First International Conference on Spoken Language Processing (ICSLP 90)
Articulatory movements of the lips have been measured for study of lip articulations and their dynamics when vowels and bilabial stops were produced in various phonetic environments. Image data of lip movements were recorded by a high-speed video recorder system at a frame rate of 5 ms, for two male subjects. Sampled images with gray-levels were processed to detect contours of upper and lower lips, which were approximated by a 4-th degree polynomial function with five coefficients. These coefficients, as well as geometric configuration parameters (mouth" opening area, vertical and horizontal width of mouth, etc.), were adopted as characteristic parameters describing lip articulatory behaviors. Various shapes of lip contour were taken in the combination of individual polynomial coefficient. The effect of phonetic environments on lip shape and individual differences were observed in their combination.
Bibliographic reference. Sonoda, Yorinobu / Mori, Keisuke / Kuriyama, Tetsuaki (1990): "Articulatory characteristics of lip shape during the production of Japanese", In ICSLP-1990, 441-444.