Abstract: The positioning of building structural components is the key to automatic progress tracking. In the existing research results, the monitoring object is a simple construction site, and the form of today’s buildings is increasingly complex and is mainly of cast-in-place concrete structure. In order to track the construction progress of this kind of building, based on building information modeling (BIM) and computer vision (CV) technology, a method was proposed to locate the structural members of cast-in-place concrete building from the top view. Firstly, target detection technology was employed to identify the structural components in the construction state from the top view of the construction site. The BIM elements were projected onto the imaging plane based on the principle of camera imaging. Finally, the mapping relationship between the actual components and BIM elements was established through the results of registration and projection, so as to realize the automatic positioning of structural components. The experimental results show that the recognition accuracy is 82.08% and the registration rate is 94.17%. The recognition and registration effect of the plane formwork is the best. Compared with the similar methods, this method reduces the degree of occlusion, makes full use of the context information, and is more in line with the actual construction process. It provides a new scheme for the construction process tracking of complex buildings. 

Key words: construction progress tracking, component positioning, building information modeling, target detection, projection model