PLANE-BASED CAMERA CALIBRATION FOR 3D-VIDEOGRAMMETRY FOR CANOEING AND ROWING

Abstract

3D kinematic analyses are normally based on calibration procedures using the DLT algorithm. Therefore, a calibration frame recorded in the center of the field of view works as reference frame for the reconstruction of the 3D object. Due to the conditions of water sports, this proceeding is not applicable to sports disciplines like canoeing or rowing. For such events, the recording with pre-calibrated cameras from a catamaran that follows the object has been proven (Hildebrand et al.,1998). It seems to be more appropriate to apply especially under the condition of competition calibration techniques which do not require a spatial calibration frame. Here, several methods have been published; these calculate the camera orientation from two or more observations of the same planar scene from different perspectives (e.g. Sturm & Maybank, 1999; Zhang, 1999), but only few applications deal with sports related tasks. Instead of these general approaches, a calibration method for 3D analysis in water sports has been developed, that uses the specific conditions of tripod based camera panning. Buoys that define the borders of the race lanes and therefore are placed in exactly measured distances serve as a planar system of control points.