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illuminated dual display indicating X and Y axis positions are additional features.
A relatively high accuracy is possible. A closely controlled environment is sug
gested for the use of the comparator (70° Fir 1°F ambient temperature and 50%
+ 5% relative humidity)--a self-controlled environmental system is furnished as
an optional item. Digitized output can be made to card punch or other optional
output devices. The comparator incorporates a self-contained leveling system.
LINK GROUP, GENERAL PRECISION, INC.
The Link Group, General Precision, Inc., Binghamton, New York, USA,
has prepared three new items of equipment, namely, Automatic Point Transfer
Instrument, High Resolution Orthophoto Output Table, and a Single Stage Measuring
Device (Air Bearing). These are described below:
a. The Automatic Point Transfer Instrument is a precision marking and
measuring device wherein conjugate photographic image points are automatically
or manually determined, the positions marked, and the coordinates read out on a
typewriter and card punch. A card reader can be used as well to "read in" the
coordinate point positions. The device consists of three comparator tables, a
control console, associated electronic cabinets, and read-out and read-in equip
ment. Additional characteristics are:
(1) The three comparators can hold either glass plate diapositives,
cut film, or film rolls; the function of the comparators is to support and trans
port the diapositives with respect to their fixed photo scan system. Various
image formats can be handled. A servosystem, linked with the correlator for
static correlation and tracking purposes, is used to drive the comparator’s
carriages.
(2) The marking system is used to mark selected photo image points
(including reseau marks and star images) on any or all three comparators. Mea
suring marks consist of dots and circles. A requirement for high position accuracy
of the measuring mark has been specified. A capability to transfer marked control
points on small film chips to one or two photos which differ widely in scale is also
inherent in the device.
(3) The photo scan system (including optics) has the capability to
adjust and/or correct for differences in photographic scale, tilt and rotation for
both manual and automatic modes of operation; its main purpose is to examine
the photographic images in a manner that will provide necessary data required
by the correlators and the stereo viewer. The system will accommodate various
types of photography up to medium degrees of tilt. Flying spot scanners, deflection
circuitry, multiplier tubes, etc., are used to scan properly the photographic image
as required by the overall logic of the system. Likewise, a variable demagnifi
cation lens system and a raster shrinking and shaping capability is introduced to
accommodate scale differences.
(4) Images on the three comparators are correlated by a system
which provides the necessary logic to control the servodrive systems. In the
static mode the correlator provides coincidence of the conjugate image points