title: Change Analysis in Structural Laser Scanning Point Clouds: The Baseline Method.
abstract: A method is introduced for detecting changes from point clouds that avoids registration. For many applications, changes are detected between two scans of the same scene obtained at different times. Traditionally, these scans are aligned to a common coordinate system having the disadvantage that this registration step introduces additional errors. In addition, registration requires stable targets or features. To avoid these issues, we propose a change detection method based on so-called baselines. Baselines connect feature points within one scan. To analyze changes, baselines connecting corresponding points in two scans are compared. As feature points either targets or virtual points corresponding to some reconstructable feature in the scene are used. The new method is implemented on two scans sampling a masonry laboratory building before and after seismic testing, that resulted in damages in the order of several centimeters. The centres of the bricks of the laboratory building are automatically extracted to serve as virtual points. Baselines connecting virtual points and/or target points are extracted and compared with respect to a suitable structural coordinate system. Changes detected from the baseline analysis are compared to a traditional cloud to cloud change analysis demonstrating the potential of the new method for structural analysis.
authors.affiliation: School of Earth Science and Engineering, Hohai University, No. 1, Xikang Road, Nanjing 210098, China. syq19881012@126.com.|Department of Geoscience and Remote Sensing, Delft University of Technology, Stevinweg 1, 2628 CN Delft, The Netherlands. syq19881012@126.com.
authors.forename: Yueqian
authors.initials: Y
authors.lastname: Shen
authors.affiliation: Department of Geoscience and Remote Sensing, Delft University of Technology, Stevinweg 1, 2628 CN Delft, The Netherlands. r.c.lindenbergh@tudelft.nl.
authors.forename: Roderik
authors.initials: R
authors.lastname: Lindenbergh
authors.affiliation: Department of Geoscience and Remote Sensing, Delft University of Technology, Stevinweg 1, 2628 CN Delft, The Netherlands. jinhu.wang@tudelft.nl.|Key Laboratory of quantitative Remote Sensing Information Technology, Academy of Opto-Electronics, Chinese Academy of Sciences, No. 9, Deng Zhuang South Road, Haidian District, Beijing 100094, China. jinhu.wang@tudelft.nl.
authors.forename: Jinhu
authors.initials: J
authors.lastname: Wang
keywords: baselines; change detection; masonry buildings; structural analysis; terrestrial laser scanning