Imaging device, endoscope apparatus, and operating method of imaging device

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.

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.