Patent ID: 7796784

Claim:
A personal authentication method using iris images, comprising a registration process and an authentication process, the registration process includes including the steps of: capturing, by a capture device, a plurality of iris images having different pupil opening degrees from a registrant; obtaining feature data and a ratio of pupil diameter to iris diameter from each of the plurality of iris images and associating the obtained ratio of pupil diameter to iris diameter with the corresponding obtained feature data; obtaining a polynomial expression defining the feature data as a function of the obtained ratio of pupil diameter to iris diameter based on a plurality of pieces of feature data and ratios of pupil diameter to iris diameter obtained from the plurality of captured iris images, wherein a degree of the polynomial expression is greater than or equal to 2; and registering parameters for expressing the polynomial expression in an iris database in conjunction with the registrant, and the authentication process including the steps of: capturing, by a capture device, an iris image from a person to be authenticated; obtaining feature data and a ratio of pupil diameter to iris diameter of the person to be authenticated from the acquired iris image; obtaining the polynomial expression from the parameters registered in the iris database corresponding to the registrant and applying the ratio of pupil diameter to iris diameter obtained in the authentication process to the polynomial expression of the registrant to obtain feature data to be collated; comparing the feature data to be collated with the feature data obtained from the person to be authenticated in the authentication process to determine whether or not the person to be authenticated is the registrant; and outputting the comparing result through an output device.