Estimation of glottal source waveforms and vocal tract shape for singing voices with wide frequency range

Estimation of glottal vibration and vocal tract for singing voices is necessary for clarifying the mechanism of singing voice production. However, accurate estimation of glottal vibration and vocal tract shape in singing voices with a high fundamental frequency (f0) is difficult using simulated models such as the auto-regressive with exogenous input (ARX) model and LiljencrantsFant (LF) model. This is caused by two problems: the inaccurate estimation method of the glottal closure instant (GCI) and the inappropriate estimation method of ARX model parameter values in singing voices with high f0. Therefore, this proposed method aims to accurately estimate glottal source waveforms and vocal tract shape for singing voices with wide frequency range. To achieve this objective, we propose two solutions: estimation of GCI using an electroglottogram (EGG) signal and estimation of ARX model parameter values using multi-stage optimization and an evaluation function including the leaking effect from forwarded periods. In experiments using simulated singing voices and real singing voices, it was indicated that the accurate estimation of GCI, the reliable estimation of the parameter values of the ARX model for singing voices with high f0, and the estimation of glottal vibration and vocal tract shape in singing voices with wide frequency range were achieved by the proposed method