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Proceedings Paper

Shear speckle imaging
Author(s): John F. Belsher; David L. Fried
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Paper Abstract

A novel concept is described for generation of a high-resolution target images, even when viewing through atmospheric turbulence, based on exploitation of laser speckle statistics. A laser transmitter projects a moving sinusoidal (spatially) modulated irradiance pattern on the target. The irradiance of the backscattered speckle pattern is measured at a set of small apertures distributed over some region on the ground. By developing the correlation of the time-varying signal measured at various pairs of apertures, it is possible to obtain measurement values from which the target image can be developed. In this paper we define the details of the concept and then proceed to calculate a bound for the performance of this technique using an approximation to an estimator of the needed correlation. The estimator is unbiased over photon statistics, speckle statistics, and scintillation statistics. The shear-speckle technique requires large numbers of data frames to achieve reasonable performance at moderate spatial frequencies. However, the good signal-to-noise ratios obtained for moderate numbers of frames at low spatial frequencies suggest that shear speckle might be used to augment other imaging techniques which have trouble at lower spatial frequencies.

Paper Details

Date Published: 1 November 1990
PDF: 12 pages
Proc. SPIE 1351, Digital Image Synthesis and Inverse Optics, (1 November 1990); doi: 10.1117/12.23669
Show Author Affiliations
John F. Belsher, Optical Sciences Co. (United States)
David L. Fried, Optical Sciences Co. (United States)

Published in SPIE Proceedings Vol. 1351:
Digital Image Synthesis and Inverse Optics
Arthur F. Gmitro; Paul S. Idell; Ivan J. LaHaie, Editor(s)

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