[Yao, Wei] Changsha Univ Sci & Technol, Sch Comp & Commun Engn, Changsha 410114, Peoples R China.
[Yao, Wei] Changsha Univ Sci & Technol, Engn Lab Spatial Informat Technol Highway Geol Dis, Changsha 410114, Peoples R China.
[Wang, Chunhua; Lin, Hairong] Hunan Univ, Coll Informat Sci & Engn, Changsha 410082, Peoples R China.
[Sun, Yichuang] Univ Hertfordshire, Sch Engn & Technol, Hatfield AL10 9AB, England.
[Gong, Shuqing] Changsha Univ Sci & Technol, Sch Math & Stat, Changsha 410114, Peoples R China.