Imaging device, imaging device control method and program

An imaging device comprising:

• an imaging element that receives light from a subject and converts the light to an electrical signal;
• an infrared cut filter which is detachably provided on an optical path that connects the subject and the imaging element, and which removes an infrared region of light entering the imaging element;
• an infrared irradiation portion that irradiates infrared light onto the subject;
• a gain control portion that controls a gain such that an image has a target brightness, based on an amount of incident light entering the imaging element;
• and
• a control portion which switches between a day mode, in which image capture is performed while the infrared cut filter is placed on the optical path, and a night mode, in which image capture is performed while the infrared cut filter is removed from the optical path, and which, immediately after shifting from the day mode to the night mode, increases an irradiation intensity of the infrared irradiation portion from zero while the gain is maintained at a first gain value, as the amount of the incident light decreases in the night mode, and which increases the gain from the first gain value when the amount of the incident light further decreases after the irradiation intensity reaches a maximum,
• wherein, in the night mode, as the amount of the incident light increases, the control portion decreases the gain while the irradiation intensity of the infrared irradiation portion is maintained at the maximum, and when the amount of the incident light further increases after the gain reaches the first gain value, the control portion decreases the irradiation intensity from the maximum to zero while the gain is maintained at the first gain value.

An imaging device comprising:

• an imaging element that receives light from a subject and converts the light to an electrical signal;
• an infrared cut filter which is detachably provided on an optical path that connects the subject and the imaging element, and which removes an infrared region of light entering the imaging element;
• an infrared irradiation portion that irradiates infrared light onto the subject;
• a gain control portion that controls a gain such that an image has a target brightness, based on an amount of incident light entering the imaging element;
• and
• a control portion which switches between a day mode, in which image capture is performed while the infrared cut filter is placed on the optical path, and a night mode, in which image capture is performed while the infrared cut filter is removed from the optical path, and which, immediately after shifting from the day mode to the night mode, increases an irradiation intensity of the infrared irradiation portion from zero while the gain is maintained at a first gain value, as the amount of the incident light decreases in the night mode, and which increases the gain from the first gain value when the amount of the incident light further decreases after the irradiation intensity reaches a maximum,
• wherein the control portion switches from the day mode to the night mode if two conditions are satisfied, the two conditions being that the gain is saturated and that the amount of the incident light is smaller than a value determined in advance.

An imaging device comprising:

• an imaging element that receives light from a subject and converts the light to an electrical signal;
• an infrared cut filter which is detachably provided on an optical path that connects the subject and the imaging element, and which removes an infrared region of light entering the imaging element;
• an infrared irradiation portion that irradiates infrared light onto the subject;
• a gain control portion that controls a gain such that an image has a target brightness, based on an amount of incident light entering the imaging element;
• and
• a control portion which switches between a day mode, in which image capture is performed while the infrared cut filter is placed on the optical path, and a night mode, in which image capture is performed while the infrared cut filter is removed from the optical path, and which, immediately after shifting from the day mode to the night mode, increases an irradiation intensity of the infrared irradiation portion from zero while the gain is maintained at a first gain value, as the amount of the incident light decreases in the night mode, and which increases the gain from the first gain value when the amount of the incident light further decreases after the irradiation intensity reaches a maximum,
• wherein the control portion switches from the night mode to the day mode when the gain decreases and becomes smaller than a value obtained by subtracting hysteresis from the first gain value.

An imaging device control method comprising:

• in an imaging device comprising an imaging element that receives light from a subject:
• switching between a day mode in which image capture is performed while an infrared cut filter, which removes an infrared region of light entering the imaging element, is placed on an optical path that connects the imaging element and the subject, and a night mode in which image capture is performed while the infrared cut filter is removed from the optical path;
• increasing from zero, immediately after shifting from the day mode to the night mode, an irradiation intensity of an infrared irradiation portion that irradiates infrared light onto the subject while a gain is maintained at a first gain value, the gain controlling brightness of an image based on an amount of the incident light;
• and
• increasing the gain from the first gain value when the amount of the incident light decreases after the irradiation intensity reaches a maximum value,
• wherein a mode of image capture is switched from the night mode to the day mode when the gain decreases and becomes smaller than a value obtained by subtracting hysteresis from the first gain value.

A non-transitory computer readable medium having stored thereon a program having instructions being executable by a computer for causing the computer to perform steps comprising:

• in an imaging device:
• switching between a day mode in which image capture is performed while an infrared cut filter, which removes an infrared region of light entering the imaging element, is placed on an optical path that connects an imaging element and the subject, and a night mode in which image capture is performed while the infrared cut filter is removed from the optical path;
• increasing from zero, immediately after shifting from the day mode to the night mode, an irradiation intensity of an infrared irradiation portion that irradiates infrared light onto the subject while a gain is maintained at a first gain value, the gain controlling brightness of an image based on an amount of the incident light;
• and
• increasing the gain from the first gain value when the amount of the incident light decreases after the irradiation intensity reaches a maximum value,
• wherein a mode of image capture is switched from the night mode to the day mode when the gain decreases and becomes smaller than a value obtained by subtracting hysteresis from the first gain value.