LAUSR

ABSTRACT Extensive research has been conducted to realize highly expressive android faces. In contrast, not much is being discussed which android faces are mechanically better and how advanced each android is because a fair and meaningful standard index of expressiveness does not exist. Therefore, in this study, we propose a numerical index and three types of visualization methods for facial deformation expressiveness to investigate the mechanical performance of android faces compared to humans. We used a data set of three-dimensional displacement vectors of over 100 facial points on the faces of two androids and three human males to calculate the expressiveness that reflects how diversely each facial point could move. As a result, we found that the expressiveness of the androids was significantly lower than humans, especially in the lower faces. The expressiveness of the androids was approximately only 20 that of humans even in the most expressive axis and two orders of magnitude lower than humans in three-dimensional evaluation. Thus, our method revealed the lackness of mechanical performance in recently developed androids to move facial skin widely. This method enabled us to reasonably discuss future directions to realize next generation androids with expressiveness similar to that in humans. GRAPHICAL ABSTRACT