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Optical Engineering

Holographic associative memories with a true brightness tone rendering
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Paper Abstract

We consider the problem of a holographic associative memory (HAM) which must reconstruct a 2-D optical signal with corrected amplitude errors. The experimental conditions for an associative reconstruction with true brightness tone rendering by a regular HAM based on the ghost-image hologram are determined. More universal all-optical error-correcting (EC) HAMs are also presented and demonstrated. These HAMs perform a reconstruction of the second image of a stored memory that is angularly separated from the readout beam of its partial version. We describe the scheme solution of an ECHAM problem using Denisyuk's hologram, which reconstructs an error-corrected associative response in reflection. Then the original all-optical ECHAM using the so-called quadric hologram (QH) is presented. This term here refers to a thin off-axis nonlinearly recorded hologram used as the matched filter of a regular coherent correlator. When a QH is read out by the partial or distorted version of the stored memory, the complex conjugated associative response is reconstructed at the output plane with an original brightness distribution. A QH-based ECHAM is equivalent in efficiency to nonlinear HAMs based on the resonator architectures using phase-conjugation techniques and external nonlinearities, but it differs from these in arrangement simplicity and implementation flexibility as an EC associative module of the more general neural network architectures.

Paper Details

Date Published: 1 April 1995
PDF: 9 pages
Opt. Eng. 34(4) doi: 10.1117/12.197162
Published in: Optical Engineering Volume 34, Issue 4
Show Author Affiliations
Vyacheslav K. Polyanskii, Chernovtsy Univ. (Ukraine)
Peter V. Polyanskii, Chernovtsy Univ. (Ukraine)

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