Vital sign detection method and equipment based on microwave radar

Abstract

The invention relates to a microwave radar-based vital sign detection method and device, and the method comprises the following steps: S1, transmitting and receiving a radar signal through a microwave radar, and searching the position of a human body; s2, controlling the microwave radar to rotate and / or translate, and searching a vital sign detection area; and S3, receiving a radar signal returned by the vital sign detection area, and extracting vital signs from the radar signal. According to the method, the microwave radar can be controlled to rotate and / or translate to search the vital sign detection area, so that the microwave radar for detecting vital signs can be placed at multiple indoor positions, manual adjustment of the scanning area of the microwave radar is not needed before use, and the detection efficiency is improved. The microwave radar can automatically find a vital sign detection area and carry out 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 vital signs of the human body, such as breathing, heartbeat, etc.

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

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

[0010] S3, receiving the radar signal returned by the vital sign detection area, and extracting the vital sign from the radar signal.

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

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

[0013] Further, 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 a 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 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.

[0019] Further, 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] Further, 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 comprises:

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

[0023] Multiple phases are calculated through a vital sign algorithm to obtain multiple vital signs.

[0024] Further, 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] Further, rotating and / or translating the microwave radar according to the vital signs of the plurality of sub-areas comprises:

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

[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 working.

[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 microwave radar to rotate and / or translate 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 reacts to vital signs. This 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 partly 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 area for microwave radar, where the shaded area represents the micromotion area.

[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 It 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 area into four square areas arranged from top to bottom when measuring the respiratory frequency.

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

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

[0047] Fig.10 This is a structural diagram of a vital signs detection device. DETAILED DESCRIPTION

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

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

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

[0051] In this embodiment, a radar signal is transmitted by a microwave radar and a radar signal returned by a human body in the room is received. The microwave radar can be placed in the room, for example, on a bedside table, a wall, a wardrobe, etc., without limitation. The microwave radar can scan multiple positions in the room. At this time, the position of the radar or the position of the human body is unknown. The method of searching for a human body by a microwave radar is an existing technology. For example, when the human body is in a sitting or lying state, the human body does not walk or make large body movements, and the preliminary position of the human body is obtained according to the characteristics of the echo data on the microwave radar in this state.

[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 finds the position of the human body, and it is necessary to further find the vital sign detection area. This step can be based on the situation that the human body is in a resting state such as sitting or lying down, the human body does not move in a large range, the human body's breathing will produce a small ups and downs, the human body's heartbeat will produce a small shake, etc., and according to the performance of this situation in the radar echo data, the vital sign detection area can be found.

[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, receiving the radar signal returned by the vital sign detection area, and extracting the vital sign from the radar signal.

[0058] In step S2, the human vital sign detection area is found. At this time, only the radar signal of the vital sign detection area is extracted to calculate the vital sign, which can greatly improve the accuracy of the vital sign calculation result. The method of vital sign detection can refer to the existing application with publication number CN118452869A and the name of the method, device, equipment and medium for monitoring vital signs based on millimeter wave radar.

[0059] Alternatively, first construct the ADC data collected by each frame of microwave radar within a period of time as 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, so as to reconstruct the original ADC data. Then, by referring to Fig. 9 The provided calculation process realizes vital signs analysis.

[0060] Further, 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 is used to collect ADC data, perform one-dimensional FFT calculation, two-dimensional FFT calculation, select the target position, and then map the horizontal angle and pitch angle between the human body and the microwave radar and the target to the direct coordinate system, so that the human body can be identified, and the microwave radar is rotated or translated through 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 a preset point cloud data amount threshold.

[0064] Further, 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 that are 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 of 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 and other parts 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 produces a slight tremor under the action of the heartbeat, thereby producing an area in a micro-motion state.

[0070] Theoretically, the frequencies corresponding to the tiny vibrations generated by the human heartbeat at various locations on the chest should be the same. Correspondingly, the heartbeat data calculated from the radar signal reflected back by the tiny vibrations generated by the heartbeat should be the same at multiple locations within the micro-motion state area. Vital signs are calculated at multiple locations within the micro-motion state area obtained in step S21, so as to be used in subsequent steps to determine whether the best signal-to-noise ratio scanning area of ​​the microwave radar is directly corresponding to 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 a 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 signs calculated at multiple locations are the same or similar, it means that the best detection area of ​​the microwave radar is right for the micro-movement of vital signs such as the chest or abdomen of the human body. The best detection area of ​​the microwave radar can be considered to be the center of the radar detection area.

[0073] Due to different sleeping postures of the human body, the radar signal of the micro-motion area captured by the microwave radar may be too weak, interfered, or have calculation errors, or the micro-motion signal may be too weak to be captured when it is transmitted from the center of the chest or abdomen to the edge of the human body, resulting in different vital signs calculated at multiple locations. Therefore, this step needs to be performed.

[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 exact 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 heart rate will be calculated to 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 during breathing, at this time, the area of ​​the micro-motion state can be divided into N rectangles arranged up and down, for example, 4 rectangles are divided, such as Figure 7 As shown, in this area, the breathing frequency 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 breathing frequency is calculated to 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 and then the vital signs can be calculated.

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

[0079] Therefore, through this step, it is found whether the center of the scanning range of the microwave radar is located at the center of the human body part from which the vital signs data can be extracted. At this time, the radar data obtained by the microwave radar can correctly reflect the vital signs of the human body. If the vital signs of multiple positions are different, the microwave radar can be rotated or moved to make the scanning area of ​​the microwave radar translate or rotate, thereby changing the center point of the scanning area of ​​the microwave radar.

[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 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.

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

[0083] Further, 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] Further, 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 comprises:

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

[0087] Multiple phases are calculated through 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 area can be extracted first, and the phase data can be phase unwrapped to generate unwrapped data; then the unwrapped data can be preprocessed, and the preprocessed unwrapped data can be subjected to FFT operation to generate heart rate data and track the heart rate data. For details, reference can be made to the existing application entitled "Method, device, equipment and medium for monitoring vital signs based on millimeter wave radar" with publication number CN118452869A.

[0090] Further, 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.

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

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

[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, and 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 working.

[0098] Experimental data

[0099] The method or system provided in this embodiment was used to detect the respiratory rates of five persons for one minute, 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 one minute by 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 one minute by an existing application with publication number CN118452869A and titled 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, and the data obtained is closer to the actual situation of the human vital signs. However, 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 signal corresponding to the human vital signs, and the obtained frequency is lower than the true situation of the human vital signs.

[0101] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, devices, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, 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 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 flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, 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 flowchart and / or block diagram. 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 capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture including an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A 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 other 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 description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means 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 representation 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 may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

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 position of the human body; S2, controlling the microwave radar to rotate and / or translate to find a vital sign detection area; 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: 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; S23, if the vital signs at multiple positions are similar, the area in the micro-motion state is determined to be a 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.

4. The method for detecting vital signs based on microwave radar according to claim 3, 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.

5. The method for detecting vital signs based on microwave radar according to claim 3, characterized in that: Step S22 includes: 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.

6. The method for detecting vital signs based on microwave radar according to claim 5, characterized in that: 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 comprises: The radar signal in the area of ​​the micro-motion state is equally divided and the phases are calculated respectively; Multiple phases are calculated through a vital sign algorithm to obtain multiple vital signs.

7. The method for detecting vital signs based on microwave radar according to claim 5, 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.

8. The method for detecting vital signs based on microwave radar according to claim 7, characterized in that: Rotating and / or translating the microwave radar according to the vital signs of the plurality of sub-areas comprises: Calculate the mean of vital signs of multiple sub-areas; The microwave radar is rotated and / or translated toward the sub-region where the vital sign is close to the vital sign mean value.

9. The method for detecting vital signs based on microwave radar according to claim 3, 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.

10. A vital sign detection device based on microwave radar, characterized in that: include: The microwave radar is rotatable, and the vital signs detection device, when working, implements the vital signs detection method based on microwave radar as described in any one of claims 1 to 9.

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