Analysis of Soccer Ball Collision Kinematics and Kinetics Using Image Processing Techniques #

Ieuan Phillips, Andy Harland, Séan Mitchell, Paul Lepper

11:50 Tuesday in 2Q42.

Part of the Mathematical modelling in sport session.

Abstract #

The ball is the most essential element of soccer matches. Since its first specification in the 1872 Laws of the Game, manufacturers have sought to innovate its design by changing constructions, assembly methods and materials, to improve the performance, consistency, and market appeal of their products. Players can often detect subtle differences between ball types during collisions such as kicking and heading, more readily than current laboratory tests. The extraction of more advanced kinematic and kinetic parameters from laboratory tests may help quantify such differences and inform future designs and governance strategies. This study reports a method for silhouette-based image analysis from single camera high-speed video data for soccer balls normally impacting a flat rigid plate. Balls were fired at game realistic velocities using a bespoke pneumatic actuator. The extraction of characteristic dynamic parameters from these short duration collisions, using a custom mathematical model, were used to provide detailed understanding of the kinematics and deformation. This included deformation of the ball radius through contact, to different magnitudes and shapes dependent on ball type, inflation pressure and condition. Further, by discretisation of the ball area into constituent mass elements and tracking their momentum changes through the collision, kinetic parameters such as impact force could also be derived, giving rise to an ability to detect kinematic and kinetic parameters from single camera footage.