Motion analysis of athletes often provides important information to improve training and strategy meetings. Visual player-tracking techniques are being developed that do not need devices. In this paper, we focus on racket sports, since they suffer from technical issues for visual tracking such as small observation size (low resolution) and large variation of player appearances. Moreover, racket sports video is usually captured by a monocular camera at a set position so that each player is observed at a top and a bottom region of the video across a net on the court. As a result, tracking accuracy is damaged by the net that often occludes players on the far side. As a solution, this paper proposes a method to improve the player-tracking accuracy in badminton video by applying an image pixel compensation technique, such as Image Inpainting. We confirm the effectiveness of our method using videos of badminton singles games.

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In this paper, a method for extraction of important players in soccer videos based on link analysis is proposed. In a soccer match, players perform shoot tackles, assistance, and covering. Furthermore, the soccer tactics are defined the formation of players based on various relationships between players. The proposed method extracts the important players, in order to obtain information for understanding the soccer matches for various audiences. Specifically, our method notes that relationship between players, who cooperate with each other by the pass and the covering, is similar to relationship between web pages which are connected by links. First, the proposed method obtains player networks based on relationship between players in each team. The relationships are defined based on player positions and the possibility of the pass or the covering between players. Finally, in the proposed method, by applying the link analysis to the obtained player networks, important players are extracted. By realizing this approach, important players are extracted from the player networks based on the possibility of the pass or the covering between players. In the last of this paper, the above link analysis-based method was applied to actual soccer matches to show the reasonability of our method.

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In this paper, we propose a system that enables users to interact with virtual objects that are displayed on a mobile display in a precisely-aligned view using their hands. By projecting a 3D scene obtained by a depth camera according to the user's viewpoint position, the scene including the user's hand displayed on the screen appears seamlessly connected to the actual scene outside the screen, which enables natural interaction with virtual objects through the screen. We conducted an experiment to evaluate the positional accuracy in the presented images. The maximum mean error was 8.60 mm, and the maximum standard deviation was 1.69 mm, which could be improved by further refinement. We also conducted an experiment to evaluate the usability of the system. We asked the participants to perform tasks using the proposed system in the aligned and non-aligned see-through modes. Despite some restrictions in our prototype system, 9 out of 14 participants completed the task faster in the aligned see-through mode. This result shows the future potential of the proposed system in interaction with virtual objects.

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Projector-camera (ProCam) systems have a potential to become popular and affordable as they can create interactive surfaces for example on tabletops, walls, household items or on a palm of a hand. The possibility that these systems will be used at homes in the future is increasing. The elderly living alone at home often need assistance in their daily tasks as the likelihood of cognitive and motor skill related impairments increases with age. ProCam systems could be used for guidance due to easy to manipulate large interaction surfaces, but research on its suitability for elderly users is scarce. Our research focus is on elderly users and examining their characteristics as potential users of ProCam systems and the implications for interaction design. We conducted a user study with a mixed impairments group of elderly aged 82-94 to investigate how a personalized and skill-suited user interface should be designed. In our qualitative approach, we discovered that the combinations of both cognitive and motor skill deficiencies of the elderly prohibit one-for-all designs so the user interface design should be adapted to each individual's interaction skills. Lastly, we make suggestions for designing ProCam interaction for elderly.

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A secure identification scheme for JPEG XR images is proposed in this paper.The aim is to securely identify JPEG XR images which are generated from the same original image under various compression levels. The positive and negative signs of lapped biorthogonal transform coefficients are used as features.The proposed scheme is robust against a difference in compression levels, and does not produce false negative matches in any compression level. In addition, to construct a secure identification system, we propose a novel identification system that consists of an error correction technique and a fuzzy commitment scheme, which is a well-known biometric cryptosystem. There is no existing scheme having these properties for JPEG XR images. Moreover, a way for speeding up the identification is also proposed. The experimental results show the proposed scheme is effective for identifying JPEG XR images in terms of true positive matches.

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