Patent US6690424B1 successfully refreshed from Google Patents.
US6690424B1
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US
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Exposure control apparatus for controlling the exposure of an image pickup plane in a camera
Assignee: Sony Corp
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Filing: 1998-03-19
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Granted: 2004-02-10
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Expires: 2018-03-19
Abstract
Abstract An exposure controller including a backlight correction calculator where the amount of incident light is integrated to obtain an average luminance of an entire image pickup plane, and the average luminance is multiplied by a predetermined factor to set a HIST reference level. In a HIST detector, an object scene portion in the image pickup plane is separated from a background portion on the basis of the HIST reference level, and the average luminance of the object scene portion is detected. Further the difference between the average luminance of the entire plane and that of the object scene portion is calculated in the backlight correction calculator, and gain control is executed with respect to the calculated luminance difference to thereby obtain a backlight correction quantity. Then automatic exposure is performed in accordance with such backlight correction quantity, hence ensuring exact prevention of a phenomenon that the object scene in a backlight state is rendered dark. This exposure controller is adapted for down-sizing a software processor while eliminating the necessity of any complicated process such as functional operation.
Inventors
- 👤 Takashi Hanagata
- 👤 Daisuke Kumagai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 10:54
CPC Classifications
H; H04; H04N; H04N23/00; H04N23/70; H04N23/73; H04N23/71; H04N23/76
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
140 words
An exposure controller comprising: a detection means for separating an image pickup plane into an object scene portion and a background portion, the location of said object scene portion within the image pickup plane being unrestricted, and detecting the brightness of the object scene portion; and a control means for executing exposure control on the basis of the output of said detection means, wherein said detection means has an average luminance calculation means for calculating the average luminance of the entire image pickup plane; reference level setting means for setting first and second reference levels on the basis of the average luminance calculated by said average luminance calculation means; and a separation means for separating the object scene portion on the basis of said first reference level while separating the background portion on the basis of said second reference level.
Claim 2
Dependent Claim
140 words
An exposure controller comprising: a detection means for separating an image pickup plane into an object scene portion and a background portion, the location of said object scene portion within the image pickup plane being unrestricted, and detecting the brightness of the object scene portion; and a control means for executing exposure control on the basis of the output of said detection means, wherein said detection means has an average luminance calculation means for calculating the average luminance of the entire image pickup plane; reference level setting means for setting first and second reference levels on the basis of the average luminance calculated by said average luminance calculation means; and a separation means for separating the object scene portion on the basis of said first reference level while separating the background portion on the basis of said second reference level.
Claim 3
Dependent Claim
32 words
The exposure controller according to claim 1 , wherein said first reference level is higher than the average luminance level, and said second reference level is lower than the average luminance level.
Claim 4
Dependent Claim
36 words
The exposure controller according to claim 1 , wherein said detection means further has a first integration means for integrating the luminance of the object scene portion separated on the basis of said first reference level.
Claim 5
Dependent Claim
38 words
The exposure controller according to claim 1 , wherein said detection means further has a first count means for counting the number of pixels of the object scene portion separated on the basis of said first reference level.
Claim 6
Dependent Claim
35 words
The exposure controller according to claim 1 , wherein said detection means further has a second integration means for integrating the luminance of the background portion separated on the basis of said second reference level.
Claim 7
Dependent Claim
37 words
The exposure controller according to claim 1 , wherein said detection means further has a second count means for counting the number of pixels of the background portion separated on the basis of said second reference level.
Claim 8
Dependent Claim
79 words
The exposure controller according to claim 1 , further comprising: an averaging means for detecting the average luminance of the object scene portion; and a difference detection means for detecting the difference between the average luminance of the object scene portion detected by said averaging means, and the average luminance of the entire plane calculated by said average luminance calculation means; wherein said control means executes exposure control on the basis of the output of said difference detection means.
Claim 9
Dependent Claim
82 words
The exposure controller according to claim 4 or 6 , further comprising a gain control means for controlling the gain with respect to the output of said difference detection means on the basis of the correlation between the result of adding the pixel count values of said first and second count means and the number of pixels of the entire image pickup plane; wherein said control means executes the exposure control on the basis of the output of said gain control means.
Claim 10
Dependent Claim
106 words
An exposure control method for automatically controlling the brightness of an image pickup plane, comprising the steps of: detecting the average luminance of the entire image pickup plane, and setting first and second reference levels on the basis of such average luminance; separating the image pickup plane into an object scene portion and a background portion on the basis of said first and second reference levels, and detecting the average luminance of the object scene portion; calculating the difference between the average luminance of the entire plane and that of the object scene portion; and controlling the exposure on the basis of the difference thus calculated.
Claim 11
Dependent Claim
106 words
An exposure control method for automatically controlling the brightness of an image pickup plane, comprising the steps of: detecting the average luminance of the entire image pickup plane, and setting first and second reference levels on the basis of such average luminance; separating the image pickup plane into an object scene portion and a background portion on the basis of said first and second reference levels, and detecting the average luminance of the object scene portion; calculating the difference between the average luminance of the entire plane and that of the object scene portion; and controlling the exposure on the basis of the difference thus calculated.
Claim 12
Dependent Claim
71 words
The exposure control method according to claim 9 , further comprising a step of controlling the gain with respect to the calculated luminance difference on the basis of the correlation between the sum total of pixels of the object scene portion and the background portion, and the number of pixels of the entire plane, wherein the exposure control is executed on the basis of the difference after the gain is controlled.
Claim 13
Dependent Claim
207 words
A camera comprising: an image sensor for converting incident light into an electric signal and outputting the same; an optical system for guiding the incident light from an object scene onto an image pickup plane of said image sensor; a signal processing means for processing the output signal of said image sensor; a detection means for separating the image pickup plane into an object scene portion and a background portion on the basis of the signal supplied from said signal processing means, the location of said object scene portion within the image pickup plane being unrestricted, and then detecting the brightness of the object scene portion; and a control means for executing exposure control with regard to said image sensor on the basis of the output of said detection means, wherein said detection means has an average luminance calculation means for calculating the average luminance of the entire image pickup plane; reference level setting means for setting first and second reference levels on the basis of the average luminance calculated by said average luminance calculation means; and a separation means for separating the object scene portion on the basis of said first reference level while separating the background portion on the basis of said second reference level.
Claim 14
Dependent Claim
207 words
A camera comprising: an image sensor for converting incident light into an electric signal and outputting the same; an optical system for guiding the incident light from an object scene onto an image pickup plane of said image sensor; a signal processing means for processing the output signal of said image sensor; a detection means for separating the image pickup plane into an object scene portion and a background portion on the basis of the signal supplied from said signal processing means, the location of said object scene portion within the image pickup plane being unrestricted, and then detecting the brightness of the object scene portion; and a control means for executing exposure control with regard to said image sensor on the basis of the output of said detection means, wherein said detection means has an average luminance calculation means for calculating the average luminance of the entire image pickup plane; reference level setting means for setting first and second reference levels on the basis of the average luminance calculated by said average luminance calculation means; and a separation means for separating the object scene portion on the basis of said first reference level while separating the background portion on the basis of said second reference level.
Claim 15
Dependent Claim
31 words
The camera according to claim 11 , wherein said first reference level is higher than the average luminance level, and said second reference level is lower than the average luminance level.
Claim 16
Dependent Claim
35 words
The camera according to claim 11 , wherein said detection means further has a first integration means for integrating the luminance of the object scene portion separated on the basis of said first reference level.
Claim 17
Dependent Claim
37 words
The camera according to claim 11 , wherein said detection means further has a first count means for counting the number of pixels of the object scene portion separated on the basis of said first reference level.
Claim 18
Dependent Claim
34 words
The camera according to claim 11 , wherein said detection means further has a second integration means for integrating the luminance of the background portion separated on the basis of said second reference level.
Claim 19
Dependent Claim
36 words
The camera according to claim 11 , wherein said detection means further has a second count means for counting the number of pixels of the background portion separated on the basis of the second reference level.
Claim 20
Dependent Claim
78 words
The camera according to claim 11 , further comprising: an averaging means for detecting the average luminance of the object scene portion; and a difference detection means for detecting the difference between the average luminance of the object scene portion detected by said averaging means, and the average luminance of the, entire plane calculated by said average luminance calculation means; wherein said control means executes exposure control on the basis of the output of said difference detection means.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2007-02-09 | 2007-08-11 | 2008-02-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2011-02-09 | 2011-08-11 | 2012-02-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2015-02-09 | 2015-08-11 | 2016-02-10 | $7700.00 | Window Closed / Lapsed |