Patent ID: 7676068

Claim:
A biometric authentication system, comprising: a database of digital images of biometrics of known people; a camera for capturing a digital image of a biometric of an unknown person; a two-dimensional gradient filter coupled with said database and said camera for deriving a spatial gradient of a digital image; and a match processor coupled with said two-dimensional gradient filter for determining the extent to which the unknown biometric corresponds with a known biometric, by (i) processing a plurality of pairs of blocks of pixels of two spatial gradients derived by said two-dimensional gradient filter, one spatial gradient derived from a digital image of a biometric of a known person and one spatial gradient derived from the digital image of the biometric of the unknown person, wherein each pair of blocks comprises a block from one of the spatial gradients and a similar block from the other of the spatial gradients, to derive metrics related to the relative placements of the pairs of blocks, and (ii) calculating a probability that the known biometric does not correspond with the unknown biometric, based on the derived metrics.