Image processing device, imaging device, and imaging method

An imaging device, comprising:

• an image processing device that includes:
• an image sensor configured to output an image signal of a subject;
• an infrared light irradiation unit configured to irradiate the subject with infrared light;
• an exposure control unit configured to:
• control timing from exposure start to exposure stop of the image sensor;
• and
• alternately repeat a first frame in which an exposure time is set to a first exposure time and a second frame in which the exposure time is set to a second exposure time longer than the first exposure time, wherein
• a difference between a time of start of the second frame and a reset time in the second frame, is smaller than a difference between a time of start of the first frame and a reset time in the first frame;
• an infrared light irradiation control unit configured to control the infrared light irradiation unit to irradiate the subject with the infrared light in an infrared light irradiation period, wherein the infrared light irradiation period is one of shorter than or equal to an aggregate period of the first frame and the second frame;
• an image signal acquisition unit configured to acquire a first image signal which is an image signal in the first frame, and a second image signal which is an image signal in the second frame;
• an extraction unit configured to extract a visible light intensity per unit time and an infrared light intensity per unit time from the first image signal and the second image signal;
• and
• a generation unit configured to generate an image signal corresponding to visible light and an image signal corresponding to the infrared light based on the extracted visible light intensity per unit time and the extracted infrared light intensity per unit time.

An imaging method, comprising:

• controlling timing from exposure start to exposure stop of an image sensor which outputs an image signal of a subject;
• alternately repeating a first frame in which an exposure time is set to a first exposure time and a second frame in which the exposure time is set to a second exposure time longer than the first exposure time, wherein
• a difference between a time of start of the second frame and a reset time in the second frame, is smaller than a difference between a time of start of the first frame and a reset time in the first frame;
• irradiating the subject with infrared light in an infrared light irradiation period, wherein the infrared light irradiation period is one of shorter than or equal to an aggregate period of the first frame and the second frame;
• acquiring a first image signal which is an image signal in the first frame, and a second image signal which is an image signal in the second frame;
• extracting a visible light intensity per unit time and an infrared light intensity per unit time from the first image signal and the second image signal;
• and
• generating an image signal corresponding to visible light and an image signal corresponding to the infrared light based on the extracted visible light intensity per unit time and the extracted infrared light intensity per unit time.