TSG NEWSLETTER

• Document Type: CREST
• Collection: NGA Records (Formerly NIMA)
• Document Number (FOIA) /ESDN (CREST): CIA-RDP78T04759A010300010105-7
• Release Decision: RIPPUB
• Original Classification: S
• Document Page Count: 9
• Document Creation Date: December 28, 2016
• Document Release Date: April 22, 2002
• Sequence Number: 105
• Publication Date: July 1, 1973
• Content Type: PERRPT

Approved For Release 2002/Opt-RDP78T04759A010300010105-7
.25X1
NATIONAL
PHOTOGRAPHIC
INTERPRETATION
CENTER
TCS-851 1 /73
JULY 1973
NO. 3
6 PAGES
COPY
Declass Review by
NIMA/DOD
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b ons about items appearing in the newsletter, please contact
This is the third issue of a newsletter designed to
familiarize photo interpreters with the services, techniques,
and equipments available to assist them in imagery inter-
pretation problems. Should you have any comments or ques-
Many of the problems experienced with the P.I. optical
equipment can be corrected easily by ESD Equipment Performance
Branch personnel. Examples of problems whicr~ are common and
which can be repaired immediately are:
a) Focus changes when zooming from high to
low power.
b) Image separation while zooming from high
to low power.
c) Images separating while rotating in mono.
d) Obvious mechanical defects and dirty lenses.
25X1 If~you experience these or any other difficulties
bring your problem and o tics to the EPB optical shop.
25X1
1540 Light Table problem? For Emergency repair call
TEST AND EVALUATION BRANCH CONTRIBUTIONS
TO NPIC EQUIPMENT DEVELOPMENT
The first photo shows the prototype Binocular Tube
Magnifier undergoing tests to measure vertical misalig~.ment
of the eyepieces. Vertical misalignment is present in an
optical device when the left and right fields of view do
not overlap vertically to give comfortable binocular
fusion. Eyestrain, headaches or excessive fatigue are
likely effects on the user. Our measurements were used
to convince the. manufacturer that the misalignment needed
correction before the magnifier would be acceptable.
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25X1 The second photo shows a test set-up whicY~ was used
to measure depth of field of the Zoom 240 with the prototype
120X Capability. The micrometer head just to the right of
the optics is used to very precisely control the focus posi-
tion of a resolution target. TEB's measurements show that
moving the resolution target just 21 micrometers from the
best focus position causes a 20~ loss in resolution.
The effect of this relatively small depth of field on
the development of the PI Stage Reticle is currently being
considered. The graduations marks on the prototype reticles
are .001 " (25 micrometers) above the film plane so that
the marks and imagery may not be in suitable focus at the
same time.
NPIC DUPLICATION GUIDELINES
GIVEN TO PROCESSING CENTERS
TSG has recently completed an updated version of the
NPIC Duplication Guidelines.. The intent of these guidelines
is to insure the PI of receiving the best possible product.
These guidelines recommend the reproduction parameters (den-
sities, contrasts, quality, etc.) for all satellite photogra-
phy received at NPIC. These guidelines have evolved through
the years from objective and subjective testing of the photo
product. Interpreter's inputs to new products and procedures
have also contributed significantly to these guidelines.
All processing facilities supplying reproductions to NPIC
generally follow the recommendations outlined in the NPIC
Guidelines.
DUPLICATION IMPROVEMENT
BETTER FILM FOR THE PI
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TSG would like to express many thanks to the Building
PIs that participated in the now completed duplication
improvement project. The objective of this combined TSG/
Processing Facility project was to investigate PI preference
of density and contrast for reproduction of individual tar-
get types. Secondly, we intended to recommend modification
of the duplication system if PI preferences indicated such
action was necessary. The test plain included PI analysis
of different target types at varied density and contrast
levels. The study concluded that the PIs are generally being
supplied duplicates of optimum density and contrast when
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i.argets do not have extreme highlights. However, PIs are
generally receiving lighter than preferred duplicates of
t=argets that have extreme highlights (e.g., aircraft scenes).
Based on this study greater consideration will be given to
the reproduction of imagery having extreme highlight areas.
STAR EXPOSURE TECHNIQUE FOR CAMERA CALIBRATION
A camera, to be used for precise mensuration purposes,
can be calibrated from a photograph taken of the stars. No
special equipment is needed and thf~ procedure of photographing
i~he stars is relatively simple. It can be performed by anyone
with some general knowledge of photography. The star photo-
graph must be made on a night when moonlight, haze or clouds
do not obscure the smaller magnitude stars. The film should
be developed, examined for proper exposure, and then forwarded
with the data sheet to TSG, Photogrammetry Division, for
calibration.
A calibration is good only for the particular camera