Xedar Corporation

Donald E Hodd

Hans R Bucher

A system and method are disclosed for pyroelectric camera signal processing, which processing includes multi-parameter automatic signal level adjustment to compensate for the effects of pedestal level variations. The pyroelectric vidicon tube generates an electrical output signal component indicative of target signal information based upon the sensed thermal energy emitted from the target, and also generates a pedestal component around which the target signal information is centered, and this information is processed to provide field video signals which are utilized to provide a composite video output. An automatic adjustment control unit, responsive to the field video signal, provides automatic adjustment of gain, balance, and offset to thereby allow the pyroelectric camera to operate at an optimized signal-to-noise ratio.

Pyroelectric camera signal processing having interrelated

A system and method are disclosed for pyroelectric camera signal processing, which processing includes compensating for the effects of pedestal level variations. The pyroelectric videcon tube generates an electrical output signal component indicative of target signal information based upon the sensed thermal energy emitted from the target, and also generates a pedestal component around which the target signal information is centered. A line-by-line DC restorer is provided to re-establish the DC level of the video signal, with the DC level of the restorer being automatically controlled to thereby compensate for variations in pedestal levels due to drift, tube aging, and/or generated by shutter to scene temperature differences.

Pyroelectric camera signal processing having pedestal signal level

A signal processing system is disclosed for a pyroelectric camera having a mechanical chopper in the optical path for causing information sensed by the camera to appear as dynamic information. The pyroelectric camera includes a pyroelectric vidicon tube which senses thermal energy emitted by a target and provides an electrical output signal indicative of the received thermal information. The output signal developed by the pyroelectric vidicon tube includes a relatively large pedestal signal component that is established during flyback due to secondary electron generation and a slightly wider but relatively small pedestal signal that is established due to differences in temperature sensed by the pyroelectric vidicon tube, which pedestal signal is timewise aligned with the relatively large pedestal signal generated due to secondary electron generation. Removal of the pedestal signals avoids saturation of the system amplifiers and limiting of the dynamic range of the camera by thus enabling processing of only the signal components indicative of sensed thermal energy from the target. Background flicker is also eliminated, or reduced, by adding signals of adjacent fields.

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Niwot, CO, United States of America

Donald E Hodd