A hybrid radar-camera sensing system with phase compensation for random body movement cancellation in doppler vital sign detection

Changzhan Gu, Guochao Wang, Yiran Li, Takao Inoue, Changzhi Li

Research output: Contribution to journalArticle

56 Scopus citations

Abstract

This paper presents a Doppler radar vital sign detection system with random body movement cancellation (RBMC) technique based on adaptive phase compensation. An ordinary camera was integrated with the system to measure the subject's random body movement (RBM) that is fed back as phase information to the radar system for RBMC. The linearity of the radar system, which is strictly related to the circuit saturation problem in noncontact vital sign detection, has been thoroughly analyzed and discussed. It shows that larger body movement does not necessarily mean larger radar baseband output. High gain configuration at baseband is required for acceptable SNR in noncontact vital sign detection. The phase compensation at radar RF front-end helps to relieve the high-gain baseband from potential saturation in the presence of large body movement. A simple video processing algorithm was presented to extract the RBM without using any marker. Both theoretical analysis and simulation have been carried out to validate the linearity analysis and the proposed RBMC technique. Two experiments were carried out in the lab environment. One is the phase compensation at RF front end to extract a phantom motion in the presence of another large shaker motion, and the other one is to measure the subject person breathing normally but randomly moving his body back and forth. The experimental results show that the proposed radar system is effective to relieve the linearity burden of the baseband circuit and help compensate the RBM.

Original languageEnglish
Article number6662489
Pages (from-to)4678-4688
Number of pages11
JournalIEEE Transactions on Microwave Theory and Techniques
Volume61
Issue number12
DOIs
StatePublished - Dec 2013

Keywords

  • Doppler radar
  • Linearity
  • Noncontact
  • Random body movement
  • Saturation
  • Vital sign detection

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