In competitive sports, judges often scrutinize replay videos from multiple views to adjudicate uncertain or contentious actions, and ultimately ascertain the definitive score. Most existing action quality assessment methods regress from a single video or a pairwise exemplar and input videos, which are limited by the viewpoint and zoom scale of videos. To end this, we construct a Replay Figure Skating Jumping dataset (RFSJ), containing additional view information provided by the post-match replay video and fine-grained annotations. We also propose a Replay-Guided approach for action quality assessment, learned by a Triple-Stream Contrastive Transformer and a Temporal Concentration Module. Specifically, besides the pairwise input and exemplar, we contrast the input and its replay by an extra contrastive module. Then the consistency of scores guides the model to learn features of the same action under different views and zoom scales. In addition, based on the fact that errors or highlight moments of athletes are crucial factors affecting scoring, these moments are concentrated in parts of the video rather than a uniform distribution. The proposed temporal concentration module encourages the model to concentrate on these features, then cooperates with the contrastive regression module to obtain an effective scoring mechanism. Extensive experiments demonstrate that our method achieves Spearman's Rank Correlation of 0.9346 on the proposed RFSJ dataset, improving over the existing state-of-the-art methods.

In the volleyball game, estimating the 3D pose of the spiker is very valuable for training and analysis, because the spiker’s technique level determines the scoring or not of a round. The development of computer vision provides the possibility for the acquisition of the 3D pose. Most conventional pose estimation works are data-dependent methods, which mainly focus on reaching a high level on the dataset with the controllable scene, but fail to get good results in the wild real volleyball competition scene because of the lack of large labelled data, abnormal pose, occlusion and overlap. To refine the inaccurate estimated pose, this paper proposes a motion-aware and data-independent method based on a calibrated multi-camera system for a real volleyball competition scene. The proposed methods consist of three key components: 1) By utilizing the relationship of multi-views, an irrelevant projection based potential joint restore approach is proposed, which refines the wrong pose of one view with the other three views projected information to reduce the influence of occlusion and overlap. 2) Instead of training with a large amount labelled data, the proposed motion-aware method utilizes the similarity of specific motion in sports to achieve construct a spike model. Based on the spike model, joint and trajectory matching is proposed for coarse refinement. 3) To finely refine, a point distribution based posterior decision network is proposed. While expanding the receptive field, the pose estimation task is decomposed into a classification decision problem, which greatly avoids the dependence on a large amount of labelled data. The experimental dataset videos with four synchronous camera views are from a real game, the Game of 2014 Japan Inter High School of Men Volleyball. The experiment result achieves 76.25%, 81.89%, and 86.13% success rate at the 30mm, 50mm, and 70mm error range, respectively. Since the proposed refinement framework is based on a real volleyball competition, it is expected to be applied in the volleyball analysis.

Mirror and glass are ubiquitous materials in the 3D indoor living environment. However, the existing vision system always tends to neglect or misdiagnose them since they always perform the special visual feature of reflectivity or transparency, which causes severe consequences, i.e., a robot or drone may crash into a glass wall or be wrongly positioned by the reflections in mirrors, or wireless signals with high frequency may be influenced by these high-reflective materials. The exploration of segmenting mirrors and glass in static images has garnered notable research interest in recent years. However, accurately segmenting mirrors and glass within dynamic scenes remains a formidable challenge, primarily due to the lack of a high-quality dataset and effective methodologies. To accurately segment the mirror and glass regions in videos, this paper proposes key points trajectory and multi-level depth distinction to improve the segmentation quality of mirror and glass regions that are generated by any existing segmentation model. Firstly, key points trajectory is used to extract the special motion feature of reflection in the mirror and glass region. And the distinction in trajectory is used to remove wrong segmentation. Secondly, a multi-level depth map is generated for region and edge segmentation which contributes to the accuracy improvement. Further, an original dataset for video mirror and glass segmentation (MAGD) is constructed, which contains 9,960 images from 36 videos with corresponding manually annotated masks. Extensive experiments demonstrate that the proposed method consistently reduces the segmentation errors generated from various state-of-the-art models and reach the highest successful rate at 0.969, mIoU (mean Intersection over Union) at 0.852, and mPA (mean Pixel Accuracy) at 0.950, which is around 40% - 50% higher on average on an original video mirror and glass dataset.