| 摘要 |
PURPOSE:To measure the spin of a ball accurately, by combining a linear image sensor camera with the ball having a longitude marked by a black felt-tipped pen or the like. CONSTITUTION:A ball 2 having a longitude marked by a black felt-tipped ink or like is made to fly along the line of a linear image sensor camera 3 so that the axis center of rotation is almost orthogonal to the line connecting the ball 2 and the camera 3. The ball 2 is taken many times at a very short cycle while crossing the area within a photographing range of the camera 3. The detection signal of the camera 3 depending on the colored longitude is inputted into an I/O unit 7 of a microcomputer 6 via an A/D converter 5. Then, a drop in the level of the detection signal of the camera 3 depending on the colored longitude is checked to detect the phase of rotation of the ball 2 and based on the phase of rotation and a photographing interval, the revolutions per unit time of the ball is computed to display 10 spin of the ball. This only requires the marking of the longitude by the felt-tipped pen, thereby enabling accurate measurement of the spin of the ball with the shape of a dimple and the weight of the ball remaining unchanged.
|
