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CN-122029468-A - Image pickup apparatus

CN122029468ACN 122029468 ACN122029468 ACN 122029468ACN-122029468-A

Abstract

The imaging device includes an imaging unit having a first pixel that photoelectrically converts light transmitted through an optical system and outputs a signal for use in focus detection, and a second pixel that photoelectrically converts light transmitted through the optical system and outputs a signal for use in image generation, a focus detection unit that performs focus detection of the optical system based on the signal output from the first pixel, an evaluation unit that evaluates a contrast of an image of an area including an object within the image based on the signal output from the second pixel, and a control unit that controls focus detection of the focus detection unit based on the evaluation by the evaluation unit.

Inventors

  • YAMAMURA HIROAKI
  • OHTA ATSUYA
  • Ruogu Yongwu

Assignees

  • 株式会社尼康

Dates

Publication Date
20260512
Application Date
20240924
Priority Date
20231002

Claims (14)

  1. 1. An imaging device is provided with: An imaging unit having a first pixel that photoelectrically converts light transmitted through an optical system and outputs a signal for focus detection, and a second pixel that photoelectrically converts light transmitted through the optical system and outputs a signal for image generation; A focus detection unit that performs focus detection of the optical system based on a signal output from the first pixel; An evaluation unit that evaluates a contrast of an image based on a signal output from the second pixel in a region including an object within the image based on the signal output from the second pixel, and And a control unit that controls focus detection by the focus detection unit based on the evaluation by the evaluation unit.
  2. 2. The photographing apparatus according to claim 1, The control unit controls whether or not to perform focus detection by the focus detection unit based on the evaluation by the evaluation unit.
  3. 3. The photographing device according to claim 1 or 2, Comprises an object detection unit for detecting an object from the image, The control unit performs focus detection by the focus detection unit when the subject detection unit detects a subject.
  4. 4. A photographing apparatus according to claim 3, The evaluation unit evaluates the contrast of the image in the region when the subject detection unit detects the subject, and performs focus detection by the focus detection unit.
  5. 5. The photographing device according to claim 3 or 4, The control unit does not perform focus detection by the focus detection unit when the subject detection unit does not detect the subject.
  6. 6. The photographing device according to any of claims 1 to 5, The control unit performs focus detection by the focus detection unit when the evaluation by the evaluation unit indicates a state in which the subject is not focused.
  7. 7. The photographing device according to any of claims 1 to 6, The focus detection unit performs first focus detection of the optical system in a first region of a photographing surface of the photographing unit, performs second focus detection of the optical system in a second region including the first region and larger than the first region, The control unit controls which focus detection of the first focus detection and the second focus detection is performed based on the evaluation by the evaluation unit.
  8. 8. The photographing apparatus according to claim 7, The focus detection section detects a first amount of shift between an image plane of the optical system in the region and a photographing surface of the photographing section as the first focus detection, detects a second amount of shift between an image plane of the optical system in the second region and a photographing surface of the photographing section as the second focus detection, The evaluation unit calculates a first evaluation value regarding the contrast of the image in a third region including the center of the region, and a second evaluation value regarding the contrast of the image in a fourth region surrounding the third region.
  9. 9. The photographing apparatus according to claim 8, The control unit performs the second focus detection when a relationship between the first evaluation value and the second evaluation value indicates a state in which the subject is not focused.
  10. 10. The photographing device according to claim 8 or 9, The control unit performs the second focus detection when the relationship between the first evaluation value and the second evaluation value indicates a state of not focusing on the subject and the second offset amount in the second region corresponding to the first portion of the subject is a value indicating closest.
  11. 11. The photographing device according to any of the claims 8 to 10, The control unit performs the second focus detection when the second shift amount in each of the adjacent second areas is a value indicating the closest, and the second shift amount indicating the closest is detected a predetermined number or more of times in a detection history of a plurality of times of the second shift amount, in a case where the subject cannot be detected in the image.
  12. 12. The photographing device according to any of the claims 8 to 11, The image processing apparatus includes a calculating unit that calculates a degree of reliability that an object in the image is a predetermined object specified in advance, The control unit changes the position of the optical system to a position on the nearest side when the reliability is smaller than a threshold value and the relationship between the first evaluation value and the second evaluation value indicates a state in which the subject is not focused.
  13. 13. The photographing device according to any of the claims 8 to 12, The focus detection section detects the first shift amount in each of a plurality of first areas in a preset area including the plurality of first areas, The evaluation unit calculates an evaluation value concerning the contrast of an image in each of a plurality of first regions, The control unit changes a position of the optical system or changes an aperture diameter of the diaphragm based on the first offsets and the evaluation values in the plurality of first areas.
  14. 14. The photographing apparatus according to claim 13, When the first offset amount in each of the plurality of first regions is within a predetermined range indicating a vicinity of focusing and the evaluation value of a part of the first regions of the plurality of first regions is smaller than the evaluation value of the other part of the first regions of the plurality of first regions by a predetermined value or more, the position of the optical system is changed to a nearest position or the aperture diameter of the diaphragm is reduced.

Description

Image pickup apparatus Technical Field The present disclosure relates to a photographing apparatus. Background Various methods have been proposed for focusing on a desired subject (for example, patent document 1). Conventionally, improvement in focusing accuracy has been demanded. Prior art literature Patent literature Patent document 1 Japanese patent application laid-open No. 2014-132321 Disclosure of Invention According to the disclosed embodiment, an imaging device includes an imaging unit having a first pixel that photoelectrically converts light transmitted through an optical system and outputs a signal for focus detection, and a second pixel that photoelectrically converts light transmitted through the optical system and outputs a signal for image generation, a focus detection unit that performs focus detection of the optical system based on the signal output from the first pixel, an evaluation unit that evaluates a contrast of an image of an object in an image including the image based on the signal output from the second pixel, and a control unit that controls focus detection of the focus detection unit based on the evaluation by the evaluation unit. The structure of the embodiment described below may be modified as appropriate, and at least a part of the structure may be replaced with another structure. Further, the configuration elements not particularly limited to the configuration thereof are not limited to the configuration disclosed in the embodiment, and may be arranged in a position where the functions thereof can be realized. Drawings Fig. 1 is a diagram showing an example of the configuration of an imaging device according to one embodiment. Fig. 2 (a) is a diagram showing a first focus detection area of the imaging surface of the imaging element, and fig. 2 (B) is a diagram showing a second focus detection area of the imaging surface of the imaging element. Fig. 3 is a diagram showing an example of the arrangement of pixels in the first focus detection area and the second focus detection area. Fig. 4 (a) to 4 (C) are diagrams for explaining a configuration example of a focus detection pixel and an imaging pixel provided in a pixel section. Fig. 5 is a diagram showing an image generated based on a signal from a shooting pixel and an image showing that an object detected by an object detection section is superimposed as an AF frame to be focused. Fig. 6 is a flowchart (one of them) showing an example of processing performed by the body control unit according to the present embodiment. Fig. 7 is a flowchart showing an example of processing performed by the body control unit according to the present embodiment (second example). Fig. 8 is a flowchart showing an example of processing performed by the body control unit according to the present embodiment (third). Fig. 9 (a) to 9 (D) are diagrams for explaining the contrast evaluation value calculated by the second focus detection unit. Fig. 10 (a) to 10 (D) are diagrams for explaining a relationship between a focus state on an object and a contrast evaluation value. Fig. 11 (a) is a diagram showing an image generated based on a signal from a photographing pixel, a first focus detection area, and an AF frame showing an object detected by an object detection unit as a focusing object superimposed, and fig. 11 (B) is a diagram showing an image generated based on a signal from a photographing pixel, a second focus detection area, and an AF frame showing an object detected by an object detection unit as a focusing object superimposed. Fig. 12 (a) is a diagram showing an example of the position of a focus lens (focus lens) obtained when the scanning operation is performed and the reliability of the subject detected by the subject detection unit as a predetermined subject, fig. 12 (B) is a diagram showing an image generated based on a signal output from the imaging pixel when the focus lens is at the position P1 of fig. 12 (a), and fig. 12 (C) is a diagram showing the distribution of the contrast evaluation value of the region including the subject in the image shown in fig. 12 (B). Fig. 13 (a) is a diagram showing an image generated based on a signal from a shooting pixel and an AF frame, fig. 13 (B) is a diagram showing an example of defocus amounts in the respective first focus detection areas in the AF frame, and fig. 13 (C) is a diagram showing an example of contrast evaluation values in the respective first focus detection areas in the AF frame. Detailed Description Hereinafter, an electronic camera 1 (hereinafter referred to as a camera 1) as an example of an imaging device according to an embodiment will be described with reference to fig. 1 to 13. Fig. 1 is a diagram showing a configuration example of an electronic camera 1 (hereinafter referred to as a camera 1) according to one embodiment. The camera 1 includes a camera body (camera body) 2 and an interchangeable lens 3. Since the camera 1 includes the camera body 2 and the interchangeable