EP0444952A2
Expired / Lapsed
EP
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Focus detecting apparatus
Assignee: Nikon Corp
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Filing: 1991-03-01
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Granted: —
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Expires: 2011-03-01
Abstract
Abstract In a focus detecting apparatus, comprising a focus detecting optical system (30) which leads two images created by the light passing through two different points of an objective lens (20) onto a pair of one-dimensional image sensor arrays (40), a dividing means (53) for dividing said pair of image sensor arrays (40) into small blocks to take out the image output from each block, a focus detection calculating means (54) for shifting, from each other, the image outputs obtained from said pair of image sensor arrays (40) to calculate the relative shift amount of said two images, and a modifying means (52) for changing the width of said blocks; a focus detecting apparatus comprising a deciding means (51) which decreases the width of said blocks through said modifying means (52) when it analyzes the space frequency component of said subject and determines that said subject includes a high-frequency component, or increases the width of said blocks when it determines that said subject includes a low-frequency component.
Inventors
- 👤 Shigeyuki Uchiyama
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 13:15
CPC Classifications
G; G02; G02B; G02B7/00; G02B7/28; G02B7/34; G02B7/346
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
156 words
In a focus detecting apparatus, comprising a focus detecting optical system 30 which leads two images created by the light passing through two different points of an objective lens onto a pair of the one-dimensional image sensor arrays; a dividing means for dividing said pair of image sensor arrays into small blocks to take out the image output from each block; a focus detection calculating means for relatively shifting the image outputs obtained from said pair of image sensor arrays to calculate the relative shift amount of said two images; and said modifying means for changing the width of said blocks; said focus detecting apparatus comprising the deciding means which decreases the width of said blocks through said modifying means when it analyzes the space frequency component of said subject and determines that said subject includes a high-frequency component, or increases the width of said blocks when it determines that said subject includes a low-frequency component.
Claim 2
Dependent Claim
22 words
The focus detecting apparatus according to claim 1, wherein two-dimensional image sensor arrays are used in place of said image sensor arrays.
Claim 3
Dependent Claim
85 words
The focus detecting apparatus according to claim 1, which comprises the decider that decides whether or not there are reliable relative shift amounts among the relative shift amounts of two images calculated by said focus detection calculating means, and the selecting means that selects a relative amount satisfying a certain requirement from the relative shift amounts that have been judged to be reliable, and which drives the objective lens to a focusing position in accordance with the relative shift amount selected by said selecting means.
Claim 4
Dependent Claim
73 words
The focus detecting apparatus according to claim 1, which analyzes the space frequency component of said subject, and, if it determines that there is a mixture of a low-frequency pattern and a high-frequency pattern in the focus detection area, increases the width of said block in the low-frequency pattern section or decreases the width of said block in the high-frequency pattern section, in order to perform the focus detecting calculation for each block.
Claim 5
Dependent Claim
168 words
In a focus detecting apparatus, comprising: a focus detecting optical system which have two pairs of one-dimensional image sensor arrays oriented in a plurality of directions to lead two images, which have a parallax with reference to a subject, onto the pair of image sensor arrays oriented in each direction; a dividing means for dividing said pairs of image snesor arrays into small blocks to take out the image output from each block; a focus detection calculating means for relatively shifting the image outputs obtained from said pairs of image sensor arrays to calculate the relative shift amount of said two images; and a modifying means for changing the width of said blocks; said focus detecting apparatus comprising a deciding means which decreases the width of said blocks through said modifying means when it analyzes the space frequency component of said subject and determines that said subject includes a high-frequency component, or increases the width of said blocks when it determines that said subject includes a low-frequency component.
Claim 6
Dependent Claim
21 words
The focus detecting apparatus according to claim 5, which uses two-dimensional image sensor arrays in place of said image sensor arrays.
Claim 7
Dependent Claim
85 words
The focus detecting apparatus according to claim 5, which comprises a decider that decides whether or not there are reliable relative shift amounts among the relative shift amounts of two images calculated by said focus detection calculating means, and a selecting means that selects a relative amount satisfying a certain requirement from the relative shift amounts that have been judged to be reliable, and which drives the objective lens to a focusing position in accordance with the relative shift amount selected by said selecting means.
Claim 8
Dependent Claim
73 words
The focus detecting apparatus according to claim 5, which analyzes the space frequency component of said subject, and, if it determines that there is a mixture of a low-frequency pattern and a high-frequency pattern in the focus detection area, increases the width of said block in the low-frequency pattern section or decreases the width of said block in the high-frequency pattern section, in order to perform the focus detecting calculation for each block.
Claim 9
Dependent Claim
100 words
A focus detecting apparatus having at least two arrays of image sensors, each array being arranged in use to receive a respective image of an object, means being provided to correlate signals representing respective portions of the image received by each array with signals representing respective portions of the image received by another array so as to determine whether a lens system forming said images is focussed on said object by determining the relative positions of said images, characterised by means responsive to the spatial frequency of the light from the object for controlling the sizes of said image portions.
Claim 10
Dependent Claim
25 words
Apparatus as claimed in claim 9, including means for calculating a defocus amount by interpolation of correlation result for a plurality of relative image positions.
Claim 11
Dependent Claim
27 words
A camera having a lens system and focus detecting apparatus as claimed in any preceding claim for determining whether the lens system is focussed on an object.
References Cited (Backward Citations)
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