# A UWB-Driven Self-Actuated Projector Platform for Interactive Augmented Reality Applications
## 1 Introduction
Considering that a museum environment contains several exhibition halls where interactive content needs to be displayed in different locations, using many fixed or steerable projection-based AR could be a good solution. However, it is costly and requires effort for precise setup and calibration. The nature of the cyclic change of in-show content in each exhibition hall may require a continuous displacement of interactive equipment. Therefore, increasing the projector unit mobility may be a suitable solution utilizing only a single project to surpass the room-scale limit. Mobile interactive projection augmentation may be effective for a dynamic and varying-scale interactive environment. An example of using mobile projection indoors is shown in [17] to map accurate images on 3D objects. In our study, we chose the ultra-wideband (UWB) wireless network to locate objects in 3D with a moderate tracking accuracy as long as these objects are present inside the tracking envelope. This tracking network provides greater freedom for users to move and perform interaction within the tracking envelope and not restrict their movement to a specific area. Besides, the UWB wireless network governs the mobile projector platform's navigation and widens the interaction area by converting passive indoor surfaces to interactive ones. Following this strategy results in a comprehensive interactive environment within a single room and allows the interaction to be designed in a symmetric way outside room boundaries. We name the described mobile projector platform as a UWB-driven self-actuated projector (USAP). It supports a mobile augmented screen in any position according to the user's desire. The user could define the interactive window and start interacting with the augmented screen using a hand-held input device. We designed the USAP as an information provider platform, where displayed content changes according to the detected position (e.g., defining hall number, surface ID, and USAP spatial position). Therefore, it could be an effective assisting platform for people such as tour-guides or teachers to present interactive, informative content to an audience or group of students for relatively large-scale indoor spaces. This study aims to enhance interaction capabilities within a single room and suggest a scheme that can enlarge the interactive area beyond the room-scale systematically using a commercial-of-the-self, cheap, and portable technology to meet the need of large-scale interactive areas. Additionally, we seek to give the user more freedom to use any position to perform interactions without limiting movement. We also seek to support the user with a dynamic ability to define an augmented screen's position and dimensions within any surface indoors, where a light-computational UWB-based calibration algorithm runs to localize the augmented screen. To achieve our study goal, we conducted a study to answer the following research questions (RQs):  
* RQ1: How effectively deploying a UWB wireless sensor network help to convert passive surfaces into interactive ones for a dynamically change interactive indoor environment? * RQ2: How the deployment of a UWB network propose a solution to overcome limitations in conventional interactive spatial projection systems? * RQ3: What does system performance in terms of interaction accuracy, interaction time, workload, and system usability indicate about the system design and a user's interaction experience? To address these questions, we recruited 16 participants to experience our system in a laboratory-controlled environment to test the system's different aspects. The analysis of the collected data alongside participant behavior observations led to the following contributions:  
1. We developed an accurate, mobile, user-friendly, and expandable projection-based AR interactive system for indoor environments by deploying a UWB wireless sensor network and designing a UWB-driven self-actuated projector platform. 2.