3D touch point detection on load sensitive surface based on continuous fluctuation of a user hand.

We present a load sensitive surface which provides exact contact position in 3D and a force vector of user's touch from low cost load sensors without any prior knowledge about shape of objects. Load based approach is advantageous since they provide a force vector, however, there have been mathematical ambiguity of the touch position along the line of action. To address this problem, we develop algorithm based on pseudo-inverse matrix framework, utilizing the notion that user's hands are always fluctuating slightly and unconsciously during touch interaction. In this paper, we introduce the design space of the surface, outline of the algorithm and highlighted applications. This technique to localize the touch position in physical spaces enables us to design tangible interaction with inert everyday objects and analyze user's activities happening on the surfaces.