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Proceedings Paper

Focus Compensation Techniques For Reconnaissance
Author(s): John McKeough; Tom Glavich
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Paper Abstract

For photo-reconnaissance aircraft to survive in the future, long range oblique photography and high altitude photography are two modes presently being considered that will require cameras to have very long focal length lens. In addition, these cameras will have higher resolution than today's. With some existing cameras, unexpected changes in performance of the optical system have been observed due to changes in the local environment. Since focus control becomes more critical with higher resolution cameras, degradation will be more severe. Therefore, to retain optimum resolution under adverse environmental conditions, these cameras must have a more accurate form of focus control. Several methods have been developed but all have their limitations, especially when dealing with radial thermal gradients. This paper describes a unique focusing compensation system that is not only very accurate and capable of detecting rapid focus changes but also requires minimum modification to existing systems. The developed system uses a laser measurement system along with environmental sensors and a micro-computer to generate a focus correction for changes in radial thermal gradients, external temperature and range.

Paper Details

Date Published: 1 August 1979
PDF: 8 pages
Proc. SPIE 0175, Airborne Reconnaissance IV, (1 August 1979); doi: 10.1117/12.957196
Show Author Affiliations
John McKeough, Naval Air Development Center (United States)
Tom Glavich, Naval Air Development Center (United States)

Published in SPIE Proceedings Vol. 0175:
Airborne Reconnaissance IV
Charles Haney; Donald Jarvis, Editor(s)

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