International Workshop on Models and Analysis of Vocal Emissions for Biomedical Applications (MAVEBA 1999)

Florence, Italy
September 1-3, 1999

Characterising Vowel Phonation by Fundamental Spectral Normalisation of LX-Waveforms

C. J. Moore (1), N. Slevin (2), S. Winstanley (3)

(1) North Western Medical Physics, Christie Hospital, Manchester, UK
(2) Department of Radiation Oncology, Christie Hospital, Manchester, UK
(3) South Manchester University Hospitals Trust, Withington Hospital, Manchester, UK

Objective spectral reference standards for normal vowel phonation are described. Application in larynx cancer monitoring is envisaged. 120 individuals contributed to a database of vowels /æ/ and /i/ in the form of trans-larynx impedance lime scries captured using an electrolaryngograph. The impedance signals are used for iterated power spectral estimation followed by spectral intra-pooling for each individual. Pooling of spectra across many individuals is complicated by significant variations in the precise frequencies and powers of the fundamental, harmonics and any other characteristic peaks that may be present. Fundamental-harmonic normalisation (FHN) of individual spectra circumvents these obstacles by normalising all powers relative to that of the fundamental and by transforming the entire frequency range into floating point multiples of the fundamental-frequency F0. Population pooling then results in stable FHN-spectral patterns and associated characteristic distributions of U values. For females it is FHN-spectral pattern that matters most. For males the F0 distribution is also highly characteristic.

Full Paper

Bibliographic reference.  Moore, C. J. / Slevin, N. / Winstanley, S. (1999): "Characterising vowel phonation by fundamental spectral normalisation of LX-waveforms", In MAVEBA-1999, 1-6.