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Optical Engineering • Open Access

Lensless coded-aperture imaging with separable Doubly-Toeplitz masks
Author(s): Michael J. DeWeert; Brian P. Farm

Paper Abstract

In certain imaging applications, conventional lens technology is constrained by the lack of materials which can effectively focus the radiation within a reasonable weight and volume. One solution is to use coded apertures—opaque plates perforated with multiple pinhole-like openings. If the openings are arranged in an appropriate pattern, then the images can be decoded and a clear image computed. Recently, computational imaging and the search for a means of producing programmable software-defined optics have revived interest in coded apertures. The former state-of-the-art masks, modified uniformly redundant arrays (MURAs), are effective for compact objects against uniform backgrounds, but have substantial drawbacks for extended scenes: (1) MURAs present an inherently ill-posed inversion problem that is unmanageable for large images, and (2) they are susceptible to diffraction: a diffracted MURA is no longer a MURA. We present a new class of coded apertures, separable Doubly-Toeplitz masks, which are efficiently decodable even for very large images—orders of magnitude faster than MURAs, and which remain decodable when diffracted. We implemented the masks using programmable spatial-light-modulators. Imaging experiments confirmed the effectiveness of separable Doubly-Toeplitz masks—images collected in natural light of extended outdoor scenes are rendered clearly.

Paper Details

Date Published: 3 February 2015
PDF: 9 pages
Opt. Eng. 54(2) 023102 doi: 10.1117/1.OE.54.2.023102
Published in: Optical Engineering Volume 54, Issue 2
Show Author Affiliations
Michael J. DeWeert, BAE Systems (United States)
Brian P. Farm, BAE Systems (United States)

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