Virtual object manipulation on a table-top AR environment

We address the problems of virtual object interaction and user tracking in a table-top augmented reality (AR) interface. In this setting there is a need for very accurate tracking and registration techniques and an intuitive and useful interface. This is especially true in AR interfaces for supporting face to face collaboration where users need to be able to easily cooperate with each other. We describe an accurate vision-based tracking method for table-top AR environments and tangible user interface (TUI) techniques based on this method that allow users to manipulate virtual objects in a natural and intuitive manner. Our approach is robust, allowing users to cover some of the tracking markers while still returning camera viewpoint information, overcoming one of the limitations of traditional computer vision based systems. After describing this technique we describe its use in prototype AR applications.