Patent EP0347042A1 successfully refreshed from Google Patents.
EP0347042A1
Expired / Lapsed
EP
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Automatic focusing apparatus
Assignee: Nikon Corp
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Filing: 1989-05-15
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Granted: —
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Expires: 2009-05-15
Abstract
Abstract An automatic focusing apparatus comprising: focusing means for repetitively detecting a defocus amount of a photographing lens, moving object discriminating means for discriminating whether or not an object is moving, pursuit correction amount calculating means for calculating a pursuit correction amount for the moving object on the basis of the present and previous defocus amounts, lens drive means for, when the discriminating means discriminates that the object is not moved, calculating a drive amount of the lens on the basis of the present defocus amount and for, when the discriminating means discriminates that the object is moving, calculating the drive amount of the lens on the basis of a pursuit drive amount as a sum of the present defocus amount and the pursuit correction amount, so as to drive the lens, and pursuit enable/disable determining means for determining whether the drive means calculates the drive amount of the lens on the basis of the discrimination result of the discriminating means or calculates the drive amount of the lens on the basis of the present defocus amount, wherein when a drive direction of the lens is reversed, the pursuit enable/disable determining means causes the lens drive means to calculate the drive amount of the photographing lens on the basis of the present defocus amount to drive the lens in a predetermined number of times of drive operation after the reversal..
Inventors
- 👤 Yosuke Kusaka
- 👤 Masaru Muramatsu
- 👤 Ken Utagawa
- 👤 Shozo Yamano
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 11:33
CPC Classifications
G; G02; G02B; G02B7/00; G02B7/28; G02B7/36
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
252 words
An automatic focusing apparatus comprising: focusing means for repetitively detecting a defocus amount of a photographing lens; moving object discriminating means for discriminating on the basis of present and previous defocus amounts whether or not an object is moving; pursuit correction amount calculating means for calculating a pursuit correction amount for the moving object on the basis of the present and previous defocus amounts; lens drive means for, when said moving object discriminating means discriminates that the object is not moved, calculating a drive amount of said photographing lens on the basis of the present defocus amount and for, when said moving object discriminating means discriminates that the object is moving, calculating the drive amount of said photographing lens on the basis of a pursuit drive amount as a sum of the present defocus amount and the pursuit correction amount, so as to drive said photographing lens; and pursuit enable/disable determining means for determining whether said lens drive means calculates the drive amount of said photographing lens on the basis of the discrimination result of said moving object discriminating means or calculates the drive amount of said photographing lens on the basis of the present defocus amount, wherein when a drive direction of said photographing lens is reversed, said pursuit enableidisable determining means causes said lens drive means to calculate the drive amount of said photographing lens on the basis of the present defocus amount to drive said photographing lens in a predetermined number of times of drive operations after the reversal.
Claim 2
Dependent Claim
252 words
An automatic focusing apparatus comprising: focusing means for repetitively detecting a defocus amount of a photographing lens; moving object discriminating means for discriminating on the basis of present and previous defocus amounts whether or not an object is moving; pursuit correction amount calculating means for calculating a pursuit correction amount for the moving object on the basis of the present and previous defocus amounts; lens drive means for, when said moving object discriminating means discriminates that the object is not moved, calculating a drive amount of said photographing lens on the basis of the present defocus amount and for, when said moving object discriminating means discriminates that the object is moving, calculating the drive amount of said photographing lens on the basis of a pursuit drive amount as a sum of the present defocus amount and the pursuit correction amount, so as to drive said photographing lens; and pursuit enable/disable determining means for determining whether said lens drive means calculates the drive amount of said photographing lens on the basis of the discrimination result of said moving object discriminating means or calculates the drive amount of said photographing lens on the basis of the present defocus amount, wherein when a drive direction of said photographing lens is reversed, said pursuit enableidisable determining means causes said lens drive means to calculate the drive amount of said photographing lens on the basis of the present defocus amount to drive said photographing lens in a predetermined number of times of drive operations after the reversal.
Claim 3
Dependent Claim
138 words
An automatic focusing apparatus which comprises focusing means for repetitively detecting a defocus amount of a photographing lens, calculates a change in defocus amount caused by movement of an object on the basis of previous and present defocus amounts, and corrects a drive amount of the lens on the basis of the calculated change, wherein a method of calculating a correction amount of a drive amount from the change is altered on the basis of one of: (1) an identification result indicating one of a state before full-depression of a release button, a state immediately after full-depression of the release button, and a state after a single mirror-up/down operation; (2) an identification result indicating a focal length of said photographing lens; and (3) an identification result indicating whether or not the object is coming closer or going away.
Claim 4
Dependent Claim
138 words
An automatic focusing apparatus which comprises focusing means for repetitively detecting a defocus amount of a photographing lens, calculates a change in defocus amount caused by movement of an object on the basis of previous and present defocus amounts, and corrects a drive amount of the lens on the basis of the calculated change, wherein a method of calculating a correction amount of a drive amount from the change is altered on the basis of one of: (1) an identification result indicating one of a state before full-depression of a release button, a state immediately after full-depression of the release button, and a state after a single mirror-up/down operation; (2) an identification result indicating a focal length of said photographing lens; and (3) an identification result indicating whether or not the object is coming closer or going away.
Claim 5
Dependent Claim
173 words
An automatic focusing apparatus according to claim 2, further comprising: pursuit correction amount calculating means for calculating the change in defocus amount caused by movement of the object during a defocus detection cycle as a pursuit defocus amount (PRED) and calculating a pursuit correction amount (COMP) from the pursuit defocus amount; and lens drive means for driving said photographing lens on the basis of a pursuit drive amount (DRIV) as a sum of a present defocus amount (DEF) and the pursuit correction amount (COMP), wherein said pursuit correction amount calculating means alters the method of calculating a correction amount of a drive amount from the change on the basis of one of: (1) the identification result indicating one of the state before full-depression of said release button, the state immediately after full-depression of the release button, and the state after the single mirror-up/down operation; (2) the identification result indicating a focal length of said photographing lens; and (3) the identification result indicating whether or not the object is coming closer or going away.
Claim 6
Dependent Claim
192 words
An automatic focusing apparatus comprising: focusing means for repetitively detecting a defocus amount of a photographing lens; moving object discriminating means for discriminating on the basis of present and previous defocus amounts whether or not an object is moving; pursuit correction amount calculating means for calculating a pursuit correction amount for the moving object on the basis of the present and previous defocus amounts; lens drive means for, when said moving object discriminating means discriminates that the object is not moved, driving said photographing lens on the basis of the present defocus amount and for, when said moving object discriminating means discriminates that the object is moving, driving said photographing lens on the basis of a pursuit drive amount as a sum of the present defocus amount and the pursuit correction amount; first display means for displaying a focusing state of said photographing lens using a first display member on the basis of the present defocus amount or the present and previous defocus amounts; and second display means for displaying an object moving state using a second display member on the basis of the discrimination result of said moving object discriminating means.
Claim 7
Dependent Claim
192 words
An automatic focusing apparatus comprising: focusing means for repetitively detecting a defocus amount of a photographing lens; moving object discriminating means for discriminating on the basis of present and previous defocus amounts whether or not an object is moving; pursuit correction amount calculating means for calculating a pursuit correction amount for the moving object on the basis of the present and previous defocus amounts; lens drive means for, when said moving object discriminating means discriminates that the object is not moved, driving said photographing lens on the basis of the present defocus amount and for, when said moving object discriminating means discriminates that the object is moving, driving said photographing lens on the basis of a pursuit drive amount as a sum of the present defocus amount and the pursuit correction amount; first display means for displaying a focusing state of said photographing lens using a first display member on the basis of the present defocus amount or the present and previous defocus amounts; and second display means for displaying an object moving state using a second display member on the basis of the discrimination result of said moving object discriminating means.
Claim 8
Dependent Claim
62 words
An apparatus according to claim 4, wherein said first and second display members are commonly used; when said moving object discriminating means discriminates that the object is not moved, a display is performed by only said first display means; and when said moving object discriminating means discriminates that the object is moving, a display is performed by only said second display means.
Claim 9
Dependent Claim
132 words
An automatic focusing apparatus comprising: focusing means for repetitively calculating a defocus amount corresponding to a difference between an image forming surface of a photographing lens and a prospective focal plane; acceleration information calculating means for calculating information associated with an acceleration of movement of an image surface with respect to the prospective focal plane upon movement of an object on the basis of the repetitively calculated defocus amounts; pursuit correction amount calculating means for calculating a pursuit correction amount for correcting a variation in defocus amount caused by movement of the object on the basis of the defocus amount and the information associated with the acceleration; and drive control means for controlling a drive operation of said photographing lens on the basis of the defocus amount and the pursuit correction amount.
Claim 10
Dependent Claim
132 words
An automatic focusing apparatus comprising: focusing means for repetitively calculating a defocus amount corresponding to a difference between an image forming surface of a photographing lens and a prospective focal plane; acceleration information calculating means for calculating information associated with an acceleration of movement of an image surface with respect to the prospective focal plane upon movement of an object on the basis of the repetitively calculated defocus amounts; pursuit correction amount calculating means for calculating a pursuit correction amount for correcting a variation in defocus amount caused by movement of the object on the basis of the defocus amount and the information associated with the acceleration; and drive control means for controlling a drive operation of said photographing lens on the basis of the defocus amount and the pursuit correction amount.
Claim 11
Dependent Claim
89 words
An automatic focusing apparatus having means for calculating the amount by which the focusing of a lens should be altered on the basis of a current detected amount indicative of a focusing error and of an alteration amount indicative of the way in which the focusing error has been found to be changing, to take into account changes in the distance between the lens and an object, characterised by means for causing the alteration amount to be temporarily disregarded when the direction of adjustment of the lens focusing reverses.
Claim 12
Dependent Claim
89 words
An automatic focusing apparatus having means for calculating the amount by which the focusing of a lens should be altered on the basis of a current detected amount indicative of a focusing error and of an alteration amount indicative of the way in which the focusing error has been found to be changing, to take into account changes in the distance between the lens and an object, characterised by means for causing the alteration amount to be temporarily disregarded when the direction of adjustment of the lens focusing reverses.
Claim 13
Dependent Claim
45 words
Apparatus as claimed in claim 2 or claim 3, including means for generating two or more of said identification results, wherein the focusing means is operable to alter the method of calculating the correction amount on the basis of said two or more identification results.
References Cited (Backward Citations)
US4445761A
Cited
US4702584A
Cited
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