Real-time color image correlation with a color liquid-crystal television and a Fresnel holographic filter

Wang, Z Q; Cartwright, Colin M.; Soutar, Colin; Gillespie, W. A.

doi:10.1364/ao.32.000715

Cited by 14 publications

(4 citation statements)

References 11 publications

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“…They have been also employed for the design of real-time optical processors that contain color information [3,4]. Ferroelectric liquid crystal (FLC) displays have found applications in diffractive optics for the generation of digital holograms [5,6], adaptive beam steering systems [7] and polarization gratings [8,9].…”

Section: Introductionmentioning

confidence: 99%

Performance of ferroelectric liquid crystal spatial light modulators for polarization and color diffractive elements

et al. 2009

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In this work we applied a ferroelectric liquid crystal on silicon (FLCoS) display for implementing monochrome and color diffractive optical elements (DOE). We first apply a reverse engineering process specifically adapted to characterize the optical parameters of a commercial FLCoS display, specifically the phase shift and the tilt angle. We then analyze the performance of the device for implementing a binary polarization diffraction grating (PDG), and how it adopts the form of either a binary amplitude grating or a binary phase grating as particular cases when the polarization states emerging from the display are projected to an analyzer. As a final experiment, we have applied the FLCoS display to generate RGB improved dynamic color binary-phase Fourier computer-generated holograms (CGHs). We have electronically synchronized the properly scaled image addressed to the display with a color filter wheel with RGB filters. Experimental results show an excellent chromatic compensation of the color image reconstruction.

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Section: Introductionmentioning

confidence: 99%

Performance of ferroelectric liquid crystal spatial light modulators for polarization and color diffractive elements

et al. 2009

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“…1,[16][17][18][19][20][21][22] Based on these general concepts, a variety of techniques are currently available for spectral image filtering. 1,23 These include, among others, dichroic coated filters, [24][25][26][27] holographic filters, [28][29][30][31][32][33][34][35] acousto-optic tunable filters, 35 Fabry-Perot tunable filters, 24,[35][36][37][38][39] tunable birefringent filters, 23,[40][41][42][43][44][45][46] and Lyot filters. 23,[47][48][49] The filtration mechanisms vary from the use of Bragg diffraction caused by periodically modulated refractive indices in holographic and acousto-optic tunable filters, to the use of selectivity in transmission by polarization in Lyot filters.…”

Section: Introductionmentioning

confidence: 99%

Novel continuously tunable high spectral resolution optical filter for two-dimensional imaging

Mukherjee

Chen

Witanachchi

2001

Review of Scientific Instruments

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Despite the existence of a variety of optical filters for the separation of spectral components in a multicolor image, a filter that is both continuously wavelength tunable and capable of high spectral resolution while preserving the spatial integrity of a two-dimensional image is not currently available. We present, in this article, the introduction of a novel optical filtering concept that permits the development of such a system. Both the concept and its implementation in an optical-fiber-based prototype that converts two-dimensional images to a one-dimensional array followed by interconversion for image reconstruction are presented. The performance of the prototype is analyzed using both a xenon arc lamp as a standard broadband illumination source as well as He–Ne and Ar lasers as sources of coherent radiation. An unoptimized throughput efficiency of approximately 30% and a bandwidth of 6 Å without spectral leakage or spatial crosstalk is obtained over the entire investigated tuning range from 430 to 807 nm. Potential applications of such an optical filtration system, with wavelength tunability on the angstrom scale and potential spatial resolutions in the micrometer range, using suitable optical imaging are discussed.

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“…The RGB components of the scene are displayed in the correlator either on an achromatic spatial light modulator 3 or on a color spatial light modulator. 4 This method permits digital preprocessing of the acquired image before it is displayed.Different problems in polychromatic pattern recognition have been studied in Refs. 1-6.…”

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confidence: 99%

Optical pattern recognition based on color vision models

et al. 1995

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A channel transformation based on opponent-color theory of the color vision models is applied to optical pattern recognition so that the conventional red, green, and blue (RGB) channels are transformed into bright -dark, red -green, and yellow -blue (ATD) channels. Matched f iltering and correlation are performed over the new components of the target and the scene in the ATD system. The proposed transformation allows us to reduce the number of channels commonly used in color pattern recognition, passing from the three RGB channels to the two red -green and yellow -blue opponent-color channels. © 1995 Optical Society of AmericaThe introduction of color information in pattern recognition is especially useful when the contours and the intensity distribution do not provide enough information to permit the discrimination of images. The most extensive way to incorporate color into pattern recognition is through a trichromatic decomposition of the image into red, green, and blue (RGB) components that are independently analyzed. The RGB multichannel decomposition has been associated with matched filtering and optical correlation techniques for the performance of optical color pattern recognition. One of the methods used for the RGB decomposition is the illumination of a color transparency containing the target by three monochromatic wavelengths separately. 1,2The three wavelengths, belonging to the red, green, and blue regions, must be distributed in the visible spectrum. For the illumination of the optical correlator it has been proposed that the same wavelengths be used for the generation of the filters 2 or that a white-light source combined with a grating in the scene plane be used. 3Another method used for RGB decomposition is the acquisition and digitization of the image by a color camera. In this case the channels are defined by the response of the camera in a wide bandwidth. The RGB components of the scene are displayed in the correlator either on an achromatic spatial light modulator 3 or on a color spatial light modulator. 4 This method permits digital preprocessing of the acquired image before it is displayed.Different problems in polychromatic pattern recognition have been studied in Refs. 1-6. The most common problem is the recognition of a given object, taking into account both the shape and the color distribution. 1 -4 Other problems are the recognition of a given shape regardless of the color distribution of the object and the identif ication of the color of the diverse zones that compose the object. 5,6 Millán et al. 5 proposed a recognition strategy that involves the signals used to generate the matched filters and the decision criteria applied to the RGB multichannel correlation results. Yamaba and Miyake 6 proposed a transformation of the RGB components provided by the camera that considers the Hurvich-Jameson color vision model 7 with some modifications. Their recognition system is based on the projected weight values obtained from a learning process by a neural board.Color human vision models ba...

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Real-time color image correlation with a color liquid-crystal television and a Fresnel holographic filter

Abstract: Incoherent color image correlation with a multiwavelength Fresnel holographic filter and a color liquid-crystal television as a real-time input device is demonstrated.

Cited by 14 publications

References 11 publications

Performance of ferroelectric liquid crystal spatial light modulators for polarization and color diffractive elements

Performance of ferroelectric liquid crystal spatial light modulators for polarization and color diffractive elements

Novel continuously tunable high spectral resolution optical filter for two-dimensional imaging

Optical pattern recognition based on color vision models

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