# Mobile LiDAR for Scalable Monitoring of Mechanically Stabilized Earth Walls with Smooth Panels
## 5 Experimental Results
### Comparative Analysis of TLS and MLS Serviceability Measures
The overall statistics for the serviceability measures of the examined 76 panels covering faces 2, 3, and 4 along facade 2 using the TLS and MLS point clouds are provided in Table 3. The results in Table 3 show how the TLS-derived measures (i.e., angular orientation and panel-to-panel displacements) are quite similar to the performance measures derived using MLS. This similarity validates the capability of using an MLS system to obtain the serviceability measures for MSE walls. A graphical summary of the listed values for the statistics in Table 3 is provided in Figure 20, which shows the cumulative distribution functions (CDFs) for the three angular values (\(\theta_{xp}\), \(\theta_{yp}\), and \(\theta_{zp}\)) and the panel-to-panel normal distance for the TLS and MLS datasets. As an overall comparison between TLS and MLS-based serviceability measures, Table 4 shows a statistical comparison of such measures, as well as the width and the height of the panels. It can be concluded from Table 4 that the MLS-based measures were within 1 cm and 0.3\({}^{\circ}\) for the recently available serviceability measures and within 0.3/1000 for the standard measures (i.e., \(\alpha_{L}\) and \(\alpha_{T}\)) when compared to those from TLS. In addition, the measures for the width and height of the panels that are complete in size, were similar compared to those derived from the TLS dataset within an RMSE range of 1 to 2 cm (which is again within the expected noise level for the used MLS). \begin{table}
\begin{tabular}{c c c c c c c c c} \hline  & \(\theta_{xp}\) **(deg.)** & \(\theta_{yp}\) **(deg.)** & \(\theta_{xp}\) **(deg.)** & \multicolumn{2}{c}{\begin{tabular}{c} **Panel-to-Panel** \\ **Displacement (mm)** \\ \end{tabular} } & \multicolumn{2}{c}{\
\begin{tabular}{c} **Panel-to-Panel** \\ **Displacement (mm)** \\ \end{tabular} } & \multicolumn{2}{c}{
\begin{tabular}{c} **Panel-to-Panel** \\ **Displacement (mm)** \\ \end{tabular} } \\ \cline{2-9}  & **TLS** & **MLS** & **TLS** & **MLS** & **TLS** & **MLS** & **TLS** & **MLS** \\ \hline Sample Size & 76 & 76 & 76 & 76 & 76 & 76 & 454 & 454 \\ Minimum Value & \(-\)1.14 & \(-\)0.48 & \(-\)1.61 & \(-\)1.49 & \(-\)0.77 & \(-\)0.77 & \(-\)14.10 & \(-\)16.00 \\ Maximum Value & 0.47 & 0.38 & 0.68 & 0.63 & 1.43 & 1.44 & 13.50 & 18.10 \\ Range & 1.60 & 0.86 & 2.29 & 2.11 & 2.21 & 2.21 & 27.60 & 34.10 \\ Average & \(-\)0.03 & 0.00 & \(-\)0.46 & \(-\)0.45 & 0.06 & 0.07 & \(-\)0.30 & \(-\)0.21 \\ Standard Deviation & 0.26 & 0.19 & 0.4 & 0.39 & 0.48 & 0.48 & 4.97 & 5.19 \\
5 th Percentile & \(-\)0.39 & \(-\)0.39 & \(-\)1.12 & \(-\)1.09 & \(-\)0.61 & \(-\)0.58 & \(-\)8.80 & \(-\)9.00 \\
25 th Percentile & \(-\)0.11 & \(-\)0.12 & \(-\)0.72 & \(-\)0.73 & \(-\)0.20 & \(-\)0.22 & \(-\)3.70 & \(-\)3.70 \\
50 th Percentile (median) & \(-\)0.03 & 0.00 & \(-\)0.45 & \(-\)0.44 & 0.01 & 0.01 & \(-\)0.20 & \(-\)0.20 \\
75 th Percentile & 0.09 & 0.14 & \(-\)0.21 & \(-\)0.20 & 0.18 & 0.18 & 3.10 & 3.20 \\
95 th Percentile & 0.34 & 0.28 & 0.12 & 0.14 & 1.19 & 1.19 & 7.70 & 8.40 \\ Interquartile Range (IQR) & 0.20 & 0.26 & 0.52 & 0.53 & 0.39 & 0.40 & 6.80 & 6.90 \\ \hline \end{tabular}
\end{table} 
Table 3: Summary statistics of TLS and MLS-based serviceability measures for 76 panels covering faces 2, 3, and 4 along facade 2 for the MSE wall. Figure 20: Cumulative Distribution Functions (CDF) for panel-to-leveled face orientation angles and panel-to-panel displacement using TLS point cloud (in blue) and MLS point cloud (in red) for 76 panels constituting three faces along MSE wall facade 2. As mentioned earlier, one of the assumptions for a well-constructed MSE wall is that joints (i.e., gaps) between neighboring panels are within a tolerable range and have minimum offsets along the \(x\)-axis of the \(P_{cs}\) (i.e., along the face normal direction).