Time-frequency analysis of vocal fold's onset [optical inspection]

It is proposed to use time-frequency analysis of vocal fold's onset signal for diagnosis of different phonation disorders evoked by pathological changes. The vibration signals are acquired by direct optical inspection of the glottis using an endoscope and a high speed CCD camera system. Because of their outstanding performance the Wigner distribution is used as an analysis tool. It is shown that smoothed versions of the pseudo Wigner distribution are especially well suited from a practical point of view. Application of cone and reduced interference kernels is considered. It is described how characteristic features of the time-frequency distribution can be obtained and interpreted for diagnostics.