Short-Range Vital Signs Sensing Based on EEMD and CWT Using IR-UWB Radar.

Xikun Hu,Tian Jin

doi:10.3390/s16122025

Abstract

The radar sensor described realizes healthcare monitoring capable of detecting subject chest-wall movement caused by cardiopulmonary activities and wirelessly estimating the respiration and heartbeat rates of the subject without attaching any devices to the body. Conventional single-tone Doppler radar can only capture Doppler signatures because of a lack of bandwidth information with noncontact sensors. In contrast, we take full advantage of impulse radio ultra-wideband (IR-UWB) radar to achieve low power consumption and convenient portability, with a flexible detection range and desirable accuracy. A noise reduction method based on improved ensemble empirical mode decomposition (EEMD) and a vital sign separation method based on the continuous-wavelet transform (CWT) are proposed jointly to improve the signal-to-noise ratio (SNR) in order to acquire accurate respiration and heartbeat rates. Experimental results illustrate that respiration and heartbeat signals can be extracted accurately under different conditions. This noncontact healthcare sensor system proves the commercial feasibility and considerable accessibility of using compact IR-UWB radar for emerging biomedical applications.

Highlights

Radar sensors have been widely used in a number of applications since the 1930s [1], from primary vehicle speed measurement to advanced air-defense and marine radars, all of which are usually developed for ranging, targeting, or tracking moving subjects at large distances
Due to its non-invasive and noncontact properties, short-range radar has been an appealing approach in healthcare applications since the 1970s, when the first short-range non-invasive radar for respiration measurement was introduced [2]
We develop short-range vital sign detection methods using impulse radio ultra-wideband (IR-UWB) radar based on a fully integrated nano-scale radar transceiver chip, which has a low power consumption, flexible dynamic range and configurable output frequency

Summary

Introduction

Radar sensors have been widely used in a number of applications since the 1930s [1], from primary vehicle speed measurement to advanced air-defense and marine radars, all of which are usually developed for ranging, targeting, or tracking moving subjects at large distances. Due to its non-invasive and noncontact properties, short-range radar has been an appealing approach in healthcare applications since the 1970s, when the first short-range non-invasive radar for respiration measurement was introduced [2]. Conventional medical devices like an electrocardiograph (ECG) and respiration belts rely on electrodes alone and an inductive plethysmograph, respectively, which make subjects uncomfortable, and may even worsen the quality of physiological measurements. Wearable devices require that the subject be attached to electric poles twisted together with several wires for heartbeat monitoring or a vacuum belt for respiratory monitoring during sleep, which may have a negative impact on sleep quality [5]

Methods

Results

Conclusion