Multi-person through-wall time varying breathing signal detection method based on VMD

Abstract

The invention discloses a multi-person through-wall time varying breathing signal detection method based on VMD, comprising the steps of: an ultra wide band emission antenna emitting narrow pulse, through human thoracic cavity micro-doppler vibration, echo being received by a receiving antenna, and performing slow time sampling on ultra wide band radar echo to obtain a through-wall human body echo signal matrix; calculating the variance of each distance door through a distance door selection algorithm, the one with a largest variance being a distance door where a multi-person target exists, and employing a low pass filter to eliminate high frequency interference and superfluous frequency components; utilizing a VMD algorithm to perform mode decomposition on filtered signals, and iterating sub-signals to obtain effective information meeting the number and frequency band of breathing; and performing Hilbert transformation and time frequency treatment to obtain dynamic instantaneous information including smooth breathing characteristics. The method can effectively eliminate interference harmonic wave of different breathing components, remove metope interference, and enhance weak breathing signals, and has the characteristics of strong interference immunity and accurate time varying tracking characteristics.

Description

technical field [0001] The invention belongs to the technical field of radar detection, in particular to a time-varying breathing signal detection method for multiple people passing through walls based on variational mode decomposition (VMD). Background technique [0002] Multi-person through-wall positioning technology is more and more applied to disaster search and rescue, anti-terrorist raids, anti-terrorism rescue and other applications, and due to the good penetration and high resolution of ultra-wideband signals, ultra-wideband radars are used to detect walls The detection of behind-the-body targets has been more and more widely recognized. There are many topics in the field of through-wall detection, such as indoor target positioning, human gait detection, and through-wall human imaging. At the same time, with the rise of biomedical technology, non- Contact through-wall vital sign detection has become an emerging topic nowadays. [0003] At this stage, the detection ...

AI Technical Summary

Problems solved by technology

However, due to the single detection method at present, it is impossible to detect dynamic tracking, and there is a lot of research space for the detection of multiple people breathing through the wall. The Fourier transform method can only detect the walking gait, and the continuous wave radar does not have strong penetration, so it is not suitable for many detection tasks in complex environments. The team of Jilin University in China uses ultra-wideband radar to detect cement Two stationary targets behind the wall are detected. However, due to the limitation of the detection accuracy of the radar used, a clear breathing waveform cannot be obtained in the actual test, and it is difficult to conduct further research.

In summary, the simple Fourier transform cannot remove low-frequency interference and respiratory harmonics, nor can it obtain the dynamic change trend of breathing, so the detection algorithm for multiple people breathing through walls based on simple frequency domain analysis has great limitations in practical applications. limitations

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