Robot Learning Physical Object Properties from Human Visual Cues: A novel approach to infer the fullness level in containers

For collaborative tasks, involving handovers, humans are able to exploit visual, non-verbal cues, to infer physical object properties, like mass, to modulate their actions. In this paper, we investigate how the different levels of liquid inside a cup can be inferred from the observation of the movement of the person handling the cup. We model this mechanism from human experiments and incorporate it in an online human-to-robot handover. Finally, we provide a new dataset with human eye+head+hand motion data for human-to-human handovers and human pick-and-place of a cup with three levels of liquid: empty, half-full, and full of water. Our results show that it is possible to model (non-verbal) signals exchanged by humans during interaction and classify the level of water inside the cup being handed over.