An Automated System for Projection of Interior Construction Layouts

Layout of the interior works during building construction is time consuming and error prone. Given the cost involved, both for initial layout and for later rework where errors occur, researchers have sought to automate the layout task. Some have adopted marker-less augmented reality methods using heads-up displays or cameras, and others have proposed robots capable of marking out the works. The former encumber the workers, the latter are expensive to set up and are sensitive to site conditions, and neither has yet achieved the required accuracy. In this paper, we propose a more efficient approach to project relevant information from a building information model (BIM) onto the construction surface, directly augmenting the construction site with the design information. This is done using a portable system consisting of a 2-D laser scanner, an angled adjustable projector, and a camera. The system localizes itself within the already built outer walls using the laser scanner and the BIM model using a method derived from robotic mapping; it calibrates the projection correction parameters (keystone correction) using image analysis; and it projects the information with the angled projector. Testing results showed that the localization was accurate within a few millimeters and less than 3°, and the final projected image's error was approximately 1 cm. Initial calibration requires less than 1 min and does not require specialist skills. The system automates the layout task, preserves accuracy, and can provide rich model information on any interior surface.