US Patent 7347547 Pupil detection device and iris authentication apparatus

Pupil candidate detection unit for detecting positions of pupil candidates in an eye image; and luminance difference calculation unit for obtaining a difference between a maximum value and a minimum value of an image data of an eye image on a circumference of a circle having a center at center coordinates of a pupil candidate and a predetermined radius are provided, and when the output of luminance difference calculation unit is larger than the predetermined threshold, the corresponding pupil candidate is determined not to be the pupil.