Plane approximation-based approach for 3d reconstruction of ball trajectory for performance analysis in table tennis

A plane approximation-based approach for 3D reconstruction of ball trajectory is introduced, which was developed as a solution to the problem with conventional analysis in table tennis. There are methods of reconstructing 2D ball trajectories or 3D trajectories of balls heavier than those in table tennis. However, these methods cannot be adopted to reconstruct the 3D trajectories of table tennis balls, because there are problems that are attributed to the dimensions of the trajectories and weight of the balls. The method proposed in this chapter could reconstruct the 3D trajectories of a table tennis ball. The key feature of the method is that it approximates that a ball is traveling on tilted planes. This approximation makes reconstruction robust against failure to measure 3D ball positions. Two systems were developed based on the new method. A system using two RGB cameras experimentally demonstrated that it could provide accurate information for match analysis. A system using an RGB-D camera was experimentally demonstrated that the system could provide accurate information for service analysis.