A vital sign extraction method based on millimeter wave radar

Abstract

The present invention relates to the field of millimeter wave radar technology, and specifically discloses a method for extracting vital signs based on millimeter wave radar, which includes: obtaining an echo signal of a target human body from the millimeter wave radar and extracting distance information from the echo signal; selecting the index corresponding to the strongest power point for phase analysis based on the distance information in the echo signal to obtain an analytical phase; judging whether the target human body is in motion and whether the target human body's breathing signal is weak based on the analytical phase; when the target human body is in a non-motion state and the target human body's breathing signal is weak, expanding an alternative range gate and determining the target human body's vital sign value; when the target human body is in a non-motion state and the target human body's breathing signal is not weak, calculating the target human body's vital sign value. The method for extracting vital signs based on millimeter wave radar provided by the present invention can improve the extraction accuracy of vital sign signals.

Description

Technical Field

[0001] The present invention relates to the technical field of millimeter wave radar, and in particular to a method for extracting vital signs based on millimeter wave radar. Background Art

[0002] Millimeter-wave (mmWave) radar transmits electromagnetic waves, which are reflected back by any object in its path. By capturing and processing the reflected signals, the radar system can determine the target's range, speed, and angle. The potential for mmWave radar to provide millimeter-level accuracy in detecting target distances makes it an ideal technology for sensing human biosignals. Furthermore, mmWave technology offers the advantage of contactless, continuous patient monitoring, making it more convenient for both individuals and users.

[0003] Current technologies pre-process the reflected signal to identify the point with the highest power within the radar's monitoring range. The range gate corresponding to this point is then used as a candidate range gate for extracting vital sign signals. However, due to the high accuracy of radar ranges and the varying strengths of vital sign signals from different parts of the human body, relying solely on the highest power point as the range gate can easily lead to misjudgments. Summary of the Invention

[0004] The present invention provides a method for extracting vital signs based on millimeter-wave radar, which solves the problem of misjudgment in vital sign signal extraction existing in the related art.

[0005] As one aspect of the present invention, a method for extracting vital signs based on millimeter-wave radar is provided, which includes:

[0006] Acquire the echo signal of the millimeter wave radar for the target human body, and extract the distance information in the echo signal;

[0007] Based on the distance information in the echo signal, the index corresponding to the strongest power point is selected for phase analysis to obtain the analyzed phase;

[0008] Determining whether the target human body is in motion and whether the target human body's breathing signal is weak according to the analytical phase;

[0009] When the target person is in a non-moving state and the breathing signal of the target person is weak, the candidate range gate is expanded and the vital sign value of the target person is determined;

[0010] When the target human body is in a non-moving state and the breathing signal of the target human body is not weak, the vital sign value of the target human body is calculated.

[0011] Furthermore, judging whether the target human body is in motion and judging whether the breathing signal of the target human body is weak according to the analytical phase includes:

[0012] Determining whether the target human body is in motion according to a comparison result of the amplitude of the analytical phase and a first preset threshold;

[0013] If the target human body is in a non-moving state, determining whether the target human body's breathing signal is weak according to a comparison result of the amplitude of the analytical phase and a second preset threshold;

[0014] The second preset threshold is smaller than the first preset threshold.

[0015] Furthermore, judging whether the target human body is in motion according to a comparison result of the amplitude of the analytical phase and a first preset threshold value includes:

[0016] Determining whether the amplitude of the analytical phase is greater than the first preset threshold;

[0017] If the amplitude of the analytical phase is greater than the first preset threshold, it is determined that the target human body is in a motion state;

[0018] If the amplitude of the analytical phase is not greater than the first preset threshold, it is determined that the target human body is in a non-moving state.

[0019] Furthermore, if the target human body is in a non-moving state, determining whether the breathing signal of the target human body is weak according to a comparison result of the amplitude of the analytical phase and a second preset threshold value includes:

[0020] If the target human body is in a non-moving state, determining whether the amplitude of the analytical phase is greater than the second preset threshold;

[0021] If the amplitude of the analytical phase is greater than or equal to the second preset threshold, it is determined that the breathing signal of the target person is not weak;

[0022] If the amplitude of the analytical phase is less than the second preset threshold, it is determined that the breathing signal of the target person is weak.

[0023] Furthermore, the candidate range gates are expanded to determine the target person's vital sign values, including:

[0024] Expanding the candidate range gate to the maximum range detection range of the millimeter wave radar;

[0025] Performing phase extraction on the expanded index of each candidate range gate to obtain the index phase of the candidate range gate;

[0026] performing an autocorrelation calculation on the index phase of the candidate range gate to obtain an autocorrelation calculation result;

[0027] Determining whether the target human body has a breathing signal according to the autocorrelation calculation result;

[0028] If it is determined that the target person has a breathing signal, the breathing and heart rate value of the target person is calculated;

[0029] If it is determined that the target human body does not have a breathing signal, determining whether the target human body has a heartbeat signal based on the autocorrelation calculation result;

[0030] If it is determined that the target human body has a heartbeat signal, the heart rate value of the target human body is calculated.

[0031] Furthermore, the candidate range gates are expanded to determine the target person's vital sign values, including:

[0032] Expanding the candidate range gates according to the order of the power point accumulation results to obtain a preset number of the candidate range gates;

[0033] Performing phase extraction on the expanded preset number of indexes of the candidate range gates to obtain index phases of the candidate range gates;

[0034] performing an autocorrelation calculation on the index phase of the candidate range gate to obtain an autocorrelation calculation result;

[0035] Determining whether the target human body has a breathing signal according to the autocorrelation calculation result;

[0036] If it is determined that the target person has a breathing signal, the breathing and heart rate value of the target person is calculated;

[0037] If it is determined that the target human body does not have a breathing signal, determining whether the target human body has a heartbeat signal based on the autocorrelation calculation result;

[0038] If it is determined that the target human body has a heartbeat signal, the heart rate value of the target human body is calculated.

[0039] Further, the candidate range gates are expanded according to the order of the power point accumulation results to obtain a preset number of the candidate range gates, including:

[0040] Differentiating the power points corresponding to the distance information in the echo signal along the time dimension to obtain a differential signal;

[0041] Taking absolute values of the differential signals and summing them up to obtain a power point accumulation result;

[0042] Sorting the power point accumulation results in descending order to determine a preset number of power point accumulation results before sorting;

[0043] The distance information index corresponding to the accumulation result of each power point of the preset number before sorting is determined as the candidate range gate.

[0044] Furthermore, obtaining the echo signal of the millimeter wave radar for the target human body and extracting the distance information in the echo signal include:

[0045] Obtain the echo signal of the millimeter-wave radar targeting the target human body;

[0046] Perform distance-dimensional FFT calculation on the echo signal to obtain distance information in the echo signal.

[0047] Furthermore, when the target human body is in a motion state, the motion state of the target human body is output, and the last calculation result of the current vital sign value of the target human body is maintained.

[0048] Furthermore, the method further comprises:

[0049] Output the result of the vital sign value of the target human body.

[0050] The millimeter-wave radar-based vital sign extraction method provided by the present invention determines whether the target human body is in motion and whether the respiratory signal is weak. When the target human body is in a non-motion state and the respiratory signal is weak, the method expands the alternative range gates to find a range gate that can represent the chest cavity. This can eliminate the echo signals of the millimeter-wave radar detection point located in the non-chest cavity area, avoid the misjudgment of relying solely on the strongest power point as the range gate, and improve the accuracy of vital sign extraction. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the following detailed description, they are used to explain the present invention but do not constitute a limitation of the present invention. In the accompanying drawings:

[0052] Figure 1 This is a flow chart of the vital signs extraction method based on millimeter wave radar provided by the present invention.

[0053] Figure 2 This is a flowchart of a specific implementation of the method for extracting vital signs based on millimeter-wave radar provided by the present invention. DETAILED DESCRIPTION

[0054] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention may be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0055] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0056] It should be noted that the terms "first," "second," and the like in the specification and claims of the present invention and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a particular order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate for the embodiments of the present invention described herein. In addition, the terms "including," "having," and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to these processes, methods, products, or apparatuses.

[0057] In this embodiment, a method for extracting vital signs based on millimeter-wave radar is provided. Figure 1 FIG. 1 is a flow chart of a method for extracting vital signs based on millimeter-wave radar according to an embodiment of the present invention. Figure 1 Shown, including:

[0058] S100, obtaining an echo signal of a millimeter-wave radar targeting a target human body, and extracting distance information from the echo signal;

[0059] When the millimeter wave radar is performing vital sign detection, it transmits electromagnetic waves to the target human body, receives and processes the echo signals reflected by the target human body, and obtains the vital sign detection results.

[0060] In the embodiment of the present invention, since the echo signal includes a distance signal, a speed signal, and an angle signal, the embodiment of the present invention needs to extract the distance for processing.

[0061] Specifically, obtaining the echo signal of the millimeter wave radar for the target human body;

[0062] Perform distance-dimensional FFT calculation on the echo signal to obtain distance information in the echo signal.

[0063] It should be understood that the specific calculation of the distance-dimensional FFT of the echo signal is well known to those skilled in the art and will not be described in detail here.

[0064] S200, based on the distance information in the echo signal, select the index corresponding to the strongest power point to perform phase analysis to obtain a resolved phase;

[0065] In this embodiment of the present invention, a graph can be constructed based on the distance information in the echo signal, with distance as the horizontal axis and signal strength as the vertical axis. Furthermore, a corresponding signal strength-distance relationship graph can be constructed for each echo signal at each moment. The distance on the horizontal axis corresponding to the point with the strongest power is selected as an index, and phase resolution is performed on this index to obtain the resolved phase corresponding to the strongest power point.

[0066] S300, judging whether the target person is in motion and judging whether the breathing signal of the target person is weak according to the analytical phase;

[0067] In the embodiment of the present invention, since the analytical phase is positively correlated with the human chest micro-motion, that is, if the target moves a small distance ΔR, the phase difference of the continuous measurement signal can be expressed by the formula When the target body is in motion, the amplitude of the change in the analytical phase value of its strongest power point will be relatively large. Therefore, this principle can be used to determine whether the target body is in motion, that is, the analytical phase can be used to determine whether the target body is in motion.

[0068] If the target body is in motion, then to avoid large deviations, the vital signs values are not calculated, and the target body is directly output as being in motion, and the last calculation result of the target body's vital signs values is maintained.

[0069] That is, when the target human body is in a motion state, the motion state of the target human body is output, and the last calculation result of the current vital sign value of the target human body is maintained.

[0070] S400, when the target person is in a non-moving state and the target person's breathing signal is weak, expanding the candidate range gate and determining the target person's vital sign value;

[0071] In an embodiment of the present invention, when the target human body is in a non-moving state and the target human body's breathing signal is weak, it is necessary to improve the accuracy of vital sign value calculation by expanding the candidate range gate.

[0072] It should be noted that a range gate can be understood as the minimum distance unit in the range-intensity matrix obtained by collecting the radar intermediate frequency signal and performing a one-dimensional FFT calculation. It is divided by distance index. A range pre-calibration can be performed based on the approximate target range. The calibrated range contains multiple range gates (minimum distance units). Calibration must ensure that the target is within the calibrated range.

[0073] In the embodiment of the present invention, since the breathing signal of the target human body in a non-moving state is weak, it can be known that the range gate of the echo signal corresponding to the result has a deviation, and it is necessary to find a range gate that can characterize the breathing signal by expanding the alternative range gates, thereby improving the detection accuracy.

[0074] S500: When the target human body is in a non-moving state and the breathing signal of the target human body is not weak, calculate the vital sign value of the target human body.

[0075] In an embodiment of the present invention, when the target person is in a non-moving state and the target person's breathing signal is not weak, it indicates that the result obtained by using the strongest power point as the range gate is usable, and the target person's vital sign value can be directly calculated based on the echo signal.

[0076] In summary, the vital signs extraction method based on millimeter-wave radar provided in the embodiment of the present invention judges whether the target human body is in motion and whether the respiratory signal is weak. When the target human body is in a non-motion state and the respiratory signal is weak, the method expands the alternative range gate to find a range gate that can represent the chest part, thereby excluding the echo signal of the millimeter-wave radar detection point located in the non-chest part, avoiding the misjudgment of relying solely on the strongest power point as the range gate, and improving the accuracy of vital signs extraction.

[0077] In an embodiment of the present invention, determining whether the target human body is in motion and determining whether the target human body's breathing signal is weak according to the analytical phase includes:

[0078] Determining whether the target human body is in motion according to a comparison result of the amplitude of the analytical phase and a first preset threshold;

[0079] If the target human body is in a non-moving state, determining whether the target human body's breathing signal is weak according to a comparison result of the amplitude of the analytical phase and a second preset threshold;

[0080] The second preset threshold is smaller than the first preset threshold.

[0081] Specifically, if Figure 2 As shown, by comparing the amplitude of the analytical phase with the first preset threshold, it can be determined whether the target human body is in a motion state.

[0082] Specifically, judging whether the target human body is in motion according to a comparison result of the amplitude of the analytical phase and a first preset threshold value includes:

[0083] Determining whether the amplitude of the analytical phase is greater than the first preset threshold;

[0084] If the amplitude of the analytical phase is greater than the first preset threshold, it is determined that the target human body is in a motion state;

[0085] If the amplitude of the analytical phase is not greater than the first preset threshold, it is determined that the target human body is in a non-moving state.

[0086] It can also be judged by comparing the energy accumulation of the analytical phase with the preset energy accumulation value. For example, if the first preset energy accumulation value is 6, then when the energy accumulation value of the analytical phase is greater than 6, it can be determined that the target human body is in motion.

[0087] When the amplitude of the analytical phase is less than a second preset threshold, the target person's respiration signal is determined to be weak. This determination can also be made by comparing the energy accumulation value of the analytical phase with a second preset energy accumulation value. For example, if the second preset energy accumulation value is 4, and the energy accumulation value of the analytical phase is less than 4, the target person's respiration signal is determined to be weak.

[0088] Specifically, if the target human body is in a non-moving state, determining whether the breathing signal of the target human body is weak according to a comparison result of the amplitude of the analytical phase and a second preset threshold value includes:

[0089] If the target human body is in a non-moving state, determining whether the amplitude of the analytical phase is greater than the second preset threshold;

[0090] If the amplitude of the analytical phase is greater than or equal to the second preset threshold, it is determined that the breathing signal of the target person is not weak;

[0091] If the amplitude of the analytical phase is less than the second preset threshold, it is determined that the breathing signal of the target person is weak.

[0092] As a specific implementation method of expanding the candidate range gate, determining the vital sign value of the target person after expanding the candidate range gate includes:

[0093] Expanding the candidate range gate to the maximum range detection range of the millimeter wave radar;

[0094] Performing phase extraction on the expanded index of each candidate range gate to obtain the index phase of the candidate range gate;

[0095] performing an autocorrelation calculation on the index phase of the candidate range gate to obtain an autocorrelation calculation result;

[0096] Determining whether the target human body has a breathing signal according to the autocorrelation calculation result;

[0097] If it is determined that the target person has a breathing signal, the breathing and heart rate value of the target person is calculated;

[0098] If it is determined that the target human body does not have a breathing signal, determining whether the target human body has a heartbeat signal based on the autocorrelation calculation result;

[0099] If it is determined that the target human body has a heartbeat signal, the heart rate value of the target human body is calculated.

[0100] It should be understood that in this embodiment, when the breathing signal of the target human body is weak, the entire inspection distance range of the millimeter-wave radar signal is used as an alternative distance gate. In this way, electromagnetic waves are emitted to the target human body according to the alternative distance gate, and the corresponding echo signals are obtained, and then calculated one by one to finally obtain the calculation results.

[0101] It should be noted that if Figure 2 As shown, the phase corresponding to each distance index obtained in step S8 is autocorrelated. The cycle after each phase autocorrelation is calculated to see if it is within the respiratory cycle range. If so, a respiratory signal is present, and the process proceeds to step 11 to calculate the respiratory heart rate value corresponding to that phase. In step S12, if a respiratory signal is not present, the cycle after each phase autocorrelation is calculated to see if it is within the heartbeat cycle range. If so, a heartbeat signal is present, and the process proceeds to step 13 to calculate the heart rate value corresponding to that phase. Otherwise, a heartbeat signal is not present.

[0102] As another specific implementation of expanding the candidate range gate, determining the vital sign value of the target person after expanding the candidate range gate includes:

[0103] Expanding the candidate range gates according to the order of the power point accumulation results to obtain a preset number of the candidate range gates;

[0104] Performing phase extraction on the expanded preset number of indexes of the candidate range gates to obtain index phases of the candidate range gates;

[0105] performing an autocorrelation calculation on the index phase of the candidate range gate to obtain an autocorrelation calculation result;

[0106] Determining whether the target human body has a breathing signal according to the autocorrelation calculation result;

[0107] If it is determined that the target person has a breathing signal, the breathing and heart rate value of the target person is calculated;

[0108] If it is determined that the target human body does not have a breathing signal, determining whether the target human body has a heartbeat signal based on the autocorrelation calculation result;

[0109] If it is determined that the target human body has a heartbeat signal, the heart rate value of the target human body is calculated.

[0110] In an embodiment of the present invention, the candidate range gates are expanded according to the order of the power point accumulation results to obtain a preset number of candidate range gates, including:

[0111] Differentiating the power points corresponding to the distance information in the echo signal along the time dimension to obtain a differential signal;

[0112] Taking absolute values of the differential signals and summing them up to obtain a power point accumulation result;

[0113] Sorting the power point accumulation results in descending order to determine a preset number of power point accumulation results before sorting;

[0114] The distance information index corresponding to the accumulation result of each power point of the preset number before sorting is determined as the candidate range gate.

[0115] Specifically, the distance signal is differentiated along the time dimension, the absolute value of the differential signal is taken and then summed up, and finally, the accumulated results are sorted from large to small, and the first few indexes (i.e., the distance dimension indexes corresponding to the larger summation results) are taken.

[0116] like Figure 2 As shown, step S8, for the range gate expanded in step S7, phase extraction is performed along each range gate index. Step S9, autocorrelation is taken for the phase corresponding to each distance index obtained in step S8. Calculate whether the period after each phase autocorrelation is within the respiratory cycle range. If so, it indicates that a respiratory signal exists, and jump to step 11 to calculate the respiratory heart rate value corresponding to the phase. Step S12, if the respiratory signal does not exist, calculate whether the period after each phase autocorrelation is within the heartbeat cycle range. If so, it indicates that a heartbeat signal exists, and jump to step 13 to calculate the heart rate value corresponding to the phase. Otherwise, it indicates that the heartbeat signal does not exist, and jump to step 14 to make a decision output.

[0117] In an embodiment of the present invention, the method further includes:

[0118] Output the result of the vital sign value of the target human body.

[0119] like Figure 2 As shown in the figure, when the target body is in motion, the output is the last respiratory heart rate result; when the target body is in a non-motion state and the respiratory signal is weak, the respiratory signal is searched according to the result after the alternative distance gate expansion. If a non-weak respiratory signal can be found, the respiratory heart rate is calculated and output. If not found, the heart rate value is calculated according to the heartbeat signal and output. If the heartbeat signal does not exist, the output result is 0.

[0120] In summary, the millimeter-wave radar-based vital signs extraction method provided by the embodiment of the present invention expands the methods for extracting vital signs, avoids the occurrence of missed detections to a certain extent, and improves the accuracy of respiratory and heart rate calculations. In addition, it relies solely on millimeter-wave radar, which improves the accuracy and stability of the algorithm without increasing hardware costs.

[0121] It will be understood that the above embodiments are merely exemplary embodiments for illustrating the principles of the present invention, and the present invention is not limited thereto. Those skilled in the art will appreciate that various modifications and improvements can be made without departing from the spirit and substance of the present invention, and such modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A method for extracting vital signs based on millimeter wave radar, characterized in that: include: Acquire the echo signal of the millimeter wave radar for the target human body, and extract the distance information in the echo signal; Based on the distance information in the echo signal, the index corresponding to the strongest power point is selected for phase analysis to obtain the analyzed phase; Determining whether the target human body is in motion and whether the target human body's breathing signal is weak according to the analytical phase; When the target person is in a non-moving state and the breathing signal of the target person is weak, the candidate range gate is expanded and the vital sign value of the target person is determined; When the target human body is in a non-moving state and the respiratory signal of the target human body is not weak, calculating the vital sign value of the target human body; The method of expanding the candidate range gate to determine the vital sign values of the target person includes: Expanding the candidate range gates according to the order of the power point accumulation results to obtain a preset number of the candidate range gates; Performing phase extraction on the expanded preset number of indexes of the candidate range gates to obtain the index phases of the candidate range gates; performing an autocorrelation calculation on the index phase of the candidate range gate to obtain an autocorrelation calculation result; Determining whether the target human body has a breathing signal according to the autocorrelation calculation result; If it is determined that the target person has a breathing signal, the breathing and heart rate value of the target person is calculated; If it is determined that the target human body does not have a breathing signal, determining whether the target human body has a heartbeat signal based on the autocorrelation calculation result; If it is determined that the target human body has a heartbeat signal, the heart rate value of the target human body is calculated.

2. The method according to claim 1, characterized in that Judging whether the target human body is in motion and judging whether the breathing signal of the target human body is weak according to the analytical phase includes: Determining whether the target human body is in motion according to a comparison result of the amplitude of the analytical phase and a first preset threshold; If the target human body is in a non-moving state, determining whether the target human body's breathing signal is weak according to a comparison result of the amplitude of the analytical phase and a second preset threshold; The second preset threshold is smaller than the first preset threshold.

3. The method according to claim 2, characterized in that Determining whether the target human body is in motion according to a comparison result of the amplitude of the analytical phase and a first preset threshold value includes: Determining whether the amplitude of the analytical phase is greater than the first preset threshold; If the amplitude of the analytical phase is greater than the first preset threshold, it is determined that the target human body is in a motion state; If the amplitude of the analytical phase is not greater than the first preset threshold, it is determined that the target human body is in a non-moving state.

4. The method according to claim 2, characterized in that If the target human body is in a non-moving state, determining whether the breathing signal of the target human body is weak according to a comparison result of the amplitude of the analytical phase and a second preset threshold value includes: If the target human body is in a non-moving state, determining whether the amplitude of the analytical phase is greater than the second preset threshold; If the amplitude of the analytical phase is greater than or equal to the second preset threshold, it is determined that the breathing signal of the target person is not weak; If the amplitude of the analytical phase is less than the second preset threshold, it is determined that the breathing signal of the target person is weak.

5. The method according to any one of claims 1 to 4, characterized in that After expanding the candidate range gate, the vital signs of the target person are determined, including: Expanding the candidate range gate to the maximum range detection range of the millimeter wave radar; Performing phase extraction on the expanded index of each candidate range gate to obtain the index phase of the candidate range gate; performing an autocorrelation calculation on the index phase of the candidate range gate to obtain an autocorrelation calculation result; Determining whether the target human body has a breathing signal according to the autocorrelation calculation result; If it is determined that the target person has a breathing signal, the breathing and heart rate value of the target person is calculated; If it is determined that the target human body does not have a breathing signal, determining whether the target human body has a heartbeat signal based on the autocorrelation calculation result; If it is determined that the target human body has a heartbeat signal, the heart rate value of the target human body is calculated.

6. The method according to claim 1, characterized in that Expanding the candidate range gates according to the order of the power point accumulation results to obtain a preset number of the candidate range gates includes: Differentiating the power points corresponding to the distance information in the echo signal along the time dimension to obtain a differential signal; Taking absolute values of the differential signals and summing them up to obtain a power point accumulation result; Sorting the power point accumulation results in descending order to determine a preset number of power point accumulation results before sorting; The distance information index corresponding to the accumulation result of each power point of the preset number before sorting is determined as the candidate range gate.

7. The method according to any one of claims 1 to 4, characterized in that Obtaining the echo signal of the millimeter wave radar for the target human body and extracting the distance information in the echo signal, including: Obtain the echo signal of the millimeter-wave radar targeting the target human body; Perform distance-dimensional FFT calculation on the echo signal to obtain distance information in the echo signal.

8. The method according to any one of claims 1 to 4, characterized in that When the target human body is in a motion state, the motion state of the target human body is output, and the last calculation result of the current vital sign value of the target human body is maintained.

9. The method according to any one of claims 1 to 4, characterized in that The method further comprises: Output the result of the vital sign value of the target human body.

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