Development of Human-Recorder for Head Sway-Based Fatigue Detection

Rescue workers in disasters and operators in construction sites become fatigued because they perform demanding daily tasks. Such fatigue causes discomfort and a lack of motivation at work, and these factors can have a serious impact on work efficiency and safety. Therefore, an approach is required to constantly monitor and detect fatigue conditions accurately. A head-mounted camera refers to a camera attached to a helmet, and it is used to record video as needed in order to share the situation at the work site during daily tasks by rescue workers and operators. Additionally, a head-mounted camera allows for hands-free recording. In this paper, a human-recorder device is proposed, which can detect fatigue by recording video with a head-mounted camera. The human-recorder extracts head sway from recorded videos and performs frequency analysis on this sway to detect fatigue. In the experiment, subjects perform an n-back task for 20 minutes to cause fatigue. From this result, the frequency analysis of head sway revealed a peak frequency between 1 ∼ 2 Hz. This peak frequency enables the estimation of the subject's pulse rate. In addition, it can be observed that low frequency components (0 ∼ 1 Hz) increase or decrease after the task. Therefore, the human-recorder can detect the fatigue by increasing or decreasing low frequency.