On-board infrared illumination device

An on-board infrared illumination device, comprising:

• an infrared light source that provides for-camera infrared illumination by irradiating, with infrared radiation, a plurality of irradiation areas included in an imaging range of an on-board infrared camera within an exposure time of the on-board infrared camera;
• a light source controller configured to control the infrared light source to form a plurality of irradiation patterns at a timing different from a timing for the for-camera infrared illumination, the plurality of irradiation patterns each being formed such that one or more different irradiation areas among the plurality of irradiation areas are selectively irradiated with the infrared radiation;
• and
• an infrared sensor that is disposed so as to receive infrared radiation reflected at the imaging range and outputs a sensor signal that is based on an intensity of the received infrared radiation, wherein
• the light source controller is further configured to control the infrared light source to adjust an illuminance of the for-camera infrared illumination on each irradiation area independently of each other on the basis of the sensor signal output from the infrared sensor for each of the plurality of irradiation patterns.