Northrop Grumman Systems Corporation

James J Reis

Harold M Stoll

David D Garber

Anthony L Luk

Richard L Davis

Antonio B Lucero

In a method for addressing holograms stored in a plurality of separate storage media, a reference beam is directed to a selected one of the plurality of storage media, the reference beam is then focused so as to obtain a substantially flat wavefront within a reference beam plane of the selected storage medium, and the angle of the reference beam is then varied so as to select a hologram stored therein.

Reference beam auto-focus apparatus for modularized volume-holographic

In a method for mitigating cross-talk in high-efficiency, angle-multiplexed holograms stored in photorefractive media, a plurality of uniformly low-efficiency holograms are first stored within a common holographic storage medium and then simultaneously exposed to a like plurality of mutually incoherent reference beams. Each reference beam effects enhancement of its corresponding hologram so as to increase the level thereof while also minimizing cross-talk between holograms.

Method for mitigating cross-talk in high-efficiency holograms

A pattern recognition apparatus and a method for operating same. The apparatus includes a volume holographic medium (4) having a plurality of Fourier-space volume holograms representing pattern templates stored within. The apparatus further includes a spatial light modulator (1) and a phase encoder (2). The phase encoder has an output optically coupled to the medium by a first Fourier transform lens (3). The spatial light modulator spatially modulates a spatially uniform laser beam (7) in accordance with an unknown pattern. The two-dimensional phase encoder causes the spatially modulated laser beam to be spatially distributed prior to application to the medium. The apparatus also includes a detector (6, 11) having an input optically coupled by a second Fourier transform lens (5) means to an angular spectrum of plane waves generated by the medium in response to the output of the spatial modulator, phase encoder, and first Fourier lens. The detector detects plane waves that correspond to vector inner products generated within medium (4) in response to the unknown pattern. The apparatus further contains a means (12) for nonlinearly processing the output of detector (6, 11) and a means (13) by which the output of nonlinear processing means (12) may be temporarily stored.

Multi-layer opto-electronic neural network

Method and apparatus for guiding a projectile to a target in a scene using a scene imaging sensor in which the projectile has a guidance and control system for aiming the projectile. A first tracker analyzes the scene and selects a first track point representative of a target and a first confidence value serving as a reliability measure of the first selected track point. A second tracker analyzes the scene and selects a second track point representing the target and a second confidence value which serves as a reliability measure of the second selected track point. Each of said trackers are constructed and arranged to operate independently in a manner that is substantially statistically uncorrelated with respect to each other. A joint confidence value based on track point proximity, convergence and divergence is generated from the tracker data and a composite confidence index is calculated from the first and second confidence values and the joint confidence value. The first and second track points are linearly combined pursuant to one of a set of rules selected by the confidence index to provide a new track point which is outputted to the projectile guidance and control system and new start track points are generated that are specially suited to restart the trackers in a new operation cycle.

Hierarchical tracker and method

An automatic target acquisition and tracking system has been developed for a focal plane array seeker. The automatic target acquisition is achieved by three independent target acquisition algorithms, viz., the maximum likelihood classification, the video spatial clustering, and the target-to-interference ratio. Each algorithm operates asynchronously and provides independent target detection results. Target information is then combined hierarchically in a probabilistic fashion and prioritized. The highest priority target is handed off to a dual mode tracker consisting of a minimum absolute difference correlation tracker and a centroid tracker. The dual mode tracker subsequently provides a feedback signal to a proportional navigation system or other guidance/control system for directing the flight path of a munition.

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San Pedro, CA, United States of America

James J Reis