Towards Tabletop Interaction with Everyday Artifacts via Pressure Imaging

Tangible user interfaces enable the interaction with digital information through the physical world. For the binding of physical representations with the underlying digital information, technology-augmented artifacts and environments are used. Characteristic for tangible user interfaces is the use of physical artifacts which are either dedicated to or augmented for the purpose of serving as input devices. However, relying on special artifacts limits the widespread use of tangible user interfaces, as they are not suitable for many everyday situations in which we interact with arbitrary artifacts that are not part of the interface. In this paper, we present a novel prototype of a tabletop tangible user interface which is based on pressure imaging. It identifies physical artifacts that are placed on the table by their weight, shape and size, thus enabling the use of a wide range of technology-free artifacts as input devices. We describe the underlying technologies and methods, and discuss the results of a first experiment which shows the recognition accuracy of the presented tabletop interface. Among the positioning of artifacts, their identification is a prerequisite for further interaction modalities and applications. For the recognition of everyday artifacts, a score-based classifier and a set of shape- and weight-based features have been used. The determination of the position of an artifact is fairly simple, as it can be achieved directly from its pressure footprint.