Patent US3823263A successfully refreshed from Google Patents.
US3823263A
Expired / Lapsed
US
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Camera tube gain control circuit
Assignee: BAC AND BRITISH AEROSPACE
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Filing: 1973-01-26
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Granted: 1974-07-09
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Expires: 1993-01-26
Abstract
Abstract In an electronic camera tube circuit, a gain-control voltage is produced which varies with the level of the video signals corresponding to the background in the viewed scene. An integrator receives a steady input signal as long as the video signal from the camera exceeds the level of the integrator output. The integrator output thus rises to the background level and is sampled and reset periodically, for example at the end of each frame, the sample providing a gain-control voltage.
Inventors
- 👤 J Guppy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 10:55
CPC Classifications
H; H04; H04N; H04N23/00; H04N23/70; H04N23/749
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
97 words
An image receiver including a camera of the raster-scanning kind and further comprising: a signal generator for generating a reference signal; a comparator connected to compare a video signal derived from said camera with reference signal from the reference signal generator; means responsive to the comparator output when the video signal exceeds the reference signal level to increase progressively the level of the reference signal for the period that the video signal exceeds this level; and gain-control means controlling the gain of the image receiver as a function of the output level of said reference signal generator.
Claim 2
Dependent Claim
97 words
An image receiver including a camera of the raster-scanning kind and further comprising: a signal generator for generating a reference signal; a comparator connected to compare a video signal derived from said camera with reference signal from the reference signal generator; means responsive to the comparator output when the video signal exceeds the reference signal level to increase progressively the level of the reference signal for the period that the video signal exceeds this level; and gain-control means controlling the gain of the image receiver as a function of the output level of said reference signal generator.
Claim 3
Dependent Claim
112 words
An image receiver including a camera of the raster-scanning kind and further comprising: an integrator and a circuit for providing an input signal for said integrator; a comparator connected to compare a video signal derived from the camera with the output of said integrator; switching means for applying the said integrator input signal to the integrator when the comparator output indicates that the video signal exceeds the integrator output; a second comparator connected to compare the integrator output with a signal of a reference threshold level; and gain-control means operative when said second comparator indicates that the integrator output exceeds the reference threshold level to adjust the gain of said image receiver.
Claim 4
Dependent Claim
112 words
An image receiver including a camera of the raster-scanning kind and further comprising: an integrator and a circuit for providing an input signal for said integrator; a comparator connected to compare a video signal derived from the camera with the output of said integrator; switching means for applying the said integrator input signal to the integrator when the comparator output indicates that the video signal exceeds the integrator output; a second comparator connected to compare the integrator output with a signal of a reference threshold level; and gain-control means operative when said second comparator indicates that the integrator output exceeds the reference threshold level to adjust the gain of said image receiver.
Claim 5
Dependent Claim
22 words
An image receiver in accordance with claim 2, including means for periodically applying the output of the integrator to the second comparator.
Claim 6
Dependent Claim
33 words
An image receiver in accordance with claim 3, including a circuit operative after a delay, following the application oF the integrator output to the second comparator, to reset the integrator output to zero.
Claim 7
Dependent Claim
33 words
An image receiver in accordance with claim 2, including means for applying the output of the integrator to the second comparator at the end of a scanning period of the camera scanning raster.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-07-08 | 1978-01-07 | 1978-07-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-07-08 | 1982-01-07 | 1982-07-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-07-08 | 1986-01-07 | 1986-07-09 | $7700.00 | Window Closed / Lapsed |