It is known that there are various biometric authentication techniques such as a face authentication technique, a fingerprint authentication technique, an iris authentication technique, a blood vessel authentication technique and the like.
In the face authentication technique, light is irradiated from a light source to obtain a face image, and a face image of an authentication target is obtained within a light irradiation region by a camera. Then, a face authentication process is performed on the obtained face image.
In this face authentication technique, a surrounding environment such as an environment illuminance or the like is an important factor to be considered in obtaining a face image used for face authentication.
In a conventional face authentication apparatus, an environment light illuminance is measured by an illuminance sensor, and light is irradiated by a light irradiation apparatus in a state where an illuminance is determined to be low when the environment light illuminance is low and to be high when the environment light illuminance is high.
However, power consumption is limited in an actual driving environment of the light source that irradiates light to obtain the face image. Therefore, even when the surrounding environment light illuminance is high, the increase in the illumination illuminance is limited, which results in a problem that a face image for face authentication may not be obtained.
Patent Document 1: Korean Patent Application Publication No. 10-2009-0012330.