Focus detection device and image-capturing apparatus

Patent metadata

Field	Value
Publication number	US-2016277669-A1
Application number	US-201615165586-A
Country	US
Kind code	A1
Filing date	May 26, 2016
Priority date	Aug 21, 2012
Publication date	Sep 22, 2016
Grant date	—

Abstract

A focus detection device includes: a plurality of first pixels having first color filters, via which a pair of first signals, to be used for split-pupil phase detection, are output; a plurality of second pixels having second color filters, via which a pair of second signals, to be used for the split-pupil phase detection, are output; a phase difference detection unit that detects a phase difference manifested by the first signals or a phase difference manifested by the second signals; and a defocus amount calculation unit that calculates a defocus amount by using a first conversion coefficient corresponding to the first color when the phase difference detection unit has detected the phase difference manifested by the first signals and by using a second conversion coefficient corresponding to the second color when the phase difference detection unit has detected the phase difference manifested by the second signals.

First claim

1 . A focus detection device, comprising:
a plurality of first pixels having first color filters corresponding to a first color disposed thereat, via which a pair of first signals, to be used for split-pupil phase detection, are output; a plurality of second pixels having second color filters corresponding to a second color disposed thereat, via which a pair of second signals, to be used for the split-pupil phase detection, are output; a phase difference detection unit that detects a phase difference manifested by the first signals or a phase difference manifested by the second signals; and a defocus amount calculation unit that calculates a defocus amount by using a first conversion coefficient corresponding to the first color when the phase difference detection unit has detected the phase difference manifested by the first signals and by using a second conversion coefficient corresponding to the second color when the phase difference detection unit has detected the phase difference manifested by the second signals.

2 . A focus detection device according to claim 1 , wherein:
the first color is a color among red color, green color and blue color; the second color is either of remaining two colors among the red color, the green color and the blue color; the first conversion coefficient and the second conversion coefficient are each a conversion coefficient among a conversion coefficient corresponding to the red color, a conversion coefficient corresponding to the green color and a conversion coefficient corresponding to the blue color; and the conversion coefficient corresponding to the red color is greater than the conversion coefficient corresponding to the green color, and the conversion coefficient corresponding to the green color is greater than the conversion coefficient corresponding to the blue color.

3 . A focus detection device according to claim 1 , further comprising:
a selection unit that selects a pair of signals, which are either the first signals or the second signals, that satisfy a predetermined condition, wherein: the phase difference detection unit detects the phase difference manifested by one pair of signals satisfying the predetermined condition, having been selected by the selection unit.

4 . A focus detection device according to claim 3 , further comprising:
a contrast calculation unit that calculates a plurality of contrast values each indicating contrast in the first signals or the second signals, wherein: the pair of signals that satisfy the predetermined condition are either the first signals or the second signals that correspond to a contrast value, among the plurality of contrast values, taking a greatest value.

5 . A focus detection device according to claim 3 , further comprising:
a light source color detection sensor that estimates a light source color, wherein: the pair of signals that satisfy the predetermined condition are either the first signals or the second signals that correspond to the light source color estimated by the light source color detection sensor.

6 . A focus detection device according to claim 3 , further comprising:
a plurality of image-capturing pixels disposed around the plurality of first pixels and the plurality of second pixels, which include a plurality of first image-capturing pixels having the first color filters disposed thereat and a plurality of second image-capturing pixels having the second color filters disposed thereat, wherein: when outputs of a plurality of imaging signals provided from the plurality of first image-capturing pixels, among outputs of a plurality of imaging signals provided from the plurality of image-capturing pixels, are greatest, the pair of signals that satisfy the predetermined condition are the first signals.

7 . A focus detection device according to claim 3 , further comprising:
a read unit that reads out a specific color from an optical system at which an optical system color filter corresponding to the specific color is mounted, wherein: the pair of signals that satisfy the predetermined condition are either the first signals or the second signals that correspond to the specific color.

8 . A focus detection device according to claim 1 , further comprising:
an offset quantity setting unit that sets a first offset quantity corresponding to the first color and a second offset quantity corresponding to the second color, wherein: when the phase difference detection unit has detected the phase difference manifested by the first signals, the defocus amount calculation unit calculates the defocus amount by adding the first offset quantity to a product of the first conversion coefficient multiplied by the phase difference, and when the phase difference detection unit has detected the phase difference manifested by the second signals, the defocus amount calculation unit calculates the defocus amount by adding the second offset quantity to a product of the second conversion coefficient multiplied by the phase difference.

9 . A focus detection device according to claim 1 , further comprising:
a plurality of third pixels having third color filters corresponding to a third color disposed thereat, which output a pair of third signals to be used for split-pupil phase detection, wherein: the phase difference detection unit detects a phase difference among the phase difference manifested by the first signals, the phase difference manifested by the second signals and a phase difference manifested by the third signals; when the phase difference detection unit has detected the phase difference manifested by the first signals, the defocus amount calculation unit calculates the defocus amount by multiplying the first conversion coefficient by the phase difference, when the phase difference detection unit has detected the phase difference manifested by the second signals, the defocus amount calculation unit calculates the defocus amount by multiplying the second conversion coefficient by the phase difference, and when the phase difference detection unit has detected the phase difference manifested by the third signals, the defocus amount calculation unit calculates the defocus amount by multiplying a third conversion coefficient corresponding to the third color by the phase difference; the first color, the second color and the third color are each a color among the red color, the green color and the blue color; and the first conversion coefficient, the second conversion coefficient and the third conversion coefficient are each a conversion coefficient among a conversion coefficient corresponding to the red color, a conversion coefficient corresponding to the green color and a conversion coefficient corresponding to the blue color.

10 . A focus detection device according to claim 1 , wherein:
a focus detection pixel row that includes the plurality of first pixels and the plurality of second pixels disposed thereat and a focus detection pixel row that includes the plurality of second pixels and the plurality of third pixels disposed thereat are set adjacent to each other.

11 . A focus detection device according to claim 1 , further comprising:
a selecting unit that selects a focus detection position that is either a first focus detection position in correspondence to which a plurality of first focus detection pixel rows are disposed or a second focus detection position in correspondence to which a plurality of second focus detection pixel rows are disposed, wherein: once the selecting unit selects the first focus detection position as the focus detection position, the phase difference detection unit detects the phase difference based upon the first signals and the second signals respectivel

Assignees

• Nikon Corp

Inventors

• Kusaka Yosuke

Classifications

• H04N25/134

  based on three different wavelength filter elements · CPC title

• H04N25/70

  SSIS architectures; Circuits associated therewith · CPC title

• H04N25/704

  Pixels specially adapted for focusing, e.g. phase difference pixel sets · CPC title

• H04N23/673

  based on contrast or high frequency components of image signals, e.g. hill climbing method · CPC title

• H04N23/672 Primary

  based on the phase difference signals · CPC title