Virtual Goal Keeping

Recently, a Virtual Reality lab has been opened at the Department of Human Movement Sciences at the University Medical Center Groningen (HMS/UMCG). One of the setups in this VR lab includes a VICON motion capture system and Head-Mounted Displays (HMDs). The VR lab will be used to perform studies into the control of human movement, allowing manipulation of virtual environments and the collection of high-quality motion data. To be able to use the setups for running scientific experiments, apart from integrating motion capture and presentation of content, also a management system for presenting experimental trials has to be in place. The present project takes the paradigm of lateral interception, within an ongoing study program, to develop all the components for arriving at such a system.

The present project builds on previous work in which we attempt to identify the information that people use to control their interceptive actions. For this specific project, we consider a goalkeeper, whose movement is restricted sideways along the goal line and who will be facing balls approaching the goalmouth. These balls will follow trajectories of varying sideway curvature. The goalkeeper's task is to "catch" the balls (by having the balls hit the body).

The hardware of the setup is available at the Department of Human Movement Sciences at the University Medical Center Groningen (UMCG). The football keeper will operate in a virtual environment, offered to them through a head-mounted display (HMD). Tracking of the motion of the goalkeeper takes places with a VICON system. Several components of the integration of the motion capture and the HMD-presented virtual environment have been developed. The present project will use these components and develop additional ones to create a system in which experiments with lateral interception can be performed.

The full system will be as follows:

• The system will present a virtual environment to participants, in which the participants are goalkeepers who have to "catch" approaching balls.
• Motion of the participants will be captured with VICON; this motion will be used to update the participants point of view.
• The system will allow the presentation of balls following several predefined trajectories.
• The trials (with varying ball trajectories) will be presented in a blocked random order.
• Kinematics of the participants, synchronized with the kinematics of the balls, will be saved per trial for later analyses.
• Summary statistics (such as on success or failure to "catch") will be saved in a summary file.

This project builds on previous components, to arrive at a full operational system for experimentation. Some new components will have to be developed, and all components will have to be integrated into the final system.