Spectrum estimation method based on Doppler radar heartbeat detection

Abstract

The invention provides a non-contact accurate heartbeat detection method based on a Doppler radar. The method comprises the following steps: firstly, capturing frequency shift caused by weak chest displacement due to human heart beating by adopting the principle of continuous wave Doppler radar sign detection, namely transmitting T(t) to a subject through a transmission end by Radar, and modulating the phase of the T (t) signal by the chest wall movement x (t) of the subject, and capturing a reflected signal by a radar receiving end; secondly, passing the reflection signal through a front-end low-noise amplifier to obtain a baseband signal, demodulating the baseband signal by adopting an orthogonal mixer, and acquiring a chest wall signal through arc tangent demodulation and winding calculation after the reflection signal passes through a gain amplifier; and finally, passing the chest wall analog signal through an analog-to-digital converter to obtain a digital signal x (t), processing the digital signal x(t), separating and extracting a heart signal at a PC end through a Marithan algorithm and a matched filtering algorithm, and performing FTPR-TWV algorithm to obtain a heartbeat spectrum result.

Description

technical field [0001] The invention relates to the field of heart rate detection, in particular to a non-contact accurate heartbeat detection method based on Doppler radar in the frequency domain. Background technique [0002] With the improvement of the quality of life, people pay more and more attention to life and health, and heart rate detection plays an important role in daily health monitoring and clinical medical diagnosis. On the one hand, the frequency of the heartbeat can reflect the basic health status; on the other hand, the rhythm and intensity of the heartbeat are largely conducive to the diagnosis of heart disease. Compared with traditional contact methods for detecting heartbeat, such as electrocardiogram, photoplethysmography, and wristband pulse oximeter, non-contact heartbeat detection based on Doppler radar has advantages in some unique occasions where electrodes cannot be contacted, such as For life detection, baby monitoring and fatigue detection duri...

AI Technical Summary

Problems solved by technology

Complex signal demodulation introduces harmonic interference, which seriously reduces the accuracy of heart rate detection

In addition, arctangent demodulation is insensitive to target position and harmonic interference, but still has strong nonlinearity and discontinuity

The extended differential and cross-multiplication algorithm overcomes the shortcomings of phase winding and harmonic interference, and the problem is that it needs to solve the problem of error accumulation caused by discrete integration

[0005] Another challenge is the lack of spectral resolution in short-term time windows

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