Multiple-tiered facial recognition

A method includes receiving probe image data associated with a biometric authentication request on a mobile device. A first classifier is employed to generate a first probability metric of the probe image data being associated with the authorized user. The biometric authentication request is approved responsive to the first probability metric being greater than a first threshold. The biometric authentication request is denied responsive to the first probability metric being less than a second threshold. Responsive to the probability metric being between the first and second thresholds, a second classifier is employed to generate a second probability metric of the probe image data being associated with the authorized user. The biometric authentication request is approved responsive to the second probability metric being greater than a third threshold.