## 5 Discussion
### Synthetic Dataset Evaluation
#### 5.2.2 Wall Evaluation  
The quality of the wall reconstruction results was evaluated by comparing the created walls with the ground-truth data. Quantitative evaluations of the walls were conducted by using two metrics: completeness and correctness. The completeness and correctness metrics of walls were calculated from the number of detected walls in the reconstructed building against the ground truth. The completeness and correctness metrics of doors were calculated from the number of detected doors in the reconstructed building against the ground truth.  
The results of the assessments of walls are presented in Table 5.  
As shown in Table 5, the correctness of the wall and door numbers shows that the reconstructed walls or doors could be detected in both the reference data and the reconstructed models. Moreover, the completeness and correctness of the wall and door numbers was more than 0.82, except the second floor of Synthetic Data-7. These experiments show the stability and capability of the proposed method for indoor wall construction.  
However, certain reconstructed walls were not found in the ground-truth data, as shown in Figure 21, because certain noise points in the corner influenced the results of the wall line extraction.  
Figure 21: False positives (FP) example. **(a)** Reconstructed walls. **(b)** Ground-truth walls.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Synthetic Data**} & \multirow{2}{*}{**Floor**} & \multirow{2}{*}{\begin{tabular}{c} **Correctness** \\ **on Wall** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Completeness** \\ **on Wall** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Correctness** \\ **on Wall** \\ \end{tabular} } & \multirow{2}{*}{\
\begin{tabular}{c} **Completeness** \\ **on Wall** \\ \end{tabular} } & \multirow{2}{*}{
\begin{tabular}{c} **Completeness** \\ **on Door** \\ \end{tabular} } \\ \hline \multirow{3}{*}{Synthetic Data-1} & First Floor & 1 & 1 & 1 & 1 \\  & Second Floor & 1 & 1 & 1 & 1 \\  & Overall & 1 & 1 & 1 \\ \hline \multirow{3}{*}{Synthetic Data-2} & First Floor & 1 & 0.87 & 1 & 0.92 \\  & Second Floor & 1 & 1 & 1 & 1 \\  & Third Floor & 1 & 1 & 1 & 1 \\  & Overall & 1 & 0.94 & 1 & 0.97 \\ \hline \multirow{3}{*}{Synthetic Data-3} & First Floor & 1 & 1 & 1 & 1 \\  & Second Floor & 1 & 1 & 1 & 1 \\  & Overall & 1 & 1 & 1 & 1 \\ \hline \multirow{3}{*}{Synthetic Data-4} & First Floor & - & - & 1 & 1 \\  & Second Floor & - & - & 1 & 1 \\  & Overall & - & - & 1 & 1 \\ \hline \multirow{3}{*}{Synthetic Data-5} & Overall & 0.97 & 0.93 & 0.85 & 0.82 \\ \cline{2-2}  & First Floor & 0.92 & 0.91 & 0.98 & 0.85 \\ \cline{2-2}  & Second Floor & 0.97 & 0.91 & 0.95 & 0.95 \\ \cline{2-2}  & Overall & 0.94 & 0.91 & 0.97 & 0.88 \\ \hline \multirow{3}{*}{Synthetic Data-7} & First Floor & 0.85 & 0.54 & 0.93 & 0.83 \\ \cline{2-2}  & Second Floor & 0.97 & 0.91 & 0.95 & 0.95 \\ \cline{1-1}  & Overall & 0.90 & 0.66 & 0.93 & 0.86 \\ \hline \multirow{3}{*}{Synthetic Data-8} & First Floor & 0.92 & 0.91 & 0.98 & 0.85 \\ \cline{1-1}  & Second Floor & 0.83 & 0.81 & 1 & 0.95 \\ \cline{1-1}  & Overall & 0.89 & 0.88 & 0.97 & 0.88 \\ \hline \hline \end{tabular}
\end{table}
Table 5: Evaluation metrics.