A Rapport and Gait Monitoring System Using a Single Head-Worn IMU during Walk and Talk

Public health is promoted when physical activity and social interaction increase. One's physical activity can be measured by wearable pedometers based on step counting, which contributes to physical health. However, thus far, no wearable device supports monitoring social interactions. In this paper, a single head-worn inertial measurement unit (H-IMU) is proposed to evaluate interpersonal activities, which can measure three objective components of rapport: positivity, mutual attentiveness, and coordination. Using angular kinematics, the number of head nods is counted for positivity (recognition rate: 94.34%). In terms of mutual attentiveness, we computed angle differences between two interactants' head orientations. The H-IMU can also measure coordination of two interactants' gait patterns based on individual gait events. These results can be a reference to estimate the level of rapport during walk and talk. The H-IMU is applicable to head-worn devices, such as smart earphones and head mounted displays (HMD).