Crack detection in building walls based on geometric and radiometric point cloud information

Symptoms such as cracks and other discontinuities of the scanned surface are indicators of poor technical conditions of buildings. The efficient detection of such changes using non-destructive remote measuring techniques is an important research topic because it may minimise the risk of building disasters. Terrestrial laser scanners register radiometric information of laser beams reflected from scanned surfaces (i.e., the intensity parameter), in addition to 3D spatial coordinates. Therefore, this study was focused on integrating geometric information with radiometric information of a point cloud in crack detection. The obtained results enabled the authors to develop a measurement methodology for detecting building wall cracks using a terrestrial laser scanner considering the technical parameters of the scanner and the 'geometric' conditions of the measurement. In addition, the influence of technical parameters of the scanner (such as laser spot size and laser beam divergence) on effective crack detection was discussed.