Develppment of a remote realtime measurement system for outdoor sports using optical beam scanners

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An optical measurement system has been developed its accuracy was tested for uses of out door sports. Temporal signal of acceleration, deceleration, or velocity of players includes a lot of information which is helpful to analyze players' motion. Especially in case that data of measurement is obtained in real time and results of analysis is fedback to the player during his play, the player would find it very easy to relate his motion to the resultant performance. Video analysis, which is commonly used in movement analyses, seems helpless for this purpose, since first, spatial resolution of video camera is too poor to satisfy the requirements mentioned above in order to cover a big out door field with a diameter of larger than 40m. Second, realtime image analysis is technically difficult with current equipments.Instead of videocameras, a pair of polygon beam scanners were employed to scan horizontally across a mesurement field. A special reflector was attached to a moving object. The horizontal position was calculated from the time when the reflected light from the object returned to a detector. Vertical position was measured by the position sensing device (PSD).Spatial resolution in horizontal direction proved to be 0.3 mm at a distance of 30 m, and 3.6 mm at 45.5 m. Vertical resolution proved to be 1.2 mm at 14.4 m and 4.9 mm at 20 m.