Marker registration method informed by anatomical reference frame orientations

Accurate computation of joint angles from optical marker data using inverse kinematics methods requires that the locations of markers on a model match the locations of experimental markers on participants. Marker registration is the process of positioning the model markers so that they match the locations of the experimental markers. Markers are typically registered using a graphical user interface (GUI), but this method is subjective and may introduce errors and uncertainty to the calculated joint angles and moments. In this investigation, we use OpenSim to isolate and quantify marker registration–based error from other sources of error by analyzing the gait of a bipedal humanoid robot for which segment geometry, mass properties, and joint angles are known. We then propose a marker registration method that is informed by the orientation of anatomical reference frames derived from surface-mounted optical markers as an alternative to user registration using a GUI. The proposed orientation registration method reduced errors in joint angles and moments compared to the user registration method, and eliminated variability among users. Our results show that a systematic method for marker registration that reduces subjective user input can make marker registration more accurate and repeatable. <br/><br/>This project includes the following software/data packages: <br/> <ul> <li> <a href="https://simtk.org/frs?group_id=2055#pack_2239">Project Files </a> : Models, experimental data, and scripts to perform analysis </li> </ul>

在运用逆运动学方法精确计算光学标记数据中的关节角度时，确保模型上标记的位置与参与者实验标记的位置相吻合至关重要。标记配准是指将模型标记定位至与实验标记位置相对应的过程。标记通常通过图形用户界面（GUI）进行配准，但此方法具有主观性，可能引入误差和不确定性，从而影响计算出的关节角度和力矩。在本研究中，我们利用 OpenSim 对标记配准所基于的误差进行隔离和量化，以分析双足人形机器人的步态，该机器人的分段几何形状、质量属性和关节角度已知。随后，我们提出了一种基于表面安装的光学标记所得解剖参考框架方向的标记配准方法，作为替代用户通过 GUI 进行配准的方案。所提出的方向配准方法相较于用户配准方法，降低了关节角度和力矩的误差，并消除了用户间的变异性。我们的结果表明，通过减少主观用户输入的系统化标记配准方法，能够使标记配准更加精确和可重复。本项研究涉及以下软件/数据包：
<ul>
<li><a href="https://simtk.org/frs?group_id=2055#pack_2239">项目文件</a>：模型、实验数据和执行分析所需的脚本</li>
</ul>