Microwave radar-based vital sign detection method and device

Abstract

The present invention relates to a microwave radar-based vital sign detection method and device. The method comprises the following steps: S1, transmitting and receiving, by means of microwave radar, a radar signal to locate a position of a human body; S2, controlling the microwave radar to rotate and / or translate to search for a vital sign detection region; and S3, receiving a radar signal returned by the vital sign detection region, and extracting vital signs from the radar signal. According to the present application, the microwave radar can be controlled to rotate and / or translate to search for the vital sign detection region, such that the microwave radar used for detecting vital signs can be placed at a plurality of positions indoors. In addition, there is no need to manually adjust a scanning region of the microwave radar before use. The microwave radar can automatically search for a vital sign detection region and perform vital sign detection.

Description

Microwave radar-based vital sign detection method and device TECHNICAL FIELD

[0001] The present application relates to the field of vital sign detection method, and particularly relates to a microwave radar-based vital sign detection method and device. BACKGROUND

[0002] The microwave radar can collect echo data of a detected person, and then extract micro-motion changes of the human body from the echo data, so as to calculate vital signs of the human body, such as respiration and heartbeat.

[0003] The microwave radar for vital sign detection is fixedly arranged at a position in a room, such as a bedside or a wall. Since the vital signs of the human body are small motion changes of the human body, for example, the heartbeat corresponds to the small shaking of the chest cavity of the human body, the position of the human body in the radar scanning area is unknown, the motion caused by the vital signs is very weak, and the micro-motion signal cannot be extracted in all areas in the scanning range of the radar. Before vital sign detection, the direction and orientation of the microwave radar need to be adjusted manually, so that the human body is in an area with better signal in the radar scanning range, and only then can the vital sign detection algorithm capture vital sign data from the echo data. In the prior art, the microwave radar cannot automatically find the part of the human body that can feedback vital signs.

[0004] In view of the problems in the prior art, the present application aims to provide a microwave radar-based vital sign detection method and device.

[0005] SUMMARY

[0006] In view of the problems in the prior art, the present application aims to provide a microwave radar-based vital sign detection method and device.

[0007] The technical scheme of the present application is as follows:

[0008] A microwave radar-based vital sign detection method, comprising the following steps:

[0009] S1, transmitting and receiving radar signals by a microwave radar to find a human body position;

[0010] S2, controlling the microwave radar to rotate and / or translate to find a vital sign detection area;

[0011] S3, receiving radar signals returned by the vital sign detection area, and extracting vital signs from the radar signals.

[0012] Further, in step S1, finding the human body position comprises:

[0013] Identify a human body and get the human body position through point cloud data.

[0014] Further, the step S2 comprises:

[0015] S21, judge whether the human body is in a micro-motion state, if yes, rotate and / or translate the microwave radar to the region of the micro-motion state;

[0016] S22, calculate vital signs at multiple positions in the region of the micro-motion state;

[0017] S23, if the vital signs at multiple positions are similar, determine the region of the micro-motion state as a vital sign detection region, if the vital signs at multiple positions are different, rotate and / or translate the scanning range of the microwave radar and return to step S21.

[0018] Further, before step S21, perform:

[0019] S20, record and update the radar signal in real time, when the number of point clouds of the radar signal is less than a preset number threshold, enter step S21, and take the human body position when the number of point clouds of the radar signal is less than the preset number threshold as a micro-motion position.

[0020] Further, step S22 comprises:

[0021] equally space the region of the micro-motion state into multiple sub-regions, and calculate vital signs of the multiple sub-regions.

[0022] Further, equally spacing the region of the micro-motion state into multiple sub-regions and calculating vital signs of the multiple sub-regions comprises:

[0023] equally divide the radar signal of the region of the micro-motion state and calculate the phases respectively;

[0024] calculate multiple vital signs through the vital sign algorithm from the multiple phases.

[0025] Further, if the vital signs at multiple positions are different, rotate and / or translate the scanning range of the microwave radar according to the vital signs of the multiple sub-regions and return to step S21.

[0026] Further, rotating and / or translating the microwave radar according to the vital signs of the multiple sub-regions comprises:

[0027] calculate the mean value of vital signs of the multiple sub-regions;

[0028] rotate and / or translate the microwave radar to the sub-region whose vital sign is close to the mean value of vital signs.

[0029] Further, the vital signs of the multiple positions are determined to be similar by the following steps:

[0030] The standard deviation of the vital signs of the multiple positions is calculated, and if the standard deviation is less than a preset standard deviation threshold, the vital signs of the multiple positions are similar.

[0031] Further, the vital signs of the multiple positions are determined to be similar by the following steps:

[0032] Therefore, the present application provides the following effects and / or advantages:

[0033] The present application can find the vital sign detection area, and control the microwave radar to rotate and / or translate the center of the scanning area to the vital sign detection area, so as to improve the detection accuracy of the microwave radar in detecting the vital signs of the human body, by using the characteristics that the center of the scanning area has the best signal-to-noise ratio and the best reaction of the vital signs of the human body.

[0034] The present application can control the microwave radar to rotate and / or translate, find the vital sign detection area, so that the microwave radar for detecting vital signs can be placed at multiple positions in the room, and does not need to be manually adjusted before use. The microwave radar can find the vital sign detection area and detect the vital signs by itself.

[0035] The present application calculates the vital signs at multiple positions in the area in the micro-motion state, and determines whether the scanning center of the microwave radar is directly facing the part of the human body that reacts to the vital signs, by the vital signs at the multiple positions, so as to accurately adjust the scanning range of the microwave radar, thereby improving the accuracy of vital sign detection.

[0036] The present application divides the area in the micro-motion state into multiple sub-areas at equal intervals, which can be suitable for the characteristics of the vital signs of the human body in the process of microwave radar detection, thereby improving the detection accuracy.

[0037] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent from the description, or can be learned by practice of the present application. The objects and other advantages of the present application will be realized and attained by the structure particularly pointed out in the description and the drawings.

[0038] It should be understood that the above summary of the application and the following detailed description are exemplary and explanatory, and are intended to provide further explanation of the application as claimed. BRIEF DESCRIPTION OF DRAWINGS

[0039] Fig. 1 is a flowchart provided by an embodiment of the present application.

[0040] Fig. 2 is a logic diagram provided by an embodiment of the present application.

[0041] Fig. 3 is a schematic diagram of finding the position of a human body by a microwave radar.

[0042] Fig. 4 is a schematic diagram of finding a micro-motion area by a microwave radar, wherein the shaded part represents the micro-motion area.

[0043] Fig. 5 is a schematic diagram of rotating the scanning area of a microwave radar so that the center of the scanning area is located at the center of the micro-motion area.

[0044] Fig. 6 is a schematic diagram of dividing the micro-motion area into 2*2 square areas when measuring the heart rate.

[0045] Fig. 7 is a schematic diagram of dividing the micro-motion area into 4 square areas arranged from top to bottom when measuring the respiratory rate.

[0046] Fig. 8 is a schematic diagram of adjusting the scanning area of a microwave radar according to the respiratory rate.

[0047] Fig. 9 is a schematic diagram of the steps of vital sign calculation.

[0048] Fig. 10 is a schematic diagram of the structure of a vital sign detection device. DETAILED DESCRIPTION

[0049] For the convenience of those skilled in the art, the embodiments will be further described in detail as follows:

[0050] Referring to Figs. 1-2, a vital sign detection method based on a microwave radar includes the following steps:

[0051] S1, transmitting and receiving radar signals by a microwave radar to find the position of a human body;

[0052] In the embodiment, the microwave radar transmits radar signals and receives the radar signals returned by a human body in a room, wherein the microwave radar can be placed on a bedside table, a wall, a wardrobe, etc. in the room, which is not limited herein, and the microwave radar can scan multiple positions in the room, wherein the position of the radar or the position of the human body is unknown. The method for finding the human body by the microwave radar is a prior art, for example, when the human body is in a sitting or lying state, the human body does not perform walking or large-scale limb movement, and the preliminary position of the human body can be obtained according to the echo data characteristics of the state on the microwave radar.

[0053] In this step, the microwave radar can be rotated or translated to find the human body in the room.

[0054] This step is shown in Fig. 3.

[0055] S2, control the microwave radar to rotate and / or translate to find a vital sign detection area;

[0056] In step S1, the microwave radar finds the human body position, and further finding the vital sign detection area is needed. This step can find the vital sign detection area according to the fact that the human body is in a resting state such as sitting or lying, the human body does not have large-scale activities, the human body breathing produces slight fluctuation, the human body heartbeat produces slight jitter, and the like, and the vital sign detection area is found according to the performance of the radar echo data.

[0057] Because the signal-to-noise ratio of each area in the scanning range of the microwave radar is different, and the human body position is unknown before step S1, if the microwave radar does not find the vital sign detection area but directly extracts vital signs from the microwave radar data returned by the human body breathing or heartbeat, the data will be disturbed by external interference and different radar signal-to-noise ratios, and the vital sign data calculated by the microwave radar has the problem of insufficient accuracy, so this step finds the vital sign detection area.

[0058] S3, receiving the radar signal returned by the vital sign detection area, and extracting vital signs from the radar signal.

[0059] In step S2, the vital sign detection area of the human body is found, and only the radar signal of the vital sign detection area is extracted to calculate the vital signs, which can greatly improve the accuracy of the vital sign calculation result. The vital sign detection method can refer to the existing application with the publication number CN118452869A and the name of millimeter wave radar-based vital sign monitoring method, device, equipment and medium.

[0060] Alternatively, first, the ADC data collected by the microwave radar in each frame in a period of time is constructed into a to-be-processed matrix, and the clutter that is greatly different from the useful signal is removed by using the covariance matrix decomposition method; then the non-stationary noise is removed by using the wavelet denoising method, so as to reconstruct the original ADC data. Then, vital sign analysis is realized by referring to the calculation process provided in FIG. 9.

[0061] Further, in step S1, finding the human body position includes:

[0062] The human body is recognized by the point cloud data and the human body position is obtained.

[0063] In this step, the ADC data is collected by the microwave radar, one-dimensional FFT calculation, two-dimensional FFT calculation, target position selection, horizontal angle and pitch angle between the human body and the microwave radar, and target mapping to the direct coordinate system, so that the human body can be recognized, and the microwave radar is rotated or translated by the horizontal angle and the pitch angle between the human body and the microwave radar, so that the human body is located in the middle of the scanning area of the microwave radar.

[0064] When the human body is in a resting state, the point cloud data corresponding to the reflected radar signal is less. By using the number of point cloud data in this state, it can be determined that the human body exists at this position of the human body when the point cloud data is less than a preset point cloud data number threshold.

[0065] Further, step S2 comprises:

[0066] S21, determining whether the human body is in a micro-motion state, and if so, rotating and / or translating the microwave radar to the region in the micro-motion state;

[0067] 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 the micro-motion state are generally the chest cavity, abdomen, etc. This region is the best region for identifying vital sign detection. The micro-motion algorithm can extract the parts in the micro-motion state, as shown in FIG. 4. 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, through the extraction of the micro-motion region, the microwave radar can be rotated or translated to make the center of the scanning region face the chest cavity, abdomen, etc. of the human body, as shown in FIG. 5.

[0068] Due to the general accuracy of the micro-motion algorithm, after the microwave radar is rotated or translated to face the micro-motion region, the chest cavity or abdomen of the human body may not be in the best scanning region of the microwave radar.

[0069] S22, calculating vital signs at multiple positions in the region in the micro-motion state;

[0070] In this step, heartbeat is taken as an example. The chest cavity of the human body produces a slight jitter under the action of heartbeat to generate a micro-motion state region.

[0071] In theory, the slight jitter corresponding to the heartbeat of the human body at each position on the chest cavity should have the same frequency. Correspondingly, the heartbeat data calculated from the radar signal reflected by the slight jitter generated by the heartbeat should be the same at multiple positions in the region in the micro-motion state. The vital signs are calculated at multiple positions in the region in the micro-motion state obtained in step S21, thereby being used to determine whether the best signal-to-noise ratio scanning region of the microwave radar is facing the chest cavity of the human body in the subsequent step.

[0072] S23, if the vital signs at multiple positions are similar, determining that the region in the micro-motion state is a vital sign detection region, and if the vital signs at multiple positions are different, rotating and / or translating the scanning range of the microwave radar and returning to step S21.

[0073] If the vital signs calculated at multiple positions are the same or similar, it indicates that the optimal detection area of the microwave radar is right at the chest cavity or abdomen of the human body, where the vital signs micro-movement occurs. The optimal detection area of the microwave radar can be considered as the center of the radar detection area.

[0074] Due to different sleeping postures of the human body, the radar signals captured by the microwave radar in the micro-movement area can have problems such as too weak, interference, calculation error, or the micro-movement signal transmitted to the edge of the human body from the center of the chest cavity or abdomen is too weak to be captured, etc., resulting in different vital signs calculated at multiple positions. Therefore, this step needs to be performed.

[0075] Preferably, for the heart rate in the vital signs, since the heart is located in the chest cavity near the center, at this time, the area of the micro-movement state can be divided into N*N squares, for example, divided into a 2*2 square structure, as shown in FIG. 6, and the heart rate is detected in each square area in the area. If the position of the heart is at the center of the N*N squares, the micro-movement generated by the heart in each square area is captured by the microwave radar, and the calculated heart rate is very close.

[0076] Meanwhile, when measuring the heart rate, since the chest cavity where the heart is located is above the human body, in order to facilitate the capture of the heart rate, in this step, the area of the micro-movement state near the head of the human body can be first divided into N*N squares before calculating the vital signs.

[0077] Preferably, for the respiratory rate in the vital signs, since the abdomen of the human body will produce up and down floating during breathing, at this time, the area of the micro-movement state can be divided into N rectangles arranged in up and down directions, for example, divided into 4 rectangles, as shown in FIG. 7, and the respiratory rate is detected in each rectangular area in the area. If the center of the abdomen is at the center position of the N rectangles, the micro-movement generated by the abdomen in each rectangular area is captured by the microwave radar, and the calculated respiratory rate is very close.

[0078] Meanwhile, when measuring the respiratory rate, since the abdomen is located at the middle position of the human body, in order to facilitate the capture of the respiratory rate, in this step, the area of the micro-movement state near the legs of the human body can be first divided into N rectangles before calculating the vital signs.

[0079] The legs or head of the human body, etc. can be identified by existing technologies.

[0080] Therefore, whether the center of the scanning range of the microwave radar is located at the center of the human body part from which vital sign data can be extracted is found through this step, and only when 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 produce translation or rotation of the scanning area of the microwave radar, so as to change the center point of the scanning area of the microwave radar.

[0081] Further, before step S21, the following step is performed:

[0082] S20, real-time record and update the radar signal, when the number of point clouds of the radar signal is less than a preset number threshold, enter step S21, and take 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.

[0083] In this embodiment, when the human body is stationary, the number of point clouds of the radar signal will become very small. By the 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.

[0084] Further, step S22 includes:

[0085] The region in the micro-motion state is equally spaced into a plurality of sub-regions, and vital signs of the plurality of sub-regions are calculated.

[0086] Further, equally spacing the region in the micro-motion state into a plurality of sub-regions and calculating vital signs of the plurality of sub-regions includes:

[0087] The radar signals of the region in the micro-motion state are equally divided and the phases are calculated respectively;

[0088] A plurality of phases are calculated to obtain a plurality of vital signs by a vital sign algorithm.

[0089] In this step, reference can be made to FIG. 7 or 8 to equally space the region in the micro-motion state.

[0090] Specifically, the phase data of the micro-motion region can be extracted first, and phase unwrapping is performed on the phase data to generate unwrapping data; then the unwrapping data is preprocessed, and the preprocessed unwrapping data is subjected to FFT operation to generate heart rate data and perform tracking processing. For details, please refer to the existing application with publication number CN118452869A and the name of millimeter wave radar-based vital sign monitoring method, device, equipment and medium.

[0091] Further, if the vital signs of multiple positions are different, the scanning range of the microwave radar is rotated and / or translated according to the vital signs of the plurality of sub-regions and returns to step S21.

[0092] Further, rotating and / or translating the microwave radar according to the vital signs of the plurality of sub-regions comprises:

[0093] calculating a mean value of the vital signs of the plurality of sub-regions;

[0094] rotating and / or translating the microwave radar to the sub-region whose vital sign is close to the mean value of the vital signs.

[0095] In this step, as shown in FIG. 8, assuming that the respiratory rates of the abdomen from the plurality of positions calculated in the above step are 15, 20, 21, and 20 (times / minute) respectively, the mean value calculated is 19, and the sub-regions with respiratory rates of 20, 21, and 20 are the regions whose vital signs are close to the mean value of the vital signs. At this time, the scanning range of the microwave radar needs to be adjusted downward.

[0096] Further, the vital signs of the plurality of positions are determined to be similar by the following steps:

[0097] calculating the standard deviation of the vital signs of the plurality of positions, and if the standard deviation is less than a preset standard deviation threshold, the vital signs of the plurality of positions are similar.

[0098] Further provided is a vital sign detection device based on a microwave radar, comprising: a microwave radar 1, which is rotatably arranged, and the vital sign detection device realizes the vital sign detection method based on the microwave radar when working.

[0099] Experimental data

[0100] The method or system provided in this embodiment is used to detect the respiratory rates of 5 people for 1 minute, and the obtained respiratory rates are 18.3, 15.5, 17.8, 16.1, and 17.0 (times / minute) respectively. At the same time, the respiratory rates are detected by a medical multi-parameter monitor for 1 minute, and the obtained respiratory rates are 18.1, 15.2, 17.9, 16.0, and 16.9 (times / minute) respectively. The respiratory rates are detected by the prior application with the publication number CN118452869A and the name of vital sign monitoring method, device, equipment and medium based on millimeter wave radar for 1 minute, and the obtained respiratory rates are 16.6, 16.1, 16.4, 15.8, and 16.0 (times / minute) respectively.

[0101] It can be seen that the method or system provided in this embodiment finds the vital sign detection region of the human body before measuring the vital signs, and the obtained data is closer to the true situation of the vital signs of the human body. In the prior art, the vital signs are directly detected without finding the vital sign detection region of the human body, and the radar signals obtained are difficult to fully capture the tiny signals corresponding to the vital signs of the human body, and the obtained frequency is lower than the true situation of the vital signs of the human body.

[0102] Those skilled in the art will appreciate that embodiments of the present application can be devised for a method, an apparatus, or a computer program product. Accordingly, the present application can take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present application can take the form of a computer program product on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROMs, optical storage devices, and the like) embodying computer readable program code.

[0103] The present application is described in the context of the methods, apparatuses (systems), and computer program products according to embodiments of the present application by reference to flow diagrams and / or block diagrams of the various embodiments, by reference to flow diagrams and / or block diagrams of the various embodiments, and / or by reference to both. It will be understood that each block of the flow diagrams and / or block diagrams, and combinations of blocks in the flow diagrams 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, special purpose computer, embedded processing system, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flow diagrams and / or block diagrams block or blocks.

[0104] These computer program instructions can also be stored in a computer- readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instructions which implement the function specified in the flow diagrams and / or block diagrams block or blocks.

[0105] While the preferred embodiments of the application have been described, additional variations and modifications can be made to the embodiments by those skilled in the art once they learn of the basic inventive concepts. Therefore, the appended claims are intended to cover all such variations and modifications as fall within the scope of the application.

[0106] In the description of the specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like is intended to indicate that a specific feature, structure, material or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present application. Descriptive terms of the above-mentioned terms should not be understood as necessarily referring to the same embodiment or example. Also, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more embodiments or examples. Furthermore, those skilled in the art can combine and combine the features of different embodiments or examples described in the specification and the features of different embodiments or examples, without contradiction, if necessary.

Claims

1. A microwave radar based vital sign detection method, characterized in that: The method comprises the following steps: S1, finding a human body position by transmitting and receiving radar signals by a microwave radar; S2, controlling the microwave radar to rotate and / or translate to find a vital sign detection area; S3, receiving radar signals returned by the vital sign detection area and extracting vital signs from the radar signals.

2. The method of claim 1, wherein: In step S1, finding a human body position comprises: identifying a human body by point cloud data and obtaining a human body position.

3. The method of claim 1, wherein: Step S2 comprises: S21, determining whether the human body is in a micro-motion state, and if so, rotating and / or translating the microwave radar to a region facing the micro-motion state; S22, calculating vital signs at multiple positions in the region in the micro-motion state; S23, if the vital signs at the multiple positions are similar, determining that the region in the micro-motion state is a vital sign detection area, and if the vital signs at the multiple positions are different, rotating and / or translating the scanning range of the microwave radar and returning to step S21.

4. The method of claim 3, wherein: Before step S21, performing: S20, recording and updating the radar signals in real time, entering step S21 when the number of point clouds of the radar signals is less than a preset number threshold, and taking the human body position when the number of point clouds of the radar signals is less than the preset number threshold as a micro-motion position.

5. The method of claim 3, wherein: Step S22 comprises: equally spacing the region in the micro-motion state into multiple sub-regions and calculating vital signs of the multiple sub-regions.

6. The method of claim 5, wherein: Equally spacing the region in the micro-motion state into multiple sub-regions and calculating vital signs of the multiple sub-regions comprises: equally dividing the radar signals of the region in the micro-motion state and calculating phases respectively; calculating multiple vital signs by a vital sign algorithm from the multiple phases.

7. The method of claim 5, wherein: If the vital signs at the multiple positions are different, rotating and / or translating the scanning range of the microwave radar according to the vital signs of the multiple sub-regions and returning to step S21.

8. The method of claim 7, wherein: Rotating and / or translating the microwave radar according to the vital signs of the multiple sub-regions comprises: calculating the mean of the vital signs of the multiple sub-regions; rotating and / or translating the microwave radar to the sub-region whose vital sign is close to the mean of the vital signs.

9. The method of claim 3, wherein: The similarity of the vital signs at the multiple positions is determined by the following steps: calculating the standard deviation of the vital signs at the multiple positions, and if the standard deviation is less than a preset standard deviation threshold, the vital signs at the multiple positions are similar.

10. A microwave radar based vital sign detection device, characterized in that It comprises: a microwave radar, which is rotatably arranged, and the vital sign detection device realizes the vital sign detection method based on the microwave radar in any one of claims 1-9 when working.

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