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2. STRUCTURE OF THE ORIENTATION SYSTEM
ita stereoplotter is used to form an
optical model of the object space, and if
the photographs taken are of the normal
case, then only the direction parallel to
the direction of the camera axes will be
subject to affine deformation. If the
photographs are not at the normal case,
then the affine deformation will occur in
the three directions.
The Wild Autograph A240 is designed to plot
from photographs taken in the normal case.
The plate holders have no rotational
motions, although equal elevation or
depression angles at the two ends of the
base can be accommodated. This instrument
is used most efficiently for plotting from
photographs taken with the stereometric
cameras or the system that resembles it.
The Wild P32 terrestrial camera accepts
either glass plates or film and provides a
format size 60 by 80 mm. It has an offset
principal point and can be rotated about
its optical axis in order to make the
format fit the obiect space. The principal
distance is fixed at 64 mm, and focused at
25 m. the depth of field is from 7.3 m to
infinity at £/8, and from 3.3 m to infinity
at f/22. An orientation system is designed
and proposed to take photographs in the
normal case of photogrammetry by using
Wild P32 terrestrial camera. This system
incorporates a camera carrier and two
parallel steel bars (x-bars) (Fig. 1)
Figure 1. The Orientation System
The camera carrier is capable of sliding
on two steel bars ranging from 1 mm to
400 mm. The orientation system mounts
directly on the Wild thodolite tribrach
and supports on the Wild tripod. The
respective tilting and rotations of the
photograph are adjusted at zero by means
Of a level buble and tribrach foot-screws.
When the system carrier slides on X-bar to
take a second photograph, the optical axes
of the stereo-pairs remains parallel to
each other and perpendicular to the base.
This system, also has a steel rule at the
back and the base length can readily be
measured. Two samples of drawing output
are given in Fig. 2 and Fig. 3.