(Sanitized) IMAGE QUALITY METER

• Document Type: CREST
• Collection: NGA Records (Formerly NIMA)
• Document Number (FOIA) /ESDN (CREST): CIA-RDP78B04747A001800100036-3
• Release Decision: RIPPUB
• Original Classification: K
• Document Page Count: 2
• Document Creation Date: December 28, 2016
• Document Release Date: April 17, 2001
• Sequence Number: 36
• Content Type: REPORT

Approved For Release 2001/07/16 : CIA-RDP78BO4747AO01800100036-3
STATTNTL
IMAGE QUALITY METER
FUNCTION
The Image Quality Meter is a laboratory instrument which pro-
vides quantitative measurements of the quality of a photographic
transparancy. An operator inserts the transparancy into the instru-
ment and positions it such that suitable portions of the image are
scanned for the measurement of the three quality indices described
below. Output indications are provided on electrical meters for
visual observation.
PURPOSE
The purposes of the Image Quality Meter are to measure the per-
formance of the photographic system which produced the photograph
being scanned, to provide a common basis for comparison of dif-
ferent photographs, to measure the effect of changes in photogra-
phic procedures and processing as it affects image quality, and to
establish the necessary steps of subsequent image processing that
may be fruitfully applied to a given photograph.
QUANTITIES MEASURED
Resolution
This is a measure of the number of lines per millimeter
corresponding to the image detail recorded on the emulsion. The
meter will provide a measurement of the maximum value of the reso-
lution over the area scanned.
l7 November 19b0
DECLASS REVIEW by NIMA/DOD
Approved For Release 2001/07/16 : CIA-RDP78BO4747AO01800100036-3
 Approved For Release 2001/07/16 : CIA-RDF 78B04747AO01800100036-3
Acutance
Image sharpness is measured in accordance with the mathematical
STATINTL definition of The meter scans an area contain-
ing an abrupt gray level change (such as the edge of a building or
roadway) and provides an output which increases with the rate of
change of photographic density across the boundary.
Granularity
The scanner, functioning as an automatic microdensitometer,
provides an output proportional to the fluctuations in photographic
density, in an area of constant gray level.
PRINCIPLE OF OPERATION
'_L'he Image Quality Meter utilizes a moving spot scanner, in
which the light from a mercury are lamp is focused to a tiny spot
and moved across the image. The light passing through the photo-
graph is collected in a photomultiplier tube which provides an
electrical output signal corresponding to the line of the picture
being scanned. This electrical signal is applied to an electronic
analog computer which computes the quantities measured from the
input signal variations.
STATUS OF DEVELOPMENT
STATINTL The
is currently designing and
fabricating a preliminary model of this instrument for delivery
early in 1961. At the present time, the scanner design is under-
way, and some of the mechanical parts are about to be fabricated.
A laboratory breadboard of substantially all of the electronic
computer functions has been assembled and successfully tested.
Approved For Release 2001/07/16 : CIA-RDP78BO4747AO01800100036-3