Flat surfaces captured by 3D point clouds are often used for localization, mapping, and modeling. Dense point cloud processing has high computation and memory costs making low-dimensional representations of flat surfaces such as polygons desirable. We present Polylidar3D, a non-convex polygon extraction algorithm which takes as input unorganized 3D point clouds (e.g., LiDAR data), organized point clouds (e.g., range images), or user-provided meshes. Non-convex polygons represent flat surfaces in an environment with interior cutouts representing obstacles or holes. The Polylidar3D front-end transforms input data into a half-edge triangular mesh. This representation provides a common level of input data abstraction for subsequent back-end processing. The Polylidar3D back-end is composed of four core algorithms: mesh smoothing, dominant plane normal estimation, planar segment extraction, and finally polygon extraction. Polylidar3D is shown to be quite fast, making use of CPU multi-threading and GPU acceleration when available. We demonstrate Polylidar3D's versatility and speed with real-world datasets including aerial LiDAR point clouds for rooftop mapping, autonomous driving LiDAR point clouds for road surface detection, and RGBD cameras for indoor floor/wall detection. We also evaluate Polylidar3D on a challenging planar segmentation benchmark dataset. Results consistently show excellent speed and accuracy.
PolyBuilding: Polygon Transformer for End-to-End Building Extraction
DAMO Academy, Alibaba Group（阿里巴巴集团达摩院）；Institute of Remote Sensing and Geographic Information Systems, School of Earth and Space Sciences, Peking University（北京大学地球与空间科学学院遥感与地理信息系统研究所）
Chameleon: Fast-slow Neuro-symbolic Lane Topology Extraction
Institute for AI Industry Research (AIR), Tsinghua University（清华大学人工智能产业研究院（AIR））；Bosch Corporate Research, China（博世中国企业研究中心）；Institute for Interdisciplinary Information Sciences(IIIS), Tsinghua University（清华大学交叉信息研究院）
PolyBuild: An End-to-End Method for Polygonal Building Contour Extraction from High-Resolution Remote Sensing Images
China University of Petroleum (East China)（中国石油大学（华东））；South Surveying&Mapping Instrument Co.,Ltd.（南方测绘仪器有限公司）；China Railway Design Corporation（中国铁路设计集团有限公司）
P2PFormer: A Primitive-to-polygon Method for Regular Building Contour Extraction from Remote Sensing Images
School of Remote Sensing and Information Engineering, Wuhan University（武汉大学遥感信息工程学院）；College of Oceanography and Space Informatics, China University of Petroleum (East China)（中国石油大学（华东）海洋与空间信息学院）；School of Surveying and Geoinformation Engineering, East China University of Technology（东华理工大学测绘与地理信息工程学院）
PyCellMech: A shape-based feature extraction pipeline for use in medical and biological studies
Sorbonne Université（索邦大学）；Paris Brain Institute（巴黎脑研究所）；ICM, CNRS, Inria, Inserm（ICM、法国国家科学研究中心、法国国家信息与自动化研究所、法国健康与医学研究院）；AP-HP, Hôpital de la Pitié Salpêtrière（巴黎公共医疗集团、皮蒂-萨尔皮特里耶医院）；School of Engineering（工程学院）；University of Melbourne（墨尔本大学）
Appearance Shock Grammar for Fast Medial Axis Extraction from Real Images
McGill University（麦吉尔大学）；University of Toronto（多伦多大学）；Samsung Toronto AI Research Center（三星多伦多人工智能研究中心）；Vector Institute for Artificial Intelligence（向量人工智能研究所）
