Resolving non-uniqueness in the acoustic-to-articulatory mapping

This paper studies the role of non-uniqueness in the Acoustic-to-Articulatory Inversion. It is generally believed that applying continuity constraints to the estimates of the articulatory parameters can resolve the problem of non-uniqueness. This paper tries to find out whether all instances of non-uniqueness can be resolved using continuity constraints. The investigation reveals that applying continuity constraints provides the best estimate in roughly around 50 to 53% of the non-unique mappings. Roughly around 8 to 13% of the non-unique mappings are best estimated by choosing discontinuous paths along the hypothetical high probability estimates of articulatory trajectories.