Study on speaker verification with non-audible murmur segments

We investigated a speaker verification method that uses nonaudible murmur (NAM) segments using newly collected data and obtained several findings that will be useful when speaker verification systems are made in practice. NAM is recorded using a special microphone placed on the surface of the body, so it includes almost no external noise and is hard for other people to hear. By utilizing these properties, we have already reported a text-dependent method using NAM segments that can use a keyword phrase safely. This paper extends the examination with newly collected data consisting of NAM uttered by 18 male and 9 female imposter speakers and by 18 male and 10 female customer speakers. Experiments with various numbers of training utterances and sessions show that it is effective to use data recorded in multiple sessions. We also investigated the minimum number of training utterances needed in our method.