience has shown that it isen necessary
to oscillate the images about their correct rotary aligns technique
the
synchronously detect the resulting signal variation.
relies on the fact that the correlation signal is typically much
more sensitive to rotary alignment than the background noise is.
During the reporting period a breadboard was assembled to test the
basic system. Available equipment was used in the interest of
speed, and therefore conditions were not optimum. For example, a
low resolution, rather non-linear scanner was used, and the CRT
phosphor was not veil matched to the photo-sensor response curve.
Theta rotation was accomplished manually and DC readings of the
photo-sensor output were taken to predict the response which an
automated system would produce. Signals which appeared to be
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STATINTL
STATINTL
usable were obtained with identical artificial imagery and with
identical aerial photography. The accuracy with which the null
signal reflects the correlation position has not
been deter-
yet mined, nor-have tests been conducted on stereo-pairs.
The other two types of correlators are similar to each other in
that each uses a flying spot scanner to extract information from
the imagery. They differ in the method pf processing the video
signals to obtain the correlation signal. One method, called
the electronic analog correlator, operates on the frequency com-
'ponents _of the analog video, signal in order to establish the
phase relationships between corresponding components channels, whic}'are indicative of posionalt displacements
between the two transparencies. The second method, called the
electronic digital correlator, quantizes the video signals into
pulse trains which are then cross- ?
ccmrpared with several permuta-
tions of time delays between the two channels.
time delay which provides the best match is indican tiveesofythem the
relative displacement of the two transparencies. .
Breadboarding of the digital correlator has been under way for
several months as part of another program. It is expected
that the results of this effort will be available for use in the
Stereo Comparator design study.
During the reporting period an analysis was begun on the theory
of the electronic analog correlator. This analysis is expected
to lay the groundwork for an interpretation of the experimental
results to be obtained later in the program, and to serve as a
basis for logical changes in the breadboard as the quality of the
results becomes apparent.. Design and fabrication of breadboard
circuits will be started in the next reporting period.
D, t1eing Svc
A s
erve of metering systems has been started. The
has been contacted for information TT
e .near se Resolver and a trip is planned to inspe their
prototype and obtain detailed information about the electronic
system. Results of an evaluation of the
to be made on remises on another program, will. be available]
for comparison.
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A configuration for a laser interferometer is being developed
and an analysis has been started to determine the magnitude
of errors resulting from irregularity of table motion.
Pro ISM Areas
The major technical problems are those inherent in the performance -
,required4of the comparator, and are generally defined by the
division of the study program as described above. In additioady-
Iveraal specific questions have aris
hi
en w
ch have been submitted
via telephone to the contracting office. These are:
A. The specification requirement (Section 5.2.7) that the
illumination system have a color temperature, above 3400?K at
any intensity level appears incompatible with standard practice,
adds to the complexity of the equipment, and may increase the
? heat problem. The implication of this should be discussed at the
next personal visit.
B. The wording of Section 5.4 (Film Measurement System) raises
a question regarding the accuracy. specification. If this is
interpreted as including the effects of ambient environment on
the photographic film itself, then the humidity variations per-
mitted by the ambient environment specification could cause
errors greatly in excess of those permitted in Paragraph 5.4.1.
Compensation for this effect, if it could be accomplished at all
without lengthy film preparation, would be a very great problem.
The practical solution seems to be to interpret this section as
a specification of the performance of the comparator itself,
independent of the characteristics of the input material.
C. There is no question about the operational necessity of pro-
viding the operator with an overall view of the entire format
area (Section 3) and a means of seeing which portion of a frame is
within the field of view of the optical system. However, the
practicality of doing this in the suggested way, by direct observa-
tion of the measuring area, is very doubtful because of the require-
ment for full stage illumination, the number of frame and optical
system obstructions, and the probable distance between the operator
and the measuring stages. For this reason, consideration will be
given to electronic or optical scanning systems which will permit
transmitting an image of the entire stage area to a convenient
Position in front of the operator, pblsibly with the final display
presented on a high resolution CRT.
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4.
r ect d Wg fo j Mt Alportinx- Period
A. VMhsnical: Configuration studies will be continued
with particular emphasis on the interface between the
film transports and X-Y measurement stages. An analysis will
be started on the design of the X-Y" stage itself.
B. Qvticsl System: The analysis of the resolution and
illumination requirements of the -optical system will be
continued. Because of the high probability that a flying
spot scanner will be used to provide information to the
correlator, the study will examine the various techniques
for combining the visual optical system with the scanning
system. In particular, a study of the distribution of light
energy between the two systems and tks most advantageous
placement of image rotation, zoom, and anamorphic elements
will be started.
C.' Correlation-* Work on the optical correlator will be
continued and it is planned to evaluate the effectiveness of
this system in cross-correlating on stereo-para. Equipment
will be procured to enhance the effectiveness of the present
breadboard. This will consist principally of acanhers with
higher resolution, better linearity, and better match to the
photo-sensor characteristics.
Breadboarding of the electronic analog correlator circuits
will be started.
Q. petering System It is expected that an inspection of
the Phase Resolver System will be made during the next
reporting period. A configuration for a laser interferometer
will be developed and procurement started for the material
needed for breadboarding.
enditurea
Manhours:
Material:
Total Cost:
STATINTL
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5 Yerbal Coa ,tments and Agreements
in the first meeting (July 23, 1965) between the Contracting
Office and Contractor, three points were established. which had
not previously been apparent.
A. The film transport design must take into account the
possible use of very thin film bases. These film bases
may be - as than as 1.5 mile.
B, In the contemplated use,. spend of loading and unloading
is of great importance. T i typical operation consists of
observations made on single frames of roll film or a single
film chip.
C. The integration of an effective correlation system is vital
to the success of the Comparator. Correlation is desired
between any combination of image pairs, including. difference
in scale, rotation, type of photography, density, etc., even
when the parameters of the photography are initially unknown.
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