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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.
