Focus adjustment device and focus adjustment method

Patent metadata

Field	Value
Publication number	US-11627245-B2
Application number	US-202217687489-A
Country	US
Kind code	B2
Filing date	Mar 4, 2022
Priority date	Mar 9, 2021
Publication date	Apr 11, 2023
Grant date	Apr 11, 2023

Abstract

A focus adjustment device, comprising: a processor having a main physical object position detection circuit for detecting position of a main object based on an image signal, a distance value detection circuit for detecting distance values in accordance with object distance of a plurality of AF regions based on the image signal, a candidate region setting section for setting regions exhibiting a distance value for a close-range side of greater than a specific value, with respect to a statistic for distance value of regions corresponding to position of the main physical object, to unnecessary candidate regions, and a control section for determining regions corresponding to unnecessary physical objects based on the unnecessary candidate regions, and controlling focus adjustment based on distance value corresponding to regions that have had regions corresponding to the unnecessary physical objects excluded from the main physical object regions.

First claim

What is claimed is:

1. A focus adjustment device, having an image sensor that subjects light from a physical object that has passed through an optical system to photoelectric conversion and outputs an image signal, and that performs focus adjustment based on the image signal, comprising:
a main physical object position detection circuit for detecting position of a main physical object based on the image signal;
a distance value detection circuit for detecting distance values corresponding to object distance for a plurality of AF regions based on the image signal; and
a processor having a candidate region setting section for setting regions exhibiting a distance value for a close-range side of greater than a specific value, with respect to a statistical value for distance values of regions corresponding to position of the main physical object, to unnecessary candidate regions, and a control section for determining regions corresponding to unnecessary physical objects based on the unnecessary candidate regions, and controlling focus adjustment based on distance values corresponding to regions that have had regions corresponding to the unnecessary physical objects excluded from the main physical object regions,
wherein
the candidate region setting section sets first candidate regions within regions corresponding to the main physical object region, and second candidate regions within regions corresponding to regions other than the main physical object region, and
the control section determines regions corresponding to the unnecessary physical objects based on first distance values corresponding to the first candidate regions, and second distance values corresponding to the second candidate regions.

2. The focus adjustment device of claim 1 , wherein:
the control section determines the first candidate regions and the second candidate regions to be regions corresponding to the unnecessary physical objects, in the event that a difference between the first distance values and the second distance values is within a first specified range, and a ratio of area of the first candidate regions to area of the main physical object region is smaller than a second specified value.

3. The focus adjustment device of claim 1 , wherein:
the main physical object position detection circuit detects position of a first region that contains the entirety of a main physical object, and positions of second regions that contain parts of the main physical object;
the candidate region setting section sets third candidate regions within the second regions, and
the control section determines regions corresponding to the unnecessary physical objects based on the first distance values, the second distance values, and third distance values corresponding to the third candidate regions.

4. The focus adjustment device of claim 3 , wherein:
the control section determines the first candidate regions, the second candidate regions, and the third candidate regions to be regions corresponding to unnecessary physical objects when differences between the first distance values, the second distance values, and the third distance values are within a range of a third specified amount.

5. The focus adjustment device of claim 4 , wherein:
the control section further determines the first candidate regions, the second candidate regions, and the third candidate regions to be regions corresponding to the unnecessary physical objects, in the event that a ratio of area of the third candidate regions to area of the second region is smaller than a fourth specified amount.

6. The focus adjustment device of claim 1 , wherein:
the image sensor repeatedly images object light that has passed though the optical system at a specified frame rate, to output the image signal;
the main physical object position detection circuit detects position of a first region that contains the entirety of a main physical object, and positions of second regions that contain parts of the main physical object, for every frame, based on the image signal;
the distance value detection circuit detects distance values in accordance with object distance of a plurality of AF regions for every frame, based on the image signal;
the candidate region setting section sets regions that exhibit a closer distance than a distance value representing the closest distance, among distance values corresponding to the first region and the second region, in regions other than the first region and the second region, to unnecessary candidate regions; and
the control section determines regions corresponding to unnecessary physical objects based on the unnecessary candidate regions, and controls focus adjustment based on distance value corresponding to regions resulting from having excluded regions corresponding to the unnecessary physical object from the second regions,
wherein
in the event that unnecessary candidate regions are set across a plurality of frames, the control section determines that portions within second regions, that have a difference, between a difference in distance values corresponding to a first region of the newest frame and distance values corresponding to a first region of the previous frame, and a difference between distance values corresponding to a second region of the newest frame and distance values corresponding to second region of the previous frame, that is larger than a fifth specified amount, are regions corresponding to unnecessary physical objects.

7. The focus adjustment device of claim 1 , wherein:
the unnecessary candidate regions are made up of a plurality of AF regions.

8. A focus adjustment method, for a focus adjustment device, having an image sensor that subjects light from a physical object that has passed through an optical system to photoelectric conversion and outputs an image signal, and that performs focus adjustment based on the image signal, comprising:
detecting position of a main physical object based on the imaging signal;
detecting distance values corresponding to object distance for a plurality of AF regions based on the image signal;
setting regions exhibiting a distance value for a close-range side of greater than or equal to a specified amount, with respect to a statistical value of the distance values of regions corresponding to position of the main physical object, to unnecessary candidate regions;
determining regions corresponding to unnecessary physical objects based on the unnecessary candidate regions, and controlling focus adjustment based on distance value corresponding to regions resulting from having excluded regions corresponding to the unnecessary physical object from the main physical object region;
further, setting first candidate regions within regions corresponding to the main physical object region, and second candidate regions within regions corresponding to regions other than the main physical object region; and
determining regions corresponding to the unnecessary physical objects based on first distance values corresponding to the first candidate regions, and second distance values corresponding to the second candidate regions.

9. The focus adjustment method of claim 8 , further comprising:
determining the first candidate regions and the second candidate regions to be regions corresponding to the unnecessary physical objects, in the event that a difference between the first distance values and the second distance values is within a first specified range, and a ratio of area of the first candidate regions to area of the main physical object region is smaller than a second specified value.

10. The focus adjustment method of claim 8 , further comprising:
detecting position of a first region that contains the entirety of a main

Assignees

• Olympus Corp

Inventors

• Hoshino Tomohiro

Classifications

• H04N23/672 Primary

  based on the phase difference signals · CPC title

• G03B13/36

  Autofocus systems · CPC title

• H04N23/675 Primary

  comprising setting of focusing regions · CPC title

• H04N5/232127 Primary

  Electricity · mapped topic

• H04N5/232122

  Electricity · mapped topic