中国组织工程研究

中国组织工程研究 ›› 2022, Vol. 26 ›› Issue (12): 1822-1827.doi: 10.12307/2022.502

• 骨与关节生物力学Bone and joint biomechanics • 上一篇    下一篇

光学三维运动捕捉系统用于生物力学测试的精准度分析

谭菁华，薛静波，谢  勇，王  程，晏怡果   

  1. 南华大学衡阳医学院，附属第一医院脊柱外科，湖南省衡阳市   421001
  • 收稿日期:2021-06-04 修回日期:2021-06-23 接受日期:2021-08-07 出版日期:2022-04-28 发布日期:2021-12-14
  • 通讯作者: 晏怡果，博士，主任医师，南华大学衡阳医学院，附属第一医院脊柱外科，湖南省衡阳市 421001
  • 作者简介:谭菁华，男，1992年生，湖南省衡阳市人，汉族，2018年南华大学毕业，硕士，医师，主要从事骨与关节生物力学研究。
  • 基金资助:
    湖南省卫生计生委科研计划课题重点项目 (A2017016)，项目负责人：晏怡果；衡阳市骨科内植物研发重点实验室 (2018KJ115)，项目负责人：晏怡果

Accuracy and precision analysis of optical three-dimensional movement capture system for biomechanical testing

Tan Jinghua, Xue Jingbo, Xie Yong, Wang Cheng, Yan Yiguo   

  1. Department of Spine Surgery, First Affiliated Hospital of Hengyang Medical School of Nanhua University, Hengyang 421001, Hunan Province, China
  • Received:2021-06-04 Revised:2021-06-23 Accepted:2021-08-07 Online:2022-04-28 Published:2021-12-14
  • Contact: Yan Yiguo, MD, Chief physician, Department of Spine Surgery, First Affiliated Hospital of Hengyang Medical School of Nanhua University, Hengyang 421001, Hunan Province, China
  • About author:Tan Jinghua, Master, Physician, Department of Spine Surgery, First Affiliated Hospital of Hengyang Medical School of Nanhua University, Hengyang 421001, Hunan Province, China
  • Supported by:
    Key Project of Scientific Research Program of Hunan Provincial Health and Family Planning Commission, No. A2017016 (to YYG); Hengyang Orthopedics Endogenous Plant Research and Development Key Laboratory, No. 2018KJ115 (to YYG)

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摘要：

文题释义：
运动捕捉：实时地准确测量、记录物体在真实三维空间中的运动轨迹或姿态，并在虚拟三维空间中重建运动物体每一时刻运动状态的高新技术。
精准度：表示相同情况下进行测量的重复性，反映测量系统的稳定性。准确度描述测量值与真实值的偏差。

背景：光学三维运动捕捉系统无论在生理还是病理、体外或体内实验以及医疗或生活方面均应用广泛，但尚无研究客观分析该系统精准度及其影响因素。
目的：建立光学三维运动捕捉系统，分析其应用于生物力学测试的精准度及影响因素。
方法：首先，安装光学三维运动捕捉系统摄像机为半弧形高低交替位置，捕捉静止标记点18组坐标数据，每组400个坐标值，计算出系统精密度。应用机械臂完成沿坐标轴X、Y和Z轴方向运动，所得的坐标数据经MATLAB处理计算出运动距离(测量值)。然后，以电子千分尺为实际值基准，计算运动捕捉系统的准确度。最后，根据前述精准度测试方法分别在不同运动方向、各个坐标轴、有无室内照明、不同相机数目、不同Marker尺寸材质和不同相机位置变量下，应用单因素方差分析系统的精准度是否有差异。
结果与结论：①光学式三维运动捕捉系统摄像机为半弧形交替摆放时，X、Y和Z轴坐标精密度分别为5.00，10.26，5.50 μm，沿X、Y和Z轴运动的准确度分别为15.58，20.69，12.24 μm；②随着摄像头从单面形到环状，精密度逐渐增加，呈环形摆放时精密度最优；③室内有无开始照明灯对系统的精准度无明显影响；④随着摄像机的数目增加，捕捉系统的精密度随之上升，但数量达到一定时精密度会渐近极限；⑤该系统中塑料硬质12.7，14.0，15.9 mm和橡胶材料直径为14.0 mm的Marker点精密度无差异；⑥结果说明，光学三维运动捕捉系统的摄像机数量及摆放位置对系统精准度均有影响，Marker尺寸材质、运动方向、室内照明对系统的精准度无明显影响。该系统精准度满足生物力学测试的需求。

https://orcid.org/0000-0002-5165-3701 (谭菁华) 

中国组织工程研究杂志出版内容重点：人工关节；骨植入物；脊柱；骨折；内固定；数字化骨科；组织工程

关键词: 运动捕捉, 光学式三维运动捕捉系统, 精准度, 生物力学

Abstract: BACKGROUND: The optical three-dimensional motion capture system is widely used in physiology or pathology, in vitro or in vivo experiments, medical treatment or life, but there is no objective analysis of the accuracy of the system and its influencing factors.  
OBJECTIVE: To establish optical three-dimensional motion capture system to analyze its accuracy and influencing factors for biomechanical testing.
METHODS:  First, the optical three-dimensional motion capture system camera was installed to a semi-arc wave position to capture 18 sets of coordinate data of static marker points, each set of 400 coordinate values. The system precision was calculated. The robot arm was used to complete the movement along the coordinate axis X, Y and Z axis, and the obtained coordinate data were processed by MATLAB to calculate the movement distance (measured value). Second, the accuracy of the motion capture system was calculated based on the actual value of the electronic micrometer. Finally, according to the aforementioned precision and accuracy test method, one-way analysis of variance was used to analyze whether there were differences in the precision and accuracy of the system under different motion directions, various coordinate axes, indoor lighting, different camera numbers, different Marker sizes and materials, and different camera position variables.  
RESULTS AND CONCLUSION: (1) When the optical three-dimensional motion capture system camera was placed in a semi-arc wave, the X, Y and Z axis coordinate precisions were 5.00, 10.26, and 5.50 μm, respectively, and the accuracies of the movement along the X, Y and Z axes were: 15.58, 20.69, and 12.24 μm. (2) As the camera changed from a single-sided shape to a ring shape, the accuracy gradually increased, and the accuracy was optimal when placed in a ring. (3) The presence or absence of starting lighting in the room had no significant impact on the accuracy of the system. (4) As the number of cameras increased, the precision of the capture system rised, but when the number reached a certain level, the precision would approach its limit. (5) In this system, there was no difference in the precision of the Marker points of plastic rigid 12.7, 14.0, 15.9 mm and rubber material with a diameter of 14.0 mm. (6) Therefore, the number of cameras and the placement position of the optical 3D motion capture system have an impact on the accuracy of the system. The size and material of the Marker, the direction of movement, and the indoor lighting have no significant impact on the accuracy of the system. The precision and accuracy of the system meet the needs of biomechanical testing.

Key words: motion capture, optical three-dimensional motion capture system, precision and accuracy, biomechanics

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