US Government As Represented by the Secretary of the Army

Joseph G Duthie

Don A Gregory

Charles R Christensen

Larry Z Kennedy

Carl D Leonard

Lee O Webster

Laura L Huckabee

This device is an all-optical digital architecture for carrying out compuions. Residue number system addition and multiplication tables are produced on an optically-addressable plane composed of optically bistable material. The plane of optically bistable material devices represents a residue number system addition or multiplication tables and is addressed by two intersecting signal beams from the top and a bias beam from the bottom. A combination of two signal beams exceeds the material transmission threshold in the intersection region letting bias light emerge as a position encoded signal beam.

Optical system with an optically addressable plane of optically bistable

A method of and apparatus for acousto-optically addressed pattern recognition using Vander Lugt matched filtering. In optical correlation a beam of light containing an image to be examined is directed to fall on a matched filter array that contains a representation of an object of interest. Critical alignment between the beam and a matched filter of the array is achieved by acousto-optical deflection of the light beam. A large number of matched filters can be addressed sequentially at very high sampling rates, thereby providing a large memory capability for coherent optical image processing. In the system an object beam containing an image of interest is directed to a plane of interest where the matched filter is located. An acousto-optical device located in the object beam path is driven by a signal generator at megahertz frequencies. The acousto-optical device converts the megahertz frequency signals to acoustic waves that affect the density of the optical path of the object wave, changing the index of refraction at a selected plane in this path. This spatial modulation of the index of refraction across the path of the wave causes the incident light to be deflected at selectable angles. By proper selection of the megahertz frequency driving signals these variable angles are selected to direct the Fourier transform of the object beam to selected ones of an array of matched filters at the focal plane, allowing rapid correlation of any incoming intelligence information on the object beam with prerecorded information stored in a filter array.

Large memory acousto-optically addressed pattern recognition

A method of copying a thick hologram, recorded at wavelength .lambda..sub.1, so that the copy can be efficiently read out with a beam .lambda..sub.3 at the same incident angle as used to efficiently read out the original. The method involves copying the hologram using wavelength .lambda..sub.2 at a predetermined incident angle, which incident angle provides fringe angles in the copy to yield maximum diffraction efficiency of the read-out beam .lambda..sub.3.

Method of bragg angle adjustments for copying holograms

An image display system and method provides at least two separate and distinct images of a viewed scene for an observer. The images, taken from adjacent positions looking toward the target scene, are taken from relatively small, acute position angles with respect to the scene. These separate images are then encoded with different polarization in sequence for displaying on a television monitor. The images are prepared for viewing by an observer by focusing the monitored images onto a liquid crystal light valve. Collimated light from a coherent source addresses the light valve providing a coherent output therefrom with the encoded images thereon. These images are brought to a Fourier plane and polarized or filtered selectively to provide separately encoded images in alternate frames of polarization. An observer wearing separately polarized lens and viewing an output screen sees a stereoscopic view of the imaged scene.

Growing community of inventors

Huntsville, AL, United States of America

Joseph G Duthie