BuL 3/1964
157
Traveling speed of slit in y-direction: 5 min/sec.
Width of slit in y-direction: 2 mm
Photographic material: Agfa halftone process him B/blue
Illumination: 6 V, 15 W incandescent projection lamp
While the exposure slit A travels along its meandering course of strips, the scale of the projected
image is continuously varied in accordance with the relief of the terrain by the z-motion of the car
riage D which holds the projection system. Further functions, such as the control of the positive-lens
carriage in the auxiliary system, the coordination between illumination and pupil of projection lens,
as well as the position of pivots and principal points determining optical independence, follow
known conditions.
Fig. 3 Meandering course of the exposure
slit during orthophotoscopie rectification.
Instrument
GZ1
Fig. 4 Operation of Orthoprojector by
"direct method”.
At the present time, there are two different possiblities of driving the Orthoprojector, which are
illustrated in the block diagrams:
In the first method (Fig. 4), GZ 1 and plotting instrument are connected mechanically or through
selsyn systems in x, y and z. The plotter operator controls only the z-motion by keeping the floating
mark in contact with the surface of the terrain model, which incidentally has been oriented in the
normal manner. Any instrument may be used as a plotter, provided that it is sufficiently accurate
and that it is driven in x, y and z by spindles. The projector tilts d and a> as well as the other initial
values (x , y o , z Q ) are determined in the plotting instrument and set on the GZ 1.
4. Storage techniques
In the second method (Fig. 5), the operator records the values determined in the plotting instru
ment in a store S. This storage is effected in the form of scribing. Temporally independent, these