# US 2021/0243376 A1 · Imaging device, endoscope apparatus, and operating method of imaging device

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- Number: US 2021/0243376 A1
- Document ID: US20210243376A1
- Status: Published application
- Kind: A1
- Application number: 17/237,432
- Filed: 2021-04-22
- Published: 2021-08-05
- Earliest claimed: 2018-11-06
- Assignees: Olympus Corporation
- Applicants: Olympus Corporation
- Inventors: Koichiro YOSHINO
- Web page: https://patentgrep.com/patent/US20210243376A1

## CPC

- H04N 23/55: Optical parts specially adapted for electronic image sensors; Mounting thereof
- A61B 1/00006: {of control signals}
- A61B 1/00009: {of image signals during a use of endoscope}
- A61B 1/00188: {with focusing or zooming features}
- A61B 1/045: Control thereof
- G02B 7/28: Systems for automatic generation of focusing signals
- G02B 7/38: measured at different points on the optical axis {, e.g. focussing on two or more planes and comparing image data}
- G02B 23/2423: {of the distal end}
- G02B 23/243: {Objectives for endoscopes}
- H04N 5/265: Mixing
- H04N 7/18: Closed-circuit television [CCTV] systems, i.e. systems in which the video signal is not broadcast
- H04N 23/60: Control of cameras or camera modules
- H04N 23/667: Camera operation mode switching, e.g. between still and video, sport and normal or high- and low-resolution modes
- H04N 23/673: {based on contrast or high frequency components of image signals, e.g. hill climbing method}
- H04N 23/80: Camera processing pipelines; Components thereof
- H04N 23/958: for extended depth of field imaging
- H04N 23/555: {for picking-up images in sites, inaccessible due to their dimensions or hazardous conditions, e.g. endoscopes or borescopes}
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS

## Abstract

An imaging device includes an objective optical system that includes a focus lens, an optical path splitter that splits an object image into a first optical image and a second optical image different from each other in in-focus object plane position, an image sensor that captures the first optical image to acquire a first image and the second optical image to acquire a second image, and a processor including hardware. The processor performs a combining process of generating a single combined image based on the first image and the second image, and an Auto Focus (AF) control. The processor operates in the AF control mode including a first AF control mode of performing the AF control by using a first AF evaluation value calculated from the first image and a second AF evaluation value calculated from the second image.

## Claims

### Claim 1

An imaging device comprising:
an objective optical system that includes a focus lens for adjusting an in-focus object plane position and acquires an object image;
an optical path splitter that splits the object image into a first optical image and a second optical image different from each other in the in-focus object plane position;
an image sensor that captures the first optical image to acquire a first image and the second optical image to acquire a second image; and
a processor including hardware,
the processor performing
a combining process of selecting an image with a relatively high contrast in predetermined corresponding areas between the first image and the second image to generate a single combined image, and
an Auto Focus (AF) control of operating in accordance with a given AF control mode to control a position of the focus lens to be a position determined to bring a target object into focus,
the processor operating in the AF control mode including a first AF control mode of performing the AF control by using a first AF evaluation value calculated from the first image and a second AF evaluation value calculated from the second image.

### Claim 2 (depends on 1)

The imaging device as defined in claim 1,
wherein the processor operates in the AF control mode including a second AF control mode of performing the AF control by using either of the first AF evaluation value or the second AF evaluation value.

### Claim 3 (depends on 2)

The imaging device as defined in claim 2,
wherein the processor performs switching control between the first AF control mode and the second AF control mode.

### Claim 4 (depends on 3)

The imaging device as defined in claim 3,
wherein the processor performs the switching control between the first AF control mode and the second AF control mode, based on:
a low contrast object determination process of determining whether or not the target object is a low contrast object with a lower contrast than a given reference, based on the first AF evaluation value and the second AF evaluation value; or
a largely out-of-focus determination process of determining whether or not a focusing degree of the target object is lower than a given reference, based on the first AF evaluation value and the second AF evaluation value.

### Claim 5 (depends on 1)

The imaging device as defined in claim 1,
wherein, in the first AF control mode, the processor discriminates an in-focus direction based on a relationship between the first AF evaluation value and the second AF evaluation value.

### Claim 6 (depends on 1)

The imaging device as defined in claim 1,
wherein, in the first AF control mode, the processor determines a drive amount of the focus lens based on a relationship between the first AF evaluation value and the second AF evaluation value.

### Claim 7 (depends on 1)

The imaging device as defined in claim 1,
wherein, in the first AF control mode, the processor determines whether or not a focusing operation has been completed based on a relationship between the first AF evaluation value and the second AF evaluation value.

### Claim 8 (depends on 2)

The imaging device as defined in claim 2,
wherein, in the second AF control mode, the processor controls the position of the focus lens to be a position determined to form the object image of the target object at a first position corresponding to the image sensor that acquires the first image, and thereafter controls the position of the focus lens to a position determined to move an image formation position of the object image by a predetermined amount in a direction toward a second position corresponding to the image sensor that acquires the second image.

### Claim 9 (depends on 2)

The imaging device as defined in claim 2,
wherein, in the first AF control mode, the processor controls the position of the focus lens to be between a position of the focus lens that maximizes the first AF evaluation value and a position of the focus lens that maximizes the second AF evaluation value.

### Claim 10

An endoscope apparatus comprising:
an objective optical system that includes a focus lens for adjusting an in-focus object plane position and acquires an object image;
an optical path splitter that splits the object image into a first optical image and a second optical image different from each other in the in-focus object plane position;
an image sensor that captures the first optical image to acquire a first image and the second optical image to acquire a second image; and
a processor including hardware,
the processor performing
a combining process of selecting an image with a relatively high contrast in predetermined corresponding areas between the first image and the second image to generate a single combined image, and
an Auto Focus (AF) control of operating in accordance with a given AF control mode to control a position of the focus lens to be a position determined to bring a target object into focus,
the processor operating in the AF control mode including a first AF control mode of performing the AF control by using a first AF evaluation value calculated from the first image and a second AF evaluation value calculated from the second image.

### Claim 11

An operation method of an imaging device, the imaging device including:
an objective optical system that includes a focus lens for adjusting an in-focus object plane position and acquires an object image;
an optical path splitter that splits the object image into a first optical image and a second optical image different from each other in the in-focus object plane position; and
an image sensor that captures the first optical image to acquire a first image and the second optical image to acquire a second image,
the method comprising:
a combining process of selecting an image with a relatively high contrast in predetermined corresponding areas between the first image and the second image to generate a single combined image; and
an Auto Focus (AF) control of operating in accordance with a given AF control mode to control a position of the focus lens to be a position determined to bring a target object into focus,
the AF control mode including a first AF control mode of performing the AF control by using a first AF evaluation value calculated from the first image and a second AF evaluation value calculated from the second image.