OPTICAL POWER SPECTRUM BRIEFING

• Document Type: CREST
• Collection: NGA Records (Formerly NIMA)
• Document Number (FOIA) /ESDN (CREST): CIA-RDP79B00873A001800020078-9
• Release Decision: RIPPUB
• Original Classification: S
• Document Page Count: 3
• Document Creation Date: December 28, 2016
• Document Release Date: October 24, 2012
• Sequence Number: 78
• Publication Date: February 17, 1971
• Content Type: MISC

Declassified in Part - Sanitized Copy Approved for Release 2012/10/24: CIA-RDP79B00873A001800020078-9
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GROUP I EXCLUDED FROM
AUTOM ATIC DOWNGRADING
AND DECLASSIFICATION
ATTACHMENT TO:
EXRAND-M- 41
OPTICAL POWER SPECTRUM BRIEFING
17 February 1971
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Declassified in Part - Sanitized Copy Approved for Release 2012/10/24: CIA-RDP79B00873A001800020078-9
Declassified in Part- Sanitized Copy Approved forRelease2012/10/24 : CIA-RDP79B00873A001800020078-9
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OPTICAL POWER SPECTRUM
The briefing reported the results of an R&D contract with
to study the Optical Power Spectrum as a measure of image
quality.
The primary objective of the Optical Power Spectrum project was
to obtain a reliable, rapid, and automated technique for measuring the
quality of operational imagery. In addition, the technique was to apply
to imagery (negative or positive) of all acquisition systems, provide
for changes of scale and target, correlate well with quality judgments
made by the PI, and be suitable for use throughout the intelligence
community. These objectives have been met.
The Optical Power Spectrum measurements are made on electro-
optical equipment designed originally for the ATR/cloud detection por-
tion of the contract. The image quality clue extraction algo-
rithms developed are based on the hypothesis that the spatial frequency
content of a given image is related to the quality of that image as
judged by professional PI's.
Three sets of imagery were used to test the validity of the OPS
technique; each had been previously evaluated by NPIC personnel in
other experiments. Set A included the eight MIP reference operational
scale (1:200,000) currently in use in APSD. The OPS measurements
ranked these images as follows: 110, 115, 105, 100, 95, 90, 85, 80.
The reversal of #110 and #115 was real and not an artiface of a particu-
lar measurement. When presented to the APSD staff they acknowledged
that some of their observers had also ranked them in the reversed
order and that the OPS was probably correct.
Set B included 32 relatively low quality, non-operational aerial
images. The target was an industrial area; the resolution, MTF, grain
noise, and contract of the image had been varied in a known and con-
trolled manner. These images too had been ranked by PI's. The cor-
relation of the OPS measurements with these judgements was 0.88, a
very high result.
Set C included 32 images on negative material (3404), 1:40,000
scale each varying in focus by 0.005" of the focal length. The OPS
measurement selected the same best focus frame as that determined by
human observers.
It was concluded that the OPS can serve as a relative measure
of photographic image quality which correlates very well with quality
estimates made by professional PI's. It allows automatically for
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Declassified in Part - Sanitized Copy Approved for Release 2012/10/24: CIA-RDP79B00873A001800020078-9
Declassified in Part- Sanitized Copy Approved forRelease2012/10/24 : CIA-RDP79B00873A001800020078-9
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scale changes equally well with negative or positive imagery; it does not
require special targets or the presence of straight edges, and does not
appear to be system limited.
Its measurement is relatively simple to make but does require
special equipment and can be accomplished on or off-line as time permits.
The OPS may provide a means of quantifying image quality in terms
of information content and interpreter performance. This aspect requires
further research.
NPIC intends to conduct further experiments with a larger sample of
imagery from all acquisition systems and optimize image quality clues.
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Declassified in Part- Sanitized Copy Approved for Release 2012/10/24: CIA-RDP79B00873A001800020078-9