EXTENDED DEPTH-OF-FIELD BIOMETRIC SYSTEM

摘要

An iris recognition system may include an optical system having an intentional amount of spherical aberration that results in an extended depth of field. A raw image of an iris captured by the optical system may be normalized. In some embodiments, the normalized raw image may be processed to enhance the MTF of the normalized iris image. An iris code may be generated from the normalized raw image or the enhanced normalized raw image. The iris code may be compared to known iris codes to determine if there is a match. In some embodiments, the iris code generated by the normalized iris image may be processed with equalization function before comparison with the known iris codes.

主权项

1. A method of processing an extended depth-of-field (EDOF) image of an iris at an imaging wavelength λIM, comprising:
capturing a raw image of the iris, wherein the raw image has a reduced modulation transfer function (MTF) based on an optical system having an amount of spherical aberration (SA) of 0.2λIM≦SA≦2λIM; normalizing the raw image; and generating an iris code based on the normalized raw image, comprising
performing an MTF enhancement of the normalized raw image in polar coordinates to generate a MTF enhanced image, comprising:
selecting a plurality of bands from the normalized raw image;processing each of the bands to enhance the MTF; andfusing the bands to generate the MTF enhanced image; andgenerating the iris code from the MTF enhanced image.