Multi-State Device Tracking for Tangible Tabletops

Abstract

On tangible tabletops, Tangible User Interfaces (TUIs) can signalize their identity, position, orientation, and state by active infrared light. This provides rich interaction capabilities in complex, dynamic scenarios. If TUIs have to transfer additional high-resolution information, many bits are required for each update. This has a negative impact on the overall update rate of the system. In the first part of this paper, we present an in-house map application where interaction with time-dependent contour lines may benefit from high-resolution TUI states. Prototypical TUI concepts such as slider, ruler, and dials further motivate the benefit of high-resolution tracking. In the second part of the paper, we depart from a device tracking overview and then show how tangible devices for tabletops typically use infrared (IR) emitters and a camera to send information about their position, orientation, and state. Since transferring many additional information bits via a normal camera-based tabletop system is not feasible anymore, we introduce next a new system setup that still offers a sufficiently high update rate for a smooth interaction. The new method can be realized as a tabletop system using a low-cost camera detecting position, combined with a low-cost infrared receiver detecting the state of each device. Since both kinds of sensors are used simultaneously we call the method “dual mode.” This method combines a camera-based tracking with the possibility to transfer an almost unlimited amount of states for each device.