Biometric authentication device

A biometric authentication device comprising:

• an infrared luminescent unit configured to emit infrared light with an infrared wavelength;
• a depth sensing unit configured to receive the infrared light reflected on a vein of an object placed within a preset distance of the depth sensing unit;
• and
• a controller configured to:
• control the depth sensing unit to obtain a first vein image of a first object and calculate a first distance value corresponding to a first distance between the depth sensing unit and the first object, and
• store the first vein image and the first distance value in a memory as registration information,
• wherein the controller is further configured to:
• control the depth sensing unit to obtain a second vein image of the first object and calculate a second distance value corresponding to a second distance different than the first distance between the depth sensing unit and the first object, and
• store the second vein image and the second distance value of the first object in the memory as the registration information, and
• wherein the controller is further configured to:
• control the depth sensing unit to obtain a vein image of a second object and calculate a distance value corresponding to a distance between the depth sensing unit and the second object,
• calculate a matching rate by comparing the vein image of the second object with the first vein image of the first object when the distance value of the second object is closer to the first distance value of the first object, and comparing the vein image of the second object with the second vein image of the first object when the distance value of the second object is closer to the second distance value of the first object, and
• when the calculated matching rate is a threshold or more, output an authentication signal.