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Liebetruth M, Kehe K, Steinritz D, Sammito S. Systematic Literature Review Regarding Heart Rate and Respiratory Rate Measurement by Means of Radar Technology. SENSORS (BASEL, SWITZERLAND) 2024; 24:1003. [PMID: 38339721 PMCID: PMC10857015 DOI: 10.3390/s24031003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 01/23/2024] [Accepted: 01/30/2024] [Indexed: 02/12/2024]
Abstract
The use of radar technology for non-contact measurement of vital parameters is increasingly being examined in scientific studies. Based on a systematic literature search in the PubMed, German National Library, Austrian Library Network (Union Catalog), Swiss National Library and Common Library Network databases, the accuracy of heart rate and/or respiratory rate measurements by means of radar technology was analyzed. In 37% of the included studies on the measurement of the respiratory rate and in 48% of those on the measurement of the heart rate, the maximum deviation was 5%. For a tolerated deviation of 10%, the corresponding percentages were 85% and 87%, respectively. However, the quantitative comparability of the results available in the current literature is very limited due to a variety of variables. The elimination of the problem of confounding variables and the continuation of the tendency to focus on the algorithm applied will continue to constitute a central topic of radar-based vital parameter measurement. Promising fields of application of research can be found in particular in areas that require non-contact measurements. This includes infection events, emergency medicine, disaster situations and major catastrophic incidents.
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Affiliation(s)
- Magdalena Liebetruth
- German Air Force Centre of Aerospace Medicine, 51147 Cologne, Germany
- Department of Occupational Medicine, Faculty of Medicine, Otto von Guericke University of Magdeburg, 39120 Magdeburg, Germany
| | - Kai Kehe
- Bundeswehr Medical Service Headquarter, Department A-VI Public Health, 56072 Koblenz, Germany
| | - Dirk Steinritz
- Bundeswehr Institute of Pharmacology and Toxicology, 80937 Munich, Germany
| | - Stefan Sammito
- German Air Force Centre of Aerospace Medicine, 51147 Cologne, Germany
- Department of Occupational Medicine, Faculty of Medicine, Otto von Guericke University of Magdeburg, 39120 Magdeburg, Germany
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Bachir W, Ismael FS, Alaineya NHA. Laser spectroscopic method for remote sensing of respiratory rate. Phys Eng Sci Med 2023; 46:1249-1258. [PMID: 37358781 PMCID: PMC10480269 DOI: 10.1007/s13246-023-01292-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 06/16/2023] [Indexed: 06/27/2023]
Abstract
Noncontact sensing methods for measuring vital signs have recently gained interest, particularly for long-term monitoring. This study introduces a new method for measuring respiratory rate remotely. The proposed method is based on the reflection of a laser beam off a striped card attached to a moving platform simulating chest wall displacements. A wide range of frequencies (n = 35) from 0.06 to 2.2 Hz corresponding to both normal and pathological human respiratory rates were simulated using a moving mechanical platform. Reflected spectra (n = 105) were collected by a spectrometer in a dynamic mode. Fourier analysis was performed to retrieve the breathing frequency. The results show a striking agreement between measurements and reference frequencies. The results also show that low frequencies corresponding to respiratory rates can be detected with high accuracy (uncertainty is well below 5%). A validation test of the measuring method on a human subject demonstrated a great potential for remote respiration rate monitoring of adults and neonates in a clinical environment.
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Affiliation(s)
- Wesam Bachir
- Institute of Metrology and Biomedical Engineering, Faculty of Mechatronics, Warsaw University of Technology, Św. A. Boboli 8 St, 02-525, Warsaw, Poland.
- Biomedical Photonics Laboratory, Higher Institute for Laser Research and Applications, Damascus University, Damascus, Syria.
| | - Fatimah Samie Ismael
- Biomedical Photonics Laboratory, Higher Institute for Laser Research and Applications, Damascus University, Damascus, Syria
| | - Nour Hasan Arry Alaineya
- Biomedical Photonics Laboratory, Higher Institute for Laser Research and Applications, Damascus University, Damascus, Syria
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Lim S, Jang GS, Song W, Kim BH, Kim DH. Non-Contact VITAL Signs Monitoring of a Patient Lying on Surgical Bed Using Beamforming FMCW Radar. SENSORS (BASEL, SWITZERLAND) 2022; 22:8167. [PMID: 36365862 PMCID: PMC9656893 DOI: 10.3390/s22218167] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 10/17/2022] [Accepted: 10/20/2022] [Indexed: 06/16/2023]
Abstract
Respiration and heartrates are important information for surgery. When the vital signs of the patient lying prone are monitored using radar installed on the back of the surgical bed, the surgeon's movements reduce the accuracy of these monitored vital signs. This study proposes a method for enhancing the monitored vital sign accuracies of a patient lying on a surgical bed using a 60 GHz frequency modulated continuous wave (FMCW) radar system with beamforming. The vital sign accuracies were enhanced by applying a fast Fourier transform (FFT) for range and beamforming which suppress the noise generated at different ranges and angles from the patient's position. The experiment was performed for a patient lying on a surgical bed with or without surgeon. Comparing a continuous-wave (CW) Doppler radar, the FMCW radar with beamforming improved almost 22 dB of signal-to-interference and noise ratio (SINR) for vital signals. More than 90% accuracy of monitoring respiration and heartrates was achieved even though the surgeon was located next to the patient as an interferer. It was analyzed using a proposed vital signal model included in the radar IF equation.
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Affiliation(s)
| | | | | | | | - Dong Hyun Kim
- SMG-SNU Boramae Medical Center, 20, Boramae-ro 5-gil, Dongjak-gu, Seoul 07061, Korea
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Manullang MCT, Lin YH, Lai SJ, Chou NK. Implementation of Thermal Camera for Non-Contact Physiological Measurement: A Systematic Review. SENSORS (BASEL, SWITZERLAND) 2021; 21:7777. [PMID: 34883780 PMCID: PMC8659982 DOI: 10.3390/s21237777] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Revised: 11/06/2021] [Accepted: 11/19/2021] [Indexed: 01/03/2023]
Abstract
Non-contact physiological measurements based on image sensors have developed rapidly in recent years. Among them, thermal cameras have the advantage of measuring temperature in the environment without light and have potential to develop physiological measurement applications. Various studies have used thermal camera to measure the physiological signals such as respiratory rate, heart rate, and body temperature. In this paper, we provided a general overview of the existing studies by examining the physiological signals of measurement, the used platforms, the thermal camera models and specifications, the use of camera fusion, the image and signal processing step (including the algorithms and tools used), and the performance evaluation. The advantages and challenges of thermal camera-based physiological measurement were also discussed. Several suggestions and prospects such as healthcare applications, machine learning, multi-parameter, and image fusion, have been proposed to improve the physiological measurement of thermal camera in the future.
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Affiliation(s)
- Martin Clinton Tosima Manullang
- Department of Electronic and Computer Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan; (M.C.T.M.); (S.-J.L.)
- Department of Informatics, Institut Teknologi Sumatera, South Lampung Regency 35365, Indonesia
| | - Yuan-Hsiang Lin
- Department of Electronic and Computer Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan; (M.C.T.M.); (S.-J.L.)
| | - Sheng-Jie Lai
- Department of Electronic and Computer Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan; (M.C.T.M.); (S.-J.L.)
| | - Nai-Kuan Chou
- Department of Cardiovascular Surgery, National Taiwan University Hospital, Taipei 10002, Taiwan
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Lee IS, Park JH, Yang JR. Detrending Technique for Denoising in CW Radar. SENSORS (BASEL, SWITZERLAND) 2021; 21:6376. [PMID: 34640697 PMCID: PMC8512675 DOI: 10.3390/s21196376] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 09/14/2021] [Accepted: 09/21/2021] [Indexed: 11/16/2022]
Abstract
A detrending technique is proposed for continuous-wave (CW) radar to remove the effects of direct current (DC) offset, including DC drift, which is a very slow noise that appears near DC. DC drift is mainly caused by unwanted vibrations (generated by the radar itself, target objects, or surroundings) or characteristic changes in components in the radar owing to internal heating. It reduces the accuracy of the circle fitting method required for I/Q imbalance calibration and DC offset removal. The proposed technique effectively removes DC drift from the time-domain waveform of the baseband signals obtained for a certain time using polynomial fitting. The accuracy improvement in the circle fitting by the proposed technique using a 5.8 GHz CW radar decreases the error in the displacement measurement and increases the signal-to-noise ratio (SNR) in vital signal detection. The measurement results using a 5.8 GHz radar show that the proposed technique using a fifth-order polynomial fitting decreased the displacement error from 1.34 mm to 0.62 mm on average when the target was at a distance of 1 m. For a subject at a distance of 0.8 m, the measured SNR improved by 7.2 dB for respiration and 6.6 dB for heartbeat.
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Affiliation(s)
| | | | - Jong-Ryul Yang
- Department of Electronic Engineering, Yeungnam University, Gyeongsan 38541, Gyeongbuk, Korea; (I.-S.L.); (J.-H.P.)
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Lazaro A, Lazaro M, Villarino R, Girbau D, de Paco P. Car2Car Communication Using a Modulated Backscatter and Automotive FMCW Radar. SENSORS (BASEL, SWITZERLAND) 2021; 21:3656. [PMID: 34073982 PMCID: PMC8197406 DOI: 10.3390/s21113656] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 05/16/2021] [Accepted: 05/22/2021] [Indexed: 11/16/2022]
Abstract
This work proposes the use of a modulated tag for direct communication between two vehicles using as a carrier the wave emitted by an FMCW radar installed in the vehicle for advanced driver assistance. The system allows for real-time signals detection and classification, such as stop signal, turn signals and emergency lights, adding redundancy to computer video sensors and without incorporating additional communication systems. A proof-of-concept tag has been designed at the microwave frequency of 24 GHz, consisting of an amplifier connected between receiving and transmitting antennas. The modulation is performed by switching the power supply of the amplifier. The tag is installed on the rear of the car and it answers when it is illuminated by the radar by modulating the backscattered field. The information is encoded in the modulation switching rate used. Simulated and experimental results are given showing the feasibility of the proposed solution.
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Affiliation(s)
- Antonio Lazaro
- Department of Electronics, Electrics and Automatic Control Engineering, Rovira i Virgili University, 43007 Tarragona, Spain; (M.L.); (R.V.); (D.G.)
| | - Marc Lazaro
- Department of Electronics, Electrics and Automatic Control Engineering, Rovira i Virgili University, 43007 Tarragona, Spain; (M.L.); (R.V.); (D.G.)
| | - Ramon Villarino
- Department of Electronics, Electrics and Automatic Control Engineering, Rovira i Virgili University, 43007 Tarragona, Spain; (M.L.); (R.V.); (D.G.)
| | - David Girbau
- Department of Electronics, Electrics and Automatic Control Engineering, Rovira i Virgili University, 43007 Tarragona, Spain; (M.L.); (R.V.); (D.G.)
| | - Pedro de Paco
- Telecommunications and Systems Engineering Department, Universitat Autonoma de Barcelona (UAB), 08193 Bellaterra, Spain;
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Performance Evaluation of Vibrational Measurements through mmWave Automotive Radars. REMOTE SENSING 2020. [DOI: 10.3390/rs13010098] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Thanks to the availability of a significant amount of inexpensive commercial Frequency Modulated Continuous Wave Radar sensors, designed primarily for the automotive domain, it is interesting to understand if they can be used in alternative applications. It is well known that with a radar system it is possible to identify the micro-Doppler feature of a target, to detect the nature of the target itself (what the target is) or how it is vibrating. In fact, thanks to their high transmission frequency, large bandwidth and very short chirp signals, radars designed for automotive applications are able to provide sub-millimeter resolution and a large detection bandwidth, to the point that it is here proposed to exploit them in the vibrational analysis of a target. The aim is to evaluate what information on the vibrations can be extracted, and what are the performance obtainable. In the present work, the use of a commercial Frequency Modulated Continuous Wave radar is described, and the performances achieved in terms of displacement and vibration frequency measurement of the target are compared with the measurement results obtained through a laser vibrometer, considered as the reference instrument. The attained experimental results show that the radar under test and the reference laser vibrometer achieve comparable outcomes, even in a cluttered scenario.
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Rehouma H, Noumeir R, Essouri S, Jouvet P. Advancements in Methods and Camera-Based Sensors for the Quantification of Respiration. SENSORS (BASEL, SWITZERLAND) 2020; 20:E7252. [PMID: 33348827 PMCID: PMC7766256 DOI: 10.3390/s20247252] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Revised: 12/09/2020] [Accepted: 12/15/2020] [Indexed: 01/22/2023]
Abstract
Assessment of respiratory function allows early detection of potential disorders in the respiratory system and provides useful information for medical management. There is a wide range of applications for breathing assessment, from measurement systems in a clinical environment to applications involving athletes. Many studies on pulmonary function testing systems and breath monitoring have been conducted over the past few decades, and their results have the potential to broadly impact clinical practice. However, most of these works require physical contact with the patient to produce accurate and reliable measures of the respiratory function. There is still a significant shortcoming of non-contact measuring systems in their ability to fit into the clinical environment. The purpose of this paper is to provide a review of the current advances and systems in respiratory function assessment, particularly camera-based systems. A classification of the applicable research works is presented according to their techniques and recorded/quantified respiration parameters. In addition, the current solutions are discussed with regards to their direct applicability in different settings, such as clinical or home settings, highlighting their specific strengths and limitations in the different environments.
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Affiliation(s)
- Haythem Rehouma
- École de Technologie Supérieure, Montreal, QC H3T 1C5, Canada;
| | - Rita Noumeir
- École de Technologie Supérieure, Montreal, QC H3T 1C5, Canada;
| | - Sandrine Essouri
- CHU Sainte-Justine, Montreal, QC H3T 1C5, Canada; (S.E.); (P.J.)
| | - Philippe Jouvet
- CHU Sainte-Justine, Montreal, QC H3T 1C5, Canada; (S.E.); (P.J.)
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Shang J, He Y, Wang Q, Li Y, Ren L. Development of a High-Resolution All-Fiber Homodyne Laser Doppler Vibrometer. SENSORS (BASEL, SWITZERLAND) 2020; 20:s20205801. [PMID: 33066344 PMCID: PMC7602043 DOI: 10.3390/s20205801] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 10/08/2020] [Accepted: 10/12/2020] [Indexed: 06/11/2023]
Abstract
Based on the homodyne detection, a compact and cost-effective all-fiber laser Doppler vibrometer (LDV) with high resolution is presented. For the signal processing, the discrimination algorithm combined with the nonorthogonal correction is applied. The algorithm corrects the quadrature imbalance and other nonlinearity. In the calibration experiment, with the glass pasted on a piezoceramic transducer (PZT), the velocity resolution of 62 nm/s at 4 kHz and displacement resolution of 2.468 pm are achieved. For the LDV-based acousto-optic communication, the minimum detectable sound pressure level (SPL) reached 0.12 Pa under the hydrostatic air-water surface. The results demonstrate that the designed homodyne LDV has a low system background noise and can offer high precision in the vibration measurement.
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Affiliation(s)
- Jianhua Shang
- Shanghai Collaborative Innovation Center for High Performance Fiber Composites, School of Information Science and Technology, Donghua University, Shanghai 201620, China; (Q.W.); (Y.L.); (L.R.)
| | - Yan He
- Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China;
| | - Qi Wang
- Shanghai Collaborative Innovation Center for High Performance Fiber Composites, School of Information Science and Technology, Donghua University, Shanghai 201620, China; (Q.W.); (Y.L.); (L.R.)
| | - Yilun Li
- Shanghai Collaborative Innovation Center for High Performance Fiber Composites, School of Information Science and Technology, Donghua University, Shanghai 201620, China; (Q.W.); (Y.L.); (L.R.)
| | - Lihong Ren
- Shanghai Collaborative Innovation Center for High Performance Fiber Composites, School of Information Science and Technology, Donghua University, Shanghai 201620, China; (Q.W.); (Y.L.); (L.R.)
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