Multiscale fractal dimension applied to tactical analysis in football: A novel approach to evaluate the shapes of team organization on the pitch

Author(s)

de Oliveira Bueno, Murilo Jose ^[1] ; Silva, Maisa ^[2] ; Cunha, Sergio Augusto ^[3] ; Toffee, Ricardo da Silva ^[4] ; Moura, Felipe Arruda ^[1]

Affiliation

^[1] Univ Estadual Londrina, Sport Sci Dept, Londrina, Parana - Brazil

^[2] Univ Estadual Campinas, Inst Comp, Campinas - Brazil

^[3] Univ Estadual Campinas, Coll Phys Educ, Campinas - Brazil

^[4] NTNU Norwegian Univ Sci & Technol, Dept ICT & Nat Sci, Alesund - Norway

• Document type: Journal article
• Source: PLoS One; v. 16, n. 9 SEP 1 2021.
• Web of Science Citations: 0

Abstract

The aim of this study was to evaluate different shape descriptors applied to images of polygons that represent the organization of football teams on the pitch. The effectiveness of different shape descriptors (area/perimeter, fractal area, circularity, maximum fractal, rectangularity, multiscale fractal curve-MFC), and the concatenation of all shape descriptors (except MFC), denominated Alldescriptors (AllD)) was evaluated and applied to polygons corresponding to the shapes represented by the convex hull obtained from players' 2D coordinates. A content-based image retrieval system (CBIR) was applied for 25 users (mean age of 31.9 +/- 8.4 years) to evaluate the relevant images. Measures of effectiveness were used to evaluate the shape descriptors (P@n and R@n). The MFD (P@5, 0.46 +/- 0.37 and P@10, 0.40 +/- 0.31, p < 0.001; R@5, 0.14<plus/minus>0.13 and R@10, 0.24 +/- 0.19, p < 0.001) and AllD (P@5 = 0.43<plus/minus>0.36 and P@10 = 0.39 +/- 0.32, p < 0.001; R@5 = 0.13<plus/minus>0.11 and R@10 = 0.24 +/- 0.20, p < 0.001) descriptors presented higher values of effectiveness. As a practical demonstration, the best evaluated shape descriptor (MFC) was applied for tactical analysis of an official match. K-means clustering technique was applied, and different shapes of organization could be identified throughout the match. The MFC was the most effective shape descriptor in relation to all others, making it possible to apply this descriptor in the analysis of professional football matches. (AU)

• FAPESP's process: 18/19007-9 - Find dribbling time series in a physical-tactical-technical scenario during official professional matches
• Grantee: Sergio Augusto Cunha
• Support Opportunities: Scholarships abroad - Research
• FAPESP's process: 16/50250-1 - The secret of playing football: Brazil versus the Netherlands
• Grantee: Sergio Augusto Cunha
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 17/20945-0 - Multi-user equipment approved in great 16/50250-1: local positioning system
• Grantee: Sergio Augusto Cunha
• Support Opportunities: Multi-user Equipment Program