Recognizing prosody from the lips: Is it possible to extract prosodic focus from lip features?
The aim of this chapter is to examine the possibility of extracting prosodic information from lip features. The authors used two lip feature measurement techniques in order to evaluate the “lip pattern” of prosodic focus in French. Two corpora with Subject-Verb-Object (SVO) sentences were designed. Four focus conditions (S, V, O or neutral) were elicited in a natural dialogue situation. In the first set of experiments, they recorded two speakers of French with front and profile video cameras. The speakers wore blue lipstick and facial markers. In the second set, the authors recorded five speakers with a 3D optical tracker. An analysis of the lip features showed that visible articulatory lip correlates of focus exist for all speakers. Two types of patterns were observed: absolute and differential. A potential outcome of this study is to provide criteria for automatic visual detection of prosodic focus from lip data.