A low cost 3D markerless system for the reconstruction of athletic techniques

We present a low cost markerless system for the optimization of athlete performance in sports such as pole vault, jumping and javelin throw. The system uses a number of calibrated cameras to capture a video of an athlete from different viewpoints. The athlete's body is then segmented from the background in each video frame. The silhouettes of the segmented body are then reprojected to reconstruct an estimate of the 3D body shape of the athlete, known as the visual hull (VH). The VH is tracked over a number of frames in real testing trials. A template combining a high resolution 3D scan and a 2D mass scan is then aligned with the VH in each frame. A set of motion analysis parameters such as the take-off data are finally estimated from the aligned template and compared with the ones obtained using a gold standard marker-based system, namely the Vicon. The proposed system was tested in real-time trials and was able to provide comparable results to the Vicon system.