Hughes Aircraft Company

Hughes Electronics Corporation

Robert W Klatt

Robert S Hayes

David M Masarik

Frank N Cheung

Mario P Palombo

Preben B Jensen

A Stevens Halsted

Jesus D Lara

Daniel P Brown

An analog signal processor for use with an array of uncooled detectors. Each detector has an amplifier associated therewith and each amplifier provides gain. A first circuit (212, 294, 300, 220) is included for compensating for a DC offset of each detector/amplifier pair of the array. A second circuit (250, 294, 300) corrects for variations in the sensitivity of each detector/amplifier pair. As a result, the outputs each of the detector/amplifier pairs in response to a common input signal are equalized. In a specific implementation, additional circuits are included providing global automatic DC level control across the array (270, 280, 294, 300), global automatic gain control across the array (250, 262, 294, 300) and frame-to-frame offset adjustment (212, 230).

Signal processor for infrared camera

A perceptual delta frame processor for use with a detector array and a noninterlaced video display that produces an image equivalent to that of an image difference processing system. The processor includes a responsivity equalization circuit for processing output signals provided by the detector array that equalize the relative response of its detector elements and provide equalized output signals. A multiplier circuit is provided for inverting the polarity of alternate images to provide constant polarity signals. A contrast control circuit is provided for processing the constant polarity signal to produce optimized video signals that are applied to the noninterlaced video display at a repetition rate above its flicker fusion frequency. Consequently, alternate video frames are averaged by the eye-brain system of an observer, who perceives an image having the quality that is equivalent to an image difference processing system. The present invention provides the benefits of image difference processing, or delta frame processing, without incurring the cost of analog to digital and digital to analog conversion and digital frame storage when it is employed with chopped, thermal detectors such a pyroelectric and bolometer imaging arrays.

Perceptual delta frame processing

A digital signal processing system (100) removes DC bias in the output of a pyroelectric detector and similar types of detectors by adding together a first output signal which is inverted and a second output signal which is not inverted. The system (100) also removes offsets in the detector signal introduced by electronic circuits (readouts, amplifiers, drivers, etc.) between the detector and the system (100).

Digital signal processing system for removing DC bias in the output of

A system and method for automatically docking a vehicle with respect to a charge station. First, the system and method automatically aligns a charge probe arm 40 with respect to a vehicle charge port 50. Next, the system and method automatically establish a power connection between the probe 40 and port 50. Next, charging power is delivered through the connection to charge the electric power storage devices of the vehicle. Finally, the charging connection is automatically disconnected by disconnecting the probe 40 from the port 50 once charging is completed.

Automatic electric vehicle charging system

Image restoration methods and systems include a comparison of the outputs of two or more adjacent detector element channels in order to determine the relative responsivities or conversion gains of these channels and to adjust the conversion gains of the two channels to make them substantially equal. These methods include determining the variance for each individual channel's output, and the covariance for each pair of adjacent channel outputs; comparing the values to determine if differences in the variances result from differences in radiant input signals to the channels or from differences in the conversion gains of the channels; and adjusting the conversion gains of the channels as necessary until they are substantially equal.

Method and apparatus for equalizing the gain of multi-channel systems in

An imaging sensor for scanning an image in an object space is disclosed. The imaging sensor comprises a first and second plurality of infrared detectors. Also provided is a reflecting means for reflecting a predetermined portion of the object space on the first plurality of infrared detectors during first portion of the scanning cycle. The reflecting means is further able to reflect the predetermined portion of the object space on the second plurality of infrared detectors during the second portion of the scanning cycle. In a further embodiment, the orientation of the detectors permits each of the detectors to be calibrated with respect to another of the detectors by a sequential comparison of the outputs of pairs of the detectors whose fields-of-view overlap.

Method and apparatus for scanning thermal images

A method and apparatus for multiplexing signals from electromagnetic radiation detectors is disclosed. The apparatus (10) includes a plurality of elemental detectors (16-32) each of which is being operable to generate an output in response to receipt of electromagnetic radiation. Also provided is a circuit for frequency division multiplexing the output of said elemental detectors.

Method and apparatus for multiplexing signals from electromagnetic

In a system for imaging radiation of a subject (14), particularly infrared radiation, the radiation scanned past a set of detectors (12), each of which produces an output signal amplified by an individual amplifying channel. Each amplifying channel includes a forward amplifier (38) and a feedback amplifier (50), the latter driving a diode (46) to limit excursion of a detector signal to an amplitude which is sufficiently small to avoid saturation of the forward amplifier. The forward amplifier (38) is AC coupled between a detector (12) and an output display (18), the limiting action of the diode (46) preventing the buildup of excessive charge on the coupling capacitors (40, 42), thereby to permit a viewing of fine detail superposed on coarse detail of the subject being viewed. A low-pass filter (48) in the feedback branch provides a delayed response to the limiting action which permits the passage of high-frequency detail to be imaged on the display (18).

Detector signal conditioner

A scanning mirror position sensor operable from the back side of a scanning mirror which utilizes the front side of the mirror for scanning a scene to be interrogated or displayed. A rectangular uniformly distributed light source is reflected from the back surface of the scanning mirror across a grating consisting of alternate transparent and opaque regions placed in the focal plane in front of a single large area photodetector. As the light from the light source sweeps across the grating, the detector is alternately energized and deenergized to form a serial pulse train which is coupled to a pulse counter which accumulates the pulse count to thereby provide a continual and accurate measure of the mirror position.

Infrared scanning and display system having a noncontacting angle encoder

A system for generating a serial video signal from a plurality of parallel channels particularly useful in thermal imaging systems incorporating bi-directional scanning. Signals on parallel input lines are simultaneously sampled and held by individual sample and hold circuits in each channel. A first multiplex level having a plurality of slow multiplexers is arranged so that each slow multiplexer selects a subset of the total number of analog inputs to generate a serial output from each slow multiplexer. Each such single output is coupled to a high speed gate in a fast multiplexer to generate a serial output from a single output channel. The fast multiplexers operate at a rate determined by the output scan time divided by the number of parallel input channels. The slow multiplexers operate at a fraction of this speed where the fraction is equivalent to one over the number of slow multiplexers generating an input to the fast multiplexer.

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Rancho Palos Verdes, CA, United States of America

Robert W Klatt