Abstract: Interlace noises of the image of an iris included in the image of an eye picked up through an interlaced scheme are corrected precisely within a short time. An image processing apparatus (30) corrects a digital image P based on only low-brightness pixels configuring the image of a pupil included in the digital image P of an eye. Accordingly, interlace noises included in the image of the pupil of the eye and that of the iris can be corrected precisely within a short time. Next, a checking apparatus (50) performs authentication on a subject person based on the image of the iris specified based on the corrected digital image P. Hence, precise authentication is enabled.

Abstract: A plurality of pieces of information related to the iris pattern of an eye can be checked against each other in a short time. Characteristic curves (S(1)-S(8)), which are in accordance with eight ring areas (A1-A8) formed by dividing an image of an iris, are generated. The polarities of the gradients of these characteristic curves are then arranged, thereby generating codes (1-8) to be checked. Each of these codes (1-8) to be checked consists of a ternary combination of +, ? and zero, whereby the amount of data to be handled during the checking process can be reduced. As a result, checking the codes to be checked can be performed in a short time.

Abstract: An image of the iris contained in an image of an eye is accurately specified. An image of the iris contained in a digital image (P) of an eye is accurately specified. In view of low-intensity pixels of the digital image (P) of the eye, and high-intensity pixels having a predetermined relationship with the low-intensity pixels, a reference pixel (PX0) that defines the center of the pupil is determined. Thereby, the center of the pupil can be specified more accurately when compared to the case where, for example, it is determined only from the low-intensity pixels. Therefore, the accuracy of the process to specify the iris image on the basis of the reference pixel is improved, and as a result, the iris image can be accurately specified.