functions of stereo model location:
AX=F,; (X, Y, Z)
AYSE, (X Y. 2)
AZ=F; (X, Y, Z)
AP, SEQ Y. Z) (1)
When these functional relationships have been com-
puted, the model can be plotted in the normal way.
As the manuscript is compiled, the stereo model loca-
tion of the floating mark is supplied continually to
the computer. The computer program calculates the
coordinate errors at the present model location; the
program then sends commands to four servo motors
to remove these errors. The motors are mounted on
the plotter so asto adjust the plotting pencil in X and
Y, the floating mark height in Z, and the B, control
of one projector. This measurement and control cycle
is performed every 0.02 second during manuscript
plotting.
Instead of determining the functional relationships
equations (1) from control points, it is possible to
determine these relationships elsewhere from other
data and simply enter them into the computer pro-
gram. In this case, the relative and absolute orienta-
tions must be well determined for the stereo model.
PROTOTYPE SYSTEM
Figure 1 shows a block diagram of the prototype
hybrid stereoplotter system. A photograph of the
system is shown in Figure 2. The Photocartograph
provides for the creation and rough orientation of the
optical stereo model, holds the map manuscript, and
is sufficiently rigid to prevent the stereo model from
changing with time. The AN/UYK-1 digital computer
is programmed to (1) store control and parallax-point
r Paper =
L Tape Punch |
1 Nistri
Plotter
o, B, Zr, Py
AN/UYK-1 Computer Measurement
Computer Interface AX, AY, A2, aBy Component
| Front, Rear
Plot
m Tape True, Model, Py Commands
| aper de | Enter Data
— — 2 ce zn es me
r Control |
Unit
Figure 1 Block Diagram of Hybrid Stereoplotter
HYBRID STEREOPLOTTER
Figure 2 Prototype Hybrid Stereoplotter
data; (2) calculate functional relationships in the
form of non-conformal second-degree polynomials;
and (3) continuously compute adjustments to the
four correction. axes during plotting, based on the
polynomial equations and the present model coordi-
nates.
Phase-analog position measurement furnishes the
computer with floating-mark X, Y, and Z coordinates
and the position of the B, control for the right pro-
jector. During plotting, a servo positioning network
applies the computer-calculated adjustments to the
four coordinate axes, and the phase-analog measure-
ment serves as a feedback for the servos.
Three mechanical assemblies comprise the mea-
surement component: the radial arm, the tracing
table, and the parallax adjustment assembly. All three
are designed to keep the measurement and correction
axes parallel. The radial arm, shown in Figure 3, con-
tains two sensing elements that measure the angles of
the two arm segments and thus establish the position
of the floating mark.
The tracing table contains the floating mark, the
plotting pencil, the sensing element for floating-mark
height, and the X, Y, and Z correction servos and
feedback elements. The tracing table retains the ap-
pearance and operation of a conventional tracing
table for a double-projection direct-viewing stereo-
plotter. The parallax adjustment assembly contains
the B, correction servo and feedback element. The
same feedback also serves as the sensing element for
Y parallax during the parallax-point observations,
when manual adjustment of the B, control is per-
mitted.
The computer interface transfers data between the
computer and the measurement component, convert-
ing the data into forms acceptable to each compo-
nent. The interface also generates the reference sig-
nals used by the phase-analog measurement devices.
The interface includes the operator control unit,
101