cepstral voices are free for personal use

Michaelis, D., Frohlich, M., and Strube, H. “ Quantitative spectral evaluation of shimmer and jitter,” J. “ Normalised noise energy as an acoustic measure to evaluate pathologic voice,” J. Kasuya, H., Ogawa, S., Mashima, K., and Ebihara, S. “ A preliminary study on the generation of pathological voice types,” in Vocal Fold Physiology: Voice Production, Mechanisms and Functions, edited by O. “ Acoustic correlates of breathy vocal quality,” J. “ A methodological study of perturbation and additive noise in synthetically generated voice signals.” J. Audio, Speech Language Process., 14, 492– 501.

“ Robust glottal source estimation based on joint source-filter model optimization,” IEEE Trans. “ A four parameter model of glottal flow,” STL-QPSR 4, 1– 12. “ A cepstrum based technique for determining a harmonics-to-noise ratio in speech signals.” J. “ Spectral, cepstral and aperiodicity characteristics of pathological voice before and after phonosurgical treatment,” Clin. Speech Processing and Synthesis Toolboxes ( Wiley, New York). “ Estimation of the vocal tract transfer function for voiced speech with application to glottal wave analysis,” Speech Commun. This information is employed in a new harmonics-to-noise (HNR) estimation technique, which is shown to provide accurate HNR estimates when tested on synthetically generated voice signals. On selecting an appropriate temporal analysis window length the estimated baseline is shown to lie halfway between the glottal excited vocal tract and the noise excited vocal tract. Because the estimation process resembles the action of a MA filter, the resulting noise baseline is determined by the harmonic resolution (as determined by the temporal analysis window length) and the glottal source spectral tilt. It is shown that Fourier transforming the low-pass liftered cepstrum is comparable to applying a moving average (MA) filter to the logarithmic spectrum and hence the baseline receives contributions from the glottal source excited vocal tract and the noise excited vocal tract. Taking the Fourier transform of the liftered (filtered in the cepstral domain) cepstrum produces a noise baseline estimate. A theoretical description of cepstral processing of voiced speech containing aspiration noise, together with supporting empirical data, is provided in order to illustrate the nature of the noise baseline estimation process. Cepstral-based estimation is used to provide a baseline estimate of the noise level in the logarithmic spectrum for voiced speech.

Cepstral voices are free for personal use