Monocular Visual Analysis for Electronic Line Calling of Tennis Games

TL;DR

This paper introduces a monocular vision-based electronic line calling system for tennis that simplifies installation and reduces costs while maintaining high accuracy in determining if a ball is out of bounds.

Contribution

The paper presents a novel monocular vision approach for tennis line calling, including ball trajectory localization, bouncing point prediction, and out-of-bounds judgment, reducing reliance on complex binocular systems.

Findings

Achieved 99.4% accuracy in ball trajectory localization.

Successfully predicted bouncing points with 81.8% accuracy on test samples.

Demonstrated feasibility of monocular vision for accurate line calling in tennis.

Abstract

Electronic Line Calling is an auxiliary referee system used for tennis matches based on binocular vision technology. While ELC has been widely used, there are still many problems, such as complex installation and maintenance, high cost and etc. We propose a monocular vision technology based ELC method. The method has the following steps. First, locate the tennis ball's trajectory. We propose a multistage tennis ball positioning approach combining background subtraction and color area filtering. Then we propose a bouncing point prediction method by minimizing the fitting loss of the uncertain point. Finally, we find out whether the bouncing point of the ball is out of bounds or not according to the relative position between the bouncing point and the court side line in the two dimensional image. We collected and tagged 394 samples with an accuracy rate of 99.4%, and 81.8% of the 11 samples with bouncing points.The experimental results show that our method is feasible to judge if a ball is out of the court with monocular vision and significantly reduce complex installation and costs of ELC system with binocular vision.