[3] [3] Vosselman G. Slope based filtering of laser altimetry data[J]. International Archives of Photogrammetry and Remote Sensing, 2000: 33, 935-942.

[4] [4] Lindenberger J. Laser-profil messungen zur topogra-phisc hen gelandeaufnahme[D]. Stuttgart: Stuttgart University, 1993.

[5] [5] Axelsson P. Dem generation from laser scanner data using adaptive TIN models[J]. International Archives of Photogrammetry and Remote Sensing, 2000, 33(B4): 110-117.

[6] [6] Zhang W M, Qi J B, Wan P, et al. An easy-to-use airborne LiDAR data filtering method based on cloth simulation[J]. Remote Sensing, 2016, 8(6): 501.

[12] [12] Dong Y Q, Cui X M, Zhang L, et al. An improved progressive TIN densification filtering method considering the density and standard variance of point clouds[J]. ISPRS International Journal of Geo-Information, 2018, 7(10).

[19] [19] Du L M, Zhong R F, Sun H L, et al. Dislocation detection of shield tunnel based on dense cross-sectional point clouds[J]. in IEEE Transactions on Intelligent Transportation Systems, 2022, 23(11): 22227-22243.

[24] [24] Mirjalili S, Lewis A. The whale optimization algorithm[J]. Advances in Engineering Software, 2016, 95: 51-67.

[25] [25] Qin N, Tan W K, Ma L F, et al. OpenGF: an ultra-large-scale ground filtering dataset built upon open ALS point clouds around the world[C]//Conference on Computer Vision and Pattern Recognition Workshops. IEEE Publishing House, 2021: 1082-1091.

[26] [26] ISPRS Commission Ⅲ, working Group 3. Report: ISPRS compasion of filters[R]. Mekelweg: Delft University of Technology, 2003: 18-23.