Hughes Aircraft Company

Raytheon Company

Robert Zwirn

John W Bozeman

William D Farwell

Gerard L Rafanelli

Edward J Dragavon

Michael D Thomas

Brian Smithgall

An improved tracking and guidance system is provided for line-of sight commanded missiles. The system includes a missile mounted laser beacon which is modulated at a predetermined frequency. An infrared sensor mounted on a tracking unit receives the incoming optical energy and provides a corresponding electrical output. The output signals are filtered to eliminate clutter and those signals outside the range of frequencies within which the laser is modulated. The filtered signals are then peak detected to determine missile azimuth and elevation within a predetermined window. Azimuth and elevation error detector circuits compare the missile azimuth and elevation to predetermined signals to generate error signals. The error signals are utilized by the missile guidance system to provide updated guidance commands.

Tracking and guidance system with modulated missile-mounted laser beacon

A simplified missile tracker system that utilizes a single field of view while maintaining both the high resolution required for tracking and the wide field of view required for missile acquisition. The detectors in the acquisition portion of the field of view are clustered or ORed together to provide missile high signals of a weighted command for guiding the missile in elevation while greatly decreasing the required amount of detector signal processing. The bottom group of detectors are not clustered and they provide the high resolution and linear correction required for the accurate tracking of the missile in elevation. The azimuth tracking is provided by a synchronizing system and may be linear or nonlinear depending on the missile requirements.

Missile tracking system having nonlinear tracking coordinates

An automated system for testing imaging sensors 10 is disclosed. The automated system 10 provides an accurate and repeatable method for testing imaging sensors. The automated system 10 includes an input circuit 20 for receiving input from an imaging sensor system and providing a signal in response thereto, a processor 30 for operating on said signal and generating data therefrom, and a computer 40 for providing output in response to the data. A specific teaching of the invention includes a method for obtaining data for the lookup table and calculating addresses for the data wherein the addresses are a function of the signal and noise components of the imaging sensor system output, while the data relates to actual responses of human observers.

Automated system for testing an imaging sensor

A system for providing multiple simultaneous real time image from a single image sensor. The imaging system 10 is adapted for use with an image sensor 12 which provides a first set of electrical signals in response to inputs received thereby from a scene. The system 10 includes a processor 16 for processing the first set of electrical signals to provide a second set of electrical signals and a display 18 for displaying the combination of unzoomed portions of the scene plus enhanced views of other portions of the scene as represented by the second set of electrical signals. In a preferred embodiment, the processor includes circuitry for increasing the sampling rate of the image sensor 12 and a deconvolver 30 for processing the highly sampled signals such that the enhanced views of portions of the scene are high-resolution magnifield views of those portions of the scene.

Imaging system for providing multiple simultaneous real time images

A system is disclosed for providing separate simultaneous real time images from a single image sensor. The invention 10 is adapted for use with an image sensor 12 which provides a first set of electrical signals in response to electromagnetic energy received thereby from a scene and includes a processor 16 for processing the first set of electrical signals to provide a second set of electrical signals and at least one display 14 for providing first and second separate simultaneous real time images in response to the first and second sets of electrical signals respectively. In a preferred embodiment, the processor 16 includes circuitry for increasing the sampling rate of the image sensor 12 and a deconvolver 30 for processing the highly sampled signals to generate a second set of electrical signals which, when displayed contemporaneously with said first electrical signals, provide an enhanced magnified portion of the sensed scene.

Imaging system for providing separate simultaneous real time images from

An electronic focus correction system is provided. The invention (10) is adapted to correct focus aberrations in an electronic imaging system which provides electrical signals representative of a scene of image data. The invention includes a memory (12) for providing sets of weighting coefficients and a two dimensional convolver (18) for multiplying the input electrical signals corresponding to a window in and around each pixel of image data by a set of the weighting coefficients. The two dimensional convolved (18) assigns to each pixel a value equal to the sum of the products of the coefficients times the electrical signals within each window to provide a plurality of weighted output signals. The output signals constitute a corrected image. A controller (20), responsive to the output of the two dimensional convolver (18), is provided to measure the figure of merit for the corrected image. Coefficient control logic (108) responsive to the output of the controller (20) is included for providing signals to select an alternate set of coefficients for multiplication with the input signals to thereby provide a corrected image with an optimized figure of merit. In a more specific embodiment, model adjustment logic (112) is included for changing the power spectral density of the corrected image.

Electronic focus correction by signal convolution

An inspection system incorporating a subresolution element spatial measurement technique is disclosed. The system of the invention includes a scanner for scanning, with a beam of electromagnetic energy, an object area having first and second contiguous sections of first and second degrees of reflectivity or transmissivity with respect to the beam. A detector assembly is disposed to receive energy reflected from or transmitted through the object area and to provide a first signal having a first measured value S representing the amplitude of energy instantaneously reflected from or transmitted through the object area. Processing apparatus is included for analyzing the first signal and computing the ratio F of one of the first or second sections as a fraction of the total area instantaneously illuminated by the beam.

Subresolution element spatial measurement technique

A demand auto focus system is driven by scene information only, In a scanned video system as the camera is brought into focus the high frequency content of the video signal will increase. The video signal is passed through a band-pass filter and then rectified in a conditional integrator to generate a control signal whose amplitude indicates to the degree of focus. The control signal is stored and later compared to a control signal derived from a subsequent scanning. Once a significant change in control signal levels is deteced a drive signal is sent to the focusing device. If after being driven the subsequent scene has less high frequency content, then a drive signal in the opposite polarity or direction is sent to the focusing device. In this manner the scene is toggled toward optimum focus. When rapid toggling occurs a number of times (three for example), control logic detects this condition which is symptomatic of hunting around optimum focus, and the bidirectional focusing mechanism drive is turned off until such time as the scene becomes so defocused as to reinitiate the focusing sequence.

Demand auto focus driven by scene information only

A DC restoration circuit for a video imaging system having a detector array and AC coupled amplifiers is disclosed. The DC restoration circuit includes circuitry (15) for providing a difference signal indicative of the difference between a first scan line video signal and a second scan line video signal; a histogram circuit (20) responsive to the difference signal for generating histogram data indicative of the number of occurrences of difference values of the difference signal; a dominant shift detector circuit (30) responsive to the histogram data for determining a representative difference signal value and for providing a video correction signal which is based on the representative difference signal value; and correction circuitry (13, 17) responsive to the second scan line video signal and the video correction signal for providing a corrected video signal.

Noninvasive DC restoration to upgrade AC coupled systems

A video signal processing technique for detection and correction of the video signal from a bad video channel is disclosed for use with a video imaging system having a plurality of video channels for providing a video signal for a plurality of video scan lines. A disclosed embodiment is a bad channel detection and correction circuit (10) which includes circuitry (11, 13) responsive to a video signal for providing a difference signal indicative of the difference between a first scan line video signal and a second scan line video signal; a first histogram circuit (20, 60) responsive to the difference signal for generating difference histogram data indicative of the number of occurrences of different values of the difference signal; a second histogram circuit (30, 60) responsive to the first scan line video signal for providing video histogram data indicative of the number of occurrences of different values of the first scan line video signal; a circuit for analyzing the differece histogram data and the video histogram data for providing a decision output indicative of whether the second scan line video signal is from a bad video channel (40, 29, 31, 70); and output circuitry (15, 17, 19, 21, 23, 25, 27) responsive to the analyzing circuit for providing a delayed output signal corresponding to (a) the second scan line video signal when the decision output indicates both lines are from good video channels, or (b) a substituted value for the second scan line video signal when the decision output signal indicates that the second scan line video signal is from a bad channel.

Noninvasive bad channel detection and correction

In this invention, the resolution is enhanced first by effectively decreasing the scan angle subtended between adjacent samples significantly below that of the Rayleigh limit to obtain an image blurred by the point spread function (or diffraction pattern) of the aperture. The next step is to process this blurred image at least to partially remove the blur. The unblurring process consists of correlating each small segment of the blurred image with blurred images of preconstructed image primitives and then synthesizing a new image comprising a mosaic of spatially correlated original (unblurred) primitives. The blurred images of the primitives are obtained from a complete set of image primitives comprising, ideally, all possible unblurred primitive shapes. These primitives are then blurred by convolution with the point spread function of the aperture of the imager.

Resolution enhancement and zoom

In this invention, the resolution is enhanced by first effectively decreasing the scan angle subtended between adjacent samples significantly below that of the Rayleigh limit to obtain an image blurred by the point spread function (or diffraction pattern) of the aperture. The next step is to process this blurred image to at least partially remove the blur. The unblurring process consists of convolving this finely sampled blurred image with a specially designed convolution mask. This mask effectively outputs an enhanced pixel at each step of the convolution. The mask simultaneously performs the equivalent of the following operations:

Resolution enhancement and zoom by degradation estimates

An improved missile guidance system is provided which automatically compensates for jitter motion of the optical sight of a video tracker. The invention is adapted to receive video data input from an infrared detector or conventional camera. The invention includes circuits for filtering, gating, and digitalizing the incoming data as well as a formatter for directing successive frames into memory. Two memories are provided; the contents of which are sampled by matching logic as the second memory is being loaded. The matching logic thereby compares one frame of data to another at plurality of positions and provides a signal to an address latch when the best match is obtained. The format circuitry provides the position information to the address latch where it is stored for further processing. The output of the address latch is filtered to eliminate any signals representative of intentional tracking motion. The filtered output thus provides the jitter correction to the missile guidance system where missile guidance signals are compensated by the jitter correction.

Jitter compensating scene stabilizing missile guidance system

Circuitry is disclosed which generates signals which may be applied to subsequent processing circuitry, such as a display device. Applied signals having a first predetermined number of intensity levels are transformed by the circuitry into signals having a smaller predetermined number of intensity levels suitable for application to the display device. A histogram representing the number of occurrences of each particular intensity level in the first predetermined set of intensity levels is generated. This histogram is analyzed, and a plurality of peak intensity levels are selected for application to the display device. Mapping signals are generated which are determinative of which subsets of the remaining intensity levels are mapped into particular ones of the selected peak intensity levels. The mapping signals are then utilized to transform applied signals received during a subsequent time period into signals having the selected peak intensity levels. Output signals are provided having the selected peak intensity levels to the display device. The circuitry preserves the gross statistics of the image scene by selecting the dominently populated intensity levels for display.

Real time dynamic range compression for image enhancement

An improved line-of-sight commanded missile guidance system is provided which provides the operator of a missile system with the capability of hitting targets which would otherwise be obscured by darkness, smoke, aerosols or poor atmospheric visibility. The system includes a tracker equipped with an infrared sensor and means for periodically blinking a laser beacon which is mounted on the missile. The laser operates in a range in which it would be most visible under the above described atmospheric conditions. Blinking provides countermeasure resistance. The sensor provides electrical signals representing frames of data corresponding to the target scene. Alternate frames contain the beacon signature. Electronic circuitry is provided for subtracting successive frames to eliminate clutter and to then provide signals indicative of the position of the missile relative to the center of the field of view.

Growing community of inventors

Los Angeles, CA, United States of America

Robert Zwirn