# A UWB-Driven Self-Actuated Projector Platform for Interactive Augmented Reality Applications
## 7 Discussion and Candidate Applications
### Overall System Abilities and Candidate Applications  
To our knowledge, we are the first to use the UWB positioning system to enable the interaction with projection-based augmented content over a dynamically changing user-defined projection screen at room-scale. Our proposed system delivers a comparable interaction accuracy to the state-of-the-art systems in this field [37, 42]. We can achieve an interaction accuracy lower than 0.1 m in most interaction cases. Different conventional systems confine the user interaction area to achieve the best interaction accuracy [33, 39], where our system improves the user's ability to define their best interaction distance. The user is fully involved in the projection process to customize the projected screen's size and location; on the other hand, several systems remove this facility from the user by restricting the interaction area to a specific location and size due to the pre-setup requirements [10, 15]. Some conventional projection-based interactive AR systems cannot serve for applications that demand extended indoor interactive spaces, flexible assigning for the interactive areas, and larger user's interactive envelope [20, 21, 22]. Nevertheless, thanks to our system's mobility and customization capability, normal indoor spaces can support diverse interactive tasks. Extended indoor interactive spaces demand various interactive content generation. The USAP platform's awareness of its position and orientation automatically generates the suited interactive content for distinct interactive locations. Unlike systems that use a heavy processing unit to calibrate for the projected screens [36, 41], our light-computational UWB-based calibration algorithm can run even in a small microcontroller processor. Not only light-computational power but also efficient calibration performance can be achieved; our algorithm shows a similar performance to static calibration conditions when calibrating for the projected screen whenever the USAP platform navigates to meet projection requirements. The high success rate to perform mid-air interaction tasks (98.79% for selecting and 98.26% for swiping) shows the reliability of using our hand-held input device. The relatively low workload values when using hands to perform spatial projection-based interaction and the system usability score (\(M\) = 77.83) reflects our system's intimate design compare to similar functioning systems [39]. Therefore, our system abilities suit the museum environment, including large or several exhibition halls, where interactive multimedia displays are demanded in various locations indoors. To expose what this system can do, we simulated a museum environment using the same setup, as shown in Figure 8. The USAP platform could augment a display working as explanatory interactive content for artifacts shown physically inside an exhibition hall (Figure 16a). The user could be conceived as a tourist guide that can perform interactions from different distances with the projected screens (Figure 16b,c). The projected screen's size and location could be selected to provide more information about a specific artifact. The input device's pointing accuracy enables the user to illustrate a specific graphical item (Figure 16e). Drag and drop projected items are also possible for interactive demonstration purposes or designing interactive games if demanded (Figure 16d). For better controllability, the graphical control buttons could follow the user's position to makethem reachable whenever they want to use them (Figure 16f). Customizing the projected screen is not confined to bigger-sized screens; however, the user could continue interacting with a relatively small screen (1 m diameter) (Figure 16g). Since UWB wireless network can turn the room's surfaces to support interactive applications, therefore, same interaction capabilities over the first simulated wall could be performed over the second simulated wall (Figure 16h).