Abstract: A connectivity algorithm hardware implementation system wherein a subject pixel in a raster-scanned digitized image is declared a pixel of interest, in real time, by it being part of a potential target where every pixel on a closed pixel path enclosing the subject pixel differs in intensity from the intensity of the subject pixel by a predetermined intensity level, the system including a sequential delay line array producing a plurality of sequentially delayed digitized video signals representative of the spatial relationship of the pixels in the digitized image, these signals being coupled to a magnitude comparator array along with a delayed subject pixel contrast signal produced by a threshold circuit coupled to the subject pixel intensity causing the comparator array to produce a plurality of resultant signals representative of a comparison of the video signals with the subject pixel contrast signal, which resultant signals are coupled to a path checking circuit that simultaneously identifies all predeterm

Abstract: A parametric height-field ray-tracing process facilitates the construction of a perspective view display for terrain visualization by employing a map providing data in the form of a height field and wherein, prior to initiation of a ray tracing program, the set of voxels of the height field is transformed into a set of cones of empty space opening upwardly wherein the location of the vertex of each cone is near the height of the corresponding voxel. Each cone opens to a maximum cone angle which avoids intersection between the surface of the cone and vertical perturbations of the terrain such as buildings or hills. Ray tracing is conducted by calculating intercepts of a ray with surfaces of a succession of cones wherein the next cone of the succession is obtained by selecting the cone having a vertex beneath the location of the previous intersection. This procedure reduces greatly the number of computations required for a ray-tracing program.

Abstract: A fiber optic data distribution system for distributing image data between a data storage system and a plurality of image workstations using embedded control signals and a fiber optic link. The data storage system, a host computer, and a plurality of image workstations are all coupled together by way of a local area network. The host computer includes network software and associated files that provide control information and functions for the distribution system. The host computer controls access to the distribution system by setting up the data storage system and workstations and initiating data transfer to and from the workstations. The data distribution system includes a distribution circuit that comprises a high-speed logical switch that is capable of data transfer rates on the order of 100 megabits per second. The distribution circuit is also an electrical to optical converter which transforms electrical signals stored in the data storage system into optical signals and vice versa.

Abstract: In a FLIR target detection system, true targets (52) are isolated from potential false target indications produced by background clutter through the use of a connectivity algorithm which attempts to find around each potential target (52) a closed path (65) of lower (or higher) intensity without exceeding a predetermined distance from the centroid (64) of the potential target. If the attempt is successful, the potential target (52) is a true target; if not, it is clutter.

Abstract: A microwave power divider/combiner (10) comprises a preamplifier (12), a first microwave lens (14), a plurality of amplifiers (16), and a second microwave lens (18). The preamplifier (12) is coupled to receive a microwave source signal (20) and amplify it. The output of the preamplifier (12) feeds the first lens (14). The first lens (14) divides the signal received on its input into a plurality of signals of equal amplitude and phase. Each output of the first lens (14) is then provided to an input of a respective amplifier (16) from the plurality of amplifiers (16). The amplifiers (16) amplify the divided signals and output them to the second lens (18). The second lens (18) has a plurality of inputs and recombines the signals on the inputs into a single higher level signal at an output (22). The present invention also provides a compact configuration for the divider/combiner (10) of the present invention with the lenses (14, 18) mounted on top of each other separated by a mounting block (26).

Abstract: A signal detector discriminates between signals manifesting noise and signals manifesting information, both of which appear at an input. A analog-to-digital converter circuit samples the signals and a Fourier filter determines, for each signal sample, energy content of each of a plurality of frequency cells in the sample. A processor then determines the mean energy content and the average variance of energy content in all frequency cells in the signal sample. The mean energy content and average variance of energy content of the signal sample are then compared, and if the comparison indicates an approximate equality, the sample is declared to be noise. The processor further determines a centroid center frequency for the frequency cells in the sample which indicates, if it is on-center, that the sample is likely to be noise. The processor further determines the bandwidth of the Fourier components of the input signal, to determine if it is indicative of noise.

Abstract: High speed transfer of data over any distance can be easily achieved using high speed optical fibers and an optical fiber interface that couples signals transferred using the optical fibers to and from a computer. A specific implementation of the present invention is a fiber optic interface for a Macintosh brand computer that provides a direct fiber optic interface having no parts external to the computer that couples data to and from an optical image storage unit. The fiber optic interface circuit comprises an optical receiver coupled to a fiber optic cable for receiving optical signals from the image storage unit that converts them into corresponding electrical signals. An optical transmitter is coupled to a second fiber optic cable for converting electrical signals derived from the computer into optical signals and for transmitting them to the image storage unit.

Abstract: An antenna for reception of signals in a plurality of frequency bands employed in portable and vehicular communications is constructed of a dielectric layer disposed on a metallic plate which serves as a ground plane. Microstrip antenna elements in the form of a planar radiator encircled by a loop radiator are disposed upon the dielectric layer. A rod radiator oriented normally to the plate extends through the patch radiator and the dielectric layer, and is surrounded by a dielectric cylinder which insulates the rod radiator from the planar radiator and the plate. The planar radiator may be configured as a patch radiator, a spiral radiator, or a crossed dipole radiator. Also, one or more additional layers of patch radiator elements may stacked upon the patch radiator to provide a stacked microstrip radiator. Terminals are positioned about the planar radiator for extracting orthogonal components of a circularly polarized electromagnetic signal.

Abstract: An equipment tracking system that provides for configuration management control over a plurality of pieces of equipment. The system includes a plurality of sets of sensors, a plurality of collectors, each individually coupled to a selected set of sensors, a concentrator coupled to the plurality of collectors, and a computer having a database for storing sensor data is coupled to the concentrator by way of a communication link. Each sensor is attached to a piece of equipment, and each sensor has a unique ID code. Each collector is coupled to a selected set of sensors, and is adapted to read out the ID code of each of the sensors at selected times, and store the changes for those sensors that have changed since the prior reading. The concentrator communicates with the plurality of collectors and causes the collectors to transmit the changed information.

Abstract: The present invention provides for a compression scheme tailored to the compression of large radiological images processed with image processing workstations. The compression scheme is a variation of the CCITT JPEG compression scheme with special care taken to suppress blocking effects of the 8.times.8 discrete cosine transform used therein. In accordance with the present invention, an original image is downsampled, then interpolated back to its original size, resulting in a smoothed image. The difference between the smoothed image and the original image is then compressed using an 8.times.8 discrete cosine transform with 12 bit data. Major artifacts present in the original image are due to the mismatching of the low frequency components of the image at the edges of the blocks. When the low frequencies are removed by subtracting out the low frequency components, the artifacts disappear except in areas having very large dynamic changes.

Abstract: A conical TEM power divider/combiner (10) comprises an input port (12), a first circular waveguide (14), a coaxial device (16), a plurality of amplifiers (18), a plurality of cooling fins (20), a second circular waveguide (22), an output port (24), a conical dividing waveguide (42, 32), a first parallel plate waveguide (40, 50), a second parallel plate waveguide (40, 52) and a conical combining waveguide (34, 44). The input port (12) is coupled to the first circular waveguide (14). The first circular waveguide (14) is in turn coupled to the coaxial device (16). The coaxial device (16) divides the signal using the conical dividing waveguide (42, 32), a first parallel plate waveguide (40, 50), and a first plurality of striplines (54). The striplines (54) couple the first parallel plate waveguide (40, 50) to the inputs of the plurality of amplifiers (18). The amplifiers (18) each amplify a respective divided signal and output the result to the second the second parallel plate waveguide (40, 52).

Abstract: An apparatus and method that accurately and reliably detects ice on a target surface (20). Intrinsic birefringent properties of hexagonal ice crystals are used to detect ice by analyzing elliptically-polarized reflection of linearly-polarized radiation from ice. A linearly-polarized radiation beam (15) is focused on the target surface (20), and returned radiation (25) is filtered (30) as a function of its elliptical polarization. Filtered radiation (35) is directed to a sensor (40) and quantified according to the intensity of radiation received at various points (41.sub.1 -41.sub.n) on the filter (30), and an output signal for each point is produced (45.sub.1 -45.sub.n). The presence or formation of ice is determined by a signal processor (50) that detects the variance among the output signals (45.sub.1 -45.sub.n)--a variance (55) reaching a threshold value being indicative of ice.

Abstract: Apparatus and methods for reducing the quantization error in shift-matrix finite impulse response (FIR) filters (210) operate on a sampled analog signal (11) converted to a sequence of digital signal samples (13). A weight conversion device (23) converts a weight signal W comprising a sequence of tap weights W.sub.i into both a corresponding series of logarithmically-encoded weights W'.sub.i and a series of weight error values .DELTA.W.sub.i. A multiplication device (30) multiplies each of the digital signal samples (13) with the first series of logarithmically-encoded weights W'.sub.i and provides the results to an accumulator (26). A signal encoding device (40) converts the digital signal samples (13) into a sequence of logarithmically-encoded digital signal samples (42). A quantization error correction device (220) multiplies each of the weight error values .DELTA.W.sub.i by the logarithmically-encoded digital signal samples (42) and also provides the results simultaneously to the accumulator (26).

Abstract: A method for constructing an infrared detector array directly upon a detector interface device is disclosed. The detector interface device mechanically and electrically connects the infrared detector array to signal processing equipment. In a first embodiment of the invention encapsulated single crystalline material is formed within a cavity formed in a substrate. The encapsulated single crystalline material formed within the substrate cavity is suitable for use as a seed crystal for graphotaxial crystal growth of a detector element support layer across the surface of the substrate. Detector elements can then be formed upon the detector element support layer. In a second embodiment of the invention a plurality of detector element support layers can be formed within an array of cavities formed upon the substrate. An individual infrared detector element can then be formed directly upon each of the detector element support layers to form a detector array upon the substrate.

Abstract: A digital computer architecture specifically tailored for implementing a neural network. Several simultaneously operable processors (10) each have their own local memory (17) for storing weight and connectivity information corresponding to nodes of the neural network whose output values will be calculated by said processor (10). A global memory (55,56) is coupled to each of the processors (10) via a common data bus (30). Output values corresponding to a first layer of the neural network are broadcast from the global memory (55,56) into each of the processors (10). The processors (10) calculate output values for a set of nodes of the next higher-ordered layer of the neural network. Said newly-calculated output values are broadcast from each processor (10) to the global memory (55,56) and to all the other processors (10), which use the output values as a head start in calculating a new set of output values corresponding to the next layer of the neural network.

Abstract: An electronic detection system for detecting vibration patterns from physical events, such as engine knocking or articulated speech, senses a vibration source with a wideband transducer to provide a sensed signal, then converts this signal to energy amplitude and spectral frequency form to extract detectable features of the vibration pattern. Events are detected when a controller determines that the sensed energy and spectral data exceed adaptively-predetermined energy and spectral thresholds, preferably for a duration exceeding predefined time windows.

Abstract: A dual integration circuit is disclosed for extending the dynamic range of on focal plane signal processor used in a space based infrared detection system. The circuit comprises an input port in connection with a dedicated detector element and first and second integration circuits operative to generate an output signal responsive to a detected infrared image. The first and second integration circuits are provided with associated switching circuitry for generating output signals at different times to facilitate detection of objects having bright and dim infrared images.

Abstract: A pre-processor (10) for target trackers is disclosed which allows several image analysis algorithms to be computed simultaneously so as to provide improved real-time target recognition. The pre-processor (10) is also equipped to compensate for the rapid rotation of the target image when the tracking aircraft performs abrupt turning maneuvers.

Abstract: An equalizer (10) for removing parabolic phase distortion from an analog signal (3), utilizing a pair of series connected transversal filters. The parabolic phase distortion is cancelled by generating an inverse parabolic approximation using a sinusoidal phase control filter (18). The signal (3) is then passed through an amplitude control filter (21) to remove magnitude ripple components.

Abstract: An electronic data filter system (10), which functions as an approximation of a perfect matched filter, receives a conventional square-wave digital input signal (12) and outputs a filtered output signal (18). Output signal (18) appears as the summed integral of input signal (12). Filter system (10) includes a rate detector (50), which receives input signal (12) and provides a tuning voltage (16), and a data filter (30) which provides output signal (18). Data filter (30) includes, arranged in series, a notch filter (80) and a low-pass filter (90), wherein such filters (80, 90) contain capacitive-inductive circuits having certain value ratios which are tunable responsive to tuning voltage (16). Signal degradation of the filtered signal (12, 18) is minimized by filter system (10), which reduces the bit error rate (BER) and noise bandwidth of the filtered signal (12, 18). In one embodiment, data filters (30) are cascaded in parallel to extend data filtering bandwidth.