Tangible information displays

The goal of this thesis is to provide a generic architecture and software framework for graphical multi-touch and multi-user interfaces. In recent years, research in novel types of computer-human interaction has increased considerably. Particularly multi-touch and multi-user interfaces have received a lot of interest, partly due to the availability of robust and affordable sensor hardware. This trend has been accelerated by the emergence of commercial products which have made these interaction concepts available to a wide user base in a surprisingly short timeframe. Although a considerable amount of useful applications has already been written based on these new modalities, they share some deficiencies from a developer’s point of view. Even when source code is available, most of these applications are written in a monolithic fashion, making reuse of code difficult. Furthermore, they duplicate large amounts of core functionality such as gesture recognition and are often locked to a single type of input hardware. To address this lack of reusability and portability, a layered architecture is presented in this thesis to describe an interactive application in a generalised fashion. As part of this architecture, a formal description of gestures will also be specified. A reference implementation of this architecture, libTISCH, is presented. When using this framework, a developer should not require more time for creating a novel user interface than for a conventional one. The same applies to integration of new types of input hardware existing software should “just work” after a suitable adapter has been provided. A number of example applications have been created with libTISCH and tested on various input sensors. The results show the suitability of libTISCH for the intended tasks regarding software development and hardware integration.