US3576393A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic exposure control for a slow scan vidicon
Assignee: United States Department of the Navy
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Filing: 1967-12-15
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Granted: 1971-04-27
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Expires: 1987-12-15
Abstract
Abstract The present invention provides an automatic exposure control circuit for a vidicon camera tube wherein the target element of the vidicon is utilized as the ''''heart'''' of its own exposure control. More specifically, the target element output signal is integrated to produce a voltage whose magnitude is proportional to average image intensity; which proportionate or analog voltage is then compared to a reference voltage preselected in accordance with desired video output level. The comparator output is then used as instantaneous feedback to operate the vidicon shutter when the proportionate or analog voltage signal comes into agreement with the reference voltage.
Inventors
- 👤 Thomas Thompson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 09:32
CPC Classifications
H; H04; H04N; H04N23/00; H04N23/70; H04N23/73
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
112 words
In combination: a vidicon camera tube having a target element and being equipped with a shutter having open and closed positions, said target element being exposed to an image when said shutter is in its open position, circuit means operably connected to said target element and effective during a frame interval when said target element is exposed to an image to produce an analog output signal proportionate to the average image intensity at said target element, and control means responsive to said analog output signal for closing said shutter during the same frame interval to terminate exposure of said target element to said image when said output signal exceeds a predetermined value.
Claim 2
Dependent Claim
112 words
In combination: a vidicon camera tube having a target element and being equipped with a shutter having open and closed positions, said target element being exposed to an image when said shutter is in its open position, circuit means operably connected to said target element and effective during a frame interval when said target element is exposed to an image to produce an analog output signal proportionate to the average image intensity at said target element, and control means responsive to said analog output signal for closing said shutter during the same frame interval to terminate exposure of said target element to said image when said output signal exceeds a predetermined value.
Claim 3
Dependent Claim
57 words
The combination specified in claim 1, wherein said control means includes: a reference signal source, comparator means operably connected to compare the output signal from said circuit means with said reference signal, and means operably connected to said comparator means for closing said shutter when said analog output signal from said circuit means exceeds said reference signal.
Claim 4
Dependent Claim
25 words
The combination specified in claim 2, wherein said reference signal is preset in accordance with the desired video output level for said vidicon camera tube.
Claim 5
Dependent Claim
61 words
The combination specified in claim 1, wherein said circuit means includes: a resistor connected in circuit series with said vidicon target element and across which is developed a voltage signal proportionate to the instantaneous image intensity at said target element when said shutter is open, and integrator means having its input connected across said resistor for integrating said resistor voltage signal.
Claim 6
Dependent Claim
36 words
The combination specified in claim 4, further including a switch means responsive to the condition of said shutter and adapted to close the connection of said integrator input across said resistor when said shutter is open.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-04-26 | 1974-10-26 | 1975-04-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-04-26 | 1978-10-26 | 1979-04-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-04-26 | 1982-10-26 | 1983-04-27 | $7700.00 | Window Closed / Lapsed |