HEFES: An Hybrid Engine for Facial Expressions Synthesis to control human-like androids and avatars

Nowadays advances in robotics and computer science have made possible the development of sociable and attractive robots. A challenging objective of the field of humanoid robotics is to make robots able to interact with people in a believable way. Recent studies have demonstrated that human-like robots with high similarity to human beings do not generate the sense of unease that is typically associated to human-like robots. For this reason designing of aesthetically appealing and socially attractive robots becomes necessary for realistic human-robot interactions. In this paper HEFES (Hybrid Engine for Facial Expressions Synthesis), an engine for generating and controlling facial expressions both on physical androids and 3D avatars is described. HEFES is part of a software library that controls a human robot called FACE (Facial Automaton for Conveying Emotions). HEFES was designed to allow users to create facial expressions without requiring artistic or animatronics skills and it is able to animate both FACE and its 3D replica. The system was tested in human-robot interaction studies aimed to help children with autism to interpret their interlocutors' mood through facial expressions understanding.