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Proceedings Paper

Experiments with new phase image encrypting method
Author(s): Paul C. Mogensen; Jesper Glueckstad; Haruyoshi Toyoda; Tsutomu Hara
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Paper Abstract

Recently, there has been considerable interest in the application of combined phase/amplitude encryption to the field of optical pattern recognition based security systems, due to the high level of security that it offers1. We have developed a new phase-only encryption technique based in principle on a phase-coding method which uses a generalization of the Zernike phase contrast technique, but breaks the small-phase-angle limitation of Zernike's method2. This phase-coding technique for image formation, in which the spatial average value of an input phase modulated image is combined with a pre-estimated phase retardation produced by a phase contrast filter, has been demonstrated experimentally3. In this paper we describe an extension of our phase-coding method4 and its application in an experimental system for the decryption and visualization of phase encrypted images using commercially available Parallel-Aligned Liquid Crystal Spatial Light Modulators (PAL-SLM) supplied by Hamamatsu Photonics5.

Paper Details

Date Published: 19 July 1999
PDF: 2 pages
Proc. SPIE 3749, 18th Congress of the International Commission for Optics, (19 July 1999); doi: 10.1117/12.354745
Show Author Affiliations
Paul C. Mogensen, Riso National Lab. (Denmark)
Jesper Glueckstad, Riso National Lab. (Denmark)
Haruyoshi Toyoda, Hamamatsu Photonics KK (Japan)
Tsutomu Hara, Hamamatsu Photonics KK (Japan)

Published in SPIE Proceedings Vol. 3749:
18th Congress of the International Commission for Optics
Alexander J. Glass; Joseph W. Goodman; Milton Chang; Arthur H. Guenther; Toshimitsu Asakura, Editor(s)

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