Effects of Context on Voiceprint Identification

Abstract

This study investigated how well the file card system of Voiceprint Identification reported by Kersta (1962) fulfills its purpose of minimizing the effects of contextually caused spectral variation, and how well it serves as either a population reduction or identification tool. Subjects received training equivalent to that received by the experimenter in the Voiceprint Identification Training Course, and achieved error rates approximating those achieved by Kersta's subjects for similar training tasks. Experimental tasks required subjects to identify unknown speakers from a population of 50 known speakers by first eliminating all known speakers they were certain were not the unknown speaker, and then attempting identification. Ten attempts were made where the unknown and known speech samples of the same speaker were excerpted from the same phonetic contexts, and 10 attempts where they were excerpted from different contexts. Statistically significant differences in subject performance for same and different context tasks indicated that the file card system does not substantially minimize the effects of contextually caused spectral variation. The magnitude of error rates suggests that it cannot be used for either population reduction or identification.