1. Department of Geomatics, National Cheng Kung University, No. 1, Daxue Rd., East Dist., Tainan City 701401, Taiwan (R.O.C.)
2. Department of Geomatics, National Cheng Kung University, No. 1, Daxue Road, East District, Tainan City 701401, Taiwan (R.O.C.)
3. Institute for Photogrammetry and Geoinformatics, University of Stuttgart, Geschwister-Scholl-Str. 24D, 70174 Stuttgart, Germany