Results 261 to 270 of about 2,943,799 (310)
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Applied Optics, 1975
A real-time coherent optical correlator is described that uses the Itek PROM as a recyclable filter recording medium. Operation of a joint transform correlator is compared to a conventional Vander Lugt system. Experimental results are shown for the joint transform system, including demonstrations of the effects of target alignment and scale and the ...
P, Nisenson, R A, Sprague
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A real-time coherent optical correlator is described that uses the Itek PROM as a recyclable filter recording medium. Operation of a joint transform correlator is compared to a conventional Vander Lugt system. Experimental results are shown for the joint transform system, including demonstrations of the effects of target alignment and scale and the ...
P, Nisenson, R A, Sprague
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Single Nanowire Optical Correlator
Nano Letters, 2014Integration of miniaturized elements has been a major driving force behind modern photonics. Nanowires have emerged as potential building blocks for compact photonic circuits and devices in nanophotonics. We demonstrate here a single nanowire optical correlator (SNOC) for ultrafast pulse characterization based on imaging of the second harmonic (SH ...
Huakang, Yu +7 more
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Optical Correlators: Applications
2015Optical correlators (OCs) have received much attention since VanderLugt’s invention in the mid-1960s, when he showed that pattern recognition can be optically realized using matched spatial filtering techniques. The classical VanderLugt correlator used photographic plates or film for carrying both pieces of information: the input and the reference, in ...
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New Multichannel Optical Correlator
Applied Optics, 1971This paper describes a multichannel optical correlator that uses two spatial dimensions to achieve multi-channel capability and operates in real time. Given I signals, r(i)(t), and J signals, s(j)(t), it can produce the I x J cross products, r(i)(t)s(j)(t), averaged over some interval.
G J, Aitken, L, Wang
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Optical Correlation of Fresnel Images
Applied Optics, 1968A real-time optical correlator is described that uses an ultrasonic light modulator (ULM) in conjunction with an amplitude mask or replica of the signal to achieve linear, phase-coherent detection, without need for high quality optics. When the mask is placed in a Fresnel image plane of the ULM, optimum correlation and collinear heterodyning are ...
G, Meltz, W T, Maloney
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Phase correlations and optical coherence
Optics Letters, 2012We examine the properties of the recently introduced degrees of coherence regarding the phase correlations of the optical field. It is seen that some of these quantities are straightforwardly related to the limits of complete dependence and complete independence of phases, which were used as the extremes of complete coherence and complete incoherence ...
Jani, Tervo +2 more
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Light utilization in optical correlators
Applied Optics, 1982An analysis is made of the overall light efficiency in a coherent optical correlator. The results are applied to a matched filter and an inverse filter. Kogelnik's coupled wave theory is applied to analyze the diffraction efficiency of a filter recorded on a high-efficiency phase medium such as dichromated gelatin.
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Compact planar optical correlator
Optics Letters, 1997A compact planar configuration for performing optical correlation is described. It comprises two pairs of identical holographic lenses and a holographic filter. Each pair of lenses is recorded on a single substrate; together the lenses perform exact Fourier transformation.
S, Reinhorn, Y, Amitai, A A, Friesem
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Quadratic correlation filters for optical correlators
SPIE Proceedings, 2003Linear correlation filters have been implemented in optical correlators and successfully used for a variety of applications. The output of an optical correlator is usually sensed using a square law device (such as a CCD array) which forces the output to be the squared magnitude of the desired correlation.
Abhijit Mahalanobis +2 more
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A multichannel optical correlator
Optics Communications, 1987Abstract A multichannel parallel optical pattern recognition system is proposed. The synthesis of a large capacity matched filter is discussed. The technique uses a phase mask and telescopic arrangement for the mass filter construction. The processing capacity of the proposed optical correlator, which is over 400 times of a single channel system, is ...
Francis T.S. Yu, Q.H. Zhou
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