抄録
For the sake of an evaluation of ball velocity, flight angle, spin rate and spin axis of a spinning sports ball, an automated image processing system for an analysis of images during flight of the ball captured using a high speed video camera has been developed. The tested ball is marked with mutually perpendicular three great circles for the detection of its attitude. An ellipse which is the projection of the great circle on the image is detected by the generalized Hough transform. The ball attitude is decided by directions of three great circles. The spin axis and spin rate are calculated from variations of the ball attitude. From the analysis of experimental flight images of a table tennis ball using the developed system, it is found that the obtained results are accurate and reliable through the comparison with manually analyzed results and three-dimensional spin measurement is possible using only one camera.
