# Optical Flow Odometry with Panoramic Image Based on Spherical Congruence Projection
## 4 Experiments and Discussion
### Comparative Experimental Results
\begin{table}
\begin{tabular}{c c c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**VIO-Method**} & \multirow{2}{*}{**Index**} & \multicolumn{2}{c}{**RS01**} & \multicolumn{2}{c}{**RS02**} & \multicolumn{2}{c}{**RS03**} & \multicolumn{2}{c}{**RS04**} & \multicolumn{2}{c}{**RS05**} & \multicolumn{2}{c}{**RS06**} \\  & & **RMSE** & **Std** & **RMSE** & **Std** & **RMSE** & **Std** & **RMSE** & **Std** & **RMSE** & **Std** & **RMSE** & **Std** \\ \hline \multirow{3}{*}{SCP -VIO} & RPE (\%) & **1.863** & **1.240** & **1.831** & **1.299** & **2.041** & **1.267** & **2.344** & **1.473** & **1.953** & **1.095** & **2.929** & 2.021 \\  & RPE (deg/m) & **2.292** & 1.938 & **2.648** & **2.271** & **2.245** & **1.776** & **2.578** & **2.122** & **2.444** & **2.030** & **2.934** & 2.483 \\  & ATE (m) & **0.153** & **0.046** & **0.095** & **0.037** & **0.139** & **0.067** & 0.131 & 0.064 & 0.163 & 0.050 & 0.301 & 0.153 \\ \hline \multirow{3}{*}{LF} & RPE (\%) & 2.382 & 1.584 & 2.622 & 1.933 & 2.548 & 1.674 & 2.609 & 1.655 & 2.446 & 1.478 & 2.954 & **1.841** \\  & RPE (deg/m) & 2.206 & **1.853** & 2.833 & 2.385 & 2.872 & 2.382 & 2.720 & 2.261 & 2.598 & 2.087 & 2.951 & **2.467** \\  & ATE (m) & 0.191 & 0.062 & 0.185 & 0.067 & 0.149 & 0.058 & 0.156 & 0.058 & 0.191 & 0.081 & 0.169 & 0.064 \\ \hline \multirow{3}{*}{VINS -MONO} & RPE (\%) & 2.758 & 1.660 & 2.641 & 1.861 & 2.559 & 1.728 & 2.480 & 1.703 & 2.376 & 1.599 & 2.668 & 1.874 \\  & RPE (deg/m) & 2.301 & 1.922 & 2.924 & 2.459 & 2.768 & 2.311 & 2.956 & 2.479 & 2.792 & 2.346 & 2.992 & 2.575 \\  & ATE (m) & 0.239 & 0.116 & 0.202 & 0.083 & 0.148 & 0.069 & **0.127** & **0.047** & **0.119** & **0.041** & **0.145** & **0.045** \\ \hline \multirow{3}{*}{VIO Method} & Index & \multicolumn{2}{c}{RS07} & \multicolumn{2}{c}{RS08} & \multicolumn{2}{c}{RS09} & \multicolumn{2}{c}{RS10} & \multicolumn{2}{c}{RS11} & \multicolumn{2}{c}{RS12} \\  & RMSE & std & RMSE & std & RMSE & std & RMSE & std & RMSE & std & RMSE & std \\ \hline \multirow{3}{*}{SCP -VIO} & RPE (\%) & **2.342** & **1.662** & **2.693** & **1.841** & **2.297** & **1.464** & **2.667** & **1.795** & **2.999** & **2.058** & **3.155** & **2.193** \\  & RPE (deg/m) & 3.283 & 2.936 & 3.384 & 2.753 & 2.808 & 2.349 & **3.736** & **3.171** & **1.417** & **1.075** & **0.736** \\  & ATE (m) & **0.140** & **0.047** & 0.189 & 0.075 & **0.158** & 0.065 & 0.201 & 0.076 & 0.228 & 0.081 & **0.293** & **0.087** \\ \hline \multirow{3}{*}{LF} & RPE (\%) & 3.736 & 2.357 & 3.109 & 2.093 & 2.709 & 1.847 & 3.537 & 2.302 & 3.562 & 2.447 & 3.261 & 2.268 \\  & RPE (deg/m) & **3.004** & **2.459** & **3.240** & **2.616** & 3.194 & 2.764 & 3.875 & 3.255 & 3.709 & 3.165 & 1.981 & 1.334 \\ \cline{1-1}  & ATE (m) & 0.352 & 0.073 & 0.191 & 0.066 & 0.168 & **0.042** & 0.155 & 0.069 & 0.220 & 0.080 & 0.283 & 0.085 \\ \hline \multirow{3}{*}{VINS -MONO} & RPE (\%) & 2.963 & 2.245 & 3.174 & 2.221 & 2.458 & 1.708 & 3.543 & 2.496 & 3.410 & 2.373 & 3.420 & 2.351 \\ \cline{1-1}  & RPE (deg/m) & 3.129 & 2.766 & 3.326 & 2.696 & **2.475** & **2.017** & 3.809 & 3.223 & 3.679 & 3.092 & 2.034 & 1.333 \\ \cline{1-1}  & ATE (m) & 0.191 & 0.048 & **0.176** & **0.052** & 0.206 & 0.085 & **0.136** & **0.053** & **0.187** & **0.074** & 0.312 & 0.186 \\ \hline \hline \end{tabular}  
* The bold numbers represent the best results in the same scenario.  
\end{table} 
Table 3: Experimental results in the SCP-Image dataset. Additionally, more experiments under challenging environmental conditions, including glare, overexposure, and motion blur, were conducted to further verify the robustness of the SCP method. We take the ID01 scenario from the SCP-Image dataset as a representative case, which exhibits glare and overexposure due to multiple overhead light sources. As shown in Figure 12, significant RPEt error spikes appeared in the LF-VIO and VINS-MONO algorithms when the images were affected by the above artifacts. Specifically, VINS-MONO demonstrated pronounced deviations at about 31s, 34s, and 36s, with RPEt values of 7.45%, 5.73%, and 6.43% respectively.