Automation of point cloud processing to increase the deformation monitoring accuracy

Abstract

The weather conditions and the loading during operation cause changes in the shape of engineering structures that affect static and dynamic function and reliability of these structures. Due to this fact, geodetic monitoring is an integral part of engineering structure diagnostics and gives important information about the current state (condition) of the structure. Terrestrial laser scanning (TLS) is often used for data acquisition in cases, requiring 3D information with high resolution. Therefore, TLS is used in different surveying applications, even in deformation monitoring of buildings or engineering structures. TLS allows non-contact documentation of the behaviour of the monitored structure. The accuracy of determination of the 3D coordinates of single measured points by currently commercially available laser scanners is several millimetres. The precision can be increased using suitable data processing, when valid assumptions about the scanned surface are available. The paper presents the possibility of deformation monitoring using TLS. To increase the precision of the results, the chosen parts of the monitored structure are approximated by fitting planes to point cloud. In this case, the position of the monitored point (part of structure) is calculated from tens or hundreds of scanned points instead of a single measurement. An application based on software MATLAB®, Displacement_TLS, was developed for automated data processing. It takes only several minutes, as the calculation is executed automatically for all monitored points at once. The proposed method represents fast and simple data processing. Benefits of the proposed method are demonstrated by experimental measurements of different structures and building elements.