1. An apparatus for capturing images of the eyes of a subject for use in an iris identification system, said apparatus comprising: one or two sensor arrays which capture a single image or two images, respectively, representing the different eyes of a subject captured at or approximately at the same time, in which when a single image is captured having both eyes of a subject a dimension extends in said single image associated with zero head tilt, and when two images are captured each having a different eye of the subject each of said sensor arrays are calibrated along a common plane to enable locations in images of different eyes of a subject captured by the sensor arrays to be related to coordinates along said common plane, and a dimension along said common plane is associated with zero head tilt; means for determining a location of a predefined feature associated with each of the different eyes of the subject present in said single image or two images, in which when two images are captured said location of said predefined feature is determined in each of the images in coordinates along said common plane; means for determining an angle between a virtual line extending between the two eyes of the subject, in which said virtual line extends through said location of the predefined feature of each of the different eyes of the subject in said single image or two images, and said dimension associated with zero head tilt along said single image or said common plane, respectively; means for segmenting left and right iris images from said single image or two images of the different eyes of the subject; and means for rotating said segmented left and right iris image in accordance with said angle to substantially remove head tilt when present and thereby provide left and right iris images with substantially zero head tilt.