Voiceprint Identification

Abstract

Initial successes indicated that a voiceprint identification system analogous to existing fingerprint identification is a possibility. Subjective matching of voiceprints has resulted in success scores of better than 97%. For the purposes of voiceprint identification, a library tape was recorded containing the voices of 15 male and 10 female, essentially normal American voices. The recording consisted of 10 cue words chosen for the high frequency with which they appear in telephone conversation. The cue words were uttered four times by each speaker, first singly, then in two five-word sentences, and finally in narrative during which each cue word appeared at least two times. Spectrograms were made from the above recordings and prepared for subjective testing. The voiceprints were randomly arranged for presentation in groups of 20, each group comprising four different utterances of a cue word by five different speakers. Upon initial presentation of five groups of 20 voiceprints to seven experienced subjects, four recorded perfect scores, two recorded one error, and one subject recorded two errors. A panel of naive female students under 18 years of age was chosen next and given five days of voiceprint reading experience. Upon presentation of the first voiceprint identification problem, the panel recorded only two errors in seven groups of 20 voiceprints In successive experiments, the matrices were expanded to 9 and then 12 talkers. Identification success scores exceeded 98% for over 5000 decisions. In a later series of experiments, simulated identification problems were investigated resulting in success scores exceeding 97%.