Wavelet analysis of sustained vowel spectra in view of the characterization of hoarseness

This article concerns the spectral analysis of vowels sustained by hoarse and healthy speakers. Conventional cues of noise in spectral data are founded on the segregation of hannonics and interharmonics. What we propose here is an alternative that consists of flattening the spectral contour and performing a multivariate statistical analysis of the residual ( i.e. flattened ) spectral components. The residual spectrum is obtained by means of the wavelet transform of the power spectrum of the vowels. The results show that a principal components analysis of the flattened spectra enables hoarse voices to be separated from clear.