A vital sign detection method and device based on microwave radar

Abstract

The present invention relates to a method and device for detecting vital signs based on microwave radar, comprising the following steps: S1, emitting and receiving radar signals via a microwave radar to locate a human body; S2, controlling the microwave radar to rotate and / or translate to locate a vital sign detection area; and S3, receiving radar signals returned from the vital sign detection area and extracting vital signs from the radar signals. The present application can control the microwave radar to rotate and / or translate to locate a vital sign detection area, thereby allowing the microwave radar used to detect vital signs to be placed in multiple locations indoors. Furthermore, there is no need to manually adjust the scanning area of ​​the microwave radar before use; the microwave radar can automatically locate the vital sign detection area and perform vital sign detection.

Description

Technical Field

[0001] The present invention relates to the field of vital sign detection methods, and in particular to a vital sign detection method and device based on microwave radar. Background Art

[0002] Microwave radar can collect echo data of the detected person, and then extract the micro-movement changes of the human body from the echo data, thereby calculating the human body's vital signs, such as breathing, heartbeat, etc.

[0003] The microwave radar used for vital sign detection is fixed in a certain position in the room, such as the head of the bed, on the wall, etc. Since the human body's vital signs are tiny changes in movement, such as a heartbeat corresponding to a tiny vibration of the human chest, the position of the human body in the radar scanning area is unknown, and the movement generated by vital signs is very weak. Not all areas within the radar's scanning range can extract micro-motion signals. Before performing vital sign detection, the microwave radar's position and direction need to be manually adjusted to place the human body in an area with better signal within the radar scanning range. Only then can the subsequent vital sign detection algorithm capture the vital sign data from the echo data. In the existing technology, it is impossible to realize that the microwave radar can automatically find the part of the human body that can feedback vital signs.

[0004] The purpose of the present invention is to design a method and device for detecting vital signs based on microwave radar in order to solve the above problems in the prior art. Summary of the Invention

[0005] In response to the problems existing in the above-mentioned prior art, the present invention provides a method and device for detecting vital signs based on microwave radar, which can effectively solve at least one problem existing in the above-mentioned prior art.

[0006] The technical solution of the present invention is:

[0007] A method for detecting vital signs based on microwave radar comprises the following steps:

[0008] S1, uses microwave radar to transmit and receive radar signals to find the human body position;

[0009] S2, controlling the microwave radar to rotate and / or translate to find a vital sign detection area;

[0010] S3: Receive the radar signal returned by the vital sign detection area, and extract the vital sign from the radar signal.

[0011] Furthermore, in step S1, searching for the human body position includes:

[0012] Identify the human body and obtain its position through point cloud data.

[0013] Furthermore, step S2 includes:

[0014] S21, determining whether the human body is in a micro-motion state, and if so, rotating and / or translating the microwave radar to an area facing the micro-motion state;

[0015] S22, calculating vital signs at multiple locations within the region of the micro-motion state;

[0016] S23, if the vital signs at multiple positions are similar, the area in the micro-motion state is determined to be the vital sign detection area; if the vital signs at multiple positions are different, the scanning range of the microwave radar is rotated and / or translated and the process returns to step S21.

[0017] Furthermore, before step S21, execute:

[0018] S20, record and update the radar signal in real time, and enter step S21 when the number of point clouds of the radar signal is less than a preset threshold, and use the human body position when the number of point clouds of the radar signal is less than the preset threshold as the micro-motion position.

[0019] Furthermore, step S22 includes:

[0020] The region in the micro-motion state is divided into a plurality of sub-regions at equal intervals, and the vital signs of the plurality of sub-regions are calculated.

[0021] Furthermore, dividing the micro-motion state region into a plurality of sub-regions at equal intervals, and calculating the vital signs of the plurality of sub-regions includes:

[0022] The radar signal in the micro-motion state area is divided equally and the phases are calculated respectively;

[0023] The multiple phases are calculated using a vital sign algorithm to obtain multiple vital signs.

[0024] Furthermore, if the vital signs at multiple locations are different, the scanning range of the microwave radar is rotated and / or translated according to the vital signs of the multiple sub-areas and returns to step S21.

[0025] Furthermore, rotating and / or translating the microwave radar according to the vital signs of the plurality of sub-areas includes:

[0026] Calculate the mean of vital signs in multiple sub-regions;

[0027] The microwave radar is rotated and / or translated toward the sub-region where the vital sign is close to the vital sign mean value.

[0028] Furthermore, the following steps are performed to determine whether the vital signs at multiple locations are similar:

[0029] The standard deviation of the vital signs at the multiple locations is calculated. If the standard deviation is less than a preset standard deviation threshold, the vital signs at the multiple locations are similar.

[0030] A microwave radar-based vital sign detection device is further provided, comprising a microwave radar, wherein the microwave radar is rotatable and the vital sign detection device implements the microwave radar-based vital sign detection method when in operation.

[0031] Therefore, the present invention provides the following effects and / or advantages:

[0032] The present application can control the rotation and / or translation of the microwave radar to direct the center of its scanning area toward the vital signs detection area by finding the vital signs detection area, and utilize the characteristics of the center of the scanning area having the best signal-to-noise ratio and the best response of human vital signs, thereby improving the detection accuracy of the microwave radar in detecting human vital signs.

[0033] The present application can control the rotation and / or translation of the microwave radar to find the vital signs detection area, so that the microwave radar used to detect vital signs can be placed in multiple locations indoors, and there is no need to manually adjust the scanning area of ​​the microwave radar before use. The microwave radar can automatically find the vital signs detection area and perform vital signs detection.

[0034] The present application calculates vital signs at multiple positions within the area of ​​the micro-motion state, and through the vital signs at multiple positions, it is possible to determine whether the scanning center of the microwave radar is facing the part of the human body that reflects vital signs. It can be used to accurately adjust the scanning range of the microwave radar, thereby improving the accuracy of vital signs detection.

[0035] The present application divides the area of ​​the micro-motion state into multiple sub-areas at equal intervals, which can be applicable to the characteristics of human vital signs in the microwave radar detection process, thereby improving the detection accuracy.

[0036] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention are realized and obtained by the structures particularly pointed out in the description and the drawings.

[0037] It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 A schematic diagram of a flow chart provided for an embodiment of the present invention.

[0039] Figure 2A logical diagram provided for an embodiment of the present invention.

[0040] Figure 3 Schematic diagram for finding the human body position for microwave radar.

[0041] Figure 4 Schematic diagram of finding the micromotion region for microwave radar, where the shaded area represents the micromotion region.

[0042] Figure 5 This is a schematic diagram showing that the center of the scanning area of ​​the microwave radar is located at the center of the micro-motion area after rotation.

[0043] Figure 6 This is a schematic diagram of dividing the micro-motion state area into 2*2 square areas when measuring heart rate.

[0044] Figure 7 This is a schematic diagram of dividing the micro-motion state region into four square regions arranged from top to bottom when measuring respiratory frequency.

[0045] Figure 8 A schematic diagram of adjusting the scanning area of ​​a microwave radar according to breathing frequency.

[0046] Figure 9 Schematic diagram of the steps for calculating vital signs.

[0047] Figure 10 This is a structural diagram of the vital signs detection equipment. DETAILED DESCRIPTION

[0048] In order to facilitate understanding by those skilled in the art, the present invention is now described in further detail with reference to the following examples:

[0049] refer to Figure 1-2 , a vital sign detection method based on microwave radar, comprising the following steps:

[0050] S1, uses microwave radar to transmit and receive radar signals to find the human body position;

[0051] In this embodiment, a microwave radar transmits radar signals and receives return radar signals from a person in the room. The microwave radar can be placed anywhere in the room, such as on a bedside table, a wall, or a wardrobe, but this is not a limitation. As long as the microwave radar can scan multiple locations in the room, the radar's position or the person's position is unknown. Microwave radar methods for locating a person are conventional. For example, the initial position of a person can be determined by analyzing the echo data characteristics of the microwave radar when the person is sitting or lying down, without walking or making large body movements.

[0052] In this step, the microwave radar can rotate or translate to search for a human body in the room.

[0053] This step is as follows Figure 3 shown.

[0054] S2, controlling the microwave radar to rotate and / or translate to find a vital sign detection area;

[0055] In step S1, the microwave radar locates the human body. Further work is needed to identify a vital sign detection area. This step can be performed based on the radar echo data, based on the presence of a person in a resting state, such as sitting or lying down, where the body does not move extensively, with slight fluctuations in breathing and heartbeats.

[0056] Because the signal-to-noise ratio of each area within the scanning range of the microwave radar is different, and the position of the human body is unknown before step S1, if the microwave radar does not look for the vital signs detection area but directly extracts vital signs through the microwave radar data returned by the human body's breathing or heartbeat, its data will be affected by external interference and different radar signal-to-noise ratios, and the calculated vital signs data will have problems such as insufficient accuracy. Therefore, this step searches for the vital signs detection area.

[0057] S3: Receive the radar signal returned by the vital sign detection area, and extract the vital sign from the radar signal.

[0058] In step S2, the human vital sign detection area is found. At this point, only the radar signal in the vital sign detection area is extracted for vital sign calculation, which can greatly improve the accuracy of the vital sign calculation results. For methods of vital sign detection, reference can be made to the prior application entitled "Millimeter-wave Radar-Based Vital Sign Monitoring Method, Apparatus, Device, and Medium," with publication number CN118452869A.

[0059] Alternatively, first construct the ADC data collected by each frame of microwave radar within a period of time into a matrix to be processed, and use the covariance matrix decomposition method to remove the clutter that is significantly different from the useful signal; then use the wavelet denoising method to remove the non-stationary noise, and thus reconstruct the original ADC data. Then, by referring to Figure 9 The provided calculation process realizes vital signs analysis.

[0060] Furthermore, in step S1, searching for the human body position includes:

[0061] Identify the human body and obtain its position through point cloud data.

[0062] In this step, the microwave radar performs ADC data acquisition, one-dimensional FFT calculation, two-dimensional FFT calculation, and target position selection. The horizontal angle and pitch angle between the human body and the microwave radar, and the target are mapped to a direct coordinate system so that the human body can be identified. The microwave radar is then rotated or translated according to the horizontal angle and pitch angle between the human body and the microwave radar so that the human body is located in the middle of the microwave radar scanning area.

[0063] When the human body is in a resting state, the point cloud data corresponding to the reflected radar signal is relatively small. By utilizing the amount of point cloud data in this state, it can be determined that there is a human body at that position when the point cloud data is less than the preset point cloud data number threshold.

[0064] Furthermore, step S2 includes:

[0065] S21, determining whether the human body is in a micro-motion state, and if so, rotating and / or translating the microwave radar to an area facing the micro-motion state;

[0066] In this step, the radar signal can be calculated by the micro-motion algorithm to determine whether the human body is in a micro-motion state. The parts of the human body in a micro-motion state are generally the chest and abdomen, etc. This area is used to identify the best area for vital sign detection. The micro-motion algorithm can be used to extract the parts in the micro-motion state, such as Figure 4 As shown, in step S1, the microwave radar finds the position of the human body. At this time, the microwave radar can be rotated or translated to face the human body. In this step, by extracting the micro-motion area, the microwave radar can be rotated or translated to face the center of the scanning area toward the chest, abdomen, etc. of the human body, as shown in FIG. Figure 5 shown.

[0067] Since the accuracy of the micro-motion algorithm is average, in this step, when the microwave radar rotates or translates toward the micro-motion area, the chest or abdomen of the human body may not be in the optimal scanning area of ​​the microwave radar.

[0068] S22, calculating vital signs at multiple locations within the region of the micro-motion state;

[0069] In this step, the heartbeat is used as an example to illustrate that the human chest cavity vibrates slightly under the action of the heartbeat, thereby generating an area in a micro-motion state.

[0070] Theoretically, the frequencies corresponding to the micro-tremors generated by a human heartbeat at various locations on the chest should be the same. Accordingly, the heartbeat data calculated from the radar signal reflected back from these micro-tremors should be the same at multiple locations within the micro-tremor region. Vital sign calculations are performed at multiple locations within the micro-tremor region obtained in step S21, which are then used in subsequent steps to determine whether the microwave radar's optimal signal-to-noise ratio scanning area is directly over the human chest.

[0071] S23, if the vital signs at multiple positions are similar, the area in the micro-motion state is determined to be the vital sign detection area; if the vital signs at multiple positions are different, the scanning range of the microwave radar is rotated and / or translated and the process returns to step S21.

[0072] If the vital sign calculations at multiple locations are the same or similar, it means that the microwave radar's optimal detection area is precisely aligned with micro-movements of vital signs such as the chest or abdomen. The microwave radar's optimal detection area can be considered to be the exact center of the radar's detection area.

[0073] Due to different sleeping positions, the radar signals captured by the microwave radar in the micro-motion area may be too weak, interfered with, or have calculation errors. Or, by the time the micro-motion signals originate from the center of the chest or abdomen and reach the edge of the body, they may be too weak to be captured. This can lead to different calculated vital signs at different locations. Therefore, this step is necessary.

[0074] Preferably, for the heart rate in the vital signs, since the heart is located near the center of the chest cavity, the region of the micro-motion state can be divided into N*N squares, for example, into a 2*2 field-shaped structure, such as Figure 6 As shown, heartbeat detection is performed in each square area in the area. If the heart is located in the center of N*N squares, the micro-movements generated by the heartbeat in each square area will be captured by the microwave radar and the calculated heart rate will be very close.

[0075] At the same time, when measuring the heart rate, since the chest cavity where the heart is located is located above the human body, in order to facilitate capturing the heart rate, in this step, the area of ​​the micro-motion state close to the human head can first be divided into N*N squares and then the vital signs can be calculated.

[0076] Preferably, for the respiratory rate in the vital signs, since the abdomen of the human body will float up and down when breathing, the area of ​​the micro-motion state can be divided into N rectangles arranged up and down, for example, 4 rectangles, such as Figure 7 As shown, in this area, the respiratory rate is detected in each rectangular area. If the center of the abdomen is located at the center of N rectangles, the micro-movements generated by the ups and downs of the abdomen in each rectangular area are captured by the microwave radar and the calculated respiratory rate will be very close.

[0077] At the same time, when measuring the respiratory rate, since the abdomen is located in the middle of the human body, in order to facilitate capturing the respiratory rate, in this step, the area of ​​the micro-motion state close to the human legs can be first divided into N rectangles before calculating the vital signs.

[0078] The legs or head of the human body can be identified using existing technologies.

[0079] Therefore, this step determines whether the center of the microwave radar's scanning range is located at the center of the human body part from which vital sign data can be extracted. Only then can the radar data obtained by the microwave radar accurately reflect the human vital signs. If the vital signs at multiple locations are different, the microwave radar can be rotated or moved to cause the microwave radar's scanning area to shift or rotate, thereby changing the center point of the microwave radar's scanning area.

[0080] Furthermore, before step S21, execute:

[0081] S20, record and update the radar signal in real time, and enter step S21 when the number of point clouds of the radar signal is less than a preset threshold, and use the human body position when the number of point clouds of the radar signal is less than the preset threshold as the micro-motion position.

[0082] In this embodiment, if the human body is stationary, the number of point clouds of the radar signal will become very small. By setting a preset number threshold, it can be determined that the human body is in a stationary state when the number is reduced to below the preset number threshold.

[0083] Furthermore, step S22 includes:

[0084] The region in the micro-motion state is divided into a plurality of sub-regions at equal intervals, and the vital signs of the plurality of sub-regions are calculated.

[0085] Furthermore, dividing the micro-motion state region into a plurality of sub-regions at equal intervals, and calculating the vital signs of the plurality of sub-regions includes:

[0086] The radar signal in the micro-motion state area is divided equally and the phases are calculated respectively;

[0087] The multiple phases are calculated using a vital sign algorithm to obtain multiple vital signs.

[0088] In this step, you can refer to Figure 7 or 8, thereby dividing the area of ​​the micro-motion state into equal intervals.

[0089] Specifically, the phase data of the micro-motion region can be first extracted and phase unwrapped to generate unwrapped data. The unwrapped data can then be preprocessed and an FFT operation performed on the preprocessed unwrapped data to generate heart rate data for tracking. For details, please refer to the prior application entitled "Millimeter-wave Radar-Based Vital Sign Monitoring Method, Apparatus, Device, and Medium" with publication number CN118452869A.

[0090] Furthermore, if the vital signs of multiple locations are different, the scanning range of the microwave radar is rotated and / or translated according to the vital signs of the multiple sub-areas and the process returns to step S21.

[0091] Furthermore, rotating and / or translating the microwave radar according to the vital signs of the plurality of sub-areas includes:

[0092] Calculate the mean of vital signs in multiple sub-regions;

[0093] The microwave radar is rotated and / or translated toward the sub-region where the vital sign is close to the vital sign mean value.

[0094] In this step, if Figure 8 As shown, assuming that the respiratory rates from multiple positions on the abdomen calculated in the above steps are 15, 20, 21, and 20 (times / minute), respectively, the calculated average is 19. The sub-areas with respiratory rates of 20, 21, and 20 are areas where vital signs are close to the mean of the vital signs. At this time, the scanning range of the microwave radar needs to be adjusted downward.

[0095] Furthermore, the following steps are performed to determine whether the vital signs at multiple locations are similar:

[0096] The standard deviation of the vital signs at the multiple locations is calculated. If the standard deviation is less than a preset standard deviation threshold, the vital signs at the multiple locations are similar.

[0097] A microwave radar-based vital sign detection device is further provided, comprising: a microwave radar 1, wherein the microwave radar 1 is rotatable and the vital sign detection device implements the microwave radar-based vital sign detection method when in operation.

[0098] Experimental data

[0099] The respiratory rates of five people were detected for 1 minute using the method or system provided in this embodiment, and the obtained respiratory rates were 18.3, 15.5, 17.8, 16.1, and 17.0 (times / minute), respectively. At the same time, the respiratory rate was detected for 1 minute using a medical multi-parameter monitor, and the obtained respiratory rates were 18.1, 15.2, 17.9, 16.0, and 16.9 (times / minute). The respiratory rate was detected for 1 minute using the existing application with publication number CN118452869A, entitled Method, device, equipment, and medium for vital signs monitoring based on millimeter wave radar, and the obtained respiratory rates were 16.6, 16.1, 16.4, 15.8, and 16.0 (times / minute), respectively.

[0100] It can be seen that the method or system provided in this embodiment finds the human vital signs detection area and then measures the vital signs. The data obtained is closer to the actual situation of the human vital signs. In the prior art, the human vital signs detection area is not found and life detection is directly performed. The radar signal obtained is difficult to fully capture the tiny signals corresponding to the human vital signs, and the frequency obtained is lower than the true situation of the human vital signs.

[0101] It will be understood by those skilled in the art that embodiments of the present invention may be provided as methods, apparatus, or computer program products. Thus, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0102] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowcharts and / or block diagrams, as well as combinations of processes and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowcharts and / or block diagrams. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0103] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0104] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0105] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms should not be understood as necessarily referring to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

Claims

1. A method for detecting vital signs based on microwave radar, characterized in that: The following steps are involved: S1, uses microwave radar to transmit and receive radar signals to find the human body position; S2, controlling the microwave radar to rotate and / or translate to find a vital sign detection area; step S2 includes: S21, determining whether the human body is in a micro-motion state, and if so, rotating and / or translating the microwave radar to an area facing the micro-motion state; S22, calculating vital signs at multiple locations within the region of the micro-motion state; step S22 includes: Dividing the region in the micro-motion state into a plurality of sub-regions at equal intervals, and calculating the vital signs of the plurality of sub-regions; S23, if the vital signs at multiple locations are similar, determining the area in the micro-motion state as a vital sign detection area; if the vital signs at multiple locations are different, rotating and / or translating the scanning range of the microwave radar and returning to step S21; S3, receiving the radar signal returned by the vital sign detection area, and extracting the vital sign from the radar signal.

2. The method for detecting vital signs based on microwave radar according to claim 1, characterized in that: In step S1, searching for the human body position includes: Identify the human body and obtain its position through point cloud data.

3. The method for detecting vital signs based on microwave radar according to claim 1, characterized in that: Before step S21, execute: S20, record and update the radar signal in real time, and enter step S21 when the number of point clouds of the radar signal is less than the preset number threshold, and use the human body position when the number of point clouds of the radar signal is less than the preset number threshold as the micro-motion position.

4. The method for detecting vital signs based on microwave radar according to claim 1, characterized in that: Dividing the micro-motion state region into multiple sub-regions at equal intervals, and calculating the vital signs of the multiple sub-regions includes: The radar signal in the micro-motion state area is divided equally and the phases are calculated respectively; The multiple phases are calculated using a vital sign algorithm to obtain multiple vital signs.

5. The method for detecting vital signs based on microwave radar according to claim 1, characterized in that: If the vital signs at multiple locations are different, the scanning range of the microwave radar is rotated and / or translated according to the vital signs of the multiple sub-areas and the process returns to step S21.

6. The method for detecting vital signs based on microwave radar according to claim 5, characterized in that: Rotating and / or translating the microwave radar according to the vital signs of the plurality of sub-areas includes: Calculate the mean of vital signs in multiple sub-regions; The microwave radar is rotated and / or translated toward the sub-region where the vital sign is close to the vital sign mean value.

7. The method for detecting vital signs based on microwave radar according to claim 1, characterized in that: Use the following steps to determine if vital signs are similar in multiple locations: The standard deviation of the vital signs at the multiple locations is calculated. If the standard deviation is less than a preset standard deviation threshold, the vital signs at the multiple locations are similar.

8. A vital sign detection device based on microwave radar, characterized in that: include: The microwave radar is rotatable, and the vital signs detection device implements the vital signs detection method based on microwave radar according to any one of claims 1 to 7 when in operation.

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