Rally Counting Method Integrating Image and Audio Processing Based on Table Tennis Match Video Characteristics

This paper proposes a method for automatically estimating the number of rallies in table tennis match videos as part of improving the efficiency of play analysis. By using this method, the manual effort previously required for recording rally counts can be eliminated. The analysis assumes a vertically oriented camera view, as commonly seen in broadcast footage. Since the ball in the lower court may be occluded by players, only the upper court is analyzed. The ball in the upper court is detected by analyzing the pixel value differences between the ball and the table. The number of rallies is measured by counting the number of times a ball hit by a player passes through the upper court. To ensure accurate counting, hit balls are distinguished from high-toss serves and failures due to the net. Experimental results show that the proposed method correctly counted the number of rallies in 87.0 % of 623 scenes from Japanese T-League match videos. Furthermore, when the existing scoring/losing rate calculation method was applied to the automatically measured rally counts, the results closely matched those obtained from manually recorded rally counts, confirming the effectiveness of the proposed rally counting method. Large-scale quantitative analysis becomes feasible through automated processing.