High-accuracy gait measurement system using multiple laser range sensors (Application to timed up and go test in the elderly)

Abstract

Gait measurements and physical fitness tests are carried out in the community health activities for health promotion and care prevention services in the growing elderly population. In particular, the timed up and go test (TUG) is the clinical test most often used to evaluate functional mobility in many clinical institutions or local communities. To evaluate the functional mobility during the TUG, a gait measurement system (Laser-TUG system) using a laser range sensor (LRS) has been proposed. The system tracks both legs and measures the foot contact positions to obtain walking parameters such as stride length and step length. To reduce the false tracking and improve the measurement accuracy during the turning phase of the TUG, a data association considering gait phase and a spline-based interpolation have been proposed. However, the false tracking is likely to be occurred in the elderly and the measurement accuracy during the turning phase is still deteriorated because of occlusion and inaccurate observation of legs. Therefore, this paper presents a high-accuracy gait measurement system using multiple LRSs. Using multiple LRSs is able to reduce the situation of leg occlusion. However, the measurement accuracy of leg position depends on the distance from the LRS. To improve the measurement accuracy, an integrated leg detection method by a weighted mean of the observation candidates from each LRS data based on the distance from the LRS is proposed. We confirm that the proposed leg detection method can improve the success rate of leg tracking in the elderly and measurement accuracy of the leg trajectory and walking parameters.