Volume IV-2/W5
ISPRS Ann. Photogramm. Remote Sens. Spatial Inf. Sci., IV-2/W5, 373-380, 2019
https://doi.org/10.5194/isprs-annals-IV-2-W5-373-2019
© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.
ISPRS Ann. Photogramm. Remote Sens. Spatial Inf. Sci., IV-2/W5, 373-380, 2019
https://doi.org/10.5194/isprs-annals-IV-2-W5-373-2019
© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

  29 May 2019

29 May 2019

FEATURE RELEVANCE ANALYSIS FOR 3D POINT CLOUD CLASSIFICATION USING DEEP LEARNING

A. Kumar1,2, K. Anders3,4, L Winiwarter3, and B. Höfle3,4 A. Kumar et al.
  • 1Institute of Industrial Science, The University of Tokyo, Komaba, Japan
  • 2School of Engineering, The University of Tokyo, Hongo, Japan
  • 33D Geospatial Data Processing Research Group (3DGeo), Institute of Geography, Heidelberg University, Heidelberg, Germany
  • 4Interdisciplinary Center for Scientific Computing (IWR), Heidelberg University, Heidelberg, Germany

Keywords: Terrestrial Laser Scanning, Machine Learning, Semantic Labelling, Neural Network, Fully Connected Network

Abstract. 3D point clouds acquired by laser scanning and other techniques are difficult to interpret because of their irregular structure. To make sense of this data and to allow for the derivation of useful information, a segmentation of the points in groups, units, or classes fit for the specific use case is required. In this paper, we present a non-end-to-end deep learning classifier for 3D point clouds using multiple sets of input features and compare it with an implementation of the state-of-the-art deep learning framework PointNet++. We first start by extracting features derived from the local normal vector (normal vectors, eigenvalues, and eigenvectors) from the point cloud, and study the result of classification for different local search radii. We extract additional features related to spatial point distribution and use them together with the normal vector-based features. We find that the classification accuracy improves by up to 33% as we include normal vector features with multiple search radii and features related to spatial point distribution. Our method achieves a mean Intersection over Union (mIoU) of 94% outperforming PointNet++’s Multi Scale Grouping by up to 12%. The study presents the importance of multiple search radii for different point cloud features for classification in an urban 3D point cloud scene acquired by terrestrial laser scanning.