Abstract: An optoelectronic tomographic reconstruction system utilizes spacial light modulators in charge couple devices to perform projection iterative reconstruction techniques and simultaneous iterative reconstruction techniques. A back projection processor uses a linear array of analog spacial light modulators in a cylindrical lens, an image detection array, and an image rotator. The image rotator smears a projected image at the same angle as the projection was taken. The back projection processor thus smears the projection back to the image space. An optoelectronic forward projection processor uses an spacial light modulator array, an image rotator, and an image detecting array. A reconstructed image displayed by the spacial light modulator is smeared by the rotator to forward project the reconstructed image on the image detecting array at the same angle as when the measured projection was taken. The forward projection processor thus smears the reconstructed image back into the projection space.

Abstract: A range cell formation process that are used to enhance the quality of an image following a perspective transformation from range-azimuth coordinates (B-scan) into elevation-azimuth coordinates (C-scan). The present range cell formation process eliminate situations where there are missing data points at the far range, and large areas that have the same data point at the near range. The range cell formation process evaluates the data content in range cells on a case by case basis using a prioritized system to determine what is to be displayed so that a high level of image contrast is maintained. In the far range, range cell data that are in between range points defined by every two adjacent elevation points are processed and a priority system is used to determine the best intensity value to use for the elevation points. The priority system is such that bright objects have the highest priority, followed by dark objects, and then followed by an average background level.

Abstract: The invention relates to an all weather visual system that combines information from a ROSAR type radar sensor with navigation and flight information to provide artificial vision for the pilot. The radar utilizes the movements of rotating arms fixedly mounted on the rotor head of a helicopter. For this purpose, a turnstile is used as the central carrier structure, which is protected by an aerodynamically shaped body against atmospheric forces. The radar transmitter and radar receiver are located on the rotor head and in the tips of the rotating arms, respectively.

Abstract: A wideband holographic surveillance system including a transceiver for generating a plurality of electromagnetic waves; antenna for transmitting the electromagnetic waves toward a target at a plurality of predetermined positions in space; the transceiver also receiving and converting electromagnetic waves reflected from the target to electrical signals at a plurality of predetermined positions in space; a computer for processing the electrical signals to obtain signals corresponding to a holographic reconstruction of the target; and a display for displaying the processed information to determine nature of the target. The computer has instructions to apply a three dimensional backward wave algorithm.

Abstract: A dynamic image is recreated from an observation radar whose extractor supplies an output of blips which are stored. These blips are firstly subject to a range/azimuth processing, which enables the image to be constructed. Then, they are subject to a pre-display processing in order to determine the geometry of the image and its brightness, after which the actual display takes place.

Abstract: A holographic surveillance system including means for generating electromagnetic waves; means for transmitting the electromagnetic waves toward a target at a plurality of predetermined positions in space; means for receiving and converting electromagnetic waves reflected from the target to electrical signals at a plurality of predetermined positions in space; means for processing the electrical signals to obtain signals corresponding to a holographic reconstruction of the target; and means for displaying the processed information to determine nature of the target.The means for processing the electrical signals includes means for converting analog signals to digital signals followed by a computer means to apply a backward wave algorithm.

Abstract: Radar apparatus provided with a signal generator (1), transmitter means (2), antenna means (3), receiver means (4), a video processor (6) and an indication device (7) for the generation of a radar picture of the surroundings of the radar apparatus with a first resolution. A selected target, designated with control unit (8), may be displayed on the indication device (7) with a second, higher resolution. To this end signal generator (1) generates in the direction of the selected target control signals for transmitter (2) with an increased bandwidth. Selection and conversion unit (5) matches echoes of these increased bandwidth signals to the bandwidth of video processor (6) and indication device (7).

Abstract: A method and apparatus for producing an image of a target area, by: at an observation location spaced from the target area, transmitting a beam of electromagnetic radiation toward the target area, and receiving reflections of the radiation from the target area; providing a representation of the magnitude and direction of the distance between points on the target area which produce reflections that travel in phase to the observation location; varying the spatial relation between the observation location and the target area and/or the given radiation frequency, in order to establish a plurality of different observation states which succeed one another in time, each state being associated with a distinct combination of magnitude and direction of the distance between points on the target area which produce reflections that travel in phase to the observation location; producing two coherent radiation beams, directing the two beams onto a receiving plane provided with an array of radiation receiving cells and stori

Abstract: A camera system in which microwave radiation from objects in a field-of-view is collected by an antenna having beam directions which are a function of the beam frequency. The collected radiation is used to modulate an optical beam to impose upon the beam spectral components which are functions of the frequencies of the microwave radiation. The modulated beam is then analyzed by an optical spectrum analyzer to produce an image of objects in the field of view. In a simple embodiment of the invention a one dimensional image is produced. This one dimensional image can be converted to a two dimensional image by panning the camera system or mounting the camera on a moving platform. In this preferred embodiment the spectrum analyzer comprises an angle-frequency filter (preferably an etalon). The portion of the modulated beam passing through the etalon is directed in a number of directions, the directions being a function of the spectral components of the modulated beam.

Abstract: A simple and inexpensive method for using aerial or satellite photographs of an area of terrain to form images to be used in the simulation of a series of synthetic aperture radar (SAR) images of the terrain as would be observed by a down-looking SAR mounted on an aircraft over the terrain. Scanned and digitized photographic pixels are formed and converted into radar image pixels and combined into composite images as required for SAR simulation. Terrain elevation data are assembled, correlated with the radar image pixels and converted to elevation images. These images are stored on media accessible by aircraft simulators and correlated with simulated aircraft position and altitude data to form composite images with obscured terrain features for display as darkened areas closely duplicating actual SAR images when displayed in an aircraft simulator.

Abstract: The method for avoiding collision between a motor vehicle and obstacles placed in the path of the vehicle comprises the stages of forming a radar map of the area in front of the vehicle, reconstructing the geometry of the road, identifying its edges, detecting the position and speed of the vehicle with respect to the road, determining the presumed path of the vehicle on the basis of the road geometry and the manoeuvre being carried out by the vehicle at that instant, detecting objects on the radar map found lying in the presumed path of the motor vehicle and displaying the map found in a perspective representation, ignoring objects which are off the road and indicating objects in the path of the vehicle in a different manner according to their hazard and if appropriate generating alarms of an acoustic type.

Abstract: A three dimensional imaging radar system and method for generating and processing radar information to produce a three dimensional image of objects viewed by the system. The system is designed to create three dimensional images of physical objects at relatively short range, up to a distance of about 1000 feet. The radar system comprises a servo controlled antenna system, wherein the servo system provides azimuth and elevation pointing angle output signals. Two radar transmitters provide radar signals in two different radar bands that are selectively transmitted by the antenna system as a radar beam. A radar receiver preprocesses radar return signals reflected from targets.

Abstract: Apparatus for detecting the position of a vessel in a broadcast image of the radar scan in a radar monitored area includes a television monitor for displaying a broadcast image of a radar scan of the area, and a controllable reflector for varying reflection of the radar waves impinging thereon from the monitoring radar to produce identifiable signal components in the broadcast image of the radar scan received on the television monitor. This controllable reflector may be actuated by the vessel operator to vary the reflection of the radar waves and produce variations in the broadcast image to enable the operator to identify the position of the vessel in the radar scan image appearing on the monitor. The monitoring installation includes a monitoring radar transmitter/receiver, and a television transmitter televising an image of the radar scan. Desirably, it includes a scan converter which receives the signals in polar coordinate form and provides rectangular raster signals with X and Y coordinates.

Abstract: A method of and a system for scanning a scene for the purpose of classifying a plurality of moving objects located in the scene and having an average distance between them, including the steps of performing a sweep of the scene, during the sweep, producing a multiplicity of detections of at least one portion of the scene at a rate such that a distance traveled by the moving objects between detections is small with respect to the average distance, and calculating, from the multiple detections, two-dimensional motion information for at least some of the moving objects.

Abstract: A process for reducing the likelihood of runway incursions wherein the major components of an aircraft are individually tracked by radar instead of tracking only the overall image of the aircraft to more accurately predict possible runway incursions due to the rapid and accurate indication of any change in aircraft orientation during each sweep of the radar.

Abstract: A method and system for detecting wire in a terrain avoidance, terrain following, or a terrain obstacle system. Radiant energy pulses orthogonally polarized are alternately transmitted. Selected dimensions of a full scattering matrix of adjacent reflected pulses for a particular range are collected and combined to form a null matrix. A null matrix with the two reflected pulses being within a predetermined distance from one another is detected as a wire.

Abstract: A microwave image scanning apparatus which utilizes a dispersive waveguide wedge in front of a microwave sensor. Similar to an optical prism, the waveguide wedge resolves multi-spectral microwave energy from various directions into the same direction for detection by the microwave sensor and subsequent formation of a refined high quality video image. The waveguide wedge consists of a collection of waveguide channels having their longitudinal axes aligned substantially in parallel.

Abstract: A spinning strip aperture imaging radiometer sensor system and data processing method that is capable of synthesizing full circular aperture images from a plurality of image frames acquired by the strip aperture imaging sensor. One embodiment of the imaging system comprises a rotating strip aperture wide field of view telescope, a two dimensional detector array used to detect images in the telescope's focal plane, a rotation compensation device used to prevent rotational smear during the integration time of the detectors, a signal processor used to record a plurality of image frames of a target scene that is imaged by the telescope as it rotates around its optical axis, and a signal processor and method used to synthesize the full circular aperture image from the recorded images. The operation of the full aperture image synthesis method hinges upon the ability of the rotating strip aperture to measure all of the spatial frequencies contained in a full circular aperture image measurement.

Abstract: A contraband detection system especially suited for detecting concealed non-metallic contraband such as ceramic or plastic weapons or illegal drugs carried by a person is disclosed. Plural sources of quasi-coherent millimeter wave radiation are disposed so as to uniformly illuminate a field of view. In the preferred embodiment, the radiation emitted by the sources is linearly polarized in a single plane such that the polarization of the radiation with respect to the plane in which linearly polarized radiation is preferentially received by the detectors can be controlled. For detection of dielectric objects, such as ceramic weapons or narcotics, these planes of polarization should be orthogonal to one another. The detector is a staring array which does not require scanning to generate an image of the entire field of view; the signal provided by each element of the detector array corresponds to the illumination reflected from objects in a single portion of the field of view.

Abstract: A millimeter wave imaging system is disclosed which has wide applicability throughout transportation and related industries. For example, the system may be used to provide an aircraft pilot with an image of a landing field which is essentially unaffected by fog, rain, snow, blowing sand, etc. The system comprises an array of imaging elements as its fundamental component. Each of the imaging elements of the basic array comprises an antenna consisting of a pair of conductive elements and a non-linear circuit element connected thereacross. A image can then be formed responsive to millimeter-wave radiation without complex processing steps or any form of mechanical or electronic scanning.To increase the sensitivity of the imaging array system, a local oscillator signal may be mixed with the energy received from the field of view in each of the imaging elements by the non-linear circuit element. The oscillator used to provide the local oscillator signal can also be used to illuminate the field of view.

Abstract: A system for radiation imaging of an object in response to echo signals from a target area of the object, such as a region of the anatomy of a body. Data is obtained by time domain measurements at monostatic transducers which can be disposed in different locations. The data is processed by two-dimensional Fourier transformations reconstructed using a mapping function and which compensates for variation in the radiation pattern at the various detector locations by using a phase correction function which avoids the need for Fresnel or plane wave approximations.

Abstract: An apparatus for the selective transmission or reflection of incident electromagnetic radiation. The apparatus comprises a plurality of dielectric substrates combined so as to form a stack, wherein at least two of the substrates comprise conductive elements extending in first and second directions on a surface of the substrates and at least one of the substrates includes diodes which connect adjacent conductive elements in at least the first direction. The apparatus is electronically controllable between a reflection mode and a transmission mode, wherein in the reflection mode the diodes are reverse-biased and electromagnetic radiation incident on the apparatus is substantially reflected and in the transmission mode the diodes are forward-biased and incident electromagnetic radiation is substantially transmitted.

Abstract: An imaging radar system for an aircraft includes four transmit antennas, connected to a central transmitter, and four receive antenna arrays for respectively receiving reflections of signals transmitted by the transmit antennas. A receiver circuit, associated with each antenna element of each receive antenna array, heterodynes the received signal to yield a resultant signal and combines the resultant signal with a reference signal to yield an interference grating signal. The grating signal of each receiver circuit is digitized and provided to a central processing unit that performs a spatial Fourier transform on the grating signals to determine angles of reflecting objects relative to each receive array.

Abstract: A camera system in which microwave radiation from objects in a field-of-view is collected by an antenna having a beam direction which is a function of the beam frequency. The collected radiation is analyzed to produce an image of the objects in the field-of-view. In a simple embodiment of the invention a one dimensional image is produced. This one dimensional image can be converted to a two dimensional image by rotating the camera system or mounting the camera on a moving platform. In a preferred embodiment of the present invention the microwave radiation collected by the antenna is converted into electronic acoustic signals which sets up a diffraction pattern in a Bragg cell to diffract a laser beam which is focused on a television camera to produce one dimensional image of the field-of-view. The antenna can be scanned to produce a two dimensional image. In another preferred embodiment an array of antennas and a multi-channel Bragg cell is used to produce a two dimensional real time image.

Abstract: A method and apparatus for producing an image of a target area, by: at an observation location spaced from the target area, transmitting a beam of electromagnetic radiation toward the target area, and receiving reflections of the radiation from the target area; providing a representation of the magnitude and direction of the distance between points on the target area which produce reflections that travel in phase to the observation location; varying the spatial relation between the observation location and the target area and/or the given radiation frequency, in order to establish a plurality of different observation states which succeed one another in time, each state being associated with a distinct combination of magnitude and direction of the distance between points on the target area which produce reflections that travel in phase to the observation location; producing two coherent radiation beams, directing the two beams onto a receiving plane provided with an array of radiation receiving cells and stori

Abstract: A contraband detection system especially suited for detecting concealed non-metallic contraband such as ceramic or plastic weapons or illegal drugs carried by a person is disclosed. Plural sources of quasi-coherent millimeter wave radiation are disposed so as to uniformly illuminate a field of view. In the preferred embodiment, the radiation emitted by the sources is linearly polarized in a single plane such that the polarization of the radiation with respect to the plane in which linearly polarized radiation is preferentially received by the detectors can be controlled. For detection of dielectric objects, such as ceramic weapons or narcotics, these planes of polarization should be orthogonal to one another. The detector is a staring array which does not require scanning to generate an image of the entire field of view; the signal provided by each element of the detector array corresponds to the illumination reflected from objects in a single portion of the field of view.

Abstract: A new architecture for the implementation of radar displays is provided which uses a mixed architecture superposing a PPI (Plan Position Indicator) type display on a raster display. The polar (analog) signal and the cartesian (digital) signal are displayed on the screen by means of suitable multiplexing and synchronization electronics so that the processor managing the screen "sees" a cartesian display, but the cartesian display is periodically interrupted and the polar display is interjected and is displayed in a polar format.

Abstract: An improved millimeter imaging system is disclosed which generates high quality images from the field of view. Such system can be employed in a variety of application ranging from providing an aircraft pilot with an image of the landing field in fog, rain, snow, blowing sand, etc. to detection of concealed non-metallic contraband. The system elements, in which different elements detect signals from different portions of the field of view, so that images of the entire field of view are generated in real time, without using electrical or mechanical scanning. The outputs of the array elements are mapped to display pixels. The resolution of such images has previously been limited by the response characteristics of array elements to energy from only a portion of the corresponding field of view. One aspect of the invention is a significant improvement in image resolution.

Abstract: The object of the invention is a device to display several radar images in a single resultant image, formed by a mosaic image of different radar images. To this effect, the invention provides for the use of means for mutual exclusion of the radar images so that a given point of the resultant image corresponds to the display on one and only one radar.

Abstract: A digital information storage and read-out system in which digital elevation and cultural terrain data is read from a magnetic tape in compressed form into an intermediate memory which operates as a speed buffer memory. The data in the intermediate memory is read out to a reconstruction processor in which the compressed data is reconstructed and applied to a scene memory. A nagivation computer determines the instantaneous position of a vehicle with respect to the terrain and controls the reading of data into the scene memory in blocks with the vehicle position occupying a center of scene location. In order to provide a heading up display of the terrain, the data in the scene memory is read out at an angle to its north-up storage orientation and interlaced scanning of pixel data in the scene memory improves resolution and enhances line display.

Abstract: An image of a target (11) is produced by illumination of the target (11) with overlapping fields (18, 20) of wave energy, such as coherent light, producing an interference pattern (22) moving across the target. At least one pair (12) of sources (14, 16) wave energy provide the moving interference pattern (22). The scattered illumination reflected from the target is detected by a non-imaging receiver (24); a two dimensional spatial frequency map is recorded (30, 62), based upon the amplitude, frequency and phase of the illumination received; and a two dimensional image of the target is formed (32, 72) by applying a Fourier transform to the two dimensional frequency map.

Abstract: A millimeter wave sensing device is disclosed comprising a local oscillator source generating a millimeter wave signal which is mixed with millimeter wave radiation reflected from or emitted by objects in a field of view. The mixing is performed in a staring array of mixer/detector elements which need not be mechanically or electronically scanned to generate signals responsive to the entire field of view. In a first embodiment of the invention, the device detects millimeter wave radiation emitted by or reflected from the object to be imaged. In a second embodiment of the invention, the oscillator used to provide the local oscillator signal is also used to illuminate the field of view. In the second embodiment of the invention, the oscillator signal is preferably linearly polarized, and a polarizing grid is used to separate the local oscillator signal and illumination beam and direct them in a simple and efficient manner.

Abstract: A millimeter wave object detection and location system is disclosed comprising a source generating a millimeter wave signal which is divided into an illumination beam, directed onto a field of view, and a local oscillator portion, mixed with radiation reflected from objects in the field of view. The mixing is performed in a staring array of mixer/detector elements which need not be mechanically or electronically scanned to generate signals responsive to the entire field of view. The detected signal from each element is directly responsive to a portion of the field of view. The oscillator signal is preferably linearly polarized, and a polarizing grid is used to separate the local oscillator signal and illumination beam and direct them in a simple and efficient manner. A twist reflector may also be used to rotate the polarization of a portion of the beam to direct it onto the mixer/detector array for mixing with the received signal from the field of view.

Abstract: A digital mapping display system for an aircraft wherein map data from a mass memory unit is periodically loaded into RAM in the form of a cache memory in accordance with the aircraft trajectory. The cache memory is randomly addressable within the physical address space of a control processor, individual segments of the cache memory being loaded with map data and updated while other segments are being displayed, thereby avoiding the inherent delay of accessing the mass memory unit and addressing the entire RAM array. Parallel processing of map data and symbology facilitate a real-time display.

Abstract: A method of high resolution imaging and identifying of targets with an Inverse Synthetic Aperture RADAR (ISAR) coupled with Adaptive Beam Forming (ABF) is disclosed. The ISAR system utilizes a pulsed RADAR transmitter and a highly thinned, dispersed phased array with random, non-colinear elements. An adaptive processor and feedback loop performs the ABF process such that high resolution of a moving target is possible. The high resolution signal allows accurate imaging and identification of the moving target.

Abstract: A radar transmission, reception and signal processing system generates high esolution synthetic aperture radar ground maps from air or space platforms using waveforms in which frequency is changed pulse-to-pulse. The transmitted radar signal is comprised of a series N bursts with n pulses per burst wherein each of the pulses is a fixed frequency step, .DELTA.f, either above or below one or the other of the n pulses, i.e. the n pulses comprises an ordered set and further, preferably, wherein the set of n pulses is arranged in time as a random permutation of the ordered set. In each of the k sample gates for each burst the n complex samples of reflectivity are inverse Fourier transformed from frequency domain samples of reflectivity to synthetic range domain profiles to result in an array of aligned range profiles in each of k coarse range delay positions.

Abstract: For the evaluation of a film independent of its predetermined recording velocity, a film storage drum is provided on which a film take-up reel is mounted. The film storage drum and the film take-up reel are capable of rotating with respect to each other in both directions. The film is fed via the storage drum to the film take-up reel, whereat a film evaluating device is mounted on the storage drum with the film passing the evaluating device on its way from the storage drum to the film take-up reel.

Abstract: An improved imaging system has applications to synthetic aperture radar, inverse synthetic aperture radar, delay-doppler radar, positron-emission topography sonar, radiometry and other applications having a target image provided by a series of data parameterized by a variable such as .theta.. A receiver structure includes a bandpass matched-filter, square law envelope-detector, specialized processing and convolving to produce the improved images irrespective that the radar signals have practical side lobe structures and other features. Despite the demands of specialized processing the architecture of the algorithm permits real-time implementations.

Abstract: Capability is provided using coherent synthetic aperture radar (SAR) techniques for substantially extending the useful range for producing 3 scaled high resolution orthogonal image projections on a CRT of a translating ship under the influence of rotational motions arising from sea state conditions, for the purpose of ship classification and weapon delivery from an airborne platform at long stand-off ranges. This advantage is brought about by determining image coordinates on the basis of range, doppler, and doppler rate measurements of individual scatterers and from ship angular rotational velocities derived from a weighted multivariate regression solution to doppler processed interferometric azimuth and elevation angle measurements of all significant ship target scatterers. In this manner, the image degradation suffered by plotting angular measurements directly, whose location accuracies are known to deteriorate rapidly with increased range due to high signal-to-noise requirements, is circumvented.

Abstract: A method and apparatus for imaging a target, such as a ship, exhibiting rotational movement about respective, mutually orthogonal axes. The method involves identifying a scattering center at the target exhibiting rotational movement about one axis only (the yaw axis, say, in the case of a ship) and then correlating an electrical signal related to the Doppler frequency of a return derived from that scattering center, and indicative of the angular velocity of the target about the one axis, with other electrical signals related to the Doppler frequencies of returns derived from other scattering centers. Correlation signals generated in this way provide an indication of the relative positions of the other scattering centers in relation to the one axis.

Abstract: A system for simultaneously locating a plurality of targets and distinguishing the targets from noise which utilizes phase detector techniques to generate complex voltage signals and obtain phase information. Spectral analysis is performed on the complex voltage temporal functions to generate doppler frequency functions. Both spectral phase functions and spectral amplitude functions are generated from the doppler frequency functions. Spectral phase functions are analyzed using interferometry techniques to determine if a potential target has a common locational source from returns of a plurality of sensors. A zenith angle is also generated using interferometry techniques to provide locational information of the multiple targets. Range gating and two frequency range detection methods provide high resolution range information as to the location of the targets. High resolution range information and two dimensional zenith angle information are used to provide an image of the targets.

Abstract: A super resolution imaging system employing coherent radiation comprises transmitting, receiving and processing means to provide complex amplitude image data. The image data is processed by a weight function generator to provide a weight function. The weight function has values at individual image pixels consisting of a background or clutter intensity term added to a pixel intensity dependent term. The latter term is non-zero for pixel intensities exceeding a threshold level well above background. A computer generates singular functions from the weight function and system impulse response, and employs the singular functions to decompose the image data and subsequent object reconstruction. This provides enhanced resolution compared to that available from the image data alone. An iteration controller employs the reconstructed object data to iterate resolution enhancement until no significant improvement is obtained.

Abstract: A system for measuring angles, including a lens or antenna for focusing the radiation from an object scene onto an image sensor which is shifted by a clock, thereby producing the real time imaging of the object scene wherein each element of the object scene is detected as a pulse, representing the element angular displacement from the lens, at the output of the image sensor. A system for measuring angles of objects relative to the centerline of a lens or antenna. A goniometer for measuring the bearing of objects. A system for measuring the vector speed of objects. A velocity meter for measuring the speed of objects. A system for tracking objects. A system for motion compensation. A search, track or track-while-scan detection system. Without the lens or antenna, a system for recording and reproducing halograms.

Abstract: A display system employing a stigmator coil disposed on the neck of a cathode-ray tube to widen an electron beam primarily in a direction normal to the electron beam scanning direction to produce a continuous shading effect for displaying weather information. A bidirectional pseudo-raster scan writing pattern is used to obtain maximum fill effect between scan lines and illumination uniformity with far fewer raster lines than in a conventional raster display.