Step length measurement in the wild using FMCW radar
Parthipan Siva Alexander Wong Patricia Hewston George Ioannidis Dr. Jonathan Adachi Dr. Alexander Rabinovich Andrea Lee Alexandra Papaioannou
With an aging population, numerous assistive and monitoring technologies are
under development to enable older adults to age in place. To facilitate aging
in place predicting risk factors such as falls, and hospitalization and
providing early interventions are important. Much of the work on ambient
monitoring for risk prediction has centered on gait speed analysis, utilizing
privacy-preserving sensors like radar. Despite compelling evidence that
monitoring step length, in addition to gait speed, is crucial for predicting
risk, radar-based methods have not explored step length measurement in the
home. Furthermore, laboratory experiments on step length measurement using
radars are limited to proof of concept studies with few healthy subjects. To
address this gap, a radar-based step length measurement system for the home is
proposed based on detection and tracking using radar point cloud, followed by
Doppler speed profiling of the torso to obtain step lengths in the home. The
proposed method was evaluated in a clinical environment, involving 35 frail
older adults, to establish its validity. Additionally, the method was assessed
in people's homes, with 21 frail older adults who had participated in the
clinical assessment. The proposed radar-based step length measurement method
was compared to the gold standard Zeno Walkway Gait Analysis System, revealing
a 4.5cm/8.3% error in a clinical setting. Furthermore, it exhibited excellent
reliability (ICC(2,k)=0.91, 95% CI 0.82 to 0.96) in uncontrolled home settings.
The method also proved accurate in uncontrolled home settings, as indicated by
a strong agreement (ICC(3,k)=0.81 (95% CI 0.53 to 0.92)) between home
measurements and in-clinic assessments.