Comparison of the observer, single-frame video and computer vision hand activity levels

Observer, manual single-frame video, and automated computer vision measures of the Hand Activity Level (HAL) were compared. HAL can be measured three ways: (1) observer rating (HAL_O), (2) calculated from single-frame multimedia video task analysis for measuring frequency (F) and duty cycle (D) (HAL_F), or (3) from automated computer vision (HAL_C). This study analysed videos collected from three prospective cohort studies to ascertain HAL_O, HAL_F, and HAL_C for 419 industrial videos. Although the differences for the three methods were relatively small on average (<1), they were statistically significant (p < .001). A difference between the HAL_C and HAL_F ratings within ±1 point on the HAL scale was the most consistent, where more than two thirds (68%) of all the cases were within that range and had a linear regression through the mean coefficient of 1.03 (R² = 0.89). The results suggest that the computer vision methodology yields comparable results as single-frame video analysis.Practitioner summary: The ACGIH Hand Activity Level (HAL) was obtained for 419 industrial tasks using three methods: observation, calculated using single-frame video analysis and computer vision. The computer vision methodology produced results that were comparable to single-frame video analysis.