# Comparative Analysis of Skeleton-Based Human Pose Estimation
## 4 Experiment Results
### Image Dataset  
The PDJ value for each image was calculated to compare the performance of the HPE libraries for each image. The results are presented in a box plot, as shown in Figure 3. Among the four HPE libraries, MoveNet (orange box) achieved the highest PDJ in terms of the lower fence, first quartile, median, and third quartile values. The second best performing HPE library was OpenPose (blue box), which achieved the same median and third quartile values as MoveNet; however, OpenPose had lower first quartile and fence (outlier) values. The third best performing HPE library was PoseNet (green box), followed by MediaPipe Pose (red box). The minimum values of MediaPipe Pose and PoseNet were 0. Meanwhile, the outlier values for MoveNet and OpenPose were also 0. The value of 0 indicated that the keypoints detected in some of the images were incorrectly matched with the ground truth provided by the COCO dataset.  
Table 4 divides the performance of the HPE libraries into five groups, including 0%, 0-25%, 25-50%, 50-75%, and 75-100%. Each group shows the number of images that were recognized by the HPE library in the specific range of PDJ values. MoveNet had the least number of images that achieved 0% of PDJ, which included 5 images. OpenPose achieved the second lowest number of images at 0% (8 images), followed by PoseNet (30 images) and MediaPipe Pose (240 images). In the range of 0-25%, MoveNet had the least number of images (33 images), followed by OpenPose (87 images), PoseNet (128 images), and MediaPipe Pose (342 images). Likewise, MoveNet had the least number of images that achieved the PDJ within the range of 25-50% (68 images).  
MoveNet achieved superior performance because it had the highest number of images in the last two groups (50-100%), which indicated that more than 50% of the detected keypoints from 994 images were correctly matched with the ground truth. In contrast, MediaPipe Pose was found to have the poorest performance because it had the highest number of images in the first to third groups (0-50%). In a total of 698 images, less than 50% of the detected keypoints were correctly matched with the ground truth. Overall, MoveNet achieved the top performance because it showed the highest number of images in the fifth group, which indicated that 747 out of 1,100 images were recognized by MoveNet with 75-100% detected keypoints. In contrast, MediaPipe Pose showed the poorest performance as it only achieved the lowest number of images in the range of 75-100%, but it received the highest number of images in the 0% group. OpenPose achieved the second highest performance, which was slightly lower than MoveNet. PoseNet and MediaPipe Pose achieved the third and fourth highest performances, respectively.  
In the overall comparison, MoveNet was the most robust because it achieved the top performance in terms of lower fence, first quartile, median, and third quartile values compared to the other HPE libraries. MoveNet achieved more than 50% PDJ value for 994  
\begin{table}
\begin{tabular}{l c c c c c} \hline \hline  & **0\%** & **0\% \textless{} PDJ \(\leq\) 25\%** & **25\% \textless{} PDJ \(\leq\) 50\%** & **50\% \textless{} PDJ \(\leq\) 75\%** & **75\% \textless{} PDJ \(\leq\) 100\%** \\ \hline MediaPipe Pose & 240 & 342 & 116 & 127 & 275 \\ OpenPose & 8 & 87 & 85 & 252 & 668 \\ PoseNet & 30 & 128 & 185 & 323 & 434 \\ MoveNet & 5 & 33 & 68 & 247 & 747 \\ \hline \hline \end{tabular}
\end{table}
Table 4: Number of images recognized by each HPE library in each specific range of PDJ values.  
Figure 3: Box plot of PDJ of all images in the image dataset.  
out of 1100 images. In addition, MediaPipe Pose showed the poorest performance in the image dataset as it has the lowest PDJ in terms of first quartile, median, and third quartile values. MediaPipe Pose also showed that less than 50% of detected keypoints could be correctly matched with the ground truth in 698 out of 1100 images. OpenPose and PoseNet achieved the second best and third best performances, respectively.