Analyzing volleyball videos based on 3D ball trajectories was relatively overlooked before. In this brief, we focus on how ball trajectories can benefit volleyball video analysis. Based on videos captured by two cameras from different viewpoints, we detect the volleyball and construct 3D ball trajectories. We then propose a trajectory segmentation and classification method based on BERT (Bidirectional Encoder Representation for Transformer). The volleyball at each frame can be categorized into one of six trajectory classes, e.g., serve and attack, and a long ball trajectory showing the ball being hit back and forth is appropriately segmented. We believe that this is a very first study adopting the language model technique to analyze ball trajectories, and results of trajectory segmentation and classification can enable more advanced volleyball analysis.

中文翻译：

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它如何飞行以及为何飞行？排球轨迹分割与分类


基于 3D 球轨迹分析排球视频之前相对被忽视。在本文中，我们重点关注球轨迹如何有利于排球视频分析。基于两个摄像头从不同视角拍摄的视频，我们检测排球并构建 3D 球轨迹。然后，我们提出了一种基于 BERT（Transformer 双向编码器表示）的轨迹分割和分类方法。每一帧的排球可以分为发球和进攻等六种轨迹类别之一，并且对显示来回击球的长球轨迹进行适当分段。我们相信这是首次采用语言模型技术来分析球轨迹的研究，轨迹分割和分类的结果可以实现更高级的排球分析。