Accuracy and repeatability of joint angles measured using a single camera markerless motion capture system

Anne Schmitz, Mao Ye, Robert Shapiro, Ruigang Yang, Brian Noehren

Research output: Contribution to journalArticlepeer-review

102 Scopus citations

Abstract

Markerless motion capture systems have developed in an effort to evaluate human movement in a natural setting. However, the accuracy and reliability of these systems remain understudied. Therefore, the goals of this study were to quantify the accuracy and repeatability of joint angles using a single camera markerless motion capture system and to compare the markerless system performance with that of a marker-based system. A jig was placed in multiple static postures with marker trajectories collected using a ten camera motion analysis system. Depth and color image data were simultaneously collected from a single Microsoft Kinect camera, which was subsequently used to calculate virtual marker trajectories. A digital inclinometer provided a measure of ground-truth for sagittal and frontal plane joint angles. Joint angles were calculated with marker data from both motion capture systems using successive body-fixed rotations. The sagittal and frontal plane joint angles calculated from the marker-based and markerless system agreed with inclinometer measurements by <0.5°. The systems agreed with each other by <0.5° for sagittal and frontal plane joint angles and <2° for transverse plane rotation. Both systems showed a coefficient of reliability <0.5° for all angles. These results illustrate the feasibility of a single camera markerless motion capture system to accurately measure lower extremity kinematics and provide a first step in using this technology to discern clinically relevant differences in the joint kinematics of patient populations.

Original languageEnglish
Pages (from-to)587-591
Number of pages5
JournalJournal of Biomechanics
Volume47
Issue number2
DOIs
StatePublished - Jan 22 2014

Bibliographical note

Funding Information:
This work was funded in part by the Division of Information and Intelligent Systems of the National Science Foundation , grant 1231545 .

Keywords

  • Accuracy and reliability
  • Joint angles
  • Microsoft Kinect
  • Motion capture

ASJC Scopus subject areas

  • Biophysics
  • Orthopedics and Sports Medicine
  • Biomedical Engineering
  • Rehabilitation

Fingerprint

Dive into the research topics of 'Accuracy and repeatability of joint angles measured using a single camera markerless motion capture system'. Together they form a unique fingerprint.

Cite this