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    Capture, encryption, compression, and display of digital holograms of three-dimensional objects


    Gopinathan, Unnikrishnan and Monaghan, David S. and Shortt, Alison and Naughton, Thomas J. and Sheridan, John T. and Javidi, Bahram (2006) Capture, encryption, compression, and display of digital holograms of three-dimensional objects. In: SPIE Proceedings. SPIE, 62521F.

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    Abstract

    Digital holography can be used to capture the whole Fresnel field from a reflective or transmissive object. Applications include imaging and display of three-dimensional (3D) objects, and encryption and pattern recognition of two-dimensional (2D) and 3D objects. Often, these optica l systems employ discrete spatial light modulators (SLMs) such as liquid-crystal displays. In the 2D case, SLMs can encode the inputs and keys during encryption and decryption. For 3D processing, the SLM can be used as part of an optical reconstruction technique for 3D objects, and can also represent the key during encryption an d decryption. However, discrete SLMs can represent only discrete levels of data necessitating a quantisation o f continuous valued analog information. To date, many such optical systems have been proposed in the literature, y et there has been relatively little experimental evaluation of the practical performance of discrete SLMs in these systems. In this paper, we characterise conventional phase-modulating liquid-crystal devices and examine thei r limitations (in terms of phase quantisation, alignment tolerances, and nonlinear response) for the encryption of 2D and 3D data. Finally, we highlight the practical importance of a highly controlled discretisation (optimal quantisation) for compression of digital holograms.

    Item Type: Book Section
    Additional Information: Cite as: Unnikrishnan Gopinathan ; David S. Monaghan ; Alison E. Shortt ; Thomas J. Naughton ; John T. Sheridan, et al. "Capture, encryption, compression, and display of digital holograms of three-dimensional objects", Proc. SPIE 6252, Holography 2005: International Conference on Holography, Optical Recording, and Processing of Information, 62521F (June 09, 2006); doi:10.1117/12.677154; http://dx.doi.org/10.1117/12.677154
    Keywords: digital holography; optical encryption; quantization; spatial light modulator; image compression; three-dimensional image processing;
    Academic Unit: Faculty of Science and Engineering > Computer Science
    Item ID: 8425
    Identification Number: https://doi.org/10.1117/12.677154
    Depositing User: Thomas Naughton
    Date Deposited: 10 Jul 2017 15:39
    Publisher: SPIE
    Refereed: Yes
    Funders: Enterprise Ireland, Science Foundation Ireland
    URI:

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