Patent ID: 7382901

Claim:
An eye image taking device comprising: an imaging unit for taking an eye image of a user; a focusing degree calculating unit for calculating a focusing degree from the eye image taken at the imaging unit; a threshold setting unit for determining a focus range including a lower limit of an optimum focusing threshold intrinsic to an authorized user and that excludes other users; and a focus deciding unit for deciding a focus by comparing the focusing degree and the focus range, wherein the threshold setting unit sets the focusing threshold on the basis of the eye image of the authorized user; wherein the focusing degree calculating unit calculates the magnitude of the high-frequency components contained in the eye image taken by the imaging unit, as the focusing degree, and wherein the threshold setting unit selects the maximum from a plurality of focusing degrees, which are calculated individually from the plural eye images of different imaging distances for the authorized user, thereby to set the focusing threshold on the basis of the maximum.