| Autor: | Wanji Yu, Takumi Minemoto |
|---|---|
| Rok vydání: | 2000 |
| Předmět: |
Physics
business.industry Holography Physics::Optics Volume hologram Spectral density Bragg's law Image plane Atomic and Molecular Physics and Optics Electronic Optical and Magnetic Materials Power (physics) law.invention Interferometry Optics law Electrical and Electronic Engineering business Joint (audio engineering) |
| Zdroj: | Optical and Quantum Electronics. 32:367-382 |
| ISSN: | 0306-8919 |
| DOI: | 10.1023/a:1007048421821 |
| Popis: | An all-optical subtracted joint transform correlator (JTC) was proposed and it was experimentally shown that the correlator successfully performs the pattern recognition with the number of reference patterns. In the correlator, an optical interferometer was introduced to remove the additional correlation signals between the reference patterns themselves from the output plane and a photorefractive crystal was also introduced to record the joint power spectra as volume holograms. The processing for removing the additional correlation signals was performed by the parallel computations in the interferometer in real time. In this study it has been found that the correlator yields significantly better correlation results than the classical joint transform correlator does and the recording of the volume hologram corresponds to a nonlinear processing of the joint power spectrum in the fringe-adjusted joint transform correlator. However the volume hologram has angular selectivity for matching the Bragg condition. It would restrict the shift-invariant area of the input image plane. This restriction has been investigated experimentally. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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