Study On The Design Of Basic Technique Motion Evaluation System For Table Tennis Based On Kinect Motion Capture

According to the opinions of the General Office of the State Council on strengthening school physical education to promote the all-round development of students' physical and mental health.Deepening teaching reform,strengthening physical exercise,and extensively launching the advantages of table tennis sports have become the key content of school physical education development.In order to improve the teaching quality of table tennis,improve the deficiency of traditional teaching mode,and realize the scientific and intelligent teaching requirements,this study proposes the design and development of table tennis basic technical motion evaluation system based on Kinect motion capture technology.At the same time,in view of the lack of professional technical guidance in the current mass fitness,the design research of this system can achieve the function of technical motion guidance and evaluation for beginners or amateurs of table tennis to a certain extent,and meet the needs of beginners or amateurs in self-learning and table tennis technical motion evaluation.Firstly,through the investigation and analysis of users' needs,the function of system development is determined.The hardware device uses Kinect 2.0 motion capture technology developed by Microsoft and Kinect SDK v2.0 development toolkit to acquire the original depth data captured by Kinect 2.0 by calling related data interfaces such as color data flow,depth information data flow and skeletal data flow.As the input data of the system,the program design of the test and evaluation module is developed.Kinect 2.0 motion capture device can greatly reduce the system cost in depth information acquisition,and the data processing is simple and real-time,which is convenient for popularization and application to the public.Secondly,the system errors such as abrupt change and jitter of original coordinate data generated during data transmission and skeletal joint position are smoothed by Kinect 2.0.Double exponential smoothing filter and jitter removal filter are used to filter and denoise the original data.For the lag error caused by the smoothing filter,the prediction value is used to reduce the filtering delay,and the prediction value point is adjusted by the max deviation radius to alleviate the motion sensitivity and overshoot caused by the excessive parameters of the prediction value.Through the test of experimental data,the smoothing filter used in this study improves the stability and accuracy of Kinect' s data acquisition of skeletal joint points.It has good application effect and can meet the requirements of data testing and analysis.Thirdly,the characteristics of table tennis technical movements of excellent athletes are extracted.Through the analysis of table tennis technical movements,in this study,a complete table tennis technical action cycle is divided into three stages: the lead racket stage,the swing bat stage and the restore stage.According to Euler distance,the participation degree of human skeletal joint points in the whole movement process was calculated.Extracting the information of three groups of skeletal joint points with high participation in the process of excellent athletes' technical movements.These are used as the evaluation basis of action recognition judgment.Finally,in the motion evaluation and analysis module,the dynamic time warping algorithm is used to align the two time series with different lengths,and calculate the similarity between the two sequences to evaluate the integrity and accuracy of the overall technical motion structure of the test object.The Pearson correlation coefficient is used to calculate the correlation between the initial motion posture and the end motion posture of the three motion stages.According to the relevant calculation results,the problems existing in the specific technical motion posture of the tester in a complete action cycle can be analyzed in detail and displayed in the form of a chart on the system interface.By compiling computer programs,the evaluation and analysis functions of table tennis technical movements are realized.Intelligent feedback is used to quantify the evaluation and analysis results,so that users can understand and correct the problems existing in their technical movements in time,and achieve the system functions of teaching assistance and intelligent technical movements evaluation.