Professor of Mechanical Engineering and Smart Structures, School of Computing Engineering and Mathematics, Western Sydney University, Australia. His research interests cover Industry 4.0, Additive Manufacturing, Advanced Engineering Materials and Structures (Metals and Composites), Multi-scale Modelling of Materials and Structures, Metal Forming and Metal Surface Treatment.
Abstract—This paper provides effective techniques that can act as a guideline to calculate the velocity from a high-speed camera. A table tennis ball was vertically dropped with no initial spin from a 0.5 m drop height and collided with a rigid steel plate before rebound. A high-speed camera with a frame rate of 1000 frames/s was used to record the motion of the ball during pre- and post-impact. Manual and automatic tracking measurements were used to generate the distance–time profile of the ball during the impact event. In the manual tracking measurement, the distance–time data were manually identified, whereas in the automatic tracking measurement, the distance–time data were automatically generated by software. As a result, both these methods provide identical results. Four different methods were used to measure the velocity of the ball on the basis of the distance–time data. Three of these methods are (i) averaging the distance or velocity data, (ii) curve fitting with a linear and second-order polynomial trend line and (iii) fitting the trend line with the kinematic equation of free-fall motion. The fourth method, the automatic tracking measurement and the second-order polynomial trend line fitted with the kinematic equation of free-fall motion, was found to be the best method to obtain the velocity of the ball during impact.
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