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Time matching of separate cine camera views for three dimensional motion studies

University of British Columbia

The purpose of this study was to evaluate the importance of time-matching separate cine camera views in three-dimensional motion studies and to develop analytical methods to accomplish the time matching. An image space was calibrated using twenty-four control points and motion picture films at about 60 frames per second were taken of a moving bar, and of a subject putting a shot. Combinations of correctly and incorrectly matched views were compared for their accuracy in determining the positions of six object points. An algorithm was derived which included the timing variable in the least squares solution for the X, Y, and Z coordinates. These "best fit" solutions for the timing and for the coordinate locations were compared with criterion values. Alterations in the timing of views tended to introduce a bias into the coordinate locations. The magnitude of the bias was a function of the velocity of the object points and of the camera positioning. To keep final coordinate errors below 5% required the two views to be matched to within 0.008 seconds. The time matching algorithm was able to match the views to within 0.005 seconds. The corresponding coordinates could vary by an average of 2.4% from the correct ones. It was concluded that the analytical time matching algorithm could produce acceptable results if extreme accuracy was not required.

Text

2010-05-28

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http://hdl.handle.net/2429/25144

Physical Education

University of British Columbia

Graduate