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Proposition of a method for tennis players motion analysis on broadcast videos

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Author(s):
Cláudio Luís Roveri Vieira
Total Authors: 1
Document type: Master's Dissertation
Press: Campinas, SP.
Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Educação Física
Defense date:
Examining board members:
Ricardo Machado Leite de Barros; Neucimar Jerônimo Leite; Hans Joachim Karl Menzel
Advisor: Ricardo Machado Leite de Barros
Abstract

The aim of this study is to propose a set of methods for tennis players motion analysis from pre calibrated video using fixed cameras as well as on broadcast tennis videos. First, it was proposed and validated a novel automatic method for tracking tennis players from precalibrated videos using two fixed cameras. The percentage of automatic tracking was 99.98%. The two-dimensional coordinates reconstruction of the tennis court was validated by calculating the intra-operator repeatability (0.009 m), inter-operator repeatability (0.007 m), relative error (0.03% length and 0.06% width). The accuracy reached for the player's position was 0.36 m. For both coordinates, the linear regression was significant (R2 > 0.99, p <0.05) from the positions obtained by automatic and manual tracking methods. The covered distance performed by the players during a set of a tennis match was calculated. The second proposed method was the automatic detection of rallies in broadcast tennis videos. The method developed was based on the histogram extraction, statistical filtering and key frame similarity comparison. Three videos of tennis matches representing three different court surfaces were used to evaluate the proposed method. The average hit rate of the scene cuts was 81%. The rallies duration obtained by the proposed method was valid whether compared with the manual annotation and suitable to determine the rally duration for all sample videos. The third proposed method was proposed a dynamic calibration (frame by frame) in broadcast tennis video based on the automatic tennis court lines intersections detection. The percentage of automation of lines intersections identification and homographic matrix generation was 99.98%. The static test, based on varying by ± 2 pixels the calibration points, revealed a satisfactory accuracy (2.26 cm). The dynamic test, which have been reprocessed 522 frames using 4-8 calibration points, also showed satisfactory accuracy (23 cm). The fourth method presented was the automatic tracking of tennis players on broadcast tennis videos. The identification of the players' position was based on the sub-region of higher correlation with the players' clothes model in a region of interest (ROI) constructed by using the homographic matrix. The percentage of automation was 99.62% and the processing time was 0.86 seconds per frame processed. The errors (RMS) involved in determining the position of the tennis players were about 45 cm to the side of the court closest from the camera and 64 cm to the side of the court farthest from the camera. The covered distances, velocities and occupancy areas for both players were automatically extracted. In conclusion, the proposed methods developed and applied on broadcast tennis videos revealed to be feasible, with a high level of automation and accuracy similar to methods based on fixed cameras (AU)

FAPESP's process: 11/03928-9 - Proposition of a method of motion analysis of tennis players for broadcast videos
Grantee:Claudio Luis Roveri Vieira
Support Opportunities: Scholarships in Brazil - Master