15 
d. The start point for the output drum, mag tape and 
input carriage is established (done with a single program 
button)• 
• / 
e. Start. 
f. Printer stops automatically when the boundary limits 
have been satisfied. 
STEREOMATE PRODUCTION 
Stereomate production procedures require that the profile 
tape first go through an off-line preprocessing program. This 
program computes a set of pseudo profiles and outputs them on 
a new tape which is input to OOP along with the desired B/H. 
The remaining steps needed to produce a stereomate are the same 
as those already described for the orthophoto. 
STEREOMATE DATA PROCESSING 
Figure 6 shows the relationship between an orthophoto and 
the stereomate. Stereomate printing requires finding photo 
coordinates that correspond to the stereomate coordinates. 
The general (somewhat backwards) approach taken here is to: 
(1) establish a stereomate grid that corresponds to the printer 
drum coordinate system; (2) find the x model coordinates whose 
correct parallax shift is represented by the stereomate's x 
grid coordinates; (3) compute the corresponding photo coordi 
nates for those model coordinates; (4) print the image 
represented by those photo-coordinates on the drum. 
Figure 6A depicts the profile and pseudo profile data 
relationship. All the points are at a constant Ym (model Y). 
Em and Xm represent interpolated profile model elevations.and 
model x coordinates respectively. Xs represents the stereomate 
x coordinates which are directly related to drum position. The 
stereomate preprocessing program establishes the stereomate grid 
and computes Es using any desired B/H. The pseudo profile tape 
is generated, containing Xs, Ym and Es data. The OOP program 
computes Xms. Xms, Ym, Es is therefore a model point and its X 
parallax shift point is represented by Xs. The shutdown data 
and the interior orientation data are used by OOP to compute 
the photo coordinates from (Xms, Ym, Es). Each discrete image 
element corresponding to the expropriate photo coordinate is theft 
printed on the drum, (i.e., the photo coordinate corresponding 
to Xms will be shifted and printed at Xs. This last step is