Patch-based Graph Cut Optimization for 3D Line Segment Extraction of Building Structures from Outdoor Point Cloud Data

Abstract. The extraction of architectural structural line features can simplify the 3D spatial representation of monitored objects, reduce the storage burden of massive point clouds, and provide crucial geometric parameters for subsequent 3D modelling. To address the problem of line segment discontinuity caused by point cloud quality, this paper proposes a line segment extraction algorithm based on planar graph-cut segmentation. Specifically, a region growing and merging algorithm is employed to segment the point cloud into multiple planar patches. Subsequently, 3D-2D projection is performed to generate grayscale images, from which line segment parameters are identified and extracted using a graph-cut segmentation algorithm combined with vectorization techniques. Then, depending on spatial 3D-2D back-projection, all extracted 3D line segments are optimized by the structural regularization to further mitigates the discontinuity among collinear line segments and provide high-quality linear features for subsequent 3D reconstruction.