Modeling Gesticulation Expression in Virtual Humans

Gesticulation is the kind of unconscious, idiosyncratic and unconventional gestures humans do in conversation or narration. This chapter reviews efforts made to harness the expressiveness of gesticulation in virtual humans and proposes one such model. First, psycholinguistics research is overviewed so as to understand how gesticulation occurs in humans. Then, relevant computer graphics and computational psycholinguistics systems are reviewed. Finally, a model for virtual human gesticulation expression is presented which supports: (a) real-time gesticulation animation described as sequences of constraints on static (Portuguese Sign Language hand shapes, orientation palm axis, orientation angle and handedness) and dynamic features; (b) synchronization between gesticulation and synthesized speech; (c) automatic reproduction of annotations in GestuRA, a gesticulation transcription algorithm; (d) expression control through an abstract integrated synchronized language – Expression Markup Language (EML). Two studies, which were conducted to evaluate the model in a storytelling context, are also described.