title: Measuring elemental time and duty cycle using automated video processing.
abstract: A marker-less 2D video algorithm measured hand kinematics (location, velocity and acceleration) in a paced repetitive laboratory task for varying hand activity levels (HAL). The decision tree (DT) algorithm identified the trajectory of the hand using spatiotemporal relationships during the exertion and rest states. The feature vector training (FVT) method utilised the k-nearest neighbourhood classifier, trained using a set of samples or the first cycle. The average duty cycle (DC) error using the DT algorithm was 2.7%. The FVT algorithm had an average 3.3% error when trained using the first cycle sample of each repetitive task, and had a 2.8% average error when trained using several representative repetitive cycles. Error for HAL was 0.1 for both algorithms, which was considered negligible. Elemental time, stratified by task and subject, were not statistically different from ground truth (p < 0.05). Both algorithms performed well for automatically measuring elapsed time, DC and HAL. Practitioner Summary: A completely automated approach for measuring elapsed time and DC was developed using marker-less video tracking and the tracked kinematic record. Such an approach is automatic, repeatable, objective and unobtrusive, and is suitable for evaluating repetitive exertions, muscle fatigue and manual tasks.
authors: a Department of Industrial and Systems Engineering , University of Wisconsin-Madison , Madison , WI , USA.
authors: Oguz
authors: O
authors: Akkas
authors: b Department of Electrical and Computer Engineering , University of Wisconsin-Madison , Madison , WI , USA.
authors: Cheng-Hsien
authors: CH
authors: Lee
authors: b Department of Electrical and Computer Engineering , University of Wisconsin-Madison , Madison , WI , USA.
authors: Yu Hen
authors: YH
authors: Hu
authors: a Department of Industrial and Systems Engineering , University of Wisconsin-Madison , Madison , WI , USA.
authors: Thomas Y
authors: TY
authors: Yen
authors: a Department of Industrial and Systems Engineering , University of Wisconsin-Madison , Madison , WI , USA.
authors: Robert G
authors: RG
authors: Radwin
mesh_terms: D000054:Acceleration; D000465:Algorithms; D001696:Biomechanical Phenomena; D005260:Female; D006225:Hand / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D009068:Movement; D018763:Muscle Fatigue; D013647:Task Performance and Analysis; D014741:Video Recording
keywords: Repetitive motion; exposure assessment; time and motion study; work-related musculoskeletal disorders