Abstract:
Speech affected by colds continues to be an issue in speaker recognition technology. This study is a continuation of the ``cold-affected'' speech project [R. G. Tull and J. C. Rutledge, J. Acoust. Soc. Am. 99, 2549(A) (1996)] which compared ``cold-speech'' and normal/healthy speech of a male subject to analyze differences in vowel durations and mel-cepstral coefficients. This new study analyzes the speech of two additional male subjects during a cold and after a cold to test speaker intrasession (``cold-speech'' within the same recording session, normal speech within the same session), and speaker intersession (``cold-speech'' versus normal speech on different days). The sentence being used for recording is the recitation of numbers: ``1 2 3 4 5 6 7 8 9 10.'' The lower-order mel-cepstral coefficients are chosen as parameters (independent variable) in this study. The research for this study shows that there are patterns in the coefficients (c2 and c3) of ``cold-speech'' that are different from the patterns of the same coefficients in normal speech. These differences suggest that the cold, as a temporary communications disorder, introduces another level of intra-speaker variability that needs to be addressed in the design of speaker recognition systems. Confronting the ``cold-speech'' through manipulation of the mel-cepstral coefficients may improve a system's ability to recognize a speaker with a cold as the customer, rather than as an imposter.