Analysis of lip motion using principal component analyses

ObjectivesThe aim of this study was to quantitatively determine lip movement characteristics during the phonation of Japanese vowels.Materials and methodsLip motions of 14 normal individuals during the phonation of five Japanese vowels, /a/, /i/, /u/, /e/, and /o/ were analyzed. Using our developed motion analyzing system, range images were produced across the whole sequence during lip motions, and virtual grids were fitted onto surfaces. Principal component analyses were applied with three-dimensional coordinates of intersections for virtual grids regarded as variables.Results and conclusionThe fourth and fifth principal component scores were shown to be parameters that control mouth opening and the retraction of the corners of the mouth, respectively. Discriminate analyses show it is possible to distinguish motion during the phonation of /u/ from that of other vowels.