Vol.31 No.4(2) [2009]

Non-contact and Non-invasive Stress Evaluation Using Microwave Reflectometry

Daisuke NAGAE and Atsushi MASE


In this paper, we present a novel signal processing technique for stress evaluation using a microwave reflectometric cardiopulmonary sensing. This technique enables the heart rate variability (HRV) to be reconfigurated from measurements of body-surface dynamic motion, which is subsequently used for the stress evaluation. In particular, a novel element is due mainly to a reconfiguration of the HRV from the time variation of the heartbeat frequency which is evaluated by a repetition of the maximum entropy method (MEM). An experimental setup of a microwave reflectometer is presented and several sets of real data are analyzed using a new signal processing technique, which are subsequently used for the stress evaluation. Finally, a utility of the new signal processing technique is discussed.