A Real-Time Evaluation Algorithm for Noncontact Heart Rate Variability Monitoring

Xiangyu Han, Qian Zhai, Ning Zhang, Xiufeng Zhang, Long He, Min Pan, Bin Zhang, Tao Liu

Research output: Contribution to journalArticlepeer-review

3 Citations (SciVal)


Noncontact vital sign monitoring based on radar has attracted great interest in many fields. Heart Rate Variability (HRV), which measures the fluctuation of heartbeat intervals, has been considered as an important indicator for general health evaluation. This paper proposes a new algorithm for HRV monitoring in which frequency-modulated continuous-wave (FMCW) radar is used to separate echo signals from different distances, and the beamforming technique is adopted to improve signal quality. After the phase reflecting the chest wall motion is demodulated, the acceleration is calculated to enhance the heartbeat and suppress the impact of respiration. The time interval of each heartbeat is estimated based on the smoothed acceleration waveform. Finally, a joint optimization algorithm was developed and is used to precisely segment the acceleration signal for analyzing HRV. Experimental results from 10 participants show the potential of the proposed algorithm for obtaining a noncontact HRV estimation with high accuracy. The proposed algorithm can measure the interbeat interval (IBI) with a root mean square error (RMSE) of 14.9 ms and accurately estimate HRV parameters with an RMSE of 3.24 ms for MEAN (the average value of the IBI), 4.91 ms for the standard deviation of normal to normal (SDNN), and 9.10 ms for the root mean square of successive differences (RMSSD). These results demonstrate the effectiveness and feasibility of the proposed method in emotion recognition, sleep monitoring, and heart disease diagnosis.
Original languageEnglish
Article number6681
Number of pages19
Issue number15
Publication statusPublished - Aug 2023

Bibliographical note

This research was supported in part by the NSFC Grant No. U1913601, No. 52175033, and No. U21A20120; the Zhejiang Provincial Natural Science Foundation of China under Grant No. LZ20E050002; and the Key Research and Development Program of Zhejiang under awards 2022C03103 and 2021C03051.

Data Availability Statement
Data will be made available on request.


  • FMCW radar
  • HRV
  • algorithm
  • heartbeat
  • noncontact monitoring
  • vital sign monitoring
  • wireless signal

ASJC Scopus subject areas

  • Analytical Chemistry
  • Information Systems
  • Instrumentation
  • Atomic and Molecular Physics, and Optics
  • Electrical and Electronic Engineering
  • Biochemistry


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