Identifying Support Positions of Braced Excavations Automatically using Photogrammetry

Abstract:

A design information-based photogrammetric technique of identifying support positions of braced excavations is presented. Firstly, the acquired image is rectified based on laboratory camera calibration parameters. Then, the position and orientation of the camera in the real world are calculated using the control points method. Support regions designated in the design are projected to the image according to the pinhole camera model. Features of the support regions are extracted from the image and analyzed using a proposed color component relationship to determine whether the support is constructed or not. Finally, all support positions can be determined according to design information and their positions can be identified one by one. This technique can effectively avoid interference caused by complex construction environment. A case study of this technique in a braced excavation project is also presented. The application shows this technique is practicable and effective.