ISPRS-Archives The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences ISPRS-Archives Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci. 2194-9034 Copernicus Publications Göttingen, Germany 10.5194/isprs-archives-XLIII-B2-2022-387-2022 AUTOMATIC EXTRACTION OF FACADES AND WINDOWS FROM MLS POINT CLOUDS USING VOXELSPACE AND VISIBILITY ANALYSIS Hoegner L. 1 2 Gleixner G. 1 Photogrammetry and Remote Sensing - TUM School of Engineering and Design - Technical University of Munich, Germany Hochschule München University of Applied Sciences, Germany 30 05 2022 XLIII-B2-2022 387 394 Copyright: © 2022 L. Hoegner 2022 This work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/4.0/ This article is available from https://isprs-archives.copernicus.org/articles/XLIII-B2-2022/387/2022/isprs-archives-XLIII-B2-2022-387-2022.html The full text article is available as a PDF file from https://isprs-archives.copernicus.org/articles/XLIII-B2-2022/387/2022/isprs-archives-XLIII-B2-2022-387-2022.pdf

This contribution presents a method for extracting a 3D model of facades and windows from a point cloud. The point cloud is segmented based on a voxel octree, in which the facades are sought as planes. These can be used to filter out potential window points within the building, which are then analysed on their visibility by checking the occupancy grid of the voxel space. Here, methods of digital image processing are used for analysing both point clusters behind the facade and holes in the estimated facade planes as window candidates. Facades and windows are both simplified as rectangles. The test data set was gathered in a Mobile Laser Scanning campaign. While the segmentation fails in some cases, the extraction of facades and windows shows good results: 25 facades with 702 detected windows yield a detection rate of 86% with a false alarm rate of 13%. The reconstructed sizes of the windows differ from reference measurements in the range of centimetres to a few decimetres. These refined geometries can be used to enrich existing building models or for vehicle navigation without GNSS.