We present an active optical synthetic aperture-imaging system. A phase-step digital holographic setup is used as a wavefront sensor in the far field. The overlap of the holograms enables the estimation and compensation of their relative positions and phase with a speckle cross-correlation algorithm. Experimental results on a short-range synthetic aperture setup at 633 nm are presented that are based on 128 × 128 holograms. The synthesis is executed in one direction by means of rotation of the object. Test images show a significant gain of resolution in the synthesis direction. Processing errors are estimated through experiment. Random processing errors of a synthetic pupil composed of 33 merged holograms are negligible, but biases induced by unknown optical aberrations of the reference wave induce defocusing and astigmatism.
© 2002 Optical Society of America
(070.6020) Fourier optics and signal processing : Continuous optical signal processing
(090.0090) Holography : Holography
(100.3010) Image processing : Image reconstruction techniques
(100.6640) Image processing : Superresolution
(110.6150) Imaging systems : Speckle imaging
Renaud Binet, Joseph Colineau, and Jean-Claude Lehureau, "Short-Range Synthetic Aperture Imaging at 633 nm by Digital Holography," Appl. Opt. 41, 4775-4782 (2002)