Event-based Ball Spin Estimation in Sports

Takuya Nakabayashi, Kyota Higa, Masahiro Yamaguchi, Ryo Fujiwara, Hideo Saito; Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR) Workshops, 2024, pp. 3367-3375

Ball spin estimation in sports is important for analyzing the game. Since spin is generally too fast to be captured by a conventional camera a high-speed camera is often used to capture images of the ball and estimate its spin. However since a high-speed camera is not robust to changes in the lighting conditions it is difficult to estimate spin in some environments. To solve these problems this paper proposes a new method for ball spin estimation using an event camera. An event camera is a sensor inspired by the visual system of animals which outputs the brightness changes in a scene. Event cameras have advantages such as high temporal resolution and high dynamic range and can accurately capture the motion of a fast-spinning ball in various lighting conditions. Experimental results in a synthesized dataset showed that the proposed method can stably estimate spin up to 500 rps. It is also confirmed that the proposed method can estimate spin in the data obtained from actual sports games.