Classification of Strokes in Table Tennis with a Three Stream Spatio-Temporal CNN for MediaEval 2020

This work presents a method for classifying table tennis strokes using spatio-temporal convolutional neural networks. The finegrained classification is performed on trimmed video segments recorded at 120 fps with different players performing in natural conditions. From those segments, the frames are extracted, their optical flow is computed and the pose of the player is estimated. From the optical flow amplitude, a region of interest is inferred. A three stream spatio-temporal convolutional neural network using combination of those modalities and 3D attention mechanisms is presented in order to perform classification.