1. A method of aligning a test iris image with a candidate iris image, comprising the steps of: (a) generating a one-dimensional test list and a one-dimensional candidate list representative of measured image values along respective closed curves around respective pupils; (b) calculating a cross-correlation between the test list and the candidate list including the step of calculating respective digital fourier transforms of the lists, multiplying the respective transforms or a conjugate thereof, and calculating an inverse digital fourier transform to generate the cross-correlation; (c) determining from said cross-correlation a relative displacement at which the test list best matches the candidate list, said displacement being representative of a relative rotation at which the test iris image is best aligned with the candidate iris image; and utilizing said displacement in a biometric matching system.