[9] YANG Guojun, SANIIE J. Indoor navigation for visually impaired using AR markers[C]// 2017 IEEE International Conference on Electro Information Technology (EIT), New York: IEEE, 2017: 1-5.
[15] YAN Bei, WANG Bin, LI Yuan. Optimal ellipse fitting method based on least-square principle[J]. Journal of Beijing University of Aeronautics and Astronautics, 34(3): 295-298.
[16] CHEN T Q, GUESTRIN C. XGBoost: a scalable tree boosting system[R]. New York, USA: Association for Computing Machinery, 2016: 785-794.
