The apparatus represents a device having one or two sensors for capturing a single image or two images having the subject's eyes, and processor(s) in a housing with the one or two sensors and/or in a computer system which receives the single image or two images. Such processor(s) determine a head tilt angle between a virtual line extending between the two eyes of the subject in accordance with a predefined features associated with the eyes and a dimension characterizing zero head tilt in the single image or two images, segment left and right iris images, and rotate the segmented left and right iris images in accordance with the angle to substantially remove head tilt when present. The apparatus may also determine head tilt using predefined features associated with a single eye in the image. The resulting iris image(s) are utilized for enrollment or identification.