2003 Fiscal Year Final Research Report Summary
Optical Data Storage by Use of Optical Encryption and its Compression and Transmission
| Project/Area Number |
14550039
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Applied optics/Quantum optical engineering
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| Research Institution | Wakayama University |
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Principal Investigator |
NOMURA Takanori Wakayama University, Faculty of Systems Engineering, Associate Professor, システム工学部, 助教授 (80222206)
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| Co-Investigator(Kenkyū-buntansha) |
KAMEDA Masashi Iwate Prefectural University, Faculty of Software and Information Science, Associate Professor, ソフトウェア情報学部, 助教授 (60243325)
NITANAI Eiji Wakayama University, Faculty of Systems Engineering, Research Associate, システム工学部, 助手 (00304189)
JAVIDI Bahram University of Connecitcut, School of Engineering, Professor
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| Project Period (FY) |
2002 – 2003
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| Keywords | Optical Encryption / Optical Data Storage / Digital Holography / Three-Dimensional Object / Data Compression |
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| Research Abstract |
We proposed optical data storage by use of optical encryption and its compression and transmission.
(1)A secure optical storage based on a configuration of a joint transform correlator by use of a photorefractive material has been presented. A key code designed through the use of an optimized algorithm so that its Fourier transform has a uniform amplitude distribution and a uniformly random phase distribution has been introduced. Original two-dimensional data and the key code are placed side-by-side at the input plane. Both of them are stored in a photorefractive material as a joint power spectrum. The retrieval of the original data can be achieved with the same key code. We can record multiple two-dimensional data in the same crystal by angular multiplexing and or key code multiplexing.
(2)An encryption method of a 3D object based on phase modulation of an object wave has been proposed. The phase of the object wave is modulated by a virtual optical random phase mask using a digital holographic technique. The keys of an encryption step are both a phase distribution and a position of the virtual optical phase mask. If either of them is not correct, we can not decrypt the 3D object. Owing to a characteristic of a hologram, we can see some parallax of a reconstructed 3D object. Experimental results have been presented to confirm the proposed method.
(3)An encrypted digital holographic data reconstruction method with data compression has been proposed. We show the number of quantization levels of the digital hologram can be reduced. By computer simulations, it is confirmed that the method is especially useful for binary images. For gray-scale images, we propose a bit plane decomposition method. By this method, we have shown both high quality reconstructed image quality and a high compression ratio can be achieved.
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