ABSTRACT
This chapter distinguishes between two classes of augmented reality applications, those that require world-centric tracking and those that require object-centric tracking. Emphasis is placed on object-centric approaches that are suitable for applications in which annotated objects may move within an environment. These application classes impart differing requirements upon the tracking systems that enable the presentation of augmented reality media in spatial relationships to objects. The tracking approaches are contrasted, and an instance of an object-centric approach is detailed to illustrate the research and implementation issues. The example system overcomes a limitation of many object-centric tracking systems through its ability to sense and integrate new features into its tracking database, thereby extending the tracking region semiautomatically.
