Research On Detection Of Table Tennis Landing Point And Edge Sensing System

Table tennis is the "national ball" of our country.In order to improve the training level of table tennis players,enhance their awareness of landing and ball control ability,and objectively solve the problem that it is difficult to judge the edge ball,this paper designs a table tennis landing detection and edge perception system,which can not only assist the training of table tennis players,but also help referees to quickly and objectively judge the competition.Aiming at the application scenario of auxiliary training of table tennis players' awareness of landing point,firstly,the video of table tennis is obtained by binocular camera,then the background subtraction method is combined with the color and shape characteristics of table tennis to identify the table tennis in motion,and the search range is narrowed by dynamic window to track the flight trajectory of table tennis in real time.Experiments show that the table tennis recognition and real-time tracking method designed in this paper can overcome the problem that the background subtraction method is sensitive to illumination changes,reproduce the three-dimensional landing point and trajectory of table tennis,and provide reference for training.Additionally,compared with full-picture search,using dynamic window to track table tennis trajectory can effectively reduce the calculation time.Secondly,the force analysis of table tennis is carried out,and the motion model of table tennis is established.Because the motion model of table tennis with rotation is nonlinear,this paper uses Unscented Kalman Filter algorithm to predict the flight trajectory and landing point of table tennis.In this paper,trajectory prediction experiments are carried out for topspin and backspin balls.The average filtering time was 1.202 s,and the prediction error was no more than 20 mm.Aiming at the problem that it is difficult to define the edge ball in the competition,according to the principle of triboelectric nanogenerator,this paper designs a self-powered thin-film pressure sensor to sense the edge ball,analyzes the electrostatic field of the sensor by using FEM software,designs the detection circuit and host computer software,and builds an experimental platform.Experiments show that the sensor designed in this paper can convert the pressure into electrical signals,which can be transmitted to the host computer through the detection circuit.When the table tennis falls on the Thin film pressure sensor,the referee can know from the interface of the host computer that the incoming ball rubs the side,so as to make an objective judgement.In this paper,the perception of edge ball can be realized without changing table tennis and competition equipment,and without affecting the trajectory of table tennis,thus ensuring the fairness and justice of the competition.