Imaging device having autofocus capability
Herein disclosed is an imaging device having an imaging optical system, the device including: an imaging element configured to include a plurality of first pixels and a plurality of second pixels arranged along a predetermined direction; a first processor configured to execute focal detection processing by a phase difference detection system based on charge signals obtained from the plurality of second pixels; and a second processor configured to execute specific processing based on charge signals obtained from the plurality of first pixels, the specific processing being different from the focal detection processing by a phase difference detection system and being necessary for a function of the imaging device.
1. An imaging device, comprising:
an imager configured to:
generate an image signal of a subject; and
determine an in-focus position of a focus lens based on a contrast focus evaluation value and a phase difference focus defocus value,
wherein the contrast focus evaluation value is determined based on a contrast auto focus (AF) method from a first part of the image signal read from a normal pixel of the imager, and the phase difference focus defocus value is determined based on a phase difference AF method from a second part of the image signal read from a phase difference pixel of the imager; and
at least one processor configured to drive the focus lens to the in-focus position that corresponds to a peak focus evaluation value among a plurality of focus evaluation values,
wherein the focus lens is driven based on a determination that a ratio of the peak focus evaluation value to a previous focus evaluation value, prior to the peak focus evaluation value, is within a range of values.
2. The imaging device according to claim 1 , wherein the peak focus evaluation value is highest among the plurality of focus evaluation values.
3. The imaging device according to claim 1 , wherein
the normal pixel comprises a first color filter and the phase difference pixel comprises a second color filter, and
the first color filter and the second color filter are of same color.
4. The imaging device according to claim 1 , wherein the normal pixel and the phase difference pixel are along a same direction.
5. A method, comprising:
in an imaging device:
generating, by an imager, an image signal of a subject;
determining, by the imager, an in-focus position of a focus lens based on a contrast focus evaluation value and a phase difference focus defocus value,
wherein the contrast focus evaluation value is determined based on a contrast auto focus (AF) method from a first part of the image signal read from a normal pixel of the imager, and the phase difference focus defocus value is determined based on a phase difference AF method from a second part of the image signal read from a phase difference pixel of the imager; and
driving, by at least one processor, the focus lens to the in-focus position that corresponds to a peak focus evaluation value among a plurality of focus evaluation values,
wherein the focus lens is driven based on determination that a ratio of the peak focus evaluation value to a previous focus evaluation value, prior to the peak focus evaluation value is within a range of values.
6. The method according to claim 5 , wherein the peak focus evaluation value is highest among the plurality of focus evaluation values.
7. The method according to claim 5 ,
wherein the normal pixel comprises a first color filter and the phase difference pixel comprises a second color filter, and
the first color filter and the second color filter are of same color.
8. The method according to claim 5 , wherein the normal pixel and the phase difference pixel are along a same direction.
9. A non-transitory computer-readable medium having stored thereon, computer-executable instructions, which when executed by a computer, cause the computer to execute operations, the operations comprising:
generating an image signal of a subject;
determining an in-focus position of a focus lens based on a contrast focus evaluation value and a phase difference focus defocus value,
wherein the contrast focus evaluation value is determined based on a contrast auto focus (AF) method from a first part of the image signal read from a normal pixel of an imager, and
the phase difference focus defocus value is determined based on a phase difference AF method from a second part of the image signal read from a phase difference pixel of the imager; and
driving the focus lens to the in-focus position that corresponds to a peak focus evaluation value among a plurality of focus evaluation values,
wherein the focus lens is driven based on determination that a ratio of the peak focus evaluation value to a previous focus evaluation value, prior to the peak focus evaluation value is within a range of values.
10. The non-transitory computer-readable medium according to claim 9 , wherein the peak focus evaluation value is highest among the plurality of focus evaluation values.
11. The non-transitory computer-readable medium according to claim 9 ,
wherein the normal pixel comprises a first color filter and the phase difference pixel comprises a second color filter, and
the first color filter and the second color filter are of same color.
12. The non-transitory computer-readable medium according to claim 9 , wherein the normal pixel and the phase difference pixel are along a same direction.