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