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Proceedings Paper

Method of digital hologram synthesis for hidden image optical coding in holographic security devices
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Paper Abstract

The methods of increase the protective properties of holographic elements by using hidden image are discussed. The extension of the new method of wave equation solution is useful for providing analytical studying and numerical modeling of diffraction on amplitude-phase discrete mask. Possibilities of its practical application for structured light beam generation and wavefront reconstruction is considered. Conclusions regarding the possibilities of the representation of the arbitrary fields by using the discrete matrix of elementary diffractive aperture cells for an enhancement of the iteration algorithm of hologram synthesis are obtained. The method proposed of computer-generated holograms (CGH) synthesis enables one to synthesize CGH's and to simulate the digital image processing techniques for hidden image coding. The further improvement of this approach of coding amplitude-phase masks for both recording and reading of hidden image by holographic security devices is proposed. By using coding phase mask with quasi-stochastic distribution for diffraction pattern writing as additional structure on the protective hologram are explained. It is shown that computer generated hologram (CGH) can restore spatial structure represented by optical singularities. The conditions of reconstruction of the hidden image are discussed in case of encoding and decoding masks are not coinciding. A structure of a system that looks promising to produce a like hologram and method of operation directly images a pattern, which is previously calculated by computer and displayed on the amplitude-phase mask is explained. The results obtained by numerical and experimental means are accompanied with a discussion about extents of this method.

Paper Details

Date Published: 15 September 2006
PDF: 5 pages
Proc. SPIE 6341, Speckle06: Speckles, From Grains to Flowers, 63411Y (15 September 2006); doi: 10.1117/12.695475
Show Author Affiliations
Ruslan Lymarenko, Institute of Applied Optics (Ukraine)
Oksana Budnyk, Institute of Applied Optics (Ukraine)

Published in SPIE Proceedings Vol. 6341:
Speckle06: Speckles, From Grains to Flowers
Pierre Slangen; Christine Cerruti, Editor(s)

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