The EventTable technique: distributed fiducial markers.

ABSTRACTThe EventTable technique is a tangible object tracking technique implemented on a camera vision based tabletop platform. The technique supports an event-driven -- rather than object centric -- tracking technique. Fiducial markers are distributed between objects. When objects are brought into a proximal or connected relationship, a whole marker is formed and recognized by the tracking system. Thus, rather than tracking each individual object, the system tracks user-driven events that occur when two or more objects are proximal. The technique can be used in addition to individual object tracking and touch tracking. This approach provides a reliable and flexible approach to tabletop object tracking for a wide variety of tabletop activities. We describe three prototype applications to illustrate how the distributed marker technique can be applied. We describe the advantages and limitations of this approach. We conclude with a brief discussion of how the EventTable technique enables a shift in human computer interaction research from an information-centric to an action-centric epistemological view on how users' create meaning.