US6091452A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Focus controlling method and apparatus which uses different focusing parameters and/or selects an image having a best focus
Assignee: Ricoh Co Ltd
•
Filing: 1995-09-01
•
Granted: 2000-07-18
•
Expires: 2015-09-01
Abstract
Abstract A focusing method and apparatus which changes the shutter speed and/or the focusing sampling frequency in order to increase the speed at which an image is brought into focus while at the same time, preventing the influence of flicker from artificial light powered by an AC power source. As the focus evaluation value is based on the brightness of a signal, shutter speeds and frequencies are set in order to avoid the influence of flicker on the focusing process. A shutter speed of 1/100th of a second with a sampling frequency of 60 Hz can be used in environments which are sufficiently bright in order to increase the focusing speed. Also, the focusing sampling frequency may be set to be large when the focus is far from the focusing point in order to quickly bring the image into focus and the sampling frequency subsequently decreases as the focusing position is approached in order to reduce the chances that the focusing position will be passed. Another feature is to record images as the focus position is being approached so that when the in-focus position is passed, there is no need to back up the focusing lens to the in-focus position to obtain the still image as the still image will have been previously recorded. The other frames which have been recorded may then be discarded.
Inventors
- 👤 Kiyoharu Nishiyama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 17:48
CPC Classifications
H; H04; H04N; H04N23/00; H04N23/60; H04N23/67; H04N23/673
Claims Analysis
Total Claims: 38
Claim 1
Independent Claim
179 words
A method for focusing a lens, comprising the steps of: setting a focus sampling frequency to a first sampling frequency and setting a shutter speed to a first shutter speed; determining a first amount of light passing through the focusing lens; determining a first focus evaluation value using the first amount of light passing through the focusing lens; changing a position of the focusing lens by driving a motor by an amount calculated using the first focus evaluation value; changing at least one of the focus sampling frequency and the shutter speed when the first focus evaluation value is greater than a reference value; determining a second amount of light passing through the focusing lens, after the step of changing said at least one of the focus sampling frequency and the shutter speed; determining a second focus evaluation value using the second amount of light passing through the focusing lens; and changing a position of the focusing lens by driving the motor by an amount calculated using the second focus evaluation value and a previously determined focus evaluation value.
Claim 2
Independent Claim
179 words
A method for focusing a lens, comprising the steps of: setting a focus sampling frequency to a first sampling frequency and setting a shutter speed to a first shutter speed; determining a first amount of light passing through the focusing lens; determining a first focus evaluation value using the first amount of light passing through the focusing lens; changing a position of the focusing lens by driving a motor by an amount calculated using the first focus evaluation value; changing at least one of the focus sampling frequency and the shutter speed when the first focus evaluation value is greater than a reference value; determining a second amount of light passing through the focusing lens, after the step of changing said at least one of the focus sampling frequency and the shutter speed; determining a second focus evaluation value using the second amount of light passing through the focusing lens; and changing a position of the focusing lens by driving the motor by an amount calculated using the second focus evaluation value and a previously determined focus evaluation value.
Claim 3
Dependent Claim
43 words
A method according to claim 1, wherein: said step of changing at least one of the focus sampling frequency and the shutter speed changes the shutter speed to 1/100 of a second, when the focus evaluation value is greater than the reference value.
Claim 4
Dependent Claim
43 words
A method according to claim 2, wherein: said step of changing at least one of the focus sampling frequency and the shutter speed changes the shutter speed to 1/100 of a second from the first shutter speed which is 1/60 of a second.
Claim 5
Dependent Claim
41 words
A method according to claim 3, wherein: said step of changing at least one of the focus sampling frequency and the shutter speed changes the shutter speed only when the determined first amount of light is greater than a predetermined threshold.
Claim 6
Dependent Claim
42 words
A method according to claim 1, wherein: said step of changing at least one of the focus sampling frequency and the shutter speed changes the sampling frequency to 60 Hz, when the first focus evaluation value is greater than the reference value.
Claim 7
Dependent Claim
33 words
A method according to claim 5, wherein: said step of changing at least one of the focus sampling frequency and the shutter speed changes the sampling frequency from 20 Hz to 60 Hz.
Claim 8
Dependent Claim
41 words
A method according to claim 6, wherein: said step of changing at least one of the focus sampling frequency and the shutter speed changes the sampling frequency only when the determined first amount of light is greater than a predetermined threshold.
Claim 9
Dependent Claim
43 words
A method according to claim 7, wherein: said step of changing at least one of the focus sampling frequency and the shutter speed changes the shutter speed to 1/100 of a second from the first shutter speed which is 1/60 of a second.
Claim 10
Dependent Claim
72 words
A method according to claim 1, wherein: said step of changing at least one of the focus sampling frequency and the shutter speed changes the focus sampling frequency from the first sampling frequency to a second sampling frequency which is longer than the first sampling frequency when the focus evaluation value is greater than the reference value, indicating that the focus lens is approaching a position which achieves a best focus position.
Claim 11
Dependent Claim
46 words
A method according to claim 9, wherein: said step of changing at least one of the focus sampling frequency and the shutter speed changes the focus sampling frequency from the first sampling frequency which is 60 Hz to a second sampling frequency which is 20 Hz.
Claim 12
Dependent Claim
68 words
A method according to claim 9, wherein: said step of changing at least one of the focus sampling frequency and the shutter speed changes the focus sampling frequency; and after said step of changing at least one of the focus sampling frequency and the shutter speed, the position of the focusing lens is not changed while an amount of light passing through the focusing lens is being determined.
Claim 13
Dependent Claim
45 words
A method according to claim 11, wherein: before said step of changing at least one of the focus sampling frequency and the shutter speed, the position of the focusing lens is changed while the amount of light passing through the focusing lens is being determined.
Claim 14
Dependent Claim
50 words
A method according to claim 1, wherein the step of changing a position of the focusing lens using the first focus evaluation value changes the position of the lens using both the first focus evaluation value and a focus evaluation value determined before the first focus evaluation value was determined.
Claim 15
Independent Claim
132 words
A method of focusing and capturing an image by a camera, comprising the steps of: obtaining a first focus evaluation value; recording a first image in a memory; focusing the camera using the first focus evaluation value; obtaining a second focus evaluation value which indicates that a focus of the camera is better than a focus indicated by the first focus evaluation value; recording a second image in the memory; focusing the camera using the second focus evaluation value and a previously obtained focus evaluation value; obtaining a third focus evaluation value which indicates that a focus of the camera is worse than a focus indicated by the second focus evaluation value; and selecting the second image as an image having a best focus, using the second and third focus evaluation values.
Claim 16
Independent Claim
132 words
A method of focusing and capturing an image by a camera, comprising the steps of: obtaining a first focus evaluation value; recording a first image in a memory; focusing the camera using the first focus evaluation value; obtaining a second focus evaluation value which indicates that a focus of the camera is better than a focus indicated by the first focus evaluation value; recording a second image in the memory; focusing the camera using the second focus evaluation value and a previously obtained focus evaluation value; obtaining a third focus evaluation value which indicates that a focus of the camera is worse than a focus indicated by the second focus evaluation value; and selecting the second image as an image having a best focus, using the second and third focus evaluation values.
Claim 17
Dependent Claim
26 words
A method according to claim 14, further comprising the step of: erasing the first image from the memory while retaining the second image in the memory.
Claim 18
Dependent Claim
54 words
A method according to claim 14, further comprising the steps of: recording a third image in the memory, after the step of focusing using the second focus evaluation value and the previously obtained focus evaluation value; and erasing the first and third images from the memory while retaining the second image in the memory.
Claim 19
Dependent Claim
43 words
A method according to claim 14, wherein the step of focusing the camera using the first focus evaluation value focuses the camera using both the first focus evaluation value and a focus evaluation value obtained before the first focus evaluation value was obtained.
Claim 20
Dependent Claim
203 words
A camera, comprising: a focusing lens; a motor for driving the focusing lens; an image pick-up for recording an image focused by the focusing lens; a focus evaluation value generator which generates focus evaluation values using a brightness component of an image detected by the image pick-up; means for setting a camera focus sampling frequency to a first sampling frequency and setting a camera shutter speed to a first shutter speed; means for determining a first focus evaluation value using a first determined amount of light which has passed through the focusing lens and is detected by the image pick-up; means for calculating an amount to drive the motor in order to focus the focusing lens using the first focus evaluation value; means for changing at least one of the camera focus sampling frequency and the camera shutter speed when the first focus evaluation value is greater than a reference value; and means for determining a second focus evaluation value using a second determined amount of light which has passed through the focusing lens and is detected by the image pick-up, after the means for changing has changed said at least one of the camera focus sampling frequency and the camera shutter speed.
Claim 21
Dependent Claim
203 words
A camera, comprising: a focusing lens; a motor for driving the focusing lens; an image pick-up for recording an image focused by the focusing lens; a focus evaluation value generator which generates focus evaluation values using a brightness component of an image detected by the image pick-up; means for setting a camera focus sampling frequency to a first sampling frequency and setting a camera shutter speed to a first shutter speed; means for determining a first focus evaluation value using a first determined amount of light which has passed through the focusing lens and is detected by the image pick-up; means for calculating an amount to drive the motor in order to focus the focusing lens using the first focus evaluation value; means for changing at least one of the camera focus sampling frequency and the camera shutter speed when the first focus evaluation value is greater than a reference value; and means for determining a second focus evaluation value using a second determined amount of light which has passed through the focusing lens and is detected by the image pick-up, after the means for changing has changed said at least one of the camera focus sampling frequency and the camera shutter speed.
Claim 22
Dependent Claim
46 words
A camera according to claim 18, wherein: said means for changing at least one of the camera focus sampling frequency and the camera shutter speed changes the camera shutter speed to 1/100 of a second, when the focus evaluation value is greater than the reference value.
Claim 23
Dependent Claim
53 words
A camera according to claim 19, wherein: said means for changing at least one of the camera focus sampling frequency and the camera shutter speed changes the camera shutter speed to 1/100 of a second from the first shutter speed which is set to 1/60 of a second by the means for setting.
Claim 24
Dependent Claim
43 words
A camera according to claim 20, wherein: said means for changing at least one of the camera focus sampling frequency and the camera shutter speed changes the shutter speed only when the first determined amount of light is greater than a predetermined threshold.
Claim 25
Dependent Claim
45 words
A camera according to claim 18, wherein: said means for changing at least one of the camera focus sampling frequency and the camera shutter speed changes the camera sampling frequency to 60 Hz, when the first focus evaluation value is greater than the reference value.
Claim 26
Dependent Claim
44 words
A camera according to claim 22, wherein: said means for changing at least one of the camera focus sampling frequency and the camera shutter speed changes the camera sampling frequency from 20 Hz which was set by the means for setting to 60 Hz.
Claim 27
Dependent Claim
44 words
A camera according to claim 23, wherein: said means for changing at least one of the camera focus sampling frequency and the camera shutter speed changes the camera sampling frequency only when the determined first amount of light is greater than a predetermined threshold.
Claim 28
Dependent Claim
46 words
A camera according to claim 24, wherein: said means for changing at least one of the camera focus sampling frequency and the camera shutter speed changes the camera shutter speed to 1/100 of a second from the first shutter speed which is 1/60 of a second.
Claim 29
Dependent Claim
75 words
A camera according to claim 18, wherein: said means for changing at least one of the camera focus sampling frequency and the camera shutter speed changes the camera focus sampling frequency from the first sampling frequency to a second sampling frequency which is longer than the first sampling frequency when the focus evaluation value is greater than the reference value, indicating that the focusing lens is approaching a position which achieves a best focus position.
Claim 30
Dependent Claim
49 words
A camera according to claim 26, wherein: said means for changing at least one of the camera focus sampling frequency and the camera shutter speed changes the camera focus sampling frequency from the first sampling frequency which is 60 Hz to a second sampling frequency which is 20 Hz.
Claim 31
Dependent Claim
93 words
A camera according to claim 26, wherein: said means for changing at least one of the camera focus sampling frequency and the camera shutter speed changes the camera focus sampling frequency; and after said means for changing at least one of the camera focus sampling frequency and the camera shutter speed changes the at least one of the camera shutter speed and the camera focus sampling frequency, the position of the focusing lens is not changed while an amount of light passing through the focusing lens is being determined by the image pick-up.
Claim 32
Dependent Claim
70 words
A camera according to claim 28, wherein: before said means for changing at least one of the camera focus sampling frequency and the camera shutter speed changes the at least one of the camera shutter speed and the camera focus sampling frequency, the position of the focusing lens is changed by the motor while an amount of light passing through the focusing lens is being determined by the image pick-up.
Claim 33
Dependent Claim
39 words
A camera according to claim 18, wherein the means for calculating calculates the amount to drive the motor using both the first focus evaluation value and a focus evaluation value determined before the first focus evaluation value was determined.
Claim 34
Dependent Claim
136 words
A camera, comprising: means for obtaining a first focus evaluation value; means for recording a first image in a memory; means for focusing the camera using the first focus evaluation value; means for obtaining a second focus evaluation value which indicates that a focus of the camera is better than a focus indicated by the first focus evaluation value; means for recording a second image in the memory; means for focusing the camera using the second focus evaluation value and a previously obtained focus evaluation value; means for obtaining a third focus evaluation value which indicates that a focus of the camera is worse than a focus indicated by the second focus evaluation value; and means for selecting the second image as an image having a best focus, using the second and third focus evaluation values.
Claim 35
Dependent Claim
136 words
A camera, comprising: means for obtaining a first focus evaluation value; means for recording a first image in a memory; means for focusing the camera using the first focus evaluation value; means for obtaining a second focus evaluation value which indicates that a focus of the camera is better than a focus indicated by the first focus evaluation value; means for recording a second image in the memory; means for focusing the camera using the second focus evaluation value and a previously obtained focus evaluation value; means for obtaining a third focus evaluation value which indicates that a focus of the camera is worse than a focus indicated by the second focus evaluation value; and means for selecting the second image as an image having a best focus, using the second and third focus evaluation values.
Claim 36
Dependent Claim
25 words
A camera according to claim 31, further comprising: means for erasing the first image from the memory while retaining the second image in the memory.
Claim 37
Dependent Claim
59 words
A camera according to claim 31, further comprising: means for recording a third image in the memory, after the means for focusing focuses using the second focus evaluation value focuses the camera and the previously obtained focus evaluation value; and means for erasing the first and third images from the memory while retaining the second image in the memory.
Claim 38
Dependent Claim
43 words
A camera according to claim 31, wherein the means for focusing the camera using the first focus evaluation value focuses the camera using both the first focus evaluation value and a focus evaluation value obtained before the first focus evaluation value was obtained.
References Cited (Backward Citations)
US5101276A
Cited
US5075777A
Cited
US5206730A
Cited
US5384595A
Cited
US5486893A
Cited
US5430483A
Cited
JPH05236328A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2003-07-18 | 2004-01-17 | 2004-07-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-07-18 | 2008-01-17 | 2008-07-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-07-18 | 2012-01-17 | 2012-07-18 | $7700.00 | Window Closed / Lapsed |