Baseball swing analysis from a monocular video

Swing analysis during baseball games requires high-precision radar and stereo cameras, which makes their adoption challenging for amateur players. We propose a low-cost swing analysis method that estimates the impact and swing trajectory using a monocular video. Furthermore, our method computes the degree of the upper swing and generates trajectory-superimposed videos to facilitate an easier understanding of the swing characteristics. We evaluated the accuracy of ball and bat detection, impact estimation, and bat line segment estimation. We also conducted a questionnaire survey to assess the usefulness of the upper swing index and the superimposed trajectory videos. These results suggest that our method can provide useful information for swing analysis.