Optical Synthetic Aperture Analogues of Two Radio Interferometers

Abstract

Experimental and theoretical results are given for the one and twodimensional Covington-Drane optical synthetic apertures and the thin annular aperture. The segmented thin annulus is also discussed as a special case of the thin continuous annulus. Experiments are performed by masking a diffractionlimited lens with the appropriate pupil function and then measuring the imaging characteristics of the aperture. All the synthetic apertures are shown to have the full synthetic MTF's predicted by the theory. The Covington-Drane doubles the resolution of the central aperture and the thin annular apertures synthesize the full lens spatial frequency response. Optical processing of synthetic aperture photography is discussed and examples of inverse spatial filters are given.