Automatic initiation of target crossover recovery in a pyroelectric camera
US4686566A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 28, 1986 |
| Grant date | Aug 11, 1987 |
| Priority date | — |
| Expiry date | Jul 28, 2006 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N23/23
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A system and method are disclosed for initiating target crossover recovery in a pyroelectric camera by electronically detecting crossover and automatically initiating recovery in response thereto. The video signal appearing at the output of the video amplifier during readout of the vidicon tube is coupled to a level detector to detect crossover by sensing a positive signal having an amplitude greater than any such signal producible during readout arising from an optical input to the video amplifier, with reliability of detection being enhanced by use of an automatic balancing circuit providing a stable reference. The output from the level detector, indicative of sensed crossover of an area (or all) of the target of the pyroelectric tube, is either directly used to trigger an automatic target poling circuit which returns the pyroelectric tube back to normal operation, or is coupled to a time delay for delaying repoling of the target to allow an image to continue for a period of time after an area of the target has been crossed over in order to avoid loss of information.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.