A High-level Event System for Augmented Reality

3D graphics systems increasingly rely on sophisticated event systems derived from collision detection mechanisms, which support the discretisation of Physics as well as high-level programming and scripting. By contrast, Augmented Reality systems have not yet adopted this approach. We describe the development of a high-level event system on top of the ARToolkit environment incorporating the ODE Physics engine. We first define a typology of events encompassing interactions between virtual objects as well as interactions involving markers. We then describe how these events can be recognised in real-time from elementary collisions detected by the ODE Physics engine. We conclude by discussing examples of high-level event recognitions and how they can support the development of applications.