‘misspelled’ visual words in unsupervised range data classification: the effect of noise on classification performance

Recent work in the domain of classification of point clouds has shown that topic models can be suitable tools for inferring class groupings in an unsupervised manner. However, point clouds are frequently subject to non-negligible amounts of sensor noise. In this paper, we analyze the effect on classification accuracy of noise added to both an artificial data set and data collected from a Light Detection and Ranging (LiDAR) scanner, and show that topic models are less robust to ‘misspelled’ words than the more näive k-means classifier. Furthermore, standard spin images prove to be a more robust feature under noise than their derivative, ‘angular’ spin images. We additionally show that only a small subset of local features are required in order to give comparable classification accuracy to a full feature set.