Fig. 8. Performance of the baseline matcher, self-update and graph min-cut algorithms over time, for face biometric. The batch Ui as available over time (indicated over the x-axis) is used for updating and the batch Ui þ 1 is used for performance evaluation. The threshold is set at 0.0001% FAR for self-updating operation as well as performance evaluation. ROC curve related to self-update operating at user-specific threshold is not shown as it resulted in performance similar to self-update operating at global threshold.