## 3 Experimental Results and Evaluations
### Segments Extracted and Evaluations
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Patch** & **Precision-Manual** & **Precision-Auto** & **Precision** & **Centroid** & **Angle Difference** \\  & **(m)** & **(m)** & **Difference (m)** & **Difference (m)** & **(Degree)** \\ \hline P1 & 0.020 & 0.057 & 0.030 & 0.221 & 0.105 \\ P2 & 0.034 & 0.044 & 0.010 & 0.476 & 0.103 \\ P3 & 0.035 & 0.032 & \(-\)0.003 & 0.586 & 0.040 \\ P4 & 0.025 & 0.022 & \(-\)0.004 & 0.186 & 0.031 \\ P5 & 0.115 & 0.094 & \(-\)0.022 & 0.210 & 0.017 \\ P6 & 0.095 & N.A. & N.A. & N.A. \\ P7 & 0.070 & N.A. & N.A. & N.A. \\ P8 & 0.094 & N.A. & N.A. & N.A. \\ P9 & 0.101 & N.A. & N.A. & N.A. \\ P10 & 0.021 & N.A. & N.A. & N.A. \\ P11 & 0.080 & N.A. & N.A. & N.A. \\ Mean & 0.063 & N.A. & N.A. & N.A. \\ \hline \hline \end{tabular}
\end{table} 
Table 11: Plane fitting precision, plane fitting precision difference, centroid difference, and angle difference values for building #2 (Spherical approach). \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Patch** & **Precision-Manual** & **Precision-Auto** & **Precision** & **Centroid** & **Angle Difference** \\  & **(m)** & **(m)** & **Difference (m)** & **Difference (m)** & **(Degree)** \\ \hline P1 & 0.027 & 0.057 & 0.030 & 0.221 & 0.105 \\ P2 & 0.034 & 0.044 & 0.010 & 0.476 & 0.103 \\ P3 & 0.035 & 0.032 & \(-\)0.003 & 0.586 & 0.040 \\ P4 & 0.025 & 0.022 & \(-\)0.004 & 0.186 & 0.031 \\ P5 & 0.115 & 0.094 & \(-\)0.022 & 0.210 & 0.017 \\ P6 & 0.095 & N.A. & N.A. & N.A. \\ P7 & 0.070 & N.A. & N.A. & N.A. \\ P8 & 0.094 & N.A. Upon close examination of Tables 6-9 for the adaptive cylindrical approach, it is evident that building #2 has the maximum value of mean precision difference (_i.e._, around 0.02 m) compared with the other three buildings. As for the centroid difference, the mean value for building #1 (_i.e._, around 0.4 m) is greater than those of the other buildings. In the case of the angle difference, buildings #2 and #3 show around 1.4 and 1.2 degrees, respectively. Among the four buildings' 38 patches, P8 in building #1, P9 in building #2, and P11 in building #3 significantly affected the values of three measures: precision difference, centroid difference, and angle difference. The numbers of laser points belonging to the three patches (the manually derived ones) were quite small (_i.e._, 40, 42, and 84, respectively). It should be emphasized that the plane fitting quality of patches having a small number of points can be more affected by missing points than is the case for patches having a large number of points. On the other hand, building #4 showed quite good values for the three measures. In case of Tables 10-13 for the spherical approach, there are many missing patches (_i.e._, which are expressed as N.A.) except for building #1. The three measures, which are plane fitting precision, precision difference, and centroid difference for building #1 in Table 10, are similar to the values from the adaptive cylindrical one in Table 6. However, the angle difference between the approaches is a bit different due to P7 and P8. Building #2 in Table 11 shows a slightly better result than that in Table 7. It is also evident that the evaluation results for buildings #3 and #4 in Tables 12 and 13 are worse than those in Tables 8 and 9. Additionally, the mean values of the centroid and angle differences were computed, as listed in Table 14, using all of the patches (_i.e._, 38 patches) belonging to the four buildings, so as to confirm the overall performance of the adaptive cylindrical segmentation algorithm. At this stage, one should note that the results from the spherical approach are not considered for the overall mean values of the centroid and angle differences since it produced many missing patches. It is also important to note that neither the plane fitting precision nor the plane fitting precision difference are included in Table 14, since the characteristics of the laser points (_i.e._, the degree of laser point accuracy) in building #4 differ so markedly from those in the other three datasets.