Spoof Detection for Biometric Authentication

Abstract

This specification describes technologies relating to biometric authentication based on images of the eye. In general, one aspect of the subject matter described in this specification can be embodied in methods that include obtaining images of a subject including a view of an eye. The methods may further include determining a behavioral metric based on detected movement of the eye as the eye appears in a plurality of the images, determining a spatial metric based on a distance from a sensor to a landmark that appears in a plurality of the images each having a different respective focus distance, and determining a reflectance metric based on detected changes in surface glare or specular reflection patterns on a surface of the eye. The methods may further include determining a score based on the behavioral, spatial, and reflectance metrics and rejecting or accepting the one or more images based on the score.

What is claimed is: 
     
         1 . A computer-implemented method comprising:
 obtaining two or more images of a subject including a view of an eye, wherein the images collectively include a plurality of focus distances;   determining a behavioral metric based on, at least, detected movement of the eye as the eye appears in a plurality of the images, wherein the behavioral metric is a measure of deviation of detected movement and timing from expected movement of the eye;   determining a spatial metric based on, at least, a distance from a sensor to a landmark that appears in a plurality of the images each having a different respective focus distance;   determining a reflectance metric based on, at least, detected changes in surface glare or specular reflection patterns on a surface of the eye as the eye appears in a plurality of the images, wherein the reflectance metric is a measure of changes in glare or specular reflection patterns on the surface of the eye;   determining a score based on, at least, the behavioral, spatial, and reflectance metrics; and   rejecting or accepting the two or more images based on the score.