Automatic Focus Sensing And Control Of Optical Reconnaissance Sensors

David G. Stites

doi:10.1117/12.954804

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8 September 1976 Automatic Focus Sensing And Control Of Optical Reconnaissance Sensors

David G. Stites

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Proceedings Volume 0079, Aerial Reconnaissance Systems: Pods/Aircraft I; (1976) https://doi.org/10.1117/12.954804
Event: 1976 SPIE/SPSE Technical Symposium East, 1976, Reston, United States

Abstract

Tactical aerial photographic reconnaissance requires the acquisition of high acuity photography under adverse environmental conditions. In cameras with medium to long focal length lenses, large focus errors resulting from uncontrolled pressure and temperature variations have been experienced with loss of image sharpness and resolution. An autofocusing system has been developed at CAI that uses a photoconductive cell to detect image contrast as a measure of "out-of-focus. " The system was built into an 18-inch focal length f/4 panoramic camera where it demonstrated the ability to maintain the image focus within .001 inch of the film plane for a large range of varying temperatures and pressures. Inflight test data showed improved photointerpretation; ground target detection was increased by 30 percent. This automatic focusing method results in significant improvements in sensor acuity through near optimum focus under all conditions of transient wavefront quality of the optics and the imaging environment.

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David G. Stites "Automatic Focus Sensing And Control Of Optical Reconnaissance Sensors", Proc. SPIE 0079, Aerial Reconnaissance Systems: Pods/Aircraft I, (8 September 1976); https://doi.org/10.1117/12.954804

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