Audio-visual synthesized attitudes presented by the German speaking robot SMiRAE

Abstract

This paper presents the acoustic and visual modeling of nine attitudinal expressions that were realized by the German speaking robot SMiRAE which is a speech-enabled version of the non-speaking robotic face MiRAE previously developed at Indiana University. The parameter-oriented acoustic model is based on the German Mary TTS which is part of the speech processing system InproTK. Visual realization of expressions is based on five defined basic emotions of the Facial Action Coding System (FACS) developed by Ekman. Both models were additionally modified with respect to results of an audiovisual analysis and evaluation of human portrayals of attitudes recorded in our previous work. The plausibility of synthesized attitudinal expressions is shown by an association study in which 18 participants described 54 attitudes in a free association. Basis for a 5cluster classification was the first four dimensions of a correspondence analysis which accounted 78% of variance in participant perception. Significant correlations were seen between 66 normalized participant descriptions and the robot’s displayed attitudes. For instance, the attitudes admiration and politeness were associated with the terms freundlich and gluecklich, the interrogative attitudes surprise and doubt with the terms fragend, verwundert and skeptisch, the expression uncertatinty was perceived with traurig and besorgt.