Detection of Human Heartbeat and Breath by Radar
Development of Multi-Frequency Radar Methods for Registration of Human Biometric Signals and Their Use in Medical Applications
Tech Area / Field
- INS-DET/Detection Devices/Instrumentation
3 Approved without Funding
MGTU (Moscow State Technical University) / Research Institute of Applied Mathematics and Mechanics, Russia, Moscow
- Pennsylvania State University / College of Medicine, USA, PA, Hershey\nWalnut Ltd., Japan, Tokyo\nUniversity of Florence / Department of Electronic Engineering, Italy, Florence\nIntegrity Testing Laboratory Inc., Canada, ON, Markham\nISS Inc., USA, IL, Champaign\nEnviroscan, Inc., USA, PA, Lancaster\nCalifornia Institute of Technology / Jet Propulsion Laboratory, USA, CA, Pasadena\nUniversity of Pennsylvania / School of Arts and Sciences / Department of Earth and Environmental Science, USA, PA, Philadelphia
Project summaryThe main objective of the project is creation of effective radar technologies for remote detection and registration of breathing and heart beat parameters of a human on a background of reflections by local objects and optically nontransparent obstacles (bio-radiolocation). The main advantage of bio-radiolocation is the possibility to detect remotely any presence of humans behind lightproof obstacles and obtain information about human functional condition. Search for live people blocked under ruins, after disasters such like earthquakes, avalanches, industrial accidents, etc., is very important.
Potential areas of bio-radiolocation application may include:
- somnology, or patient monitoring at sleep with the purpose to detect sleep disfunctions such as sleep apnea/hypopnea syndrome;
- cardioreanimation when application of contact sensors is difficult or impossible;
- functional diagnostics, the implementation as a diagnostic feedback with the purpose to evaluate therapy effectiveness (by medicine or physiotherapy) by the analysis of heart rate slow variations; study of heartbeat and breath rhythms interaction;
- patient’s heart rate and breathing monitoring when application of contact sensors is difficult or impossible, e.g. monitoring of a patient with burns.
- fetus monitoring instead of application of existing contact ultrasound sensors requiring a direct contact with a patient;
- evaluation of blood vessels elasticity by measuring blood pressure impulse speed during heartbeat, which can be used to determine susceptibility to heart diseases;
- non-contact evaluation of the psycho-emotional human condition, e.g. the emotional condition of machinery complex operators.
In some of the application areas mentioned above, especially when detecting movements of human behind building constructions, there already exist experimental radiolocation devices or prototypes. However, medical applications lack for research and approvement, which can be associated with the absence or imperfection of application technique with the aid of bio-radiolocation equipment.
The existing prototypes and models of radars implement both continuous-wave and video pulse (time-domain impulse) signals differing significantly in design complexity. The simplest of them have an LED diode as an indicator and no range selection, while others may have a color LCD display and high range resolution. The radars with continuous-wave single-frequency signals have the simplest signal processing such as detection of reflected signal low frequency components by means of the Fourier transform and have no range resolution. The radars with video pulse signals may have range resolution but have a short detection range. It is worth mentioning that no one device have found any significant area of use. This can be explained by small equipment sensitivity when sensing through obstacles, e.g. detection of people buried alive under ruins after disaster, low noise immunity, and the absence of angular selection.
The main stress in the proposed project is laid on the development of a distributed antenna system and more sophisticated signal processing, which, as researchers believe, will make it possible to obtain the disposition of people in a sounding area, extract information from biological objects themselves, e.g. obtain information depicting their disposition and working condition of their organs. Proposed in the project deployment of multi-frequency sounding signals in spatially distributed radar antenna will merge the advantages of time-domain and continuous signals to produce a system with better performance. Such a system must have a larger detection range, spatial selection capability, possibility to overview the sounding space to the stage of extracting breathing and heartbeat waveforms as well as articulation features.
At the present time, according to domestic and international papers reference, the results to be achieved in the project are absent. Namely, there is no data on informational capabilities of different UHF bands in solving different problems. Adequate mathematical models describing signal features after electromagnetic waves reflection by the human body are absent. Application of multi-frequency signals in single- and spatially multi-channel bio-radars has not been considered in earlier works. Proposed design principles and multi-frequency signal processing algorithms in the development of the spatially multi-channel radar antenna and the extraction of heartbeat and breathing signals have not been described in the literature up to the present.
While developing the principles of remote detection and diagnosis of human, in earlier team’s work it was experimentally confirmed the possibility of measuring heartbeat and breathing frequencies and their amplitudes by continuous-wave monochromatic radar. Computer simulations were also performed to study these processes. In particular, it was shown that the detected radiolocation signal had not only primary breath and heartbeat tones, but also their combinative frequencies. The results of these theoretical and experimental studies were published in scientific magazines both in Russia and abroad.
At the present, common design and separate units of the multi-frequency continuous wave radar with stepped frequency modulation (SFM) were developed. As a prototype the five-frequency radar Rascan was taken, that was earlier designed for subsurface sounding of building materials. For the design of the subsurface holographic radar Rascan, which technology will partly be used in the proposed research, the authors were awarded the Russian Federation Government Prize in the area of science and technology. The radar Rascan designed for building materials sounding is now being produced in lots and is available for commercial use.
The further development of the radar Rascan was continued through ISTC grant #2541 named Holographic Subsurface Radar Intended for Soil and Construction Designs Sounding, which fulfillment in the laboratory comes to an end. The developed technologies supported by ISTC grant #2541 permitted the team to proceed to the design of a multi-frequency bio-radar featuring high precision and sensitivity.
Both a reference list and overview of projects and research activities of the laboratory are available at http://www.english.rslab.ru.
As a whole, execution of this ISTC project will allow Russian scientists in collaboration with foreign participants to contribute significantly to research and design areas of short distance radar application in medical equipment and diagnosis.
This Project is fully consistent with the ISTC objectives. The accomplishment of this Project will allow a significant group of Russian scientists and engineers, who have experience and knowledge in military engineering and weapons, to redirect their activity to civil applications in the area of radar technology utilization in medicine. It is supposed that the exchange of ideas, scientific results, and experimental samples between Russian and foreign scientists within the Project will be conducted on regular basis. It is planned to conduct joint research with foreign colleagues from the USA, Canada, Europe, and Japan. The proposals toward commercial use of the Project results will be discussed with foreign participants and accepted when the work is complete.
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