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US4422097A
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Automatic focus controlling method
Assignee: Fujifilm Holdings Corp
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Filing: 1981-03-18
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Granted: 1983-12-20
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Expires: 2001-03-18
Abstract
Abstract In a hill-climbing method for detecting a peak of a contrast signal to detect the position to bring a taking lens to for automatic focus control, the taking lens is moved further from a first detected peak position by a predetermined distance for searching for a higher peak. When no higher peak is detected, the lens is brought to the first detected peak position. When a higher level is detected, the lens is further moved for searching another peak according to the hill-climbing method.
Inventors
- 👤 Masafumi Inuiya
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 23:46
CPC Classifications
H; H04; H04N; H04N23/00; H04N23/60; H04N23/67; H04N23/673
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
144 words
An automatic focus controlling method for a system including a lens comprising the steps of moving the lens axially in a first direction, generating a contrast signal from an image pick-up device scanning an image focused by the lens, comparing the maximum/peak contrast signal generated with a previously generated and stored maximum/peak contrast signal, moving said lens in said first direction by a predetermined distance beyond a position at which a maximum/peak contrast signal is generated while continuing to generate the contrast signal to search for another peak, said predetermined distance being established as a distance long enough to encompass lens movement corresponding to a lower contrast signal following an immediately preceding peak- signal, and moving said lens in a second opposite direction if a greater peak signal is not generated in said predetermined distance to a position corresponding to the last maximum/peak signal.
Claim 2
Dependent Claim
144 words
An automatic focus controlling method for a system including a lens comprising the steps of moving the lens axially in a first direction, generating a contrast signal from an image pick-up device scanning an image focused by the lens, comparing the maximum/peak contrast signal generated with a previously generated and stored maximum/peak contrast signal, moving said lens in said first direction by a predetermined distance beyond a position at which a maximum/peak contrast signal is generated while continuing to generate the contrast signal to search for another peak, said predetermined distance being established as a distance long enough to encompass lens movement corresponding to a lower contrast signal following an immediately preceding peak- signal, and moving said lens in a second opposite direction if a greater peak signal is not generated in said predetermined distance to a position corresponding to the last maximum/peak signal.
Claim 3
Dependent Claim
64 words
The method as defined in claim 1 wherein said previously generated and stored maximum/peak contrast signal comprises initially a predetermined threshold signal and said first mentioned moving step comprises the step of moving the lens toward a position where the level of the generated contrast signal is higher than said threshold signal when the initially generated contrast signal is lower than the threshold signal.
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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) | 1986-12-19 | 1987-06-20 | 1987-12-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-12-19 | 1991-06-20 | 1991-12-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-12-19 | 1995-06-20 | 1995-12-20 | $7700.00 | Window Closed / Lapsed |