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IMAGE CORRELATION SYSTEM FOR 
ANALYTICAL STEREOPLOTTERS 
E. C. Johnson' 1 ' and A. DiPentima** 
ABSTRACT 
An image correlation system has been developed for the AP-Z 
analytical stereoplotter to provide automatic profiling, contouring, 
and orientation. The system includes a cathode - ray-tube flying-spot 
scanner for each photograph of the stereo pair. The two scanners and 
their associated optics are mounted on a modified AP-Z viewing unit. 
A separate cabinet houses the scan generation circuitry, which de 
velops correctly shaped scan patterns for each photo under control 
of the AP-Z computer. It also contains the video correlation circuitry, 
which generates measures of image mis-alignment, degree of corre 
lation, and error in terrain slope compensation. The basic AP-Z com 
puter is expanded somewhat to perform a number of additional compu 
tational functions and to control over-all operating strategy. The 
result is a well integrated system in which the high precision and 
flexibility inherent in the analytical plotter principle are combined 
with the capability for high-speed automatic operation provided by 
image correlation techniques. 
The Bendix Corporation, Research Laboratories Division 
U. S. Air Force, Rome Air Development Center 
The system described in this paper is being developed by the Bendix 
Corporation, Research Laboratories Division, under contract to the 
U. S. Air Force, Rome Air Development Center. Portions of the work 
are being done by Ottico Meccanica Italiana (Rome, Italy). 
1