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PHOTOGRAMMETRIC ENGINEERING 19
F1G. 8. Auto-Focusing Photogrammetric
Rectifier.
Horizontal Projecting Photogrammetric Rec-
tifier
The horizontal projecting photogram-
metric rectifier (Figure 7) is designed to
produce rectified photographic prints from
6 inch focal length photography with tilts
up to 70 degrees and 12 inch focal length
photography with tilts up to 30 degrees.
Single stage rectification throughout this
range can be accomplished with this in-
strument. The magnification range is ap-
proximately 0.9 to 1.1 at the isoline for
tilts above 30 degrees, and approximately
0.6 to 2.5 at the isoline for tilts up to 30
degrees.
The rectifier is entirely mechanical and
has accurate scales and circles on all mo-
tions so that settings may be made to com-
puted values based on camera focal length
and tilt, rectifier lens focal length and the
magnification desired. It has interchange-
able projecting metrogon objectives of
41 and 71 inch focal length, standard
fluorescent tube illumination and a vac-
uum easel. The weight of the instrument is
about 300 pounds and it is suitable for in-
stallation in a standard U. S. Army motor-
ized van for operation by field units.
Autofocusing Photogrammetric Rectifier
This rectifier (Figure 8) is designed for
the quantity production of rectified or
ratioed prints for compilation of controlled
mosaics, and was developed by the Bausch
and Lomb Optical Company for the Corps
of Engineers. The instrument is the first
of its kind to be manufactured in the
United States and has a number of features
not found on other similar instruments.
It is designed to rectify 9 by 9 inch pho-
tography, both 6 and 12 inch focal lengths,
with tilts up to 20 degrees at enlargements
from 0.6 to 3.5. Photography at higher
tilts can be rectified at reduced range of
magnification. The instrument is electri-
cally operated by push button controls on
the tilt and magnification settings, and has
provision for rotating the negative through
360 degrees and shifting it laterally in both
X and Y directions. All motions are inter-
linked so that the projection is in sharp
focus at all possible settings.
The objective is a projecting metrogon.
f/6.3, 53 inch focal length. Illuminant is a
continuous fluorescent daylight tube in the
form of a grid, designed to give uniform
intensity of illumination over the negative
area.
With this instrument rectified photo-
graphic prints at desired scales may be
produced easily and rapidly. The instru-
ment is suitable for both van type mount-
ing or base plant use. It weighs approxi-
mately 800 pounds, is approximately 6 feet
high and occupies a floor space 55 by 55
inches.
Fic. 9. Auto-Focusing Reflecting Projector,
