Abstract: The invention is a method for obtaining fringe visibility in hybrid-optical interferometric processors. Encoded data defining an image is utilized to provide both a timing input signal and a method of modulating a light source in synchronization with the modulation of an optical-acoustical element. The modulated light is then detected in a receptor array and converted into signals suitable for driving a readable, visual-imaging device or other devices for image analysis.

Abstract: A method of manufacturing surface relief patterns of variable depth in solid materials is disclosed, which patterns, when seen in cross-section, are of variable geometry.

Abstract: A system for evaluating the optical characteristics of curved surfaces includes a light source disposed to scan a beam of light across a surface and ranging means for measuring the distance from the light source to the point being scanned and a controller for controlling the position of the light beam with regard to the measured distance so as to maintain reflected illumination upon a detector. By analysis of the profile of the reflected light, parameters such as gloss, distinctness of image, orange peel and surface roughness may be readily determined.

Abstract: The present invention detects the difference in phase between the modulation of a received optical beam and a reference RF signal or a second modulated optical beam. The received optical beam is modulated by the reference signal and by this reference signal phase shifted 90 degrees. The difference cross modulation in these two modulated optical beams is detected. The phase difference to be detected is formed by dividing the difference cross modulation of the modulated second optical beam by the difference cross modulation of the modulated first optical beam. This quotient is proportional to the tangent of the phase difference to be detected. The optical modulation can be achieved by bulk electro-optic modulators operating on split beams, by a bulk electro-optic modulator alternatively modulating a single beam by the reference signal and the phase shifted version of the reference signal, or by changing the coupling between two parallel, matched wave guides in an integrated optic device.

Abstract: A range dispersion sensor operative to detect objects of a preselected height "h" operates on quarterwave interference principles. Electromagnetic energy is modulated at a first frequency f.sub.1 such that objects of the preselected height h disposed upon a background create a quarter-wave length reflector. A beam of electromagnetic energy reflected from an object of height h and its proximate background interferes destructively to create a null signal. Effects of non-uniform reflectivity are normalized by modulating the beam at a second frequency f.sub.2 selected to not create constructive or destructive interference effects with objects of the preselected height. The ratio of the two signals is taken thereby normalizing the effects of non-uniform reflectivity, and the resultant ratio is indicative of the height of the objects.

Abstract: In a speckle imaging process, the contribution of non-uniform, incoherent background illumination is removed via an aperture sampling technique. A pair of uncorrelated speckle images are produced and subtracted from one another to eliminate the non-coherent background contribution. The result of this subtraction is rectified so as to provide a signal which may be displayed on a video display. Disclosed are techniques for real time video display of enhanced speckle images as well as techniques for visualizing vibrational modes and surface roughness mapping.

Abstract: A method for producing multicolor holographic optical elements useful in presentation of multicolor holographic images in a head-up display (HUD) system. Because of restricted geometries, such HUDs should allow for reconstruction of wavefronts employing all readout beams coming from the same direction, with the reconstructed wavefront being cast in a specified direction. A first method for producing a multicolor HOE satisfying these conditions makes all recording at the same wavelength but with varying record geometries. A second method for producing multicolor HOEs employs the same record geometries but uses varying wavelengths of recording light. This allows the recording to be made under conditions where the diffraction efficiency of the resulting HOEs is controlled, as are the displayed colors.

Abstract: The present invention comprises apparatus for connecting and disconnecting substantially planar arrays of electrical contact sites in a mechanically secure and functionally rapid and reversible manner. The invention utilizes technology availalble in the zipper manufacturing industry, to achieve a high contact site density by suitably disposing contact sites for electrical connections on zipper teeth, and through the use of a conventional zipper-type runner achieving the interconnection of a multiplicity of electrical contact sites.

Abstract: A waveguide created by thermo-optically induced changes in the refractive index of a medium resultant from absorption of light focused thereupon. The medium absorbs optical energy of a preselected wavelength to cause a refractive index change in response thereto. A pulsed optical switch beam of the preselected wavelength is focused on the medium. The switch beam has an energy level adapted to create an optically induced focal region waveguide therethrough. An optical probe beam is focused on the medium and angularly offset with respect to the pulsed beam. The probe beam is optically confined within the waveguide to emerge from the medium as a diverging, cone-shaped beam.

Abstract: The following invention is a passive collision avoidance alarm system. An optical sensor (which may optionally be visable, infrared or ultraviolet) is disposed to provide a continuous raster scan of the scene within a wide angle of the direction of travel of the vehicle. This sensor output is converted into digital data and stored. A computer system compares consecutive scenes to detect identifiable objects. For such identifiable objects the computer calculates the centroid of the object and its angle, and a measure of the size or extent of the object. Detection of an object having a constant angle and a increasing measure of extent causes an alarm to be triggered.

Abstract: An optical sensor includes a vortex diffuser bearing for support of the optical elements thereof in a fixed, spaced apart and angular relationship relative to a subjacent surface. The sensors are readily adapted to be fabricated into matrices adapted for high volume scanning of surfaces, as for example to detect irregularities in the coatings thereof. The sensors are also adaptable for use in photogrammetry, microdensitometry, or other applications wherein precise, stable and repeatable positioning is required.

Abstract: The present invention is a technique for use in image processing for extracting feature information from an array of pixels. Each pixel within the array of pixels has a pixel value selected from among a plurality of possible pixel values. As the pixels are recalled from the array of pixels in a raster scan fashion a pixel address memory is incremented to contain a current pixel address indicative of the location of the current pixel. If the current pixel is the first occurrence of its pixel value, the current pixel address is stored in a first occurrence pointer memory at a memory location corresponding to the current pixel value. The current pixel address is stored within a last occurrence pointer memory at the memory location corresponding to the current pixel value. The current pixel address is stored in a memory location within a linked-list memory corresponding to a pixel address stored within the last occurrence pointer memory at a memory location corresponding to the current pixel address.

Abstract: A pattern recognition system for use with a two-dimensional image, each point associated with a height and with contributions from various wavelengths of light. The image to be analyzed is first sensed by a sensor and stored in a memory. Signals, read from the memory, are filtered and processed to produce signals measuring each of the wavelengths and measuring the height. The resulting distributions of data are first scanned for areas containing appropriate height measurements. Each pixel of these areas is classified according to predetermined classification definitions, further reducing the areas to be processed. These areas are subjected to spatial classification according to other classification definitions. The spatial classification may be accomplished by a neighborhood processor. The areas of the image are then identified with the features to be recognized.

Abstract: A corner radar reflector that backscatters cross-polarized returns from a linearly polarized source is formed by three mutually perpendicular surfaces forming a concave structure. At least one of the surfaces has a depolarizing characteristic. The depolarizing surface is comprised of a grid of thin mutually parallel wires closed spaced. These wires reflect the parallel tangential component of the incident field but do not reflect the orthogonal component. Beneath the wires is a sheet of microwave absorbing material to absorb the energy that was not reflected by the wire grid.

Abstract: A compact head-up display comprising a combiner which combines light energy from an outside view with light energy transmitted within the combiner and diffracted out by means of an upper diffraction grating. The head-up display disclosed further comprises an image source, a collimating lens, and a lower diffraction grating for diffracting the collimated light energy into the combiner.

Abstract: An adaptive learning controller (ALC) for use with an inertial navigation system (INS). To correct quadratic position errors which result from acceleration bias errors, the ALC produces a position correction signal. The position correction signal is generated by twice integrating an acceleration correction signal produced by the ALC. The ALC receives signals which indicate a current system state based on the corrected position signal and the velocity bias signal. The ALC also receives a failure signal determined by comparing the corrected position signal to predetermined failure criteria, these criteria relating to excursions of the corrected position signals beyond acceptable error limits.

Abstract: Provision is made in a serial neighborhood transformation stage for generating statistical information relating to the number of transformations performed by the stage. This information can be transferred back to a host computer separately from the image pixels to indicate that there has been no change in the image being operated on by the stage or that a certain number of transformations have occured.

Abstract: A sinusoidal signal frequency multiplier, including a means for stabilizing the static input-ouput phase relationship. The static phase stabilizer compares the phase relationship between the frequency-multiplied output and the input signals, producing a signal which appropriately controls a phase shifter. This phase shifter operates on the input signal, the result serving as input to the frequency multiplier.

Abstract: Methods and apparatus for recording and displaying edge-illuminated holograms. Disclosed is a method for producing holograms whereby the reference beam, when recording, and the illumination beam, when displaying the hologram, impinge on the edge of the cover plate placed over the hologram. Edge-illumination of holograms makes possible holographic displays which fit in a volume having very little depth.

Abstract: A method and apparatus are disclosed for determining whether a shape or pattern exists anywhere in a particular image represented by a matrix of digital data signals. In the preferred embodiment, a suitably programmed general purpose computer provides means for storing the matrix of data signals representing the first image, computing the complement of the first image matrix and storing the complement image matrix, creating a structuring element representative of the target shape to be recognized and storing a matrix of digital data signals representing that structuring element, and creating a second structuring element equal to the window complement of the first structuring element and storing the second structuring element.