Using phonetic constraints in acoustic-to-articulatory inversion

TL;DR

This paper proposes a method for acoustic-to-articulatory inversion that incorporates phonetic constraints based on French vowel formants to improve the realism of the reconstructed articulatory movements.

Contribution

It introduces a novel approach using phonetic constraints derived from formant frequencies to enhance inversion accuracy and realism.

Findings

Phonetic constraints improve inversion results.

Articulatory parameters align better with X-ray data.

Method effectively distinguishes vowel transitions.

Abstract

The goal of this work is to recover articulatory information from the speech signal by acoustic-to-articulatory inversion. One of the main difficulties with inversion is that the problem is underdetermined and inversion methods generally offer no guarantee on the phonetical realism of the inverse solutions. A way to adress this issue is to use additional phonetic constraints. Knowledge of the phonetic caracteristics of French vowels enable the derivation of reasonable articulatory domains in the space of Maeda parameters: given the formants frequencies (F1,F2,F3) of a speech sample, and thus the vowel identity, an "ideal" articulatory domain can be derived. The space of formants frequencies is partitioned into vowels, using either speaker-specific data or generic information on formants. Then, to each articulatory vector can be associated a phonetic score varying with the distance to the "ideal domain" associated with the corresponding vowel. Inversion experiments were conducted on isolated vowels and vowel-to-vowel transitions. Articulatory parameters were compared with those obtained without using these constraints and those measured from X-ray data.