Title

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

Title - Alternative

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.

Publication 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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