# Chest Compression Skill Evaluation System Using Pose Estimation and Web-Based Application
## 6 Discussion
### Evaluation of Accuracy
In our opinion, overall, an angle of 30\({}^{\circ}\) and a height of 50 cm provided the highest accuracy. Regarding height, 50 cm offered better performance when capturing chest compressions from the side, likely due to a larger proportion of the subject being visible on the screen. Regarding angle, subjects in this experiment performed chest compressions with their left hand positioned below, which may have contributed to better estimation at 30\({}^{\circ}\) compared to 60\({}^{\circ}\). It is also possible that the calibration lines for depth and recoil were not optimally configured, which may explain the limited differences in accuracy between CAR and CAD. Additionally, the presence of random compressions in the dataset may have contributed to the reduced overall accuracy, especially in parameters such as CAD and CAR, where stable compression rhythm is important. One possible explanation for the improvement in IP, CC, and CAT accuracy is the difference in the recording environment. The previous study used a camera angle of 45\({}^{\circ}\), a height of 80 cm, and an unspecified distance. Furthermore, the recording was done using a GoPro in a horizontal orientation. In contrast, this study employed vertical recording, which likely increased the proportion of the subject performing chest compressions visible on the screen. As for the lack of significant improvement in the accuracy of depth and recoil estimation, two possible reasons can be considered. First, there may be limitations in the \begin{table}
\begin{tabular}{l c c c c c c} \hline \hline \multirow{2}{*}{**Metric**} & \multicolumn{2}{c}{**Angle: 30\({}^{\circ}\)**} & \multicolumn{2}{c}{**Angle: 45\({}^{\circ}\)**} & \multicolumn{2}{c}{**Angle: 60\({}^{\circ}\)**} \\ \cline{2-7}  & **Height: 50** & **Height: 80** & **Height: 50** & **Height: 80** & **Height: 50** & **Height: 80** \\ \hline
**Interruption Presence (IP)** & 83.75\% & 81.51\% & **85.54\%** & 82.45\% & 84.64\% & 81.51\% \\ \hline
**Count of Compression (CC)** & **69.64**\% & 63.21\% & 64.29\% & 63.21\% & 62.5\% & 62.64\% \\ \hline
**Appropriate Depth (CAD)** & 41.07\% & **47.17**\% & 41.96\% & 40.57\% & 41.96\% & 43.4\% \\ \hline
**Count of Appropriate Recoil (CAR)** & **31.25**\% & 26.42\% & **31.25**\% & 9.43\% & 27.68\% & 24.53\% \\ \hline
**Count of Appropriate Timing (CAT)** & **90.18**\% & 87.74\% & 89.29\% & 86.79\% & **90.18**\% & 89.62\% \\ \hline
**Appropriate Depth Timing (TAD)** & 47.71\% & 59.31\% & 64.25\% & **74.13**\% & 57.69\% & 47.1\% \\ \hline
**Appropriate Recoil Timing (TAR)** & **73.16**\% & 63.12\% & 67.48\% & 35.62\% & 67.93\% & 56.04\% \\ \hline
**Appropriate Chest Compression Timing (TAC)** & 56.45\% & 58.71\% & **64.59**\% & 55.68\% & 59.39\% & 54.9\% \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Results of evaluation system. calibration method used to estimate compression depth from the video data. Second, considering the higher accuracy reported in related studies using other methods, this may also reflect the limitations of posture estimation-based systems in accurately capturing depth and recoil parameters.