Sixth European Conference on Speech Communication and Technology
There are few operational services that use speaker verification (SV) as a means to provide secure, yet easy to use access. In this paper we describe the first semi-operational service that is offered by KPN Telecom that has been developed within the framework of the LE-4 project PICASSO. We report on the objective and subjective evaluation of a service that offers free access to directory information in the Netherlands. We concentrate on the enrolment phase, since this is the most critical phase for operational services. Hundred seventy-four persons used this service since the end of 1998; all interaction data are logged for analysis. We have interviewed 26 subjects. We have learned that naive subjects have difficulty in understanding what is expected from them; this holds both for the enrolment and for the access phase. Only half of the subjects finished the enrolment in the minimum number of two calls. The other subjects needed more calls, or did not succeed at all. During access, we observed that more than half of the calls which were refused by SV were calls in which the caller did not behave as (s)he should (screaming, whispering, not entering speech at all, or incomplete utterances). Real false rejects amount to 4 % which makes clear that from the technology point of view improvements are needed. Still, even persons who have occasional trouble using the service have a quite positive opinion about the speech-secured service.
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Bibliographic reference. Os, Els den / Jongebloed, Hans / Stijsiger, Alice / Boves, Lou (1999): "Speaker verification as a user-friendly access for the visually impaired", In EUROSPEECH'99, 1263-1266.