Abstract: A system (16) for tracking a missile (22) in flight, the missile (22) having an optical beacon generator (32) that outputs a modulated signal (26) having a predetermined frequency, including an optical system (50, 52, 54) for transmitting image data along an optical path (68) onto an array of detectors (55), such that each detector in the array (55) receives substantially simultaneously the image data from the optical system (50, 52, 54). The system (16) further includes means for processing (46) the image data transmitted onto the array of detectors (55) in order to locate the optical beacon (32).

Abstract: A free-space wireless optical communication system is disclosed that utilizes a telescope design having aspherical mirrors, such as a Ritchey-Chretien (RC) telescope. RC telescopes are characterized by a concave primary mirror and a convex secondary mirror each having a hyperbolic shape. The disclosed mirror configuration provides a larger focal plane that allows for automatic alignment between a transmitter and receiver with a stationary or fixed mirror design, further contributing to a lower fabrication cost. Among other benefits, the larger focal plane permits an n×n fiber array to be positioned in the focal plane of the RC optical telescope, thereby enabling point-to-multipoint communications with a single optical telescope. Each fiber in the n×n fiber array of a transmitting telescope can be focused on a different receiving telescope in a wireless optical communication system.

Abstract: The present invention relates to a method of processing video data comprising the transferral of the video data to a first memory buffer and the manipulation of video data. The manipulated video data is then transferred to a second memory buffer before being written to a plurality of discs.

Abstract: An apparatus for detecting topographic variations on an object such as a finger includes an array of sensing elements disposed on a substrate which each have a parasitic capacitance. An insulating receiving surface is disposed over the array of sensing elements and is adapted to receive the object such that a sensing element and a portion of the object located thereabove creates a measurable change in capacitance with respect to the parasitic capacitance. An electronic circuit is coupled to the array of sensing elements for measuring the measurable change in capacitance.

Abstract: An error detector apparatus (42) producing a signal used in the computation of a missile guidance signal in an aircraft-based missile guidance and tracking system. The error detector apparatus (42) incorporates means (146), (148), (150), (152), and (154) for producing a first envelope signal from a tracking signal emitted by a missile. The envelope signal is then converted, along with a reference signal, to a digital signal by an analog to digital converter (158). A microcontroller (168) calculates an error correction signal from the digital signals. A digital to analog converter (160) converts the digital error correction signal to an analog error correction signal and outputs the analog error correction signal to the system for use in computing a missile guidance signal.

Abstract: This invention detects leaks in small, hermetically sealed packages, especially microchips or other packages of electronic circuits. The invention includes a procedure for detecting fine leaks, and a somewhat different procedure for finding gross leaks. To detect gross leaks, one places the package in a chamber, and varies the pressure in the chamber slightly. If the leak is not too big, one wall of the package, such as its lid, initially becomes deformed, but quickly returns to its original position, due to the leak. If the leak is very large, the wall of the package may not move at all. The position of the wall is monitored with an interferometer, such as an electronic shearography apparatus. The movements of the wall show whether there is a gross leak. In the fine leak test, the package is placed in the chamber and the pressure is changed substantially, thus causing the walls of the package to deform. If there is a fine leak, a deformed wall gradually returns to its initial position.

Abstract: This invention tests a vehicle, such as an aircraft, using nondestructive interferometry. An interferometer detects movements in the vehicle surface due to stress. One applies such stress by pressurizing the vehicle. In one embodiment, a hood housing the interferometer attaches to the vehicle surface with the aid of a vacuum. One can vary the pressure in the vehicle in various ways, while monitoring the interferometer for signs of defects in the structure behind the surface. The invention also includes an arrangement for substantially automating the analysis. For example, one can automatically position the interferometer according to position information received from appropriate sensors, in combination with stored information about the structure of the vehicle. One preferably uses a real-time interferometer, such as an electronic shearography camera, in the present invention. One can quickly determine the location of defects by observing fringes on a video monitor.

Abstract: Two laterally-displaced images of a test object interfere with each other to form a shearogram. Two shearograms, taken while the object is unstressed and stressed, respectively, are compared electronically to yield a composite interference pattern. According to the invention, each shearogram is formed by the interference of pairs of distinct rays of coherent light, reflected from different points on the object. The first ray of each pair is reflected from the object, strikes a mirror spaced from the object, and is reflected from the mirror. At the same time, the second ray of each pair is reflected from the object and strikes a beam splitter positioned beside the mirror. The beam splitter directs a portion of the second ray in the same direction as the reflected first ray, and a portion of the first ray passes through the beam splitter without being reflected. Since the two rays have the same polarization angle, and are mutually parallel, the rays interfere.

Abstract: The purpose of the present invention is to improve the quality of a video signal generated by the method of nondestructive testing known as electronic shearography. In electronic shearography, two laterally-displaced images of a test object are made to interfere, and the interference pattern is stored. Another such interference pattern is obtained while the object is stressed. The two patterns are compared by computer, such as by subtracting one pattern from the other, and the resulting composite pattern is displayed on a video monitor or equivalent. According to the present invention, the subtracted signal is connected to a rectifier circuit which causes both positive-going and negative-going variations in the video signal to become positive-going variations. Thus, any changes in the intensity of the signal, due to phase changes resulting from deformation of the object, are displayed as increases in brightness of a pixel on the final display.

Abstract: This invention detects leaks in small, hermetically sealed packages, especially microchips or other packages of electronic circuits. The invention includes a procedure for detecting fine leaks, and a somewhat different procedure for finding gross leaks. To detect gross leaks, one places the package in a chamber, and varies the pressure in the chamber slightly. If the leak is not too big, one wall of the package, such as its lid, initially becomes deformed, but quickly returns to its original position, due to the leak. If the leak is very large, the wall of the package may not move at all. The position of the wall is monitored with an interferometer, preferably an electronic shearography apparatus. The movements of the wall show whether there is a gross leak. In the fine leak test, the package is placed in the chamber and the pressure is changed substantially, thus causing the walls of the package to deform. If there is a fine leak, a deformed wall gradually returns to its initial position.

Abstract: A method for measuring boresight and parallax misalignment between multiple missile track links and for compensating guidance of a missile to a selected target. The method is applicable to any missile tracking system employing multiple track links. A missile is projected toward a target along a line of sight and tracked by multiple tracking sensors. Instantaneous output signals of any two tracking sensors are compared to determine instantaneous errors in boresight, parallax, or random errors. The error information is used to compute boresight and parallax correction terms. The correction terms are fed into conventional missile guidance algorithms to correct errors between the tracking sensor's line of sight and an operator's line of sight. Misalignment is measured during missile flight and the missile is used as a reference source in measuring the misalignments. The method is useful in tracking systems mounted on moving vehicles where accurate alignment of track links is difficult.

Abstract: The present invention is a system for monitoring and displaying a measured parameter in each of a series of similar modules. In one embodiment, the invention can be used to monitor a parameter or condition, such as the amount of fuel in a tank, in each of a plurality of coupled locomotives. The parameter is measured by an analog or digital sensor, the output of which is connected to a microprocessor. Each locomotive in the train has such a microprocessor, and each microprocessor is programmed in substantially the same way. The microprocessors in the several locomotives are programmed to communicate with each other, and to determine which one is in the lead locomotive, and what signals are being received from which microprocessor. The value of the measured parameters for any of the locomotives of the train can therefore be displayed by the microprocessor in the lead locomotive. The programming of the microprocessors is such that the system will work regardless of the arrangement of the locomotives.