Glottal Source Estimation using an Automatic Chirp Decomposition

TL;DR

This paper introduces a robust method for estimating the glottal source from speech signals by extending ZZT to ZCZT, improving accuracy and robustness to GCI location errors.

Contribution

It extends the ZZT formalism by automatically determining the Z-transform contour, enhancing robustness in glottal source estimation.

Findings

ZCZT-based method is more robust to GCI errors

Automatic contour selection improves deconvolution accuracy

Extension of ZZT formalism to non-unit circle contours

Abstract

In a previous work, we showed that the glottal source can be estimated from speech signals by computing the Zeros of the Z-Transform (ZZT). Decomposition was achieved by separating the roots inside (causal contribution) and outside (anticausal contribution) the unit circle. In order to guarantee a correct deconvolution, time alignment on the Glottal Closure Instants (GCIs) was shown to be essential. This paper extends the formalism of ZZT by evaluating the Z-transform on a contour possibly different from the unit circle. A method is proposed for determining automatically this contour by inspecting the root distribution. The derived Zeros of the Chirp Z-Transform (ZCZT)-based technique turns out to be much more robust to GCI location errors.