US-20260129293-A1 - FOCUS CONTROL DEVICE, FOCUS CONTROL METHOD, AND PROGRAM

US20260129293A1US 20260129293 A1US20260129293 A1US 20260129293A1US-20260129293-A1

Abstract

A focus control device according to the present disclosure includes a processor, in which the processor is configured to execute, in a case in which a portion of an imaging element corresponding to a specific region in a captured image is exposed, at least one of first control of making a focus driving speed constant or second control of limiting the focus driving speed to be equal to or less than a predetermined speed.

Inventors

Hideaki KOKUBUN

Assignees

FUJIFILM CORPORATION

Dates

Publication Date: 20260507
Application Date: 20250911
Priority Date: 20240927

Claims (13)

1 . A focus control device comprising: a processor, wherein the processor is configured to execute, in a case in which a portion of an imaging element corresponding to a specific region in a captured image is exposed, at least one of first control of making a focus driving speed constant or second control of limiting the focus driving speed to be equal to or less than a predetermined speed.
2 . The focus control device according to claim 1 , wherein the imaging element undergoes exposure using a rolling-shutter method.
3 . The focus control device according to claim 2 , wherein the imaging element undergoes the exposure a plurality of times in response to one imaging instruction.
4 . The focus control device according to claim 3 , wherein the processor is configured to perform focus driving over a period during which the exposure is performed the plurality of times.
5 . The focus control device according to claim 1 , wherein the processor is configured to acquire a focus driving amount, and execute the second control in a case in which a change amount of a depth of field corresponding to the acquired focus driving amount is greater than a predetermined value.
6 . The focus control device according to claim 5 , wherein the predetermined speed is a focus driving speed in a case in which focus driving is performed by a focus driving amount corresponding to the predetermined value.
7 . The focus control device according to claim 5 , wherein the imaging element includes a plurality of phase-difference detection pixels, and the processor is configured to calculate the focus driving amount based on a defocus amount obtained based on output values of the plurality of phase-difference detection pixels.
8 . The focus control device according to claim 1 , wherein the processor is configured to execute, in addition to the first control or the second control, third control of performing focus driving in a non-exposure period obtained by shifting an exposure timing.
9 . The focus control device according to claim 8 , wherein the processor is configured to perform, in the third control, the focus driving at a focus driving speed greater than the predetermined speed.
10 . The focus control device according to claim 1 , wherein the specific region is a focus target region.
11 . The focus control device according to claim 1 , wherein the specific region is a region including a specific subject.
12 . A focus control method executed by a processor, comprising: executing, in a case in which a portion of an imaging element corresponding to a specific region in a captured image is exposed, at least one of first control of making a focus driving speed constant or second control of limiting the focus driving speed to be equal to or less than a predetermined speed.
13 . A non-transitory computer-readable storage medium storing a program causing a processor to execute a process comprising: executing, in a case in which a portion of an imaging element corresponding to a specific region in a captured image is exposed, at least one of first control of making a focus driving speed constant or second control of limiting the focus driving speed to be equal to or less than a predetermined speed.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS The present application claims priority under 35 U.S.C. § 119 to Japanese Patent Application No. 2024-169518, filed on Sep. 27, 2024. The above application is hereby expressly incorporated by reference, in its entirety, into the present application. BACKGROUND 1. Technical Field The technology of the present disclosure relates to a focus control device, a focus control method, and a program. 2. Description of the Related Art A focus control device disclosed in JP2006-243527A has a sequence of setting a partial region in one imaging screen as a detection region, obtaining an evaluation value by performing detection only for an exposure period corresponding to the detection region from a CMOS sensor exposed by a rolling-shutter method, and moving a focus lens to a lens position for acquiring a next evaluation value sample. In this case, since the detection region is the partial region of one imaging screen, it is possible to ensure a long time for a pause period for each detection period for every two horizontal synchronization periods. By setting a timing to move the focus lens in this pause period, it is possible to execute the evaluation value acquisition and the focus lens movement at the timing for each horizontal synchronization period. An imaging system disclosed in JP2009-516448A acquires an image sequence comprising at least two images in which at least one image is used as a measurement image and at least one image is used as a final image, and determines an exposure time for the measurement image and an exposure time for the final image. A non-exposure time can be determined from the exposure time for the measurement image and the exposure time for the final image. As a result, an imaging optical system can be adjusted during the non-exposure time. An imaging device disclosed in JP2013-106113A is an imaging device including an imaging unit having a focus lens with a variable focal length, an exposure controller that realizes a plurality of imaging operations with different sensitivities, a camera signal processing unit that generates a video signal and a focal point evaluation value indicating a degree of focusing, a video synthesis unit that synthesizes a plurality of video signals with different sensitivities generated by the camera signal processing unit and outputs the synthesized video signal, and a focus controller that controls the focus lens of the imaging unit based on the focal point evaluation value output by the camera signal processing unit, to adjust the focal length, in which the camera signal processing unit generates the focal point evaluation value for each of a plurality of imaging signals with different sensitivities output by the imaging unit, and the focus controller controls the focus lens based on the focal point evaluation value corresponding to each of the plurality of imaging operations with different sensitivities of the imaging unit. SUMMARY The technology of the present disclosure provides a focus control device, a focus control method, and a program that can suppress image quality deterioration due to focus driving in a case in which a plurality of imaging operations are continuously performed. In order to achieve the above-described object, the present disclosure provides a focus control device comprising: a processor, in which the processor is configured to execute, in a case in which a portion of an imaging element corresponding to a specific region in a captured image is exposed, at least one of first control of making a focus driving speed constant or second control of limiting the focus driving speed to be equal to or less than a predetermined speed. It is preferable that the imaging element undergo exposure using a rolling-shutter method. It is preferable that the imaging element undergo the exposure a plurality of times in response to one imaging instruction. It is preferable that the processor be configured to perform focus driving over a period during which the exposure is performed the plurality of times. It is preferable that the processor be configured to acquire a focus driving amount, and execute the second control in a case in which a change amount of a depth of field corresponding to the acquired focus driving amount is greater than a predetermined value. It is preferable that the predetermined speed be a focus driving speed in a case in which focus driving is performed by a focus driving amount corresponding to the predetermined value. It is preferable that the imaging element include a plurality of phase-difference detection pixels, and the processor be configured to calculate the focus driving amount based on a defocus amount obtained based on output values of the plurality of phase-difference detection pixels. It is preferable that the processor be configured to execute, in addition to the first control or the second control, third control of performing focus driving in a non-exposure period obtained by shif