From Tongue Movement Data to Muscle Activation – A Preliminary Study of Artisynth's Inverse Modelling

Finding the muscle activations during speech production is an important part of developing a comprehensive biomechanical model of speech production. Although there are some direct ways, like Electromyography, for measuring muscle activations, these methods usually are highly invasive and sometimes not reliable. They are more over impossible to use for all muscles. In this study we therefore explore an indirect way to estimate tongue muscle activations during speech production by combining Electromagnetic Articulography (EMA) measurements of tongue movements and the inverse modeling in Artisynth. With EMA we measure the time-changing 3D positions of four sensors attached to the tongue surface for a Swedish female subject producing vowel-vowel and vowelconsonant-vowel (VCV) sequences. The measured sensor positions are used as target points for corresponding virtual sensors introduced in the tongue model of Artisynth’s inverse modelling framework, which computes one possible combination of muscle activations that results in the observed sequence of tongue articulations. We present resynthesized tongue movements in the Artisynth model and verify the results by comparing the calculated muscle activations with literature.QC 20181116