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Nonlinear optical Materials II 1989

作者： Jäger, Dieter Universität Münster Institut für Angewandte Physik Corrensstrasse 2/4 MünsterD-4400 Germany

During the past years, rapid progress has been made in the development of optically bistable semiconductor devices that may be the key elements in future photonic switching and information processing systems. This paper examines especially the potentialities of hybrid components where a self-electrooptic effect is achieved by combining optoelectronic and electrooptic mechanisms. The switching properties of thermooptical and electrooptical Fabry-Perot SEED structures are discussed in detail. The results are compared with experimental data of best reported switching devices that are capable of achieving a processing rate of more than 1012 bits per second and chip in a two-dimensional array. © 1989 SPIE. All rights reserved.

关键词： digital devices

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hybrid electro-optical ESM intercept-receiver proposal

Hybrid electro-optical ESM intercept-receiver proposal

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IEEE International Conference on systems Engineering

作者： Ramamoorthy, P.A. Pace, Phillip E. Dep of Electr & Comput Eng Univ of Cincinnati Cincinnati OH USA

A hybrid electrooptical ESM intercept receiver is presented which utilizes two parallel optoelectronic subprocessors in the front-end to digitize the autocorrelation function and the bispectrum of the wavefront (and not the signal itself) in to be processed by a digital processor. Wavefront-correlation subprocessor output results based on simulation with a high-resolution spectral estimator (modified Yule-Walker) under various broadband signal-to-noise ratios and pulse densities are presented to demonstrate the superiority of such an approach. The false targets resulting from a second-order nonlinear phase coupling can be identified through higher-order spectra (bispectra). The wavefront-bispectral subprocessor identifies these false targets in real time. Simulation output results are also shown. The combined use of high-speed (but limited-precision) optical processing and low-speed (but high-precision) digital electronics can lead to improved dynamic range, high resolution, and the ability to track, detect, and properly classify high-density time-varying signals. Throughput rate, sensitivity, and frequency measurement error analysis are also discussed.

关键词： signal Receivers

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CCD imager digital data processing: Concepts and hardware

CCD imager digital data processing: Concepts and hardware

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digital image processing Applications 1989

作者： Dangler, Paul E. Hybrid Imaging Systems Division Photographic Research Laboratories Eastman Kodak Company RochesterNY14650-2018 United States

In the design of any high quality scanner utilizing a linear CCD imager, a set of features is required that is largely independent of the application. At the front end, sensor clocking signals are generated and analog-to-digital conversion occurs. Next, corrections for differences in pixel dark current and gain are applied, along with pixel and/or line summing to improve the signal-to-noise ratio. The corrections and summing can be done by software, but significant speed improvements are obtained when a hardware solution is employed. The log of the data may be calculated, and the data must be supplied to some form of image storage device. RAM memory on a standard computer bus, such as VME, provides a straightforward means to configure an image storage, so long as a means to transfer sensor data to the memory is provided. This paper will begin with a review of the various ways in which data from a CCD scanner is processed for use in a digital imaging system, including the correction for dark noise variations and gain errors, data space transformations, and the use of pixel or line summing to improve signal-to-noise ratio. Following that, a high speed hardware implementation of these functions will be described. © 1989 SPIE.

关键词： Pixels

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Fast image processing systems for evaluating the clinical potential of ultrasound speckle suppression and parametric imaging 3

Fast image processing systems for evaluating the clinical po...

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Medical Imaging III: image processing 1989

作者： Bamber, J.C. Bell, D.S. Crawford, D. Cook-Martin, G. Hill, C.R. Phelps, J.V. Institute of Cancer Research Royal Marsden Hospital Joint Department of Physics Downs Road Sutton SurreySM2 5PT United Kingdom

Early experience of new forms of adaptive filtering for ultrasound speckle reduction and parametric imaging, using off-line conventional digital processing, has been sufficiently encouraging to warrant attempts to build fast on-line implementations for purposes of clinical trials. This paper describes the hardware under development. The feasibility of implementing specific algorithms in real-time (video rate) at low cost was demonstrated using a hybrid digital/analogue system in which the video signal (from any scanner) is sampled to 256 points per line and passed sequentially through a series of shift registers, in order to derive a 5 by 5 window of values which surrounds the image point to be processed. These 25 video signals are then used as inputs to an analogue processor, which provides the filtered output. For greater accuracy, flexibility, spatial resolution and freedom from image artefacts, a slower system has been constructed around a commercially available digital image processor. This system has been chosen to act as the main clinical test device. Whole images maybe processed in a few tens of seconds and specified regions, if small enough, may be processed at rates approaching real-time. © 1989 SPIE. All rights reserved.

关键词： Shift registers

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Rate of digital information processing by acoustooptic space-time modulators

Russian Ultrasonics

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Russian Ultrasonics 1989年第2期19卷 94-100页

作者： Ivanov, A.I. Pilipovich, V.A. Shcherbak, Yu.M. Acad of Sciences of the Byelorussian SSR Russia

Acoustooptic space-time light modulators (STLMs) are used as input devices in optical information processing systems, real-time rf signal processing devices, and page formers in optoelectronic devices. The information capacity of such STLMs can be as high as 104 bits and the rate of processing - 109 bits/s. The two dimensional image of optical data in an acoustooptic STLM is formed by short acoustic pulses whose length is determined by the size of the light bits in the direction of propagation of the optical beam. The data pattern produced is not fixed but moves with the speed of sound in the STLM material.

关键词： Acoustooptical Devices

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optical laboratory realization of distortion invariant filters

Optical laboratory realization of distortion invariant filte...

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hybrid image and signal processing 1988

作者： Casasent, David Ye, Ren-Chao Carnegie Mellon University Center for Excellence in Optical Data Processing Department of Electrical and Computer Engineering PittsburghPA15213 United States Shanghai Institute of Technical Physics Academia Sinica Shanghai China

A hybrid optical/digital correlator filter synthesis architecture for distortion-invariant pattern recognition and scene analysis is described. Distortion-invariant correlation filter synthetic discriminant function design is reviewed. Computer generated hologram filter synthesis concepts are then reviewed. Emphasis is given to the optical laboratory realization of the filters for such systems. The issues addressed include: the number of training images, selection of the shift parameter in filter design, the ability of the system to recognize rotated (non-training) images, what the largest false class peak correlation (anywhere, not just at the correlation peak point) is, and solutions to the non-zero optical transmittance of input and filter films. Laboratory results for all major points are provided. © 1988 SPIE. All rights reserved.

关键词： optical correlation

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The influence of pacing technologies on environmental application of space-based synthetic aperture radar

The influence of pacing technologies on environmental applic...

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OCEANS

作者： S.W. McCandless J. Curlander User Systems Inc. Annandale VA USA Jet Propulsion Laboratory Pasadena CA USA

Synthetic aperture radar pacing technology areas are explored in terms of projected capabilities that will produce the most benefits for ocean users. The current state of the art and expected future developments in data handling and onboard signal processing are presented at a functional module level. The discussion covers optical and digital image processing, and digital downlink, the high-rate recorder, and the ground data system. The analysis indicates that the primary technology driver is in the spaceborne image signal processor. optical, digital, or combination hybrid designs can be considered for space-based implementations.< >

关键词： optical signal processing Marine technology Adaptive optics optical recording Oceans Data handling Radar signal processing digital images Downlink Data systems

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DESIGN OF TIME-signal optical SPECTRUM ANALYZERS

DESIGN OF TIME-SIGNAL OPTICAL SPECTRUM ANALYZERS

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作者： LIN, TSONGNENG WILLIAM Pennsylvania State University

学位级别：博士

Spectrum analysis has been shown as one of the most useful techniques in modern science. Virtually every discipline makes use of it in one form or another. Generally, spectrum analysis has been performed by electronic systems. However, due to the fundamental simplicity, parallelism and intrinsic speed of optical processing systems, the usefulness of optical spectrum analysis has grown remarkably in the past decade. These features of the optical system offer an alternative in designing spectrum analyzers for temporal signals. This thesis describes various designs of optical spectrum analyzer for temporal signals, especially for those signals within the audio frequency range. Since the processing of temporal signal by optical means necessitates the transformation of the signals to spatial formats, different temporal-to-spatial signal conversion techniques are reviewed. The general characteristics of recording media used in the signal conversion process are discussed. The designs of time-signal optical spectrum analyzers are classified as on-line (real-time) and off-line (non-real-time) spectrum analyzers based on the recording medium used in temporal-to-spatial conversion process. Three different types of optical spectrum analyzers in off-line case are described. The design of a continuous single channel spectrum analyzer is emphasized because of its simplicity and suitability for the signal of interest. In addition, a white-light optical spectrum analyzer operated under partially coherent mode is designed and evaluated. The spectrograms generated from this white-light optical system are frequency color coded, which in turn, provide a better visual discrimination in the frequency contents of the signal. Moreover, a hybrid optical spectrum analyzer is synthesized for an on-line case by means of a real-time image converter, LCLV, in conjunction with a home-built digital electronic control circuit. The feasibility of a real-time optical spectrum analyzer is also studied.

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digital processing TECHNIQUES FOR optical CORRELATOR systems.

DIGITAL PROCESSING TECHNIQUES FOR OPTICAL CORRELATOR SYSTEMS...

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Colloquium on optical Techniques in image and signal processing.

作者： Collings, N. Lindstrom, Per Standard Telecommunication Lab Ltd Harlow Engl Standard Telecommunication Lab Ltd Harlow Engl

The major aims of this project are: to simulate and develop a hybrid optical/digital cross correlator for use in 2D real time image pattern recognition, investigate accuracy and limitations of the hybrid cross correla... 详细信息

关键词： PATTERN RECOGNITION systems

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hybrid optoelectronic ANALOG-TO-digital CONVERSION SYSTEM

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optical ENGINEERING 1983年第5期22卷 619-632页

作者： KIM, JC LIU, HK UNIV ALABAMA DEPT ELECT ENGN UNIVERSITY AL 35486 USA

A new hybrid, direct, real-time, and parallel analog-to-digital (A/D) conversion system has been theoretically and experimentally investigated. Basically this system consists of an A/D conversion screen, a photosensor panel, a comparator, and a coder. For the purpose of designing an A/D conversion screen, various quantizer characteristics and the minimization of the mean-square distortion are briefly described. Based on the quantizer characteristics, the design algorithms of the A/D conversion screen are developed. It is found that charge-coupled device (CCD), charge-injection device (CID), and metal oxide semiconductor (MOS) photodiode image sensor arrays can be used for the large-area hybrid A/D conversion system, and photodiode or photocell arrays can be applied for a single-pixel A/D conversion system. An error analysis shows that the conversion errors result from the discrepancy between the fabricated and designed transmittance function of the screen cells and the nonuniform characteristics of the photosensors. Also, this system is theoretically compared with existing electronic A/D conver-sion systems. To show the feasibility of this system, a single-pixel 16-level A/D conversion system using a single-cell 16-level A/D conver-sion screen, a photosensor panel of 16 photocells, and accessory elec-tronic circuits is designed, constructed, and experimented with input op-tical signals. The experimental results proved that this system can be used for achieving A/D conversion of both coherent or incoherent and monochromatic or polychromatic optical signals. The system can be potentially applied for the interface at the optical input of a digital computer for real-time optical data processing, picture coding, and optical telemetry.

关键词： optoelectronics Photodetectors Photodiodes Semiconductors Transmittance Oxides Algorithms Charge-coupled devices Computing systems Distortion Error analysis image sensors Interfaces Metals optical signal processing

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