Collimation in Transparent Projection Screens for Panoramic Augmented Reality Environments

There are many types of display systems used in Augmented Reality (AR), each having specific application areas. Based on an extensive literature and technology review, this paper proposes the use of a transparent projection screen for users in a fixed position observing distant objects. The transparent projection screen is similar to head-up displays (HUDs) used in aircraft cockpits, since they both superimpose graphics on objects in the background. HUDs have been heavily researched, and one issue that has gotten attention is the need for collimation. Results indicate that performance in HUDs and the need for collimation depends on the real-superimposed object connectivity, i.e. how visually integrated the real and superimposed objects are. In HUDs, there has traditionally been no direct overlay of observed objects, just symbols and data at fixed screen locations (i.e. no object connectivity). AR, however, strives to perfectly overlay the real with virtual objects (i.e. full object connectivity). In the connectivity range between traditional HUDs and AR the need for collimation should be further examined. We therefore propose a series of experiments to determine the need for collimation in transparent projection screens.