Grumman Aerospace Corporation

Northrop Grumman Systems Corporation

Nils J Fonneland

Robert W Brandstetter

Benjamin J Pernick

Philip G Grieve

John V Fine, Sr

Herman Kaplan

Charles E Lindig

Stephen J Caputi

Kenneth G Leib

John Douglas Weir

Donald DiMarzio

Steven Chu

Dennis John Leyble

Douglas S Hobbs

Adrian R Doucette, Deceased

John V Fine

An improved system for visual inspection of substrates coated with paints and polymers is disclosed. Painted substrates can be inspected for environmental and physical damage such as corrosion and cracks without removing the paint. The present invention provides the ability to maximize paint thickness penetration. This is accomplished with a spectral bandpass filter that rejects reflected light from the coating opaque bands, while allowing light in the paint window to pass to an IR detector such as an IR camera focal plane. The narrow bandpass range enhances the ability for IR imaging to see through thicker paint layers and improves the contrast over standard commercial IR mid-wave cameras. The bandpass may be adjusted to coincide with the full spectral window of the paint, consistent with the ability of the imaging focal plane to detect light in the spectral region.

Spectral filter system for infrared imaging of substrates through coatings

A computer controlled optical system for angular alignment of structures which uses an optical imaging system input to a computer to synthesize regularly spaced reference and test line patterns replicated from binarized edges taken from the optical images of structures to be aligned. The two patterns are then combined resulting in an interference pattern in which the spacing of moire fringes indicates the amount of movement of the structures required to bring them to a predetermined alignment. All of the procedures are observable on the interference display. These moire fringe pattern are a quantitative measure of angular alignment between the reference and test images and of the edges from the structures from which they were taken. An operator programmed and controlled template automatically processes moire edge alignment measurements. An automatic template processor generates a test sequence template from the chosen areas for measurement by the operator. A template memory module having a library of test sequence templates allows the process to be run without the selection of areas to be measured by the operator. Process imaging and logic operations are utilized in generating the automatic test sequence template.

Computer controlled optical system for angular alignment of structures

This invention uses an optical imaging system input to a computer to synthesize regularly spaced reference and test line patterns replicated from binarized edges taken from the optical images of structures to be aligned. The two patterns are then combined resulting in an interference pattern in which the spacing of moire fringes indicates the amount of movement of the structures required to bring them to a predetermined alignment. All of the procedures are observable on the interference display. These moire fringe pattern are a quantitative measure of angular alignment between the reference and test images and of the edges from the structures from which they were taken. An operator programmed and controlled template automatically processes moire edge alignment measurements. An automatic template processor generates a test sequence template from the chosen areas for measurement by the operator. A template memory module having a library of test sequence templates allows the process to be run without the selection of areas to be measured by the operator. Process imaging and logic operations are utilized in generating the automatic test sequence template.

Angular alignment of structures using moire patterns

A method and system for searching for a given sequence in a data base having a multitude of reference sequences stored or identified therein. In accordance with this method, a light beam is modulated with patterns representing the reference sequences, and with a pattern representing the given sequence, and a correlation signal is generated representing the correlation of the reference and given sequences. Optical diffraction patterns may be used to represent the given and reference sequences. In one embodiment, a multitude of first diffraction patterns, each one representing the given sequence, are formed in an optical medium, and a light beam is modulated with each of those multitude of diffraction patterns to form a multi-channel signal beam. Each channel of that beam is then modulated with a respective one second diffraction pattern representing one of the reference sequences to form a multi-channel correlation beam. The intensity of each channel of the correlation beam is then measured to determine whether the given sequence correlates with any of the reference sequences.

Methods and systems for analyzing data

A method and system for fabricating a multiple holographic element. The method comprises the steps of forming a master multiple holographic element having an absorption grating pattern that produces a given index of refraction pattern across the master multiple holographic element, coating the master holographic element with a layer of a photopolymer, and directing a recording beam to and through the master holographic element and into the photopolymer layer. The absorption grating pattern of the master holographic element modulates the amplitude of the recording beam, and the modulated recording beam causes the monomers of the photopolymer to form a monomer pattern that produces the given index of refraction pattern across the photopolymer layer. The method further comprises the steps of fixing the monomers of the photopolymer layer in that monomer pattern to form thereby a copy of the multiple holographic element, and removing the photopolymer layer from the master holographic element.

System and method of fabricating multiple holographic elements

A system for identifying and determining the orientation and location of multiple objects includes a camera and a mechanism for permitting the camera to scan a scene containing the objects. Objects in the moving scene are identified by optical filtering. Filters representing each of the objects to be identified are stored in a digital image memory, from which they are retrieved as needed, Fourier transformed, and loaded into a spatial light modulator to form a matched filter for an input image modulated and transformed laser beam.

Circularly scanned electronically addressed optical correlator

A photo stimulated and controlled imaging neural network for providing self generating learning sets and associative memory and programmability. An image to be recognized or detected is transferred to an imaging plane, which can be as simple as a lens or as complicated as a cathode ray tube. The imaging plane whose contents forms the input for a photo receptor array transfers the stimulus from the object to the photoreceptor array. The photoreceptor array responds to the stimulus provided by the imaging plane with various couplings between an array of neuron amplifiers. The photo receptor array comprises a plurality of synaptic photo controlled resistors which respond to the stimulus provided by the imaging plane. The individual neuron amplifiers settle into a set of on or off binary states based on the couplings of the photo controlled resistors which comprise the receptor array. The output states are equally weighted and as a whole constitute a particular learning set which is then passed onto a gate array where it can be utilized to make various decisions.

Photo stimulated and controlled imaging neural network

This invention enables a laser beam, expanding from a pinhole aperture spatial filter, to be brought back on the optical axis of an optical system such as an optical correlator system and maintained there. The principle of operation is that photodetectors spaced in the outer region of the expanding beam detect a change in orientation of the incident laser beam, and the change is measured and an error signal is used to drive electrically controlled micrometers so as to restore and maintain alignment.

Automatic laser beam expander-pinhole alignment system

An optical notching filter is disclosed in which an optical spatial filter therein is formed by a spatial light modulator which is written into by light. The optical notching filter system of the present invention provides a linear phase and amplitude response with applications for high speed adaptive filtering to filter out noise and signals of no interest. In one particular disclosed embodiment, the write with light optical notching filter system of the present invention is designed to adaptively excise interference from Radio Frequency (RF) signals, such as are utilized in communications or radar systems. The technical approach of the present invention provides a more compact system design than similar electronically addressed optical notching filtering systems, and also significantly reduces the complexity and attendant power requirements of the system. Different embodiments of a write with light optical notching filter system can operate with either nonochromatic or polychromatic light sources. Moreover, the write light source can be independent of the read light source, such that any suitable write or read light source can be utilized therein, either with single pass or recursive optical arrangements.

Write with light optical notching filter

A system and method is presented for obtaining optical phase and amplitude measurements utilizing an acousto-optical modulator for modulating a laser light beam with a multifrequency electrical signal to form an image that is Fourier transformed and spatially distributed proportional to the frequency components of the electrical signal. An optical component such as a spatial light modulator is located in the Fourier plane and the modulated image is inversely transformed and optically heterodyned to produce a transformed image. The transformed image impinges a photodetector that produces an electrical output signal that is inputted to a network analyzer to measure phase and amplitude of the transformed image. The electrical output signal is compared with a reference signal and deviations from the reference signal provide a quantitative measurement of the phase and amplitude response of the spatial light modulator.

Optical heterodyning system and method for rapid optical phase and

Method of fabricating a coherently exposed multiple holographic lens including a first step of fabricating an incoherently exposed master multiple holographic lens with an array of overlapping holographic lens elements, each of said lens elements having an interference pattern substantially covering the entire area of the lens. The master multiple holographic lens is illuminated with a first beam of light from a coherent source to provide a plurality of light waves equal in number to the number of lens elements in the master lens. The plurality of light waves overlap in a region downstream of the master lens. A holographic recording medium is positioned in the region of overlap such that an area thereon is illuminated simultaneously by each of the plurality of light waves. A second beam of light from a coherent source is directed toward the area of the holographic recording medium illuminated by the plurality of light waves. The holographic recording medium is exposed simultaneously to the second beam of light and the plurality of light waves and is developed to form a coherently exposed multiple holographic lens. A larger area of overlap of the plurality of light waves illuminating to recording medium is provided by an imaging lens positioned to capture and redirect the waves. A one to one image of the master lenses can be recorded by positioning a pair of imaging lens between the master lens and the recording meidum.

Method of fabricating a multiple holographic lens

Adverse environmental effects may be canceled from an optical processor which adjusts the phase of spatially distributed frequency components. This is achieved by projecting the optical modulated signal and a local oscillator optical signal along the same optical path and through the same optical components. Multichannel operation is achieved by positioning the optical components for each stage along a common axis.

Common path multichannel optical processor

The invention features an optical spread spectrum decoder wherein linear, non-linear, and discontinuous broadband RF signals can be optically decoded. The system introduces a weighting function into a local oscillator beam, which is then combined with a laser beam which has been modulated with the RF signal, processed to remove unwanted spectral components and then compressed. The combined beams are then down-converted to recover the RF signal.

Optical spread spectrum decoder

The invention features an optical system for removing electromagnetic interference components from a radio frequency signal. The radio frequency signal is electrically cascaded through a series of multiple channels each having a common pathway. The final RF output of the system produces a notched signal whose notch depth is the cumulative depth of each channel notch depth.

Growing community of inventors

Lake Ronkonkoma, NY, United States of America

Nils J Fonneland