Acknowledgements The authors would like m thank the anonymous reviewers for providing comments to improve the quality of this paper, and iSPACE of Research Studios Austria FG (RSA) (http://ispace.researchstudio. at/) for providing the ALS datasets. The study described in this paper is funded by the National Natural Science Foundation of China (Grant No. 41301493), the High Resolution Earth Observation Science Foundation of China (GFZX04060103-5-17), and Special Fund for Surveying and Mapping Scientific Research in the Public Interest (201412007).
Airborne laser scanning (ALS) is a technique used to obtain Digital Surface Models (DSM) and Digital Terrain Models (DTM) efficiently, and filtering is the key procedure used to derive DTM from point clouds. Gen...