The effect of camera location on observation-based posture estimation.
This study used the observation-based method showing images on computer to evaluate angle estimation errors of 8 body segments in 3 motion planes at up to 28 segment angles and 5 camera locations with respect to goniometric measurements. Thirty observers participated in evaluating segment angles. Forearm (9.9°) and thigh (9.5°) had smaller errors than hand (14.0°) and foot had the smallest error (8.7°) due to its narrow range of motion (ROM). Errors were small with camera locations perpendicular to motions in the planes, such as 90° camera location for the flexion and extension of arm (6.3°), forearm (7.9°), thigh (6.5°), and leg (8.1°) in the sagittal plane. Segments had small errors of 3.1°, 4.6°, and 3.8° at segment angles of -90°, 0° and 90°, respectively. Care should be taken when estimating angles by the observation-based method for a specific segment motion and viewing direction is suggested to be perpendicular to the motion plane.
Some companies may not allow many cameras or have obstacles for working posture evaluation in the workplace. These study results can be a guideline on proper selection of the number of cameras and their locations for a specific segment and its motion of interest to reduce visual segment angle estimation errors.
Department of Industrial and Information Systems Engineering, Ajou University, Suwon, South Korea.
Yan
Y
Qu
Jaejin
J
Hwang
Kyung-Sun
KS
Lee
Myung-Chul
MC
Jung
D061827:Dimensional Measurement Accuracy; D006801:Humans; D016014:Linear Models; D009068:Movement / Q000502:physiology*; D019370:Observation / Q000379:methods*; D010781:Photography / Q000379:methods*; D011187:Posture / Q000502:physiology; D016059:Range of Motion, Articular / Q000502:physiology*; D055815:Young Adult