AUGMENTED REALITY MARKERS AS SPATIAL INDICES FOR INDOOR MOBILE AECFM APPLICATIONS

This paper presents a new methodology for utilizing Augmented Reality (AR) fiducial markers on mobile devices (smart phone/tablet) for indoor Architecture, Engineering, Construction, and Facilities Management (AECFM) applications such as navigation and inspection. On one hand, previous efforts on such applications focused mainly on exploring traditional non-visual-sensor-based methods to track user's position continuously, ignoring the advantage that in most of the built environment, human inspectors can easily navigate themselves to destinations given that they can make correct decisions at a set of discrete critical spatial locations (corner of hallway, stairs etc.). On the other hand, traditionally fiducial markers are extensively used to recover user's pose and thus serve as table-top AR display surface, benefiting from its cost-efficiency and high flexibility. A different view that combines these two observations is to attach these markers at critical locations whose global positions and orientations are known in advance, treating markers as spatial indices which help the automatic identification of key locations. Upon recognizing the marker, as well as estimating the relative pose between the user and marker, user's pose in the global coordinate frame can be calculated. Then decisions can be automatically made and users are guided to their destinations by 3D graphical instructions. An example application for complex indoor environment way-finding is built on Android platform and tested which demonstrates the efficiency of the proposed method.