Visualization and motion analysis of swimming

It is an advantage to film a swimmer's whole body in order to grasp the swimmer's technique. However, it is difficult to understand details, such as twisting arms or stroke paths. Equipment was constructed which provides a continuous image of swimming motions by blending underwater and overwater images with a video mixer. Underwater and overwater images were taken by cameras loaded onto a cart placed on a poolside rail track. The view from above the swimmer was observed by an overhanging camera to observe wave resistance.. In order to grasp detailed swimming motions, logger data were synchronized with the actual motion images. Wavelet transform, a chronological frequency analysis, was also performed on these logger data and the dominant frequency was viewed chronologically with different swimming styles.