A method for obtaining three-dimensional data on ski jumping using pan and tilt cameras

A method is presented for the three-dimensional analysis of ski jumping using two pan and tilt cameras. In each film frame two reference markers are digitized and identified so that a pseudo focal length and three angles defining camera orientation can be calculated from a knowledge of the positions of camera and markers. In each film frame 12 body landmarks are digitized and the films taken by the two cameras are synchronized using the digitized displacement data. The time histories of the center of mass location and 15 angles describing the orientation and configuration of the jumper are calculated. Digitization errors lead to an error of 0.05 m in center of mass location and an error of 1° in orientation angles