Abstract
With an increasing number of elderly people, there is growing concern about a lack of system that enable to provide immediate medical interventions for the elderly who are in poor physical condition and to prevent unattended death of the elderly who live alone. For preventing undesirable incidence to the elderly, continuous monitoring of vital signs is of great importance. We present an unconstrained sensing technique for monitoring heart rate (HR) using ballistocardiographic signals (BCG) from PVDF film sensor mounted in an ordinary bed. The intrinsic mode functions (IMF) of BCG signals were extracted by iteratively detrending operation using complementary ensemble empirical mode decomposition method. Average HR was derived from full-wave rectification of IMF2 and IMF3 waves by measuring the intervals between the peaks of the autocorrelation function every second. To show the validity of this method, the HR obtained by this method was compared with that simultaneously measured using an electrocardiogram. The results showed that mean absolute error rate was 1.56±0.85% during stationary resting condition. The proposed method may be helpful for practical use in the home health-care.
