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ABSTRACT 
A new optical orthophoto printer has been developed 
by the Rome Air Development Center. Digital profile data is 
required as in conventional systems, however, the off-line 
capability provides greater flexibility than was previously 
possible. The source of profile data is not inherently 
limited to direct plotter output but can be obtained, for 
example, from a digital terrain data base. Previously 
compiled profile data could be used to produce an updated 
orthophoto from more current imagery over a specified area. 
The optical orthophoto printer operates from camera 
parameters, orientation data, and digital elevation profiles, 
using a special purpose computer which computes model-to-photo 
transformation and derives the necessary servo control signals 
for the optical transforming elements and input and output 
photo and film carriage motions. 
In addition to rectification and orthorectification of 
vertical and convergent frame, non-conventional imagery may 
be used such as the convergent optical bar used during the 
Apollo flights. The Analytical flexibility of the system 
allows present capabilities with proper procrramming to be 
expanded to cover essentially any transformation needed. 
A program has been developed providing a capability for 
stereomate production. The system has reproduced 72 line 
pair per millimeter high contrast targets and has provided 
very good quality continuous tone imagery at accuracies of 
30-40u CMAS. Scanning of the input is done at up to lOmm/sec 
which allows production of 9x9 inch orthophotos in 50-60 
minutes. Further details of the printer performance reflecting 
an ongoing test program are presented in this paper.