A driver's appearance recognition system comprises: a camera to capture a
driver's face image; a near infrared ray LED to radiate near infrared ray
to the driver's face; an LED current control circuit to control the
amount of current supplied to the near infrared ray LED; and an image
processing circuit to execute an individual authentication process and a
closed-eye detection process. When the individual authentication process
is executed, it is necessary to increase the illumination intensity
during image capture by the camera. For this purpose, a setup current
value for the LED current control circuit is set to a high current value.
When the closed-eye detection process is executed, the illumination
intensity needs to be ensured as much as required for the closed-eye
detection process. For this purpose, a setup current value is set to a
current value lower than that used for execution of the individual
authentication process.