6. Interaction with AI-Controlled Characters in AR Worlds

With the release of commercial head worn augmented reality (AR) devices, the AR community has grown exponentially. These AR devices come with robust computer vision algorithms to perform adequate object tracking and spatial localization of the user as well as objects in the AR environment. They allow for user input in various ways to interact with the scene. In addition, these devices finally became lightweight and comfortable enough to be used for real jobs in real professional environments. A new era has begun that allows the development of AR applications on a new level. It is no longer necessary to be an expert in computer vision or computer graphics to create meaningful solutions for application ideas that mostly have been proposed already many years ago. The usage of top-level game engines enables app developers to integrate well-designed and textured models, animations, physical effects, and illumination into their solutions, even without programming knowledge. In the past, the big majority of AR applications has focused on placing additional rigid or animated objects into the AR environment. Alternatively, tracked real objects have been superimposed by virtual supplementary information such as virtual structures inside a real object. However, another type of augmented content has almost been neglected so far. This chapter addresses the integration of and interaction with virtual characters in AR environments. It provides an overview of research that has been published by the AR community in the past and classifies different types of characters. In addition, we introduce the reader to Game AI, an R&D subdiscipline of game engineering that focusses on controlling non-player characters (NPCs) in video games. Furthermore, this chapter discusses peculiarities of the interaction with NPCs in AR environments and takes a closer look at the psychological subjects namely perception, communication, and behavioral psychology.