WorldCat Identities

Upatnieks, Juris

Overview
Works: 8 works in 8 publications in 1 language and 8 library holdings
Publication Timeline
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Most widely held works about Juris Upatnieks
 
Most widely held works by Juris Upatnieks
Real Time Correlation for Missile Terminal Guidance( Book )

1 edition published in 1978 in English and held by 1 WorldCat member library worldwide

A study was conducted to determine the feasibility of using coherent optical correlators for missile terminal guidance. A laboratory area correlator was built which can perform target recognition and location at TV frame rates. This correlator uses an optically addressed liquid crystal image-forming light modulator as an input and holographic matched filters as references. Correlations were performed with optical imagery and simulated radar imagery using a TV monitor to address the modulator. Good cross-correlation signal-to-noise ratios were obtained and the input image could be tracked over a wide displacement range. Data from these experiments were used to design a compact correlator for typical low resolution radar imagery. The low informaton content of this imagery allows an array of laser diode sources to be used. By using a corresponding array of matched filter references, up to 900 correlations/second can be performed on 128 x 128 element input imagery and a range of scale, angular orientation, or aspect angle can be searched. (Author)
Coherent Optical Correlation in Real Time for Missile Terminal Guidance( Book )

1 edition published in 1978 in English and held by 1 WorldCat member library worldwide

The use of area correlation in terminal guidance requires that the system cross correlate a stored reference with the observed scene and have the capacity for handling variations in aspect angle, rotation, scale and intensity. This correlation must be made in real time at a low false alarm rate. Digital techniques can accomplish the preceding requirements but have several limiting characteristics. The number of resolution elements that can be processed is limited by the available core memory. Even with well-chosen algorithms, a large number of multiplications and additions are required and these increase with the number of resolution elements. Parallel processing can reduce the time required to perform this very large number of operations but requires increased complexity and cost
Photography by laser by Emmett N Leith( Book )

1 edition published in 1965 in English and held by 1 WorldCat member library worldwide

Compact Coherent Optical Correlator System( Book )

1 edition published in 1988 in English and held by 1 WorldCat member library worldwide

A real-time coherent optical correlator was designed, fabricated and tested. The correlator features 30 separate filters, low-light level real-time operation, and a compact design. The correlator is packaged in a cylinder 15 cm in diameter by 30 cm long, excluding imaging lens. Each of the two laser diode coherent light sources is imaged to 15 locations with holographic optical elements (HOEs). The HOEs perform a number of functions usually requiring several optical components. The HOEs correct the aspect ratio of the laser diode beams, perform the functions of collimating and Fourier transform lenses, multiplex the light beam to form multiple Fourier transforms, and correct a variety of system aberrations. Low-light operation is achieved with a microchannel image intensifier in front of a liquid crystal light modulator. This arrangement allows the correlator to operate over a wide range of light levels, from full sunlight to dusk. The image intensifier, however, reduces system resolution and response time. A computer controlled filter maker system was designed to automate filter recording. The computer, a small PC-type, controls the position of the recording plate, the reference beam angle, dwell and exposure times, and checks light source and shutter operation. (RH)
Photonic Seeker Development( Book )

1 edition published in 1982 in English and held by 1 WorldCat member library worldwide

Experiments have been performed which indicate a means to extend significantly the number of matched filters which can be simultaneously addressed in the photonic correlator. Results indicate that a total of 200 independent images of the target can be interrogated in parallel. This corresponds to an effective computation of over 10 to the 13th power complex multiplications per second. The suggested method is mechanically simple, optically easy to implement, requires little power and can be fabricated into a compact unit. Improvement in the signal to noise of a photonic correlator can be achieved by using an achromatic transform system and a thermal light source. At this time, however, the throughput of such a system is not sufficient to make a practical device. Whereas, efforts should continue to develop techniques to correlate using thermal light sources, the principal thrust for making a field operational system should, at this time, be concentrated on the use of laser diode sources together with the use of phase screens to extend the memory of these systems
 
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Audience Level
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Audience level: 0.95 (from 0.78 for Photograph ... to 0.99 for Photonic S ...)

Alternative Names
Juris Upatnieks Amerikaans natuurkundige

Juris Upatnieks amerikansk fysikar

Juris Upatnieks amerikansk fysiker

Juris Upatnieks amerykański fizyk

Juris Upatnieks físico estadounidense

Juris Upatnieks fizikan amerikan

Juris Upatnieks physicien américain

Juris Upatnieks United States physicist

Juris Upatnieks US-amerikanischer Physiker

Упатниекс, Юрис

Юріс Упатніекс

ژوریس اوپاتنیکس فیزیک‌دان آمریکایی

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