US6833871B1
Expired / Lapsed
US
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Exposure control in electronic cameras by detecting overflow from active pixels
Assignee: Foveon Inc
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Filing: 2001-07-16
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Granted: 2004-12-21
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Expires: 2021-07-16
Abstract
Abstract A method for controlling the exposure of an active pixel array electronic still camera includes the steps of: integrating photocurrent in each pixel during an integration time period; collecting overflow charge from all pixels in the array during the integration time period; developing an overflow signal as a function of the overflow charge; and terminating the integration time period when the overflow signal exceeds a preset threshold level selected to represent a desired reference exposure level. Apparatus for performing the method of the present invention includes circuitry for integrating photocurrent in each pixel during a integration time period; circuitry for diverting and detecting overflow charge from all pixels in the array during the integration time period; circuitry for developing an overflow signal as a function of the overflow charge; and circuitry for terminating said integration time period when the overflow signal exceeds a preset threshold level selected to represent a desired reference exposure level.
Inventors
- 👤 Richard B. Merrill
- 👤 Carver A. Mead
- 👤 Richard F. Lyon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 15:07
CPC Classifications
H; H04; H04N; H04N25/00; H04N25/50; H04N25/57; H04N25/59; H04N25/53; H04N25/58; H04N25/587; H04N25/60; H04N25/62; H04N25/621; H04N25/623; H04N25/67; H04N25/70; H04N25/76; H04N25/77; H04N25/771
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
140 words
A method for controlling the exposure of an active pixel array disposed on a semiconductor substrate, comprising the steps of: adjusting a charge barrier in each said pixel to a first overflow level; integrating photocurrent in each said pixel during a first integration time period while said charge barrier is set at said first overflow level; collecting overflow charge from all said pixels in said array during said first integration time period; developing an overflow signal; adjusting said charge barrier for each said pixel to a second overflow level when said overflow signal exceeds a predetermined threshold; determining a duration for a second integration time period; integrating photocurrent in each said pixel during said second integration time period while said charge barrier is set at said second overflow level; and terminating said second integration time period after said determined duration.
Claim 2
Independent Claim
140 words
A method for controlling the exposure of an active pixel array disposed on a semiconductor substrate, comprising the steps of: adjusting a charge barrier in each said pixel to a first overflow level; integrating photocurrent in each said pixel during a first integration time period while said charge barrier is set at said first overflow level; collecting overflow charge from all said pixels in said array during said first integration time period; developing an overflow signal; adjusting said charge barrier for each said pixel to a second overflow level when said overflow signal exceeds a predetermined threshold; determining a duration for a second integration time period; integrating photocurrent in each said pixel during said second integration time period while said charge barrier is set at said second overflow level; and terminating said second integration time period after said determined duration.
Claim 3
Independent Claim
148 words
A method for controlling the exposure of an active pixel array disposed on a semiconductor substrate, comprising the steps of: resetting each pixel during a reset time period; adjusting a charge barrier in each said pixel to a first overflow level; integrating photocurrent in each said pixel during a first integration time period while said charge barrier is set at said first overflow level; collecting overflow charge from all said pixels in said array during said first integration time period; developing an overflow signal; adjusting said charge barrier for each said pixel to a second overflow level when said overflow signal exceeds a predetermined threshold; determining a duration for a second integration time period; integrating photocurrent in each said pixel during said second integration time period while said charge barrier is set at said second overflow level; and terminating said second integration time period after said determined duration.
Claim 4
Independent Claim
148 words
A method for controlling the exposure of an active pixel array disposed on a semiconductor substrate, comprising the steps of: resetting each pixel during a reset time period; adjusting a charge barrier in each said pixel to a first overflow level; integrating photocurrent in each said pixel during a first integration time period while said charge barrier is set at said first overflow level; collecting overflow charge from all said pixels in said array during said first integration time period; developing an overflow signal; adjusting said charge barrier for each said pixel to a second overflow level when said overflow signal exceeds a predetermined threshold; determining a duration for a second integration time period; integrating photocurrent in each said pixel during said second integration time period while said charge barrier is set at said second overflow level; and terminating said second integration time period after said determined duration.
Claim 5
Independent Claim
146 words
An apparatus for controlling the exposure of an active pixel array, comprising: means for adjusting a charge barrier in each pixel to a first overflow level; means for integrating photocurrent in each said pixel during a first integration time period while said charge barrier is set at said first overflow level; means for collecting overflow charge from all said pixels in said array during said first integration period; means for developing an overflow signal; means for adjusting said charge barrier for each said pixel to a second overflow level when said overflow signal exceeds a predetermined threshold; means for determining a duration for a second integration time period; means for integrating photocurrent in each said pixel during said second integration time period while said charge barrier is set at said second overflow level; and means for terminating said second integration time period after said determined duration.
Claim 6
Independent Claim
146 words
An apparatus for controlling the exposure of an active pixel array, comprising: means for adjusting a charge barrier in each pixel to a first overflow level; means for integrating photocurrent in each said pixel during a first integration time period while said charge barrier is set at said first overflow level; means for collecting overflow charge from all said pixels in said array during said first integration period; means for developing an overflow signal; means for adjusting said charge barrier for each said pixel to a second overflow level when said overflow signal exceeds a predetermined threshold; means for determining a duration for a second integration time period; means for integrating photocurrent in each said pixel during said second integration time period while said charge barrier is set at said second overflow level; and means for terminating said second integration time period after said determined duration.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 2007-12-21 | 2008-06-21 | 2008-12-21 | $2000.00 | Window Closed / Lapsed |
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