Tracking futsal players with a wide-angle lens camera: accuracy analysis of the radial distortion correction based on an improved Hough transform algorithm

• Autor(a) principal: Vieira, Luiz H. P.
• Data de Publicação: 2017
• Outros Autores: Pagnoca, Emilio A., Milioni, Fabio [UNESP], Barbieri, Ricardo A. [UNESP], Menezes, Rafael P., Alvarez, Luis, Deniz, Luis G., Santana-Cedres, Daniel, Santiago, Paulo R. P.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://dx.doi.org/10.1080/21681163.2015.1072055; http://hdl.handle.net/11449/159439
• topic: Radial distortion; Hough transform; GoPro; automatic tracking; futsal; biomechanics

The aim of this study was to assess the applicability and reliability of a single wide-angle lens GoPro r camera for tracking and kinematics analysis of futsal players. An official game of a Brazilian professional team in the quarter-final round of the 2013 Sao Paulo futsal league was recorded by four digital video cameras (30 Hz; 720 x 480) placed at the highest points of the court (40 x 20 m; FIFA standard). We compared tracking performed with three cameras equipped with conventional lenses to a GoPro r camera with a wide-angle lens with a 170 degrees field of view. Manual and automatic tracking of players trajectories (n = 5; 23.20 +/- 2.39 years) during competition and in a controlled environment were performed. We found that the root-mean-square error calculated to determine the position on the court based on images captured with a GoPro r camera was 0.32 m and for the velocity was 0.71 m s-1. A 5-min excerpt of the game showed an average difference of 2.11% between the total distance covered obtained by tracking with the GoPro r with radial distortion correction (438.97 +/- 164.65 m), and cameras with conventional lenses (449.54 +/- 170.92 m). Temporal correlation analysis confirmed the great similarity between the reconstructed trajectories obtained by these cameras (r = 0.99 for movements on both x and y axes). We showed that a single GoPro r Hero3+ can provide reliable kinematic analysis of computational tracking based on videogrammetry for futsal, using the Hough transform and division model technique for radial distortion correction.