CN110448290B - Terahertz through-wall radar-based remote personnel heart rate detection method, device and system - Google Patents
Terahertz through-wall radar-based remote personnel heart rate detection method, device and system Download PDFInfo
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Abstract
The invention discloses a method, a device and a system for detecting heart rate of remote personnel based on a terahertz through-wall radar, wherein the method comprises the following steps: receiving two paths of I/Q echo signals of heart rate detection in real time; respectively suppressing static clutter and non-static clutter in the echo signal; carrying out complex signal demodulation on the echo signal subjected to clutter suppression; a filter is adopted to suppress the interference of high-frequency and low-frequency noise in the echo signal; enhancing the signal-to-noise ratio of a heartbeat signal of an echo signal; decomposing and reconstructing the echo signal after the signal-to-noise ratio is enhanced by adopting wavelet transformation; performing a signal spectrum estimation based on a time varying window selection; and (4) suppressing harmonic interference of heart rate in the signal frequency spectrum to obtain a final heart rate signal.
Description
Technical Field
The invention belongs to the technical field of heart rate detection, and particularly relates to a terahertz through-wall radar-based remote personnel heart rate detection method, device and system.
Background
The method has wide application prospect in accurately estimating the respiratory rate and the heart rate of people in both medical science and natural disaster rescue. For example, the kit can be used for diagnosing or preventing respiratory diseases and cardiovascular diseases in medicine, can provide reliable basis for rescuers in natural disasters, and reduces the loss of lives and properties of the rescuers. In the respiratory rate and heart rate detection process, because the heartbeat amplitude is in millimeter level, compared with the respiratory amplitude, the estimation is difficult to be accurate under the conditions of long distance and penetrating obstacles (such as ruins and the like) in general.
Currently, the commonly used heart rate detection means include both contact and non-contact. The contact method mainly refers to detecting the heart rate by sticking electrode plates on the body of a person and wearing devices such as sensors by means of traditional electrocardiogram, photoplethysmography signals and the like. However, this will cause a certain trouble and psychological burden to the patient, and will easily generate a repulsive emotion. In view of the limitations of the above approaches, with the wide application of radar in medical treatment, engineering, and the like, the non-contact detection approach attracts much attention.
The method for extracting the heart rate by utilizing the radar is a non-contact signal detection mode widely applied, and has the advantages of all weather, high precision and the like. However, the inventor finds that, in the research process, most of the existing non-contact heart rate extraction means are based on microwave and low-frequency millimeter wave bands, and considering that the heartbeat amplitude is usually less than 4mm, when continuous wave radar is used for detection, the micro doppler effect caused by heartbeat is not sensitive in the microwave and low-frequency millimeter wave bands, and accurate detection is difficult to achieve. Especially under the long-distance wall-through condition, microwave and low frequency millimeter wave radar are more difficult to realize the extraction of heart rate.
Disclosure of Invention
In order to overcome the defects of the prior art, the invention provides a method, a device and a system for detecting the heart rate of a remote person based on a terahertz wall-through radar.
According to an aspect of one or more embodiments of the present disclosure, there is provided a terahertz through-wall radar for remote human heart rate detection.
A terahertz through-wall radar for remote personnel heart rate detection, comprising: the terahertz wave after frequency multiplication, radio frequency up-conversion and recoupling is used as a local oscillation signal and is simultaneously output from the radio frequency output end through the first polarizer, and the radio frequency receiving end receives the I/Q two-path echo signals in real time after passing through the second polarizer.
According to one aspect of one or more embodiments of the present disclosure, a method for detecting a heart rate of a remote person based on a terahertz through-wall radar is provided.
A terahertz through-wall radar-based remote personnel heart rate detection method comprises the following steps:
receiving two paths of I/Q echo signals of heart rate detection in real time;
respectively suppressing static clutter and non-static clutter in the echo signal;
carrying out complex signal demodulation on the echo signal subjected to clutter suppression;
a filter is adopted to suppress the interference of high-frequency and low-frequency noise in the echo signal;
enhancing the signal-to-noise ratio of a heartbeat signal of an echo signal;
decomposing and reconstructing the echo signal after the signal-to-noise ratio is enhanced by adopting wavelet transformation;
performing a signal spectrum estimation based on a time varying window selection;
and (4) suppressing harmonic interference of heart rate in the signal frequency spectrum to obtain a final heart rate signal.
Furthermore, in the method, the static clutter is estimated according to a background filtering algorithm, and the estimated two paths of static clutter are respectively subtracted from the two paths of real-time received I/Q echo signals to suppress the static clutter.
Further, in the method, complex signal demodulation is carried out on the echo signal after clutter suppression according to the distance between the radar and the living body, the heartbeat amplitude, the heart rate, the wavelength and the phase noise, and logarithmic processing is carried out on the signal after complex signal adjustment.
Further, in the method, a 5 th order Butterworth filter is adopted to suppress high-frequency and low-frequency noise interference in the echo signals.
Further, in the method, a sliding filter is adopted to enhance the signal-to-noise ratio of the echo signal center jump signal.
Further, in the method, wavelet function adopted in decomposing and reconstructing the echo signal after signal-to-noise ratio enhancement by adopting wavelet transform is Morlet wavelet.
Further, in the method, the specific step of performing the signal spectrum estimation based on the time varying window selection includes:
for a signal with a fixed duration, the frequency resolution is:
i is 1,2, …, q, wherein fsIs the frequency, wiRepresents the length of the ith window, and q represents the number of windows;
fourier transform is carried out on the signal in each time window, meanwhile windowing processing is carried out on the frequency spectrum, and the window width is 0.8-2.4 Hz;
and performing accumulation operation on the obtained q groups of frequency spectrums.
According to an aspect of one or more embodiments of the present disclosure, there is provided a computer-readable storage medium.
A computer readable storage medium, wherein a plurality of instructions are stored, the instructions are suitable for being loaded by a processor of a terminal device and executing the method for detecting the heart rate of the remote personnel based on the terahertz through-wall radar.
According to an aspect of one or more embodiments of the present disclosure, there is provided a terminal device.
A terminal device comprising a processor and a computer-readable storage medium, the processor being configured to implement instructions; the computer readable storage medium is used for storing a plurality of instructions, and the instructions are suitable for being loaded by a processor and executing the method for detecting the heart rate of the remote personnel based on the terahertz through-the-wall radar.
According to one aspect of one or more embodiments of the present disclosure, a terahertz through-wall radar-based remote person heart rate detection apparatus is provided.
A remote personnel heart rate detection device based on a terahertz through-wall radar is based on a remote personnel heart rate detection method based on the terahertz through-wall radar, and comprises the following steps:
the signal receiving module is configured to receive two paths of I/Q echo signals of heart rate detection in real time;
a clutter suppression module configured to suppress static clutter and non-static clutter in the echo signal, respectively;
a complex signal demodulation module configured to perform complex signal demodulation on the echo signal after clutter suppression;
a noise interference suppression module configured to suppress high-frequency and low-frequency noise interference in the echo signal with a filter;
the signal-to-noise ratio enhancing module is configured to enhance the signal-to-noise ratio of the heartbeat signal of the echo signal;
the decomposition reconstruction module is configured to decompose and reconstruct the echo signal after the signal-to-noise ratio enhancement by adopting wavelet transformation;
a spectrum estimation module configured to perform a signal spectrum estimation based on a time varying window selection;
and the harmonic interference suppression module is configured to suppress the harmonic interference of the heart rate in the signal spectrum, and obtain a final heart rate signal.
According to an aspect of one or more embodiments of the present disclosure, a terahertz through-wall radar-based remote person heart rate detection system is provided.
The remote personnel heart rate detection system based on the terahertz through-wall radar comprises the terahertz through-wall radar, a plurality of paths of acquisition equipment and a remote personnel heart rate detection device based on the terahertz through-wall radar which are sequentially connected.
The above one or more technical solutions have the following beneficial effects:
the invention discloses a method, a device and a system for detecting the heart rate of a remote person based on a terahertz through-wall radar, wherein clutter interference in an echo signal is inhibited by utilizing a background filtering algorithm and an LTS algorithm respectively; carrying out complex signal demodulation and logarithm processing on the I/Q two paths of signals; a band-pass filter is used for restraining high-frequency noise and low-frequency noise; improving signal-to-noise ratio by using a sliding filter; reconstructing the heartbeat signal by utilizing wavelet transformation; designing a time-varying window strategy, and circularly utilizing limited time domain signals; accumulating time domain signal spectrums of different lengths; the heart rate is estimated through frequency domain windowing, and accurate detection of the heart rate under the condition of remote wall penetration is effectively achieved.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and together with the description serve to explain the invention and not to limit the invention.
FIG. 1 is a flowchart illustrating a method and apparatus for populating missing data in a very large scale database, in accordance with one or more embodiments of the present invention;
FIG. 2 is a schematic diagram of the RF output of one or more embodiments of the present invention;
FIG. 3 is a schematic diagram of a radio frequency receiving end according to one or more embodiments of the invention;
FIG. 4 is a schematic illustration of I/Q signals collected by a radar in accordance with one or more embodiments of the present invention;
FIG. 5 is a schematic diagram of an I/Q signal after filtering clutter interference according to one or more embodiments of the present disclosure;
FIG. 6 is a signal diagram illustrating an echo signal after processing according to one or more embodiments of the invention;
FIG. 7 is a schematic representation of a filtered echo signal in accordance with one or more embodiments of the present invention;
FIG. 8 is a schematic of a slip filtered signal in accordance with one or more embodiments of the present invention;
FIG. 9 is a schematic representation of a reconstructed heartbeat signal in accordance with one or more embodiments of the invention;
FIG. 10 is a schematic diagram of a timing window selection in accordance with one or more embodiments of the invention;
FIG. 11 is a schematic representation of a signal spectrum based on a time-varying windowing technique in accordance with one or more embodiments of the present invention;
fig. 12 is a graphical illustration of a base final heart rate signal in accordance with one or more embodiments of the invention.
Detailed Description
It is to be understood that the following detailed description is exemplary and is intended to provide further explanation of the invention as claimed. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.
It is noted that the flowchart and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of methods and systems according to various embodiments of the present disclosure. It should be noted that each block in the flowchart or block diagrams may represent a module, a segment, or a portion of code, which may comprise one or more executable instructions for implementing the logical function specified in the respective embodiment. It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by special purpose hardware-based systems which perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.
The embodiments and features of the embodiments of the present invention may be combined with each other without conflict.
Example one
According to an aspect of one or more embodiments of the present disclosure, there is provided a terahertz through-wall radar for remote human heart rate detection.
As shown in fig. 2 and 3, a terahertz wall-through radar for remote human heart rate detection includes: the terahertz wave after frequency multiplication, radio frequency up-conversion and recoupling is used as a local oscillation signal and is simultaneously output from the radio frequency output end through the first polarizer, and the radio frequency receiving end receives the I/Q two-path echo signals in real time after passing through the second polarizer.
The THz radar receiver (zero intermediate frequency) in the embodiment can receive two paths of I/Q echo signals in real time. In the THz radar of this embodiment, in order to effectively improve the phase consistency between the reference local oscillation signal and the transmission signal and provide the system identification accuracy, the THz wave after frequency doubling, radio frequency up-conversion and recoupling is used as the local oscillation signal, and in addition, the nonlinear phase error of the signal is reduced by linear frequency spectrum shifting, and the difficulty of system data compensation is reduced, as shown in fig. 2. The polarizers are added at the output end and the receiving end, so that the environmental clutter can be effectively eliminated, the signal-to-noise ratio of the receiver is improved, the target characteristics are obtained, the target identification dimensionality is increased, and the receiving end is shown in fig. 3.
In order to effectively improve the phase consistency of a reference local oscillation signal and a transmitting signal and provide system identification precision, THz waves after frequency doubling, radio frequency up-conversion and recoupling are used as local oscillation signals, and in addition, nonlinear phase errors of the signals are reduced through linear frequency spectrum shifting, and the difficulty of system data compensation is reduced. The polarizers are added at the output end and the receiving end, so that the environmental clutter can be effectively eliminated, the signal-to-noise ratio of the receiver is improved, the target characteristic is obtained, and the dimension of target identification is increased.
Example two
According to one aspect of one or more embodiments of the present disclosure, a method for detecting a heart rate of a remote person based on a terahertz through-wall radar is provided.
A terahertz through-wall radar-based remote personnel heart rate detection method comprises the following steps:
step 1: receiving two paths of I/Q echo signals of heart rate detection in real time;
step 2: respectively suppressing static clutter and non-static clutter in the echo signal;
and step 3: carrying out complex signal demodulation on the echo signal subjected to clutter suppression;
and 4, step 4: a filter is adopted to suppress the interference of high-frequency and low-frequency noise in the echo signal;
and 5: enhancing the signal-to-noise ratio of a heartbeat signal of an echo signal;
step 6: decomposing and reconstructing the echo signal after the signal-to-noise ratio is enhanced by adopting wavelet transformation;
and 7: performing a signal spectrum estimation based on a time varying window selection;
and 8: and (4) suppressing harmonic interference of heart rate in the signal frequency spectrum to obtain a final heart rate signal.
The acquisition of the I/Q signal acquired by the THz radar in step 1 of this embodiment is shown in fig. 4.
In the step 2 of clutter suppression in this embodiment, the step 2 mainly suppresses clutter interference in the echo signal, and mainly includes static clutter and non-static clutter. The static clutter mainly comes from a static target in a test environment, and can be considered as a time-invariant signal. The estimation of the invention by using the background filtering algorithm can be expressed as
Where N is 1, …, N, which represents sample data of the digitized echo signal. To suppress static clutter, the result of subtracting equations (1) and (2) from each sample of the digitized echo I/Q, respectively, may be expressed as
Suppressing non-static clutter in the echo can obtain:
W1＝IΤ-X(XΤX)-1XΤIT (5)
W2＝QΤ-X(XΤX)-1XΤQT (6)
wherein X ═ X1,x2],x1＝[0,1,…,N-1]Τ,
The I/Q signals after filtering out the clutter interference are shown in fig. 5.
In the signal demodulation in step 3 of the present embodiment,
performing Complex Signal Demodulation (CSD) on the I/Q signal may be expressed as:
wherein d is0Represents the distance between the radar and the living body, mhAmplitude of heartbeat, fhWhich represents the heart rate, lambda represents the wavelength,
representing phase noise.
In order to suppress the constant term interference existing in the demodulated signal, the signal is logarithmically processed, which can be expressed as:
as can be seen from this, since the heartbeat signal mainly exists in the imaginary part of the above equation, the imaginary part processing of equation (8) can obtain:
the signal after echo signal processing is shown in fig. 6.
In the step 4 of the present embodiment, in the high and low frequency clutter suppression,
after the processing of step 3, the interference of high frequency and low frequency noise existing in the echo is then mainly suppressed by using a 5 th order butterworth filter, which can be expressed as:
wherein, κi andχiRepresenting the filter coefficients. The filtered echo signal is shown in fig. 7.
In this embodiment step 5 the signal to noise ratio enhancement,
the invention utilizes the sliding filter to realize the enhancement of the signal-to-noise ratio of the heartbeat signal, which can be expressed as:
wherein,
representing the largest integer less than N/7. The slip filtered signal is shown in fig. 8.
In the present embodiment of step 6 signal reconstruction,
in order to suppress the influence of out-of-band noise on the heartbeat signal, Wavelet Transform (WT) is used to decompose and reconstruct the signal. In decomposing a signal, the wavelet transform can be expressed as:
where ψ ((n-b)/a) denotes a wavelet function employed in the transformation process, a denotes a scale factor, and b denotes an expansion factor.
The wavelet function used in the present invention is a Morlet wavelet, which can be expressed as:
using the decomposed scale and expansion factors, the signal can be reconstructed into
Wherein,
the reconstructed heartbeat signal is shown in fig. 9.
In the signal spectrum estimation based on the time varying window selection in step 7 of the present embodiment,
in order to effectively estimate the heart rate, a signal selection strategy with variable time length is provided in step 7. Typically, for a signal with a fixed duration, the frequency resolution is:
Δf＝1/Tw (17)
in order to estimate the heart rate accurately, it must be satisfied that:
Δf＜＜fh (18)
namely, it is
fr＝ρ×Δf (19)
Where ρ represents a positive integer.
In order to satisfy the requirement of the above formula and improve the estimation accuracy at the same time, the present invention proposes a time varying window selection strategy as shown in fig. 10, in which case the frequency resolution can be expressed as:
wherein, ω isiDenotes the length of the ith window and q denotes the number of windows.
To estimate the heart rate, the signal in each time window is Fourier transformed while the spectrum is windowed, with a window width of 0.8-2.4 Hz. Further, the q sets of obtained frequency spectrums are accumulated, and can be expressed as:
the spectrum of the signal based on the time-varying windowing technique is shown in fig. 11.
In step 8 in-band harmonic suppression of the present embodiment,
the signal spectrum resulting from step 7 has harmonic interference in addition to the heart rate. Therefore, suppression of harmonics is required. The suppression of in-band harmonics in the present invention can be expressed as:
H[i]＝L[i]+jL[i] (22)
wherein,
κ denotes a spectral component.
The heart rate can thus be estimated as:
fr＝H[μr] (24)
wherein, murRepresenting the peak of the accumulated spectrum. The resulting heart rate signal is shown in fig. 12.
EXAMPLE III
According to an aspect of one or more embodiments of the present disclosure, there is provided a computer-readable storage medium.
A computer readable storage medium, wherein a plurality of instructions are stored, the instructions are suitable for being loaded by a processor of a terminal device and executing the method for detecting the heart rate of the remote personnel based on the terahertz through-wall radar.
Example four
According to an aspect of one or more embodiments of the present disclosure, there is provided a terminal device.
A terminal device comprising a processor and a computer-readable storage medium, the processor being configured to implement instructions; the computer readable storage medium is used for storing a plurality of instructions, and the instructions are suitable for being loaded by a processor and executing the method for detecting the heart rate of the remote personnel based on the terahertz through-the-wall radar.
These computer-executable instructions, when executed in a device, cause the device to perform methods or processes described in accordance with various embodiments of the present disclosure.
In the present embodiments, a computer program product may include a computer-readable storage medium having computer-readable program instructions embodied thereon for performing various aspects of the present disclosure. The computer readable storage medium may be a tangible device that can hold and store the instructions for use by the instruction execution device. The computer readable storage medium may be, for example, but not limited to, an electronic memory device, a magnetic memory device, an optical memory device, an electromagnetic memory device, a semiconductor memory device, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of the computer readable storage medium would include the following: a portable computer diskette, a hard disk, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a Static Random Access Memory (SRAM), a portable compact disc read-only memory (CD-ROM), a Digital Versatile Disc (DVD), a memory stick, a floppy disk, a mechanical coding device, such as punch cards or in-groove projection structures having instructions stored thereon, and any suitable combination of the foregoing. Computer-readable storage media as used herein is not to be construed as transitory signals per se, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through a waveguide or other transmission medium (e.g., optical pulses through a fiber optic cable), or electrical signals transmitted through electrical wires.
The computer-readable program instructions described in this disclosure may be downloaded from a computer-readable storage medium to a respective computing/processing device, or to an external computer or external storage device over a network, such as the internet, a local area network, a wide area network, and/or a wireless network. The network may include copper transmission cables, fiber optic transmission, wireless transmission, routers, firewalls, switches, gateway computers and/or edge servers. The network adapter card or network interface in each computing/processing device receives computer-readable program instructions from the network and forwards the computer-readable program instructions for storage in a computer-readable storage medium in the respective computing/processing device.
The computer program instructions for carrying out operations of the present disclosure may be assembly instructions, Instruction Set Architecture (ISA) instructions, machine related instructions, microcode, firmware instructions, state setting data, or source or object code written in any combination of one or more programming languages, including an object oriented programming language such as C + + or the like and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The computer-readable program instructions may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any type of network, including a Local Area Network (LAN) or a Wide Area Network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet service provider). In some embodiments, the electronic circuitry can execute computer-readable program instructions to implement aspects of the present disclosure by utilizing state information of the computer-readable program instructions to personalize the electronic circuitry, such as a programmable logic circuit, a Field Programmable Gate Array (FPGA), or a Programmable Logic Array (PLA).
EXAMPLE five
According to one aspect of one or more embodiments of the present disclosure, a terahertz through-wall radar-based remote person heart rate detection apparatus is provided.
A remote personnel heart rate detection device based on a terahertz through-wall radar is based on a remote personnel heart rate detection method based on the terahertz through-wall radar, and comprises the following steps:
the signal receiving module is configured to receive two paths of I/Q echo signals of heart rate detection in real time;
a clutter suppression module configured to suppress static clutter and non-static clutter in the echo signal, respectively;
a complex signal demodulation module configured to perform complex signal demodulation on the echo signal after clutter suppression;
a noise interference suppression module configured to suppress high-frequency and low-frequency noise interference in the echo signal with a filter;
the signal-to-noise ratio enhancing module is configured to enhance the signal-to-noise ratio of the heartbeat signal of the echo signal;
the decomposition reconstruction module is configured to decompose and reconstruct the echo signal after the signal-to-noise ratio enhancement by adopting wavelet transformation;
a spectrum estimation module configured to perform a signal spectrum estimation based on a time varying window selection;
and the harmonic interference suppression module is configured to suppress the harmonic interference of the heart rate in the signal spectrum, and obtain a final heart rate signal.
The steps involved in the apparatuses of the above embodiments three, four, and five correspond to the method embodiment two, and the detailed description can be found in the relevant description part of the embodiment one. The term "computer-readable storage medium" should be taken to include a single medium or multiple media containing one or more sets of instructions; it should also be understood to include any medium that is capable of storing, encoding or carrying a set of instructions for execution by a processor and that cause the processor to perform any of the methods of the present invention.
EXAMPLE six
According to an aspect of one or more embodiments of the present disclosure, a terahertz through-wall radar-based remote person heart rate detection system is provided.
The remote personnel heart rate detection system based on the terahertz through-wall radar comprises the terahertz through-wall radar, a plurality of paths of acquisition equipment and a remote personnel heart rate detection device based on the terahertz through-wall radar which are sequentially connected.
In this embodiment, a multi-channel acquisition device is used to achieve the accurate acquisition of the signals, and the digitized echo signals are respectively denoted as I and Q and stored in a computer for later data processing application.
The above one or more technical solutions have the following beneficial effects:
the invention discloses a method, a device and a system for detecting the heart rate of a remote person based on a terahertz through-wall radar, wherein clutter interference in an echo signal is inhibited by utilizing a background filtering algorithm and an LTS algorithm respectively; carrying out complex signal demodulation and logarithm processing on the I/Q two paths of signals; a band-pass filter is used for restraining high-frequency noise and low-frequency noise; improving signal-to-noise ratio by using a sliding filter; reconstructing the heartbeat signal by utilizing wavelet transformation; designing a time-varying window strategy, and circularly utilizing limited time domain signals; accumulating time domain signal spectrums of different lengths; the heart rate is estimated through frequency domain windowing, and accurate detection of the heart rate under the condition of remote wall penetration is effectively achieved.
Those skilled in the art will appreciate that the modules or steps of the present invention described above can be implemented using general purpose computer means, or alternatively, they can be implemented using program code that is executable by computing means, such that they are stored in memory means for execution by the computing means, or they are separately fabricated into individual integrated circuit modules, or multiple modules or steps of them are fabricated into a single integrated circuit module. The present invention is not limited to any specific combination of hardware and software.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Although the embodiments of the present invention have been described with reference to the accompanying drawings, it is not intended to limit the scope of the present invention, and it should be understood by those skilled in the art that various modifications and variations can be made without inventive efforts by those skilled in the art based on the technical solution of the present invention.
Claims (7)
1. A terahertz through-wall radar-based remote personnel heart rate detection method is characterized by comprising the following steps:
receiving two paths of I/Q echo signals of heart rate detection in real time;
respectively suppressing static clutter and non-static clutter in the echo signal;
carrying out complex signal demodulation on the echo signal subjected to clutter suppression; the method comprises the following steps: carrying out complex signal demodulation on the echo signal subjected to clutter suppression according to the distance between the radar and the living body, the heartbeat amplitude, the heart rate, the wavelength and the phase noise, and carrying out logarithmic processing on the signal subjected to complex signal adjustment;
a filter is adopted to suppress the interference of high-frequency and low-frequency noise in the echo signal;
enhancing the signal-to-noise ratio of a heartbeat signal of an echo signal;
decomposing and reconstructing the echo signal after the signal-to-noise ratio is enhanced by adopting wavelet transformation;
performing a signal spectrum estimation based on a time varying window selection;
the specific steps for performing the signal spectrum estimation based on the time varying window selection include:
for a signal with a fixed duration, the frequency resolution is:
wherein f issIs the frequency, wiRepresents the length of the ith window, and q represents the number of windows;
performing Fourier transform on the signal in each time window, and meanwhile performing windowing processing on the frequency spectrum;
performing accumulation operation on the obtained q groups of frequency spectrums;
and (4) suppressing harmonic interference of heart rate in the signal frequency spectrum to obtain a final heart rate signal.
2. The method for detecting the heart rate of a remote person based on the terahertz through-wall radar as claimed in claim 1, wherein the static clutter is estimated according to a background filtering algorithm, and the estimated two static clutter is subtracted from the two I/Q echo signals received in real time to suppress the static clutter.
3. The method for detecting the heart rate of a remote person based on the terahertz through-wall radar as claimed in claim 1, wherein a 5 th order Butterworth filter is adopted to suppress interference of high-frequency noise and low-frequency noise in an echo signal;
enhancing the signal-to-noise ratio of a center jump signal of an echo signal by adopting a sliding filter;
the wavelet function adopted in the decomposition and reconstruction of the echo signal after the signal-to-noise ratio enhancement by adopting wavelet transform is Morlet wavelet.
4. A computer-readable storage medium having stored thereon a plurality of instructions adapted to be loaded by a processor of a terminal device and to execute a method for detecting a heart rate of a remote person based on a thz through-the-wall radar according to any one of claims 1 to 3.
5. A terminal device comprising a processor and a computer-readable storage medium, the processor being configured to implement instructions; a computer readable storage medium for storing a plurality of instructions adapted to be loaded by a processor and to execute a method for detecting a heart rate of a distant person based on a thz through-the-wall radar according to any one of claims 1 to 3.
6. A remote personnel heart rate detection device based on a terahertz through-wall radar is characterized in that the remote personnel heart rate detection method based on the terahertz through-wall radar as claimed in any one of claims 1 to 3 comprises the following steps:
the signal receiving module is configured to receive two paths of I/Q echo signals of heart rate detection in real time;
a clutter suppression module configured to suppress static clutter and non-static clutter in the echo signal, respectively;
a complex signal demodulation module configured to perform complex signal demodulation on the echo signal after clutter suppression;
a noise interference suppression module configured to suppress high-frequency and low-frequency noise interference in the echo signal with a filter;
the signal-to-noise ratio enhancing module is configured to enhance the signal-to-noise ratio of the heartbeat signal of the echo signal;
the decomposition reconstruction module is configured to decompose and reconstruct the echo signal after the signal-to-noise ratio enhancement by adopting wavelet transformation;
a spectrum estimation module configured to perform a signal spectrum estimation based on a time varying window selection;
and the harmonic interference suppression module is configured to suppress the harmonic interference of the heart rate in the signal spectrum, and obtain a final heart rate signal.
7. A remote personnel heart rate detection system based on a terahertz through-wall radar is characterized by comprising the terahertz through-wall radar, a plurality of paths of acquisition equipment and the remote personnel heart rate detection device based on the terahertz through-wall radar as claimed in claim 6 which are connected in sequence; the terahertz through-the-wall radar comprises: the terahertz wave after frequency multiplication, radio frequency up-conversion and recoupling is used as a local oscillation signal and is simultaneously output from the radio frequency output end through the first polarizer, and the radio frequency receiving end receives the I/Q two-path echo signals in real time after passing through the second polarizer.
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| CN111982856B (en) * | 2020-08-27 | 2023-08-01 | 中电科思仪科技股份有限公司 | Substance marker-free detection and identification method based on terahertz waves |
| CN114983373B (en) * | 2022-06-02 | 2023-03-28 | 谢俊 | Method for detecting human heart rate |
| CN116643247B (en) * | 2023-07-25 | 2023-10-27 | 南京航空航天大学 | Method and device for in-cabin living body detection clutter suppression |
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