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Proceedings Paper

Problem of twin-image elimination in 2-D computer synthesized hologram
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Paper Abstract

It is well known that one of the basic functions of security holograms is the maximal complication of their nonauthorized reproduction, in other words - counterfeiting. To solve the problem, concealed images that can be observed only under special conditions are placed into a structure of the hologram. A popular way to place concealed image in Diffractive Optical Variable Device (DOVID) is integration into DOVID's structure of a Concealed Laser-Readable Image (CLRI). Traditionally CLRI is a 2-D Computer-Generated Hologram (2-D CGH), which is a digitized Interference Fringe Data (IFD) structure, computed under the scheme of Fourier-hologram synthesis. Such hologram provides inspection of second level with portable laser reading devices. While it is being read, two (+/- 1 order of diffraction) identical images are formed. In this work a special kind of CGH, which restores image only in one diffractive order or two different images in +1 and -1 orders of diffraction proposed.

Paper Details

Date Published: 20 February 2007
PDF: 10 pages
Proc. SPIE 6488, Practical Holography XXI: Materials and Applications, 64880D (20 February 2007); doi: 10.1117/12.700257
Show Author Affiliations
Eugene Braginets, National Taras Shevchenko Univ. of Kyiv (Ukraine)
Vladimir Girnyk, State Enterprise Polygraphcombinat Ukraina (Ukraine)
Sergey Kostyukevych, Institute of Semiconductor Physics (Ukraine)
Alexander Soroka, National Taras Shevchenko Univ. of Kyiv (Ukraine)
Irina Androsyuk, Institute of Semiconductor Physics (Ukraine)


Published in SPIE Proceedings Vol. 6488:
Practical Holography XXI: Materials and Applications
Roger A. Lessard; Hans I. Bjelkhagen, Editor(s)

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