Using camera motion to identify different types of American football plays

This paper presents a method that uses camera motion parameters to recognise 7 types of American football plays. The approach is based on the motion information extracted from the video and it can identify short and long pass plays, short and long running plays, quarterback sacks, punt plays and kickoff plays. This method has the advantage that it is fast and it does not require player or ball tracking. The system was trained and tested using 782 plays and the results show that the system has an overall classification accuracy of 68%.<br /

The role of motion analysis in elite soccer

The optimal physical preparation of elite soccer (association football) players has become an indispensable part of the professional game especially due to the increased physical demands of match-play. The monitoring of players’ work-rate profiles during competition is now feasible through computer-aided motion analysis. Traditional methods of motion analysis were extremely labour intensive and were largely restricted to university- based research projects. Recent technological developments have meant that sophisticated systems, capable of quickly recording and processing the data of all players’ physical contributions throughout an entire match, are now being used in elite club environments. In recognition of the important role motion analysis now plays as a tool for measuring the physical performance of soccer players, this review critically appraises various motion analysis methods currently employed in elite soccer and explores research conducted using these methods. This review therefore aims to increase the awareness of both practitioners and researchers of the various motion analysis systems available, identify practical implications of the established body of knowledge, while highlighting areas that require further exploration

Play type recognition in real-world football video

This paper presents a vision system for recognizing the sequence of plays in amateur videos of American football games (e.g. offense, defense, kickoff, punt, etc). The sys-tem is aimed at reducing user effort in annotating foot-ball videos, which are posted on a web service used by over 13,000 high school, college, and professional football teams. Recognizing football plays is particularly challeng-ing in the context of such a web service, due to the huge variations across videos, in terms of camera viewpoint, mo-tion, distance from the field, as well as amateur camerawork quality, and lighting conditions, among other factors. Given a sequence of videos, where each shows a particular play of a football game, we first run noisy play-level detectors on every video. Then, we integrate responses of the play-level detectors with global game-level reasoning which accounts for statistical knowledge about football games. Our empir-ical results on more than 1450 videos from 10 diverse foot-ball games show that our approach is quite effective, and close to being usable in a real-world setting. 1

Identifying the mechanisms underpinning recognition of structured sequences of action

© 2012 The Experimental Psychology SocietyWe present three experiments to identify the specific information sources that skilled participants use to make recognition judgements when presented with dynamic, structured stimuli. A group of less skilled participants acted as controls. In all experiments, participants were presented with filmed stimuli containing structured action sequences. In a subsequent recognition phase, participants were presented with new and previously seen stimuli and were required to make judgements as to whether or not each sequence had been presented earlier (or were edited versions of earlier sequences). In Experiment 1, skilled participants demonstrated superior sensitivity in recognition when viewing dynamic clips compared with static images and clips where the frames were presented in a nonsequential, randomized manner, implicating the importance of motion information when identifying familiar or unfamiliar sequences. In Experiment 2, we presented normal and mirror-reversed sequences in order to distort access to absolute motion information. Skilled participants demonstrated superior recognition sensitivity, but no significant differences were observed across viewing conditions, leading to the suggestion that skilled participants are more likely to extract relative rather than absolute motion when making such judgements. In Experiment 3, we manipulated relative motion information by occluding several display features for the duration of each film sequence. A significant decrement in performance was reported when centrally located features were occluded compared to those located in more peripheral positions. Findings indicate that skilled participants are particularly sensitive to relative motion information when attempting to identify familiarity in dynamic, visual displays involving interaction between numerous features

Learning multi-modal densities on discriminative temporal interaction manifold for group activity recognition

While video-based activity analysis and recognition has received much attention, existing body of work mostly deals with single object/person case. Coordinated multi-object activities, or group activities, present in a variety of applications such as surveillance, sports, and biological monitoring records, etc., are the main focus of this paper. Unlike earlier attempts which model the complex spatial temporal constraints among multiple objects with a parametric Bayesian network, we propose a Discriminative Temporal Interaction Manifold (DTIM) framework as a data-driven strategy to characterize the group motion pattern without employing specific domain knowledge. In particular, we establish probability densities on the DTIM, whose element, the discriminative temporal interaction matrix, compactly describes the coordination and interaction among multiple objects in a group activity. For each class of group activity we learn a multi-modal density function on the DTIM. A Maximum a Posteriori (MAP) classifier on the manifold is then designed for recognizing new activities. Experiments on football play recognition demonstrate the effectiveness of the approach

Capturing interpersonal coordination processes in association football : from dyads to collectives

Doutoramento em Motricidade Humana, na especialidade de Ciências do DesportoThe purpose of this thesis was to investigate how football performers coordinate their behaviours in different levels of social organisation. We began with a position paper proposing the re-conceptualisation of sport teams as functional integrated superorganisms to frame a deeper understanding of the interpersonal coordination processes emerging between team players. Time-motion analysis procedures and innovative tools were developed and presented in order to capture the superorganismic properties of sports teams and the interpersonal coordination tendencies developed by players. These tendencies were captured and analysed in representative 1vs1 and 3vs3 sub-phases, as well as in the 11-a-side game format. Data showed higher levels of variability at the individual level compared to the team level. This finding suggested that micro-variability may contribute to stabilise the behavioural dynamics at the collective level. Moreover, the specificities of the interpersonal coordination tendencies displayed within attacking-defending dyads demonstrated to have influenced the performance outcome. Attacking players tend to succeed when they were more synchronised in space and time with the defenders, and their interaction were more unpredictable/irregular. Besides, the time-evolving dynamics of the collective behaviours (i.e., at 11-a-side level) during competitive football performance indicated a tendency for an increase in the predictability (i.e., more regularity). These data were interpreted as evidencing co-adaptation processes between opponent players, which suggest that team players may shift from prevalent explorative and irregular behaviours to more predictable behaviours emerging due changes in their functional movement possibilities. However, some game events such as goals scored, halftime and stoppages in play seemed to break this continuum and acted as relevant performance constraints.FCT - Fundação para Ciência e a Tecnologi

Time Motion Analysis of Men\u27s Professional Beach Volleyball

Identifying work-to-rest ratios and rate of high-intensity movements provides a better insight into the physiological demands of sports, but no such analysis has been done in beach volleyball. Videotape footage, obtained from the Association of Volleyball Professionals (AVP), consisted of 12 healthy male professional volleyball players from three different AVP final matches during the 2008 season.Rally durations and high intensity movements (HIMs) were recorded. Total work and total match time means were identified, 13.7 minutes and 74.8 minutes, respectively. Only 17% of the total time the ball was actually in play. Overall mean rally time and rest times were also identified, M = 6.7 seconds and M = 32.8 seconds, respectively. The frequency HIMs was 0.8 per minute, with each player performing approximately 33.5 HIMs per set. T-test indicate no significant difference between winning and losing teams (p = 0.73). Further analysis on women and amateur-level players is warranted