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Load Asymmetry Angle Estimation Using Multiple-View Videos

delete2021-12-01
delete7
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OA
AI
Y
Yu Hen Hu *
M
Ming‐Lun Lu
R
Robert G. Radwin
DOI:10.1109/THMS.2021.3112962delete
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Abstract

Abstract

En 中文
A robust computer vision-based approach is developed to estimate the load asymmetry angle defined in the revised NIOSH lifting equation. The angle of asymmetry enables the computation of a recommended weight limit for repetitive lifting operations in a workplace to prevent lower back injuries. An open-source package OpenPose is applied to estimate the two-dimensional (2-D) locations of skeletal joints of the worker from two synchronous videos. Combining these joint location estimates, a computer vision correspondence and depth estimation method is developed to estimate the 3-D coordinates of skeletal joints during lifting. The angle of asymmetry is then deduced from a subset of these 3-D positions. Error analysis reveals unreliable angle estimates due to occlusions of upper limbs. A robust angle estimation method that mitigates this challenge is developed. We propose a method to flag unreliable angle estimates based on the average confidence level of 2-D joint estimates provided by OpenPose. An optimal threshold is derived that balances the percentage variance reduction of the estimation error and the percentage of angle estimates flagged. Tested with 360 lifting instances in a NIOSH-provided dataset, the standard deviation of angle estimation error is reduced from 10.13 degrees to 4.99 degrees. To realize this error variance reduction, 34% of estimated angles are flagged and require further validation.
Keywords:
Cameras
Videos
Pose estimation
Estimation error
Computer vision
Wrist
Task analysis
Asymmetry angle
manual lifting
NIOSH lifting equation
three-dimensional (3-D) skeletal joints estimation
video monitoring

Journal

IEEE Transactions on Human-Machine Systems cover
IEEE Transactions on Human-Machine Systems
IF:
4.4
Papers:
1.1K
Citations:
3.5K

Organization

U
university of wisconsin madison
Scholars:
3.8W
Papers: 2.9W
Citations: 53
University of Wisconsin System cover
University of Wisconsin System
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Papers: 5.8W
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C
centers for disease control & prevention - usa
Scholars:
2.9W
Papers: 2.3W
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