Matrix Pencil Method for Vital Sign Detection from Signals Acquired by Microwave Sensors

Abstract

Microwave sensors have recently been introduced as high-temporal resolution sensors, which could be used in the contactless monitoring of artery pulsation and breathing. However, accurate and efficient signal processing methods are still required. In this paper, the matrix pencil method (MPM), as an efficient method with good frequency resolution, is applied to back-reflected microwave signals to extract vital signs. It is shown that decomposing of the signal to its damping exponentials fulfilled by MPM gives the opportunity to separate signals, e.g., breathing and heartbeat, with high precision. A publicly online dataset (GUARDIAN), obtained by a continuous wave microwave sensor, is applied to evaluate the performance of MPM. Two methods of bandpass filtering (BPF) and variational mode decomposition (VMD) are also implemented. In addition to the GUARDIAN dataset, these methods are also applied to signals acquired by an ultra-wideband (UWB) sensor. It is concluded that when the vital sign is sufficiently strong and pure, all methods, e.g., MPM, VMD, and BPF, are appropriate for vital sign monitoring. However, in noisy cases, MPM has better performance. Therefore, for non-contact microwave vital sign monitoring, which is usually subject to noisy situations, MPM is a powerful method.

Systematic Literature Review Regarding Heart Rate and Respiratory Rate Measurement by Means of Radar Technology

“…Table 1 lists the titles depending on whether the radar used belonged to the group of continuous wave (CW) radars (n = 58), frequency-modulated continuous wave (FMCW) radars (n = 24) or ultra-wideband (UWB) radars (n = 34). In three papers, different radar types were used [10][11][12]. For one study, it was not possible to make an assignment [13].…”

“…In 74 studies, both the heart rate and the respiratory rate were measured [2,5,10,12,. In 14 studies, only the respiratory rate was considered [3,11,13,[84][85][86][87][88][89][90][91][92][93][94], and in 26 studies, only the heart rate .…”

“…In Table 1, the titles are grouped in accordance with the radar types used, and within each category (group), they are sorted by the vital parameters measured. The number of test persons in the studies ranged from one test person [10,12,24,42,43,49,60,[85][86][87]108] to 212 test persons [98,99]. Five of the experiments were conducted with children and babies [17,45,84,88,89], eleven with miscellaneous patient groups [5,17,21,39,41,51,88,89,91,93,112] and one with animals [38], while seven experiments additionally measured a model [37,42,44,60,85,97] and two exclusively measured a model [90,92].…”

“…Five of the experiments were conducted with children and babies [17,45,84,88,89], eleven with miscellaneous patient groups [5,17,21,39,41,51,88,89,91,93,112] and one with animals [38], while seven experiments additionally measured a model [37,42,44,60,85,97] and two exclusively measured a model [90,92]. In 74 studies [2,3,[10][11][12][13]16,17,20,[22][23][24][25][26][27][28][29]36,40,43,[47][48][49][50][52]...…”

Experimental Feasibility Study of Using Mmwave for Arterial Radial Displacement Monitoring

“…There are some studies about using higher frequencies for radar-based heartbeat detection in 16 GHz [25], and 24 GHz [26]. In [27][28][29], mechanical pulsations of the carotid artery, which is a significant big superficial artery, were monitored. To the best of our knowledge, a study of deeper arteries using an on-body sensor has not been performed yet.…”