A Video Technique for Obtaining 3-D Coordinates in Alpine Skiing

A video technique to obtain 3-D data in an Alpine skiing competition was investigated. The flight and landing phases of a jump were recorded during the 1994 Olympic combined downhill race. A direct linear transformation (DLT) implementation was applied, which computes the DLT parameters for each video image of each camera separately. As a consequence, one is able to pan and tilt the cameras and zoom the lenses. The problem of distributing control points in the large object space could be solved satisfactorily. The method proved to be suitable for obtaining 3-D data with reasonable accuracy, which is even sufficient for inverse dynamics. The computed resultant knee joint forces and moments compare well with results reported by other authors.

[1]  Werner Nachbauer,et al.  Use of Spline-Functions in the Smoothing of Film Data for Slalom Ski Racers , 1988 .

[2]  Sauli Savolainen,et al.  A cinematographic method for determination of the kinetic friction of skis on snow , 1985 .

[3]  Jesús Dapena,et al.  Comparison of Film and Video Techniques for Estimating Three-Dimensional Coordinates within a Large Field , 1992 .

[4]  Martin Mössner,et al.  Determination of Kinetic Friction and Drag Area in Alpine Skiing , 1996 .

[5]  Walter Herzog,et al.  External Loading at the Knee Joint for Landing Movements in Alpine Skiing , 1992 .

[6]  Sabine Van Huffel,et al.  Total least squares problem - computational aspects and analysis , 1991, Frontiers in applied mathematics.

[7]  Martin Mössner,et al.  A method for obtaining 3-D data in alpine skiing using pan-and-tilt cameras with zoom lenses , 1996 .

[8]  Maurice R. Yeadon.  A Method for Obtaining Three-Dimensional Data on Ski Jumping Using Pan and Tilt Cameras , 1989 .

[9]  C D Mote,et al.  Prediction of the loading along the leg during snow skiing. , 1992, Journal of biomechanics.

[10]  P Schaff,et al.  3-D Video Motion Analysis on the Slope—A Practical Way to Analyze Motion Patterns in Alpine Skiing , 1993 .

[11]  Ernest P Hanavan,et al.  A mathematical model of the human body , 1964 .

[12]  Walter Herzog,et al.  Anterior Cruciate Ligament Forces in Alpine Skiing. , 1993, Journal of applied biomechanics.

[13]  David L. Wright,et al.  Comparison of Film and Video Techniques for Three-Dimensional DLT Repredictions , 1989 .

[14]  M L Hull,et al.  Measurement of strength and loading variables on the knee during Alpine skiing. , 1989, Journal of biomechanics.

[15]  Jm Figueras,et al.  The Anterior Cruciate Ligament Injury in Skiers , 1987 .