Image Stabilization Techniques For Long Range Reconnaissance Camera

George R. Lewis

doi:10.1117/12.959276

Abstract

International political considerations call for overt photographic intelligence collection at distances greater than 10 nmi from the reconnaissance aircraft. To obtain adequate ground resolution at those ranges, camera focal lengths have increased to 66 inches or more. Aircraft motion becomes magnified by the long focal length lens and can be the limiting factor in system resolution. Two methods of reducing aircraft motion effects are apparent: the lens aperture can be made large, collecting more light, which allows shorter exposure times and thus less smear at the film plane; or the camera can be presented with a space-stabilized image using a two-axis stabilized mirror to reduce the effects of the aircraft motion allowing a smaller aperture lens. Two-axis stabilized mirrors, usually termed scan heads, have proven in flight that this approach is a viable, attractive alternative to large aperture lenses. This paper discusses the rationale for scan heads and describes one practical example. A method of ground testing scan heads for disturbance rejection is presented. A set of data from ground tests of a scan head is shown, illustrating the dependence of the rejection on input amplitude and frequency.

Citation Download Citation

George R. Lewis, "Image Stabilization Techniques For Long Range Reconnaissance Camera", Proc. SPIE 0242, Long Focal Length, High Altitude Standoff Reconnaissance, (23 December 1980); doi: 10.1117/12.959276; https://doi.org/10.1117/12.959276

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