Third International Conference on Spoken Language Processing (ICSLP 94)
In this paper we describe the results of several vowel classification experiments, which shed light on the relative importance of certain spectral regions for achieving optimum classification accuracy in either a speaker-dependent or a speaker-independent task. The methodology adopted to conduct this investigation is based on a new formulation  of the quefrency-weighted cepstral distance measure, which allows specification of any frequency band within the available spectral range. This more flexible approach to distance computation was used to study the behaviour of classification accuracy as a function of increasing spectral range, and to identify spectral regions which predominantly carry either phonetic or speaker-specific information.
Bibliographic reference. Mokhtari, Parham / Clermont, Frantz (1994): "Contributions of selected spectral regions to vowel classification accuracy", In ICSLP-1994, 1923-1926.