Research On Parameters Analysis And Evaluation Of Tai Chi Zhuang Based On Human Body Keypoints

Tai Chi is a traditional Chinese martial art beneficial to physical and mental health.Tai Chi Zhuang is its fundamental core skill.Due to the profound connotation of Tai Chi Zhuang and the richness of language and cognition,students’ understanding of the essentials of Tai Chi Zhuang is various deviations,which also affects the training time and effect.Based on the demand,the experimental research on Tai Chi Zhuang process of experts and students is carried out in this thesis.The digital analysis and evaluation of Tai Chi Zhuang can objectively reflect its law,assist students in understanding the essentials of Tai Chi Zhuang,improve training efficiency,promote the development of Tai Chi,and improve the national health level.Tai Chi Zhuang learning begins with body shape.Image is the digital medium that can best reflect body shape.The human body keypoints in the image can reflect the joint position and describe body posture,which is the objective basis for motion analysis.Therefore,the body shape is focused on,and the image is taken as breakthrough point in this thesis.Based on the human body keypoints,the law and characteristics in the process of expert Tai Chi Zhuang are explored to help students objectively understand Tai Chi Zhuang at the cognitive level.The students’ Tai Chi Zhuang movements are evaluated to help them improve their learning effect at the behavioral level.The main research contents include the following three aspects:(1)Tai Chi Zhuang data collection and human body keypoints extraction.In order to obtain objective and accurate Tai Chi Zhuang images and human body keypoints,firstly,data collection pre-experiment is carried out in combination with the research requirements and the characteristics of Tai Chi Zhuang.The performance of AlphaPose,OpenPose 18,OpenPose25 and lightweight OpenPose algorithms for the untransformed,rotated,translated and scaled Tai Chi Zhuang images is compared and analyzed by a data-driven method.The results show that OpenPose25 algorithm has the best performance in the extraction accuracy of human body keypoints and algorithm reliability.Then,Tai Chi Zhuang images of 6 experts and 13 students from front and side perspectives are collected,and the human body keypoints are extracted.Finally,the affine transformation is used to process the human body keypoints to ensure that their coordinates are under the same benchmark,so as to provide standardized data for subsequent analysis and evaluation.(2)Parameter analysis of Tai Chi Zhuang based on expert data.In order to extract the core data characteristics of the expert Tai Chi Zhuang process and help students to understand Tai Chi Zhuang objectively,characteristic parameters are calculated according to the human body keypoints.Statistical analysis,Welch power spectrum estimation and wavelet transform are used to explore the time-frequency distribution of experts’ parameters and perform digital interpretation of Tai Chi Zhuang.The results show that Tai Chi Zhuang is a dynamic change process.In the front,the range of motion of the head,neck,shoulders and trunk is concentrated between[-5°,5°],and the degree of crotch separation is concentrated between[95°,10°].In the side,the range of motion of the trunk is concentrated between[-5°,7°],the angle formed by the trunk and thigh is concentrated between[150°,170°],and the bending degree of the knee joint is concentrated between[140°,160°].In addition,the dynamic change process of Tai Chi Zhuang has apparent periodicity,which reflects the adjustment strategy of posture.(3)Digital evaluation of Tai Chi Zhuang for student data.In order to solve the problems of solid subjectivity and insufficient accuracy in the artificial Tai Chi Zhuang evaluation,a Tai Chi Zhuang digital evaluation system is constructed for student data.Based on dynamic time warping algorithm and expert parameter distribution range,the evaluation indexes of parameters are calculated respectively,and the long-term data of students are evaluated and fed back.In addition,according to the long-term evaluation results,the coefficient of variation method is used to explore the importance of each parameter and conduct a comprehensive evaluation of Tai Chi Zhuang.The results show that the trunk,thigh,knee and hip are the more important body parts in the process of Tai Chi Zhuang,and the effect of students’ Tai Chi Zhuang has been significantly improved.Therefore,the constructed digital evaluation system can effectively assist Tai Chi Zhuang training.