Video Exposure Assessment of Hand Activity

Details

• Personal Author:
  Hu YH ; Lindstrom M ; Radwin RG ; Yen TY
• Description:
  This research investigated the feasibility of automatically evaluating the American Conference of Government Industrial Hygienists (ACGIH) Hand Activity Level (HAL) using digital video processing. There is currently no practical instrument for objectively, unobtrusively, and efficiently measuring repetitive motion exposure for evaluating the risk of musculoskeletal injuries in the workplace. Previous methods involve either direct measurements using instruments attached to a worker's hands or arms, or indirect observations. Both instrument and observation methods are mostly limited to research studies and are highly impractical for industry practitioners. The new approach leverages a vast data base of videos and associated exposure data already analyzed manually through collaboration with the University of California-Berkeley (UCB). A new equation for predicting the hand activity level (HAL) used in the ACGIH threshold limit value(TM) (TLV(TM)), was based on exertion frequency (F) and percentage duty cycle (D). The TLV(TM) includes a table for estimating HAL from F and D originating from data in Latko et al. (1997) and post-hoc adjustments that includes extrapolations outside of the data range. Multimedia video task analysis determined D for two additional jobs from Latko's study not in the original data set, and a new non-linear regression equation was developed to better fit the data and create a more accurate table. The equation, HAL = 6.56lnD[F1.31/(1+3.18F1.31)]generally matches the TLV(TM) HAL lookup table, and is a substantial improvement over the linear model, particularly for F > 1.25 Hz and D > 60% jobs. The equation more closely fits the data and applies the TLV(TM) using a continuous function. An equation was developed for estimating hand activity level (HAL) directly from tracked RMS hand speed (S) and duty cycle (D). Since automatically estimating F is sometimes complex, HAL may be more readily assessed using S. Hands from 33 videos originally used for the HAL rating were tracked to estimate S, scaled relative to hand breadth (HB), and single-frame analysis was used to measure D. Since HBs were unknown, a Monte Carlo method was employed for iteratively estimating the regression coefficients from US Army anthropometry survey data. The equation: HAL = 10[(e^-15.87+0.02D+2.25lns)/(1+e^-15.87+0.02D+2.25lns)], R2 = 0.97, had a residual range +/-0.5 HAL. The S equation superiorly fit the Latko (1997) data and predicted independently observed HAL values (Harris, 2011) better (MSE=0.16) than the F equation (MSE=1.28). A new method for automatically measuring duty cycle (proportion of time exerting force) in repetitive motion jobs was also investigated. A marker-less video tracking algorithm measured hand kinematics (location, velocity and acceleration) in a repetitive laboratory task (Move-Release-Reach-Grasp) for varying hand activity levels (HAL). Trajectory of the hand was identified using spatiotemporal curvature relationships for hand velocity and acceleration and exertion states (Move-Release). The maximum duty cycle error was 7.3%, and on average 2.7 % duty cycle error was achieved. A comparison of HAL ratings against ground truth calculated HAL ratings based on the algorithm had an average error of 0.1, which may be considered negligible. [Description provided by NIOSH]
• Subjects:
  Coal Coal Mining Mining Occupational Health Safety
• Keywords:
  Hand Injuries Measurement Equipment Monitoring Systems MSD Musculoskeletal Disorders Recording Systems Repetitive Work Threshold Limit Values TLV Video
• Series:
  Grant Final Reports
• Publisher:
  National Institute for Occupational Safety and Health
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Final Grant Report
• Place as Subject:
  OSHA Region 5 ; Wisconsin
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  OEP - Office of Extramural Programs
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  1-40
• NIOSHTIC Number:
  nn:20053809
• NTIS Accession Number:
  PB2019-100324
• Citation:
  Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, R21-OH-010221, 2015 Oct; :1-40
• Contact Point Address:
  Robert G. Radwin, University of Wisconsin-Madison, Department of Industrial and Systems Engineering, 1550 Engineering Drive, Madison, WI 53706
• Email:
  radwin@engr.wisc.edu
• Federal Fiscal Year:
  2016
• NORA Priority Area:
  Manufacturing
• Performing Organization:
  University of Wisconsin-Madison
• Peer Reviewed:
  False
• Start Date:
  20120701
• Source Full Name:
  National Institute for Occupational Safety and Health
• End Date:
  20150630
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:84bd18170ed794711fbe7d83c6eaaa52557ffb103690a25bc90470e16a06baf0eb2520980cb7f1ba3f212ef8accb8879f636364568022b7c9873fe43d2442023
• Download URL:
  https://stacks.cdc.gov/view/cdc/218781/cdc_218781_DS1.pdf
• File Type:
  [PDF - 2.01 MB ]