Pairwise three-dimensional shape context for partial object matching and retrieval on mobile laser scanning data

A novel pairwise 3-D shape context for partial object matching and retrieval is developed for extracting 3-D light poles and trees from mobile laser scanning (MLS) point clouds in a typical urban street scene. Unlike the single-point shape context describing only the local topology of a shape, the pairwise 3-D shape context can simultaneously model the local and global geometric structures of a shape in manifold space. By using histogram descriptors, the pairwise 3-D shape context has such characteristics as invariance to scale, invariance to orientation, and partial insensitivity to topological changes. Our results show that 3-D light poles and individual trees can be extracted from the RIEGL VMX-450 MLS point clouds and the performance achieved using our algorithm is much more accurate and effective than those of the other two existing algorithms.