Dynamic programming method for temporal registration of three-dimensional tongue surface motion from multiple utterances

This study proposes a new method to reconstruct three dimensional (3D) tongue surface motion during speech using only a few sections of the tongue measured with ultrasound imaging. Reconstruction of static 3D tongue surfaces has been reported. This is the first report for reconstruction of 3D tongue surface motion using ultrasound imaging. To temporally align data from multiple scan locations, a Dynamic Programming (DP) algorithm was used to line up the tokens collected from different repetitions by using the acoustic signals recorded simultaneously with the ultrasound images. Reconstruction error was evaluated by using a pseudo-motion measurement of known 3D tongue shapes. The average error was 0.39 mm, which was within the ultrasound measurement error, of 0.5mm.