There will be non-ideal iris images when the person is moving at a normal walking pace through an iris capture device.An iris localization method based on elliptical projection is proposed

which solved the localization problem of non-ideal off-angle iris images.Firstly

relative position between two eyes is calculated to determine the rotation angle of the head.Then a point within pupil is easily found.Starting from that point

iris inner boundary points are searched according to gradient variation.An elliptical inner boundary is fit using the least squares.Secondly

eye gaze direction is detected by the circularity of ellipse

and an off-angle iris image is converted into a frontal view iris image adopting projection transform.Thirdly

iris outer boundary points are searched using the boundary point optimal selection method in the frontal view iris images

and outer boundary is located by the means of three points fitting a circle.Experimental results show that the proposed algorithm can effectively locate off-angle iris in a very short time.