70. Image-Based Localization for Facilitating Construction Field Reporting on Mobile Devices

Current studies reveal the exceptional advantages of high-efficiency onsite information management for facilitating the design/building progress of construction projects. In particular, the prevailing methods of construction field reporting still primarily rely on manual on-site documentation of project information. Fortunately, state of the art computerized technologies provides solutions with great potential for boosting the efficiency of gathering and managing on-site information for field reporting. Providing on-demand access to such information in real-time requires an autonomous method for localizing and tracking (i.e. calculating the position and orientation) of a construction filed reporter on job site. This, in fact, will reduce both working time and efforts for providing on-demand access to project information. Mobile devices such as smartphones/tablets can be utilized to enable the on-site personnel to manage the project information in a portable fashion while adopting cloud technology for instant online access. In this paper, we proposed a method for on-site localization that can estimate and track the position and orientation of a hand-held device in a near real-time manner. The developed method is infrastructure-independent and marker-less. The proposed method mainly consists of mapping, localization and alignment modules. Initially, a video stream is acquired using the built-in camera of the mobile device scanning the target building. A 3D point cloud is then reconstructed from the acquired video data. Afterward, the localization algorithm outputs the location/orientation of the queried images using feature-based matching with the base 3D point cloud map generated earlier. Finally, global localization of frames is estimated by using the alignment parameters of the 3D point cloud with a Geo-referenced BIM model to transform the localized frames to the global reference. The proposed solution enables the field reporter to access, retrieve, save and edit the project information more efficiently on the construction site.