Enrolment and verification are the processes that a caller needs to go through in order to use a voice biometrics system. The enrolment process is a one-off operation that establishes the biometric identity of the caller in the system, and that precedes any subsequent verification of the caller.

Enrolment

A caller needs to enrol with a voice biometric system before they can verify themselves using their voice. A business process that identifies the caller as being eligible for voice verification and inviting them to enrol typically triggers the enrolment process. This involves establishing ground truth in relation to the callers' identity.

The act of enrolment varies depending on the mode of operation of the voice biometric system, but in a text dependent challenge response mode it will consist of the caller repeating back to the system a number of prompted, short numerical phrases, for example "0579". Between 6 and 12 such phrases are sufficient to achieve very high accuracy levels. The voice biometric system transforms these speech samples into a voiceprint that can subsequently be used to verify the caller.

Verification

Once a user has enrolled with a voice biometric system they can be verified against their enrolment voiceprint.

During the verification process, the caller will be asked to provide a form of claimed identity, which can be arbitrary but is typically an account or card number, before being asked to provide a speech sample. In a text dependent challenge response mode this speech sample will be one or more of the short numerical phrases used at enrolment time. Many variables will go into determining how many such phrases need to be spoken, including accuracy requirements, liveness testing, user experience, and so forth.

The voice biometric system will process the speech sample against the enrolment voiceprint in order to determine whether the caller definitely is; definitely is not; or could possibly be the claimed speaker.