True User Imposter Test

Last updated
23 Jun 2023

A True User Imposter Test evaluates the False Accept and False Accept rates of a Voice Biometric system by using existing users of the system to simulate imposter attempts. This is an essential step in establishing the appropriate Biometric threshold.

A True User Imposter Test is part of the Tuning and Calibration process for Voice Biometrics systems. It uses real user data to simulate imposter access attempts. For example:

  • 1000 speakers with 1 enrollment utterance and 4 verification utterances provide:
    • 4,995,000 imposter access attempts (1000 speakers x 999 imposters x 5 utterances  ) imposter attempts and
    • 4000 genuine access attempts (1000 speakers x 4 utterances).

As each trial generates a biometric score, they can be graphically plotted to help understand the performance of the system.

Based on the results of the True User Imposter Test, it is possible to calibrate the biometric decision threshold such that the risk of a False Accept (FA) is consistent with the implementing organisation’s risk appetite.

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