Hughes Aircraft Company

Hughes Electronics Corporation

Frank N Cheung

Robert S Hayes

Robert W Klatt

David M Masarik

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 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 method of electronically stabilizing an image in the presence of jitter. The jitter induced error is measured prior to the beginning of each active sampling window signal and the error is computed into a corresponding number of pixel clock signal periods. The jitter is compensated for by advancing or delaying the occurrence of the beginning of each active sampling window signal relative to the transaction edge of the frame reference signal by the number of pixel clock signal periods. The jitter induced error is measured prior to the sampling edge of each active sample signal within each active sampling window signal. The error is converted into a corresponding number of pixel clock signal periods. The occurrence of the sampling edge of each subsequent active sample signal is advanced or delayed by the number of pixel clock signal periods corresponding to the jitter induced error. Thus, the sampling of the image is locked to the measured jitter and the image is stabilized in the presence of the jitter. The jitter error measurements are sampled once, twice, or more times prior to the field active starting edge. Error signals from a plurality of sources such as a scanner motor and a turret servo may be combined and compensated for together. The method of the invention may be employed to compensate for azimuth jitter, vertical jitter, or jitter with reference to any chosen axis.

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Agoura, CA, United States of America

Frank N Cheung