Results 161 to 170 of about 113,115 (217)
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Optics Letters, 2005
A thin-film optical filter used as a one-dimensional spatial filter is presented, and its design is briefly examined. The filter consists of a stack of quarter-wave dielectric layers upon a right-angle prism that selectively cancel a reflected or transmitted plane-wave front for various angles of incidence.
Ivan Moreno, Maximino Avendaño-Alejo
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A thin-film optical filter used as a one-dimensional spatial filter is presented, and its design is briefly examined. The filter consists of a stack of quarter-wave dielectric layers upon a right-angle prism that selectively cancel a reflected or transmitted plane-wave front for various angles of incidence.
Ivan Moreno, Maximino Avendaño-Alejo
exaly +3 more sources
Color-sensitive spatial filters
Optics Letters, 1978Volume holograms are considered as Vander Lugt spatial filters that are sensitive to the color, in addition to the usual size, shape, and orientation, of the input patterns. A theoretical investigation is made for a few simple input patterns together with considerations for the conditions that limit the effectiveness of the volume filters.
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Filtering characteristics of spatial filter for spatial filtering velocimeter
Chinese Optics Letters, 2015In order to select a suitable spatial filter for the spatial filtering velocimeter, the filtering characteristics of the spatial filters with a rectangular window and rectangular transmittance are investigated by the power spectrum of transmittance function method. The filtering characteristics of differential filters are investigated and compared with
Xin He Xin He +3 more
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Optics Letters, 1979
Statistical detection theory is applied for the detection of binary images buried in speckle, with particular reference to information storage systems. Probability of error has been obtained in the presence of speckle noise when the receiver is a matched-filter-envelope squarer device. It has been shown that system performance deteriorates sharply with
P M, Shankar, H M, Gupta
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Statistical detection theory is applied for the detection of binary images buried in speckle, with particular reference to information storage systems. Probability of error has been obtained in the presence of speckle noise when the receiver is a matched-filter-envelope squarer device. It has been shown that system performance deteriorates sharply with
P M, Shankar, H M, Gupta
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Spatial Kalman Filters and Spatial-Temporal Kalman Filters
2014 12th International Conference on Signal Processing (ICSP), 2014The classic Kalman theory is established on time continuous observation. Using on the spatial-temporal duality, Spatial Kalman Filters (SKF) is introduced based on spatial continuity. Further, an improved SKF named Spatial-Temporal Kalman Filters (STKF), which is based on time and spatial distribution, is proposed.
Danqing Yan, Qi Zhong, Yunfeng Sui
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Birefringent Filters In Spatial Filtering
SPIE Proceedings, 1990In the present article we report the results of our experiments on the possibilities of using birefringent materials for achieving spatial filtering operations. These filters divide the input spectrum into two orthogonal components and also introduce a phase difference accompanied by a shear, the nature of shear being dependent on the birefringent ...
Ajay Ghosh, D K. Basu, A. K. Chakroborty
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IEEE Transactions on Information Theory, 1956
Starting with the formulation of H. H. Hopkins for the image forming properties of an optical system in terms of a coherence factor over the object plane, the two extreme cases of complete coherence and incoherence are considered. The incoherent case is treated briefly as a low-pass spatial frequency filter.
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Starting with the formulation of H. H. Hopkins for the image forming properties of an optical system in terms of a coherence factor over the object plane, the two extreme cases of complete coherence and incoherence are considered. The incoherent case is treated briefly as a low-pass spatial frequency filter.
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Programmable spatial filtering with bacteriorhodopsin
Applied Optics, 1996We describe a programmable spatial-filtering system using bacteriorhodopsin (BR) film as a programmable, optically addressed spatial light modulator illuminated by a single wavelength of light. We use a computer-controlled mirror scanning system to write time-varying filter functions to the BR film and present proof-of-principle experimental results ...
M, Storrs, D J, Mehrl, J F, Walkup
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2018
Abstract This chapter exploits the Fourier relationship between the fields at different positions for modifying images. Firstly, apodization is considered, where a filter is added in the plane of the lens to modify the spatial distribution in the focal plane.
Charles S. Adams, Ifan G. Hughes
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Abstract This chapter exploits the Fourier relationship between the fields at different positions for modifying images. Firstly, apodization is considered, where a filter is added in the plane of the lens to modify the spatial distribution in the focal plane.
Charles S. Adams, Ifan G. Hughes
openaire +1 more source