EVALUATION OF SILHOUETTE-BASED MARKERLESS TRACKING FOR KINEMATICS IN SPORT

The purpose of this study was to evaluate markerless, silhouette-based tracking for different applications in sports science. Data of segment center of gravity locations, joint center locations as well as joint angles were taken into account. To quantify the accuracy of silhouette-based in comparison to marker-based tracking, all mentioned parameters were compared with the correlation coefficient and standard deviation of the differences for three classes of movements: specific joint movements, complex movements, and highly dynamic movements (with racquet). Very strong correlations result for the segment center of gravity locations, the joint center locations as well as for joint angles in the sagittal plane except the elbow joints. Joint angle accuracy impairs in the transversal and the frontal plane with an increasing complexity and speed in the movement patterns. To obtain accurate joint angles separated into the three body planes, however, we recommend to enhance the tracking of segment rotations should be stabilized by additional information (e.g. marker or IMU)