Acquisition and Consecutive Registration of Photogrammetric Point Clouds for Construction Progress Monitoring Using a 4D BIM

Traditionally, progress monitoring of a construction site is carried out by multiple visual observations and manual records of the actual state. For automation of this procedure digital methods for comparison of the as-planned state and as-built state are proposed. This task can be performed by comparing a 4D Building Information Model (BIM) to actual acquired photogrammetric point clouds. A continuous monitoring requires a frequent acquisition and subsequent comparison of co-registered point clouds. We propose for this task a procedure consisting of three steps: (1) mounting photogrammetric ground control markers in the coordinate system of the construction site; (2) creating an image block using these control points only in this initial step; (3) registration of images from subsequent acquisitions based on 2D-features only. For evaluation, we have investigated two scenarios and two acquisitions techniques. Using a hand-held camera and an Unmanned Aerial Vehicle in total 14 acquisitions were recorded. In both scenarios the consecutive registration was successful and shows deviations of similar to 3-5 cm of planes derived from the point clouds in relation to planes of the BIM.