Scale Factor Effect in Terrestrial Laser Scanner Datum Transformation

Datum transformation is an inevitable procedure in terrestrial laser scanners (TLSs) pre-processing. By taking into account the uncertainties in multi distances measurement, neglecting the scale factor in registration and georeferencing phases should be reconsidered especially when involved with applications that demand high accuracy data. With the motivation to robustly examine the effect of scale factor in the issue raised, this study has designed experiment which consider the element of multi distances. Two types of TLSs utilised in this study, which are Faro Focus 3D and Leica ScanStation C10 to represent phase and pulse based scanners, respectively. Exploiting robust statistical analysis, all seven (7) parameters were computed from both experiments and scale factors were extracted for the further assessment. Significant analysis was performed by comparing the ideal value of scale factor (i.e. 1.000 or no scale effect) and values obtained from the experiments. The results show that, the null hypotheses for the experiment is accepted with a 95% confidence level. This result also indicates that scale factor can be neglected in datum transformation process for both type of terrestrial laser scanners.