US4615598A
Expired / Lapsed
US
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Method of extracting automatic-focusing information
Assignee: Ricoh Co Ltd
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Filing: 1985-06-14
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Granted: 1986-10-07
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Expires: 2005-06-14
Abstract
Abstract At least a portion of one line of an output signal from an image pickup device is stored in a delay line, and maximum and minimum values of the output signal are detected. Then, a coefficient is computed for shifting the minimum value to a least significant bit in an A/D converter and the maximum value to a most significant bit in the A/D converter. The stored signal is read out of the delay line, amplified by the coefficient, and converted to a digital signal representative of automatic-focusing information.
Inventors
- 👤 Shinichirou Koshiishi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 13:22
CPC Classifications
G; G02; G02B; G02B7/00; G02B7/28; G02B7/36; H; H04; H04N; H04N23/00; H04N23/60; H04N23/67
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
125 words
A method of extracting automatic-focusing information, comprising: (a) storing in a delay line at least a portion of one line of an output signal from image pickup means to thereby form a stored signal readable out of said delay line; (b) detecting maximum and minimum values of said output signal; (c) computing a coefficient for shifting said minimum value to a least significant bit in an A/D converter and said maximum value to a most significant bit in the A/D converter; (d) reading the stored signal out of said delay line to thereby provide a read signal; (e) amplifying the read signal by said coefficient to thereby provide an amplified signal; and (f) converting the amplified signal to a digital signal representative of automatic-focusing information.
Claim 2
Independent Claim
125 words
A method of extracting automatic-focusing information, comprising: (a) storing in a delay line at least a portion of one line of an output signal from image pickup means to thereby form a stored signal readable out of said delay line; (b) detecting maximum and minimum values of said output signal; (c) computing a coefficient for shifting said minimum value to a least significant bit in an A/D converter and said maximum value to a most significant bit in the A/D converter; (d) reading the stored signal out of said delay line to thereby provide a read signal; (e) amplifying the read signal by said coefficient to thereby provide an amplified signal; and (f) converting the amplified signal to a digital signal representative of automatic-focusing information.
Claim 3
Dependent Claim
20 words
A method according to claim 1, wherein said image pickup means comprises an area sensor or an image pickup tube.
Claim 4
Dependent Claim
17 words
A method according to claim 1, wherein said image pickup means comprises a CCD or a BBD.
Claim 5
Dependent Claim
26 words
A method according to claim 1, wherein said one line comprises a line disposed substantially centrally on an image pickup area of said image pickup means.
Claim 6
Dependent Claim
16 words
A method according to claim 1, wherein said delay line comprises a CCD or a BBD.
Claim 7
Dependent Claim
26 words
A method according to claim 1, wherein said one line of the output signal from said image pickup means is entirely stored in said delay line.
Claim 8
Dependent Claim
29 words
A method according to claim 1, wherein only a portion of said one line of the output signal from said image pickup means is stored in said delay line.
Claim 9
Dependent Claim
66 words
A method according to claim 1, wherein a clock frequency for driving said delay line is equal to a scanning frequency for said image pickup means when storing the signal into said delay line, and said clock frequency is selected to be a relatively low frequency dependent on the rate of conversion in said A/D converter when reading the stored signal out of said delay line.
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) | 1989-10-06 | 1990-04-07 | 1990-10-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-10-06 | 1994-04-07 | 1994-10-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-10-06 | 1998-04-07 | 1998-10-07 | $7700.00 | Window Closed / Lapsed |