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

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-tonoise 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.

Ultra-Wideband Impulse Radar Through-Wall Detection of Vital Signs

“…The respiration frequency is typically 0.2 Hz to 0.5 Hz with an amplitude of 5 to 15 mm, and the heart rate is 0.8 Hz to 2.5 Hz with an amplitude of 2 to 3 mm 38 . The SNCR can thus be improved using a window for these frequencies.…”

“…The classic EEMD i.e. ensemble empirical mode decomposition technique was used in 38 to estimate the heart rate of a living person by improving the SNR and removing clutter. An improved arctangent demodulation (AD) algorithm was proposed to increase the accuracies of human heart rate estimate 40 .…”

Non-invasive Diver Respiration Rate Monitoring in Hyperbaric Lifeboat Environments using Short-Range Radar

“…A radar-based system can perform continuous and non-intrusive tracking of the cardiopulmonary activity. Examples of almost all radar modes have been shown to have potential in this application, ranging from impulse radio ultra-wideband (IR-UWB) Radar [2]- [4] through continuous wave (CW) [5]- [9] to frequency-modulated continuous wave (FMCW) [10]- [15] Radar. While the detection of vital signs can rely solely on the Doppler information with no need to detect the range, the latter can help to isolate the signal of interest and consequently, filter out clutter and interference.…”

IR-UWB Sensor Based Fall Detection Method Using CNN Algorithm

“…The time-of-arrival is the travel time of an extremely short impulse signal with an ultra wideband (UWB) radiated from a transmitting antenna to hit the target and reflect back to the receiving antenna. Using the pattern of changes in signals affected by the movement of objects, researchers have studied the positioning of objects [ 35 , 36 ], human detection [ 37 ], measurement of bio-signals such as respiration and heartbeat rates [ 38 ], identification of non-line-of-sight condition [ 39 ], mobile phone usage detection [ 40 ], hand gesture inference [ 41 ], and hand gesture recognition based on finger-counting [ 42 ].…”