Modulation Transfer-Function Characterization And Modeling Of A Scophony Infrared Scene Projector

    Authors

    E. F. Schildwachter;G. D. Boreman

    Comments

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    Abbreviated Journal Title

    Opt. Eng.

    Keywords

    INFRARED IMAGING SYSTEMS; INFRARED SCENE PROJECTOR; SCOPHONY; HARDWARE-IN-THE-LOOP SIMULATION; SCENE GENERATION; MODULATION TRANSFER; FUNCTION; ACOUSTOOPTICS; Optics

    Abstract

    A Scophony-configuration infrared scene projector, consisting of a raster-scanned CO2 laser and an acousto-optic (AO) modulator, was characterized for modulation transfer function (MTF) performance. The MTF components considered in the model were the Gaussian beam input to the AO cell, the finite aperture of the scan mirror, the width of the detector in the image plane, the transfer function of the amplifier electronics, and a term caused by Bragg-angle detuning over the bandwidth of the amplitude modulation (AM) video signal driving the AO cell. The finite bandwidth of the input video signal caused a spread in the Bragg angle required for maximum diffraction efficiency. In the Scophony configuration, a collimated laser beam enters the AO cell at only one particular angle, so a falloff of diffraction efficiency (and hence MTF) resulted as the modulation frequency was increased. The Bragg-angle detuning term was found to dominate the measured system MTF.

    Journal Title

    Optical Engineering

    Volume

    30

    Issue/Number

    11

    Publication Date

    1-1-1991

    Document Type

    Article

    Language

    English

    First Page

    1734

    Last Page

    1738

    WOS Identifier

    WOS:A1991GP20900013

    ISSN

    0091-3286

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