Reliability of Kinect measurements for assessing the movement of operators in ergonomic studies

Analyzing human poses at workstations is a key issue in ergonomics in order to evaluate potentials risks of musculoskeletal disorders. Kinect looks promising in measuring 3D joint kinematics on site but few studies have estimated the accuracy of the kinematic data delivered by this sensor in real situations. Thus, this study aims at evaluating the accuracy of the Kinect sensor for work-related motions. To this end we compared ISB Euler joint angles estimated with a Kinect to those obtained with a well-established marker-based device. Several repetitions of four of the main manual tasks described in MTM-2 classification were performed. Results showed that the RMSE between the data obtained with the two systems were 11(±3)° and 25(±4)° for the shoulder and the elbow joints respectively. Moreover, the measurement error was not randomly distributed but strongly depended on the joint configuration. Better knowledge on the Kinect measurement errors should help scientists and engineers to design appropriate protocols to measure joint kinematics in ergonomic assessments with this promising device.