Multi-radar fusion vital sign monitoring device and monitoring method

Abstract

The invention provides a multi-radar fusion vital sign monitoring device and a monitoring method.The multi-radar fusion vital sign monitoring device comprises a mounting rack, a bottom plate, a first shell, a second shell, a 3D laser radar, an infrared area array sensor, a rotating structure and a millimeter wave radar, the bottom plate is connected with the mounting rack, and the rotating structure is arranged on the bottom plate; the first shell is connected to the rotating structure, the 3D laser radar and the infrared area array sensor are arranged in the first shell, the second shell is connected with the bottom plate and located below the first shell, and the millimeter wave radar is arranged in the second shell. Through cooperation of various different radars, whether an old person in a room is in a tumble state or not is judged, then an alarm is given in time, under the condition that privacy of the old person is ensured, the monitoring area is enlarged, the monitoring precision is improved, and the purpose of full-range monitoring is achieved.

Description

Technical Field

[0001] The present invention belongs to the field of smart health care technology, and in particular relates to a multi-radar fusion vital signs monitoring device and a monitoring method. Background Art

[0002] Existing vital sign sensors usually use 60GHz millimeter wave radar technology and are designed for human respiratory heart rate perception and sleep assessment. It uses the FMCW (frequency modulated continuous wave) radar system, which can output the respiratory heart rate frequency of people in specific occasions, and combine it with long-term sleep posture and body movement collection to timely report the sleep status and historical records of people. The maximum distance of human presence detection of this millimeter wave radar is about 2.5 meters, and the maximum distance of human respiratory rate detection is about 1.5 meters. Limited by the sensing range of the radar, it is necessary to ensure that the radar is installed within 1.5 meters of the human chest to ensure normal detection of the radar. Generally, the height difference between the radar installation position and the bed surface is about 0.9 meters, and the error does not exceed 0.2 meters. The radar is tilted at an angle of 30° to 45° and is located above the head of the bed. The sensing distance of the radar greatly limits its sensing range, so that it can only monitor the vital signs of the elderly when they are sleeping or lying in bed. Summary of the invention

[0003] The object of the present invention is to provide a multi-radar fusion vital signs monitoring device and a monitoring method, aiming to solve the problem of small monitoring range of existing vital signs monitoring devices.

[0004] The present invention is implemented as follows: a multi-radar fusion vital signs monitoring device includes a mounting frame, a base plate, a first shell, a second shell, a 3D laser radar, an infrared surface array sensor, a rotating structure and a millimeter wave radar, wherein the base plate is connected to the mounting frame, the rotating structure is arranged on the base plate, the first shell is connected to the rotating structure, the 3D laser radar and the infrared surface array sensor are arranged in the first shell, the second shell is connected to the base plate and is located below the first shell, and the millimeter wave radar is arranged in the second shell A further technical solution of the present invention is: the rotating structure includes an upper rotating shaft, a rotating fixed plate, a lower rotating shaft and a rotating gear, one end of the rotating fixed plate is connected to the bottom plate, one end of the upper rotating shaft is rotatably connected to the rotating fixed plate, the other end of the upper rotating shaft is connected to the top of the first shell, one end of the lower rotating shaft is connected to the bottom of the first shell, the other end of the lower rotating shaft is connected to the first rotating gear, and the first rotating gear is arranged in the second shell.

[0005] A further technical solution of the present invention is: a radar heat dissipation shell that plays a heat-conducting role is provided in the first shell, and the radar heat dissipation shell is connected to the chip of the 3D laser radar.

[0006] A further technical solution of the present invention is: a steering gear frame, a driving steering gear and a second rotating gear are arranged in the second housing, the driving steering gear is connected to the steering gear frame, the second rotating gear is connected to the output end of the driving steering gear, and the second rotating gear is meshed with the first rotating gear.

[0007] A further technical solution of the present invention is: a microprocessor and a communication chip are also provided inside the second shell, the microprocessor is communicatively connected to the 3D laser radar, infrared array sensor and millimeter wave radar, and the communication chip is communicatively connected to the microprocessor.

[0008] A further technical solution of the present invention is: the millimeter wave radar includes an RX antenna, a TX antenna, a synthesizer and a mixer, the synthesizer generates a 60GHz millimeter wave frequency band pulse, which is emitted by the TX transmitting antenna and directly acts on an object, the object generates a reflection of the millimeter wave frequency band pulse, the RX antenna captures the reflected pulse, and the mixer combines the signal of the RX antenna with the signal of the TX antenna to generate an intermediate frequency IF signal and outputs it to the microprocessor.

[0009] A further technical solution of the present invention is: the mounting frame is tilted, the tilt angle range of the mounting frame is 15-30°, and the tilt angle of the millimeter wave radar is 15°.

[0010] Another object of the present invention is to provide a monitoring method of a multi-radar fusion vital sign monitoring device, comprising the following steps: Step S1: When there is activity in the room, the 3D laser radar and the infrared array sensor are activated, and the 3D laser radar rotates 180 degrees to scan the entire room. The 3D laser radar uses a solid-state laser radar technology based on the time-of-flight principle, generates 3D point cloud data through a single scan, and transmits the point cloud data to the microprocessor; Step S2: The infrared array sensors scan simultaneously and communicate with the microprocessor via I2C to send back the infrared temperature readings; Step S3: The microprocessor compares the human body contour point cloud data of the 3D laser radar with the human body temperature of the infrared array sensor. If the human body contour area coincides with the human body temperature area, it is identified as a real human body. Then, the point cloud changes are used to determine whether the human body is in a falling posture. If it is in a falling posture, the communication chip transmits an alarm signal to the background system and issues an alarm.

[0011] A further technical solution of the present invention is: in step S1, the area array solid-state laser radar relies on the reflection or reception of waves to detect the characteristics of the target, and an array of photosensitive elements is arranged on the focal plane of the focal plane detector. The infrared rays emitted from an infinite distance are imaged on these photosensitive elements on the focal plane of the system through the optical system. The detector converts the received light signal into an electrical signal and performs integral amplification, sampling and holding, and finally sends it to the monitoring system to form an image through the output buffer and multiplex transmission system; The principle of time of flight is that the sensor emits modulated near-infrared light, which is reflected after encountering an object. The sensor converts the distance of the photographed scene by calculating the time difference or phase difference between the emission and reflection of the light. Combined with traditional camera shooting, the three-dimensional outline of the object is presented in the form of a topographic map with different colors representing different distances. The flight time is equal to the product of the number of pulses n and the pulse interval t, and the distance is equal to the product of the flight time and the speed of light c. The formula is: , f is the pulse frequency.

[0012] A further technical solution of the present invention is: in step S3, the dot matrix temperature obtained by the infrared matrix sensor and the human body contour point cloud data of the 3D laser radar are extracted, and the initial features are extracted and accurately matched through the ICP algorithm. The ICP algorithm merges the point cloud data under different coordinates into the same coordinate system, finds the rigid transformation between the coordinate systems, and repeatedly selects the corresponding relationship point pairing based on the least squares method, calculates the optimal rigid body transformation, until the convergence accuracy requirement of the correct registration is met, for each target point in the target data set, finds the corresponding reference point with the smallest distance to it in the reference data set, estimates the rotation matrix and translation vector through an iterative algorithm, and then removes the mismatched points through the RANSAC algorithm, and finally outputs the position of the feature point.

[0013] The beneficial effect of the present invention is that through the coordination of a variety of different radars, it is determined whether the elderly in the room is in a state of falling, and then an alarm is issued in time. While ensuring the privacy of the elderly, the monitoring area is increased and the monitoring accuracy is improved, thereby achieving the purpose of full-range monitoring. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is an overall diagram of the device of the present invention; Figure 2 is a cross-sectional view of the device of the present invention; Figure 3 It is a schematic diagram of the working range of the millimeter wave radar of the present invention; Figure 4 It is a schematic diagram of the working range of the 3D laser radar of the present invention; Figure 5 It is a schematic diagram of the detection matrix of the infrared array sensor of the present invention; Figure 6It is an algorithm flow chart of the motion position solution technology of the present invention; Figure 7 It is a schematic diagram of the connection of the internal structure of the millimeter wave radar of the present invention; Figure 8 It is a schematic diagram of the parallel light incident grating of the present invention.

[0015] Figure markings: 1-mounting frame, 2-base plate, 3-rotating fixed plate, 4-first shell, 5-infrared array sensor, 6-3D laser radar, 7-lower rotating shaft, 8-second shell, 9-millimeter wave radar, 10-upper rotating shaft, 11-radar heat dissipation shell, 12-first rotating gear, 13-second rotating gear, 14-servo frame, 15-driving servo, 16-microprocessor, 17-communication chip. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be noted that the words "front", "rear", "left", "right", "upper" and "lower" used in the following description refer to directions in the accompanying drawings, and the words "bottom surface" and "top surface", "inside" and "outside" refer to directions toward or away from the geometric center of a specific component, respectively.

[0017] The present invention provides a multi-radar fusion vital signs monitoring device, including a mounting frame 1, a base plate 2, a first shell 4, a second shell 8, a 3D laser radar 6, an infrared surface array sensor 5, a rotating structure and a millimeter wave radar 9, wherein the base plate 2 is connected to the mounting frame 1, the rotating structure is arranged on the base plate 2, the first shell 4 is connected to the rotating structure, the 3D laser radar 6 and the infrared surface array sensor 5 are arranged in the first shell 4, the second shell 8 is connected to the base plate 2 and is located below the first shell 4, and the millimeter wave radar 9 is arranged in the second shell 8.

[0018] Preferably, the rotating structure includes an upper rotating shaft 10, a rotating fixed plate 3, a lower rotating shaft 7 and a rotating gear, one end of the rotating fixed plate 3 is connected to the bottom plate 2, one end of the upper rotating shaft 10 is rotatably connected to the rotating fixed plate 3, the other end of the upper rotating shaft 10 is connected to the top of the first shell 4, one end of the lower rotating shaft 7 is connected to the bottom of the first shell 4, the other end of the lower rotating shaft 7 is connected to the first rotating gear 12, and the first rotating gear 12 is arranged in the second shell 8.

[0019] Preferably, a radar heat dissipation shell 11 having a heat conduction function is provided in the first shell 4 , and the radar heat dissipation shell 11 is connected to the chip of the 3D laser radar 6 .

[0020] Preferably, a servo frame 14, a driving servo 15 and a second rotating gear 13 are provided in the second housing 8, the driving servo 15 is connected to the servo frame 14, the second rotating gear 13 is connected to the output end of the driving servo 15, and the second rotating gear 13 is meshed with the first rotating gear 12.

[0021] Preferably, a microprocessor 16 and a communication chip 17 are further provided inside the second shell 8 . The microprocessor 16 is communicatively connected to the 3D laser radar 6 , the infrared array sensor 5 and the millimeter wave radar 9 , and the communication chip 17 is communicatively connected to the microprocessor 16 .

[0022] Preferably, the millimeter wave radar 9 includes an RX antenna, a TX antenna, a synthesizer and a mixer. The synthesizer generates a 60 GHz millimeter wave frequency band pulse, which is emitted by the TX transmitting antenna and directly acts on an object. The object reflects the millimeter wave frequency band pulse, and the RX antenna captures the reflected pulse. The mixer combines the signal of the RX antenna with the signal of the TX antenna to generate an intermediate frequency IF signal and outputs it to the microprocessor 16.

[0023] Preferably, the mounting frame 1 is tilted, the tilt angle range of the mounting frame 1 is 15-30°, and the tilt angle of the millimeter wave radar 9 is 15°.

[0024] The present invention also provides a monitoring method of a multi-radar fusion vital sign monitoring device, comprising the following steps: Step S1: When there is someone in the room, the 3D laser radar 6 and the infrared array sensor 5 are started, and the 3D laser radar 6 rotates 180 degrees to scan the entire room. The 3D laser radar 6 uses a solid-state laser radar technology based on the time-of-flight principle to generate 3D point cloud data through one scan, and transmits the point cloud data to the microprocessor 16; Step S2: The infrared array sensor 5 scans simultaneously and communicates with the microprocessor 16 via I2C to send back the infrared temperature reading; Step S3: The microprocessor 16 compares the human body contour point cloud data of the 3D laser radar 6 with the human body temperature of the infrared array sensor 5. If the human body contour area coincides with the human body temperature area, it is identified as a real human body. Then, the point cloud change is used to determine whether the human body is in a falling posture. If it is in a falling posture, the communication chip 17 transmits an alarm signal to the background system and issues an alarm.

[0025] Preferably, in step S1, the area array solid-state laser radar relies on the reflection or reception of waves to detect the characteristics of the target, and an array of photosensitive elements is arranged on the focal plane of the focal plane detector. The infrared rays emitted from an infinite distance are imaged on these photosensitive elements on the focal plane of the system through the optical system. The detector converts the received light signal into an electrical signal and performs integral amplification, sampling and holding, and finally sends it to the monitoring system to form an image through the output buffer and multiplex transmission system; The principle of time of flight is that the sensor emits modulated near-infrared light, which is reflected after encountering an object. The sensor converts the distance of the photographed scene by calculating the time difference or phase difference between the emission and reflection of the light. Combined with traditional camera shooting, the three-dimensional outline of the object is presented in the form of a topographic map with different colors representing different distances. The flight time is equal to the product of the number of pulses n and the pulse interval t, and the distance is equal to the product of the flight time and the speed of light c. The formula is: , f is the pulse frequency.

[0026] Preferably, in step S3, the dot matrix temperature obtained by the infrared array sensor 5 and the human body contour point cloud data of the 3D laser radar 6 are extracted, and the initial features are extracted and accurately matched through the ICP algorithm. The ICP algorithm merges the point cloud data under different coordinates into the same coordinate system, finds the rigid transformation between the coordinate systems, and repeatedly selects the corresponding relationship point pairing based on the least squares method, calculates the optimal rigid body transformation, until the convergence accuracy requirement of the correct registration is met, for each target point in the target data set, finds the corresponding reference point with the smallest distance to it in the reference data set, estimates the rotation matrix and translation vector through an iterative algorithm, and then removes the mismatched points through the RANSAC algorithm, and finally outputs the position of the feature point.

[0027] The multi-radar fusion vital signs monitoring device integrates three types of radars, among which the millimeter wave radar 9 is responsible for monitoring the vital signs of the elderly in bed. When the elderly are moving in the room, it is necessary to monitor in real time whether the elderly have fallen. The 3D laser radar 6 and the infrared array sensor 5 rotate to scan the entire room area, and transmit the data back to the microprocessor 16. The returned data determines whether the elderly is in a state of falling, so as to upload the alarm to the system and call medical staff to arrive in time. Without using visual sensors to ensure the privacy of the elderly, the device not only increases the monitoring area, but also improves the monitoring accuracy, achieving the purpose of full-range monitoring.

[0028] The device comprises the following structures: Rotating fixing plate 3: used to fix the upper rotating shaft 10, the rotating shaft drives the 3D laser radar 6 to rotate and scan the room area, and the rotation range is 180 degrees; Infrared array sensor 5: extracts the human body temperature range by identifying the ambient temperature value and identifies the area where the human body is located; 3D LiDAR 6: Based on the time-of-flight principle, it collects 3D point cloud information of the environment to identify human features, and uses mathematical algorithms to identify human motion features and monitor fall status; Second housing 8: encapsulates the millimeter wave radar 9 and is dustproof and waterproof; Millimeter wave radar 9: HLK-LD6001B module, 60GHz millimeter wave radar 9 sensing module, realizes non-sensing active perception of indoor personnel status all day long, millimeter wave radar 9 is not affected by light and has personal privacy protection function. Effective projection ground radius 3.5m installation height 2.7m, coverage angle is ±60, working voltage 3.3V, average power consumption is 0.3W, peak power consumption is 1.7W, and communication mode is TTL serial port. Figure 7 As shown, the synthesizer generates a 60GHz millimeter wave frequency band pulse, the linear pulse is emitted by the TX antenna and directly acts on the object, the object generates a reflection of the frequency band pulse, the RX antenna captures the reflected pulse, the mixer combines the signal of the RX antenna with the signal of the TX antenna to generate an intermediate frequency IF signal, and the IF signal is processed by Fourier transform to generate a spectrum with different separated peaks, each peak indicates the existence of an object at a specific distance; Mounting frame 1: three versions with different tilt angles are designed, namely 15 degrees, 25 degrees, and 30 degrees. When added with the 15-degree tilt angle of the millimeter-wave radar 9, the required installation requirement of 30-45 degrees is achieved; Upper rotating shaft 10: connects the rotating fixed plate 3 and the first shell 4, and is the driven shaft of the radar rotation; The first housing 4 is used to fix the infrared array sensor 5 and the 3D laser radar 6, and to seal and prevent dust; Radar heat dissipation shell 11: connected to the chip of 3D laser radar 6, plays a role of heat conduction; a millimeter wave radar 9 glass fiber cover is provided on the outside of the second shell 8, with a thickness of 2.5mm and made of glass fiber, so that millimeter waves can penetrate more easily; Lower rotating shaft 7: connected to the first rotating gear 12, transmitting the torque of the driving steering gear 15 to the first housing 4; Bottom plate 2: fixes the rotating fixed plate 3 and the second shell 8, and the back side is connected to the mounting frame 1; The first rotating gear 12 is connected to the driving steering gear 15 to transmit the torque of the driving steering gear 15 to rotate the 3D laser radar 6; Steering gear frame 14: fixed driving steering gear 15, connected to the bottom plate 2; Driving servo 15: adopts pulse width modulation PWM control, low power consumption, and can accurately control the rotation angle; Microprocessor 16: processes and analyzes the data sent back by radar and sensors, and transmits the alarm information to the communication chip 17; Communication chip 17: The model uses ESP8266, with a built-in Tensilica L106 ultra-low power 32-bit microprocessor 16, a main frequency of up to 160MHz, and 512KB of SRAM. It is used as a data transmission Wi-Fi module. The ESP8266 module supports the IEEE 802.11 b / g / n standard and has an operating frequency band of 2.4GHz. It works in Station+AP mode (as a client and hotspot at the same time), and has its own Wi-Fi hotspot for other devices to connect to, which increases its applicability in multi-room scenarios such as nursing homes.

[0029] The coverage area of ​​the millimeter wave radar 9 is as follows Figure 3 As shown in the figure, the maximum distance from the human body is 2.5 meters, the horizontal and vertical wave speeds are 20 degrees, and the coverage area is 3.3 square meters, which can completely cover the area of ​​an ordinary double bed; the detection area of ​​3D laser radar 6 is as follows Figure 4 As shown in the figure, the range is 5 meters, the emission angle is 68°*55°, and the coverage area is 160 square meters. The laser radar accuracy is ±1cm and the frame rate is 25Hz; Figure 5 As shown, the infrared array sensor 5 has a detection distance of 7 meters, a transmission angle of 60°, an accuracy of ±2.5°C, a maximum frame rate of 10Hz, and can obtain temperature values ​​through an 8X8 matrix.

[0030] The device can be installed in the corner of the room, and the millimeter wave radar 9 is tilted 30 degrees to the head of the bed, and the distance from the bed is kept between 1.5-2.5 meters. The millimeter wave radar 9 can continuously monitor the bed status of the elderly, and monitor the vital signs of the elderly in bed in real time by sensing the changes in human breathing and heartbeat. When the elderly get out of bed, the 3D laser radar 6 and the infrared surface array sensor 5 are started. As for the 3D laser radar 6 in the rotating structure, the 3D laser radar 6 can rotate 180 degrees to scan the entire room. The 3D laser radar 6 adopts the area array solid-state laser radar technology, based on the time of flight (TOF) principle, with a built-in high-performance processor and professional mathematical algorithms. It generates 3D point cloud data through a single scan, communicates with the microprocessor 16 through a high-speed communication interface, and transmits the point cloud data to the microprocessor 16. At the same time, the infrared surface array sensor 5 above the 3D laser radar 6 scans at the same time, can detect humans from a distance of up to 7 meters, and communicates with the microprocessor 16 through I2C to send back 64 infrared temperature readings. The microprocessor 16 compares the human body contour point cloud data of the 3D laser radar 6 with the human body temperature of the infrared array sensor 5. If the human body contour area coincides with the human body temperature area, it is identified as a real human body. Then, the point cloud change is used to determine whether the human body is in a falling posture. If it is in a falling posture, an alarm is immediately issued. The communication chip 17 transmits the alarm to the background, and the background system will call medical staff or relatives of the elderly. Ordinary vital signs monitoring devices rely on a single millimeter wave radar 9 to monitor the tiny movements of the human body, such as breathing, to determine the vital signs of the human body. Due to the limitations of the detection distance and accuracy of the millimeter wave radar 9, its coverage is small and the accuracy is low, which cannot fully meet the needs of full-range monitoring of single rooms in nursing homes or rooms for elderly people living alone. The multi-radar fusion vital signs monitoring device integrates 3D laser radar 6, millimeter wave radar 9 and infrared surface array sensor 5, combining the advantages of the three sensors. The 3D laser radar 6 and infrared surface array sensor 5 are responsible for detecting the characteristics of the elderly falling during indoor activities, and the millimeter wave radar 9 is responsible for monitoring the vital signs of the elderly while lying in bed. The monitoring device can accurately monitor the vital signs of the human body over a large range and issue an alarm in time, thereby improving the management quality of the nursing home and allowing the elderly to live and sleep peacefully.

[0031] A solid-state laser radar array refers to a radar without moving parts. The main technical principles used are optical phased array and Flash. Solid-state laser radar mainly relies on the reflection or reception of waves to detect the characteristics of the target. Most of them are derived from the research of three-dimensional image sensors, and actually from infrared focal plane imagers. The focal plane of the focal plane detector is arranged with an array of photosensitive elements. The infrared rays emitted from infinity are imaged on these photosensitive elements on the focal plane of the system through the optical system. The detector converts the received light signal into an electrical signal and performs integral amplification, sampling and holding. Through the output buffer and multiplex transmission system, it is finally sent to the monitoring system to form an image. There are three main technical solutions: MEMS (micro-electromechanical system), Flash, and optical phased array technology. OPA (optical phased array technology) solution. First of all, the name is derived from microwave phased array technology, but it is different from microwave phased array. It is a new type of beam pointing control technology, called optical phased array. It is composed of several phased array units, and each phased array unit uses optoelectronic materials as the working material. By utilizing the electrically controlled birefringence characteristics of the light spot material and changing the voltage loaded on different units, the optical characteristics of the light waves passing through different units, such as phase, light intensity, etc., can be changed. Independent control of each unit light wave is achieved by adjusting the phase relationship between the light waves radiated from the phase-controlled units in various directions to generate mutually reinforcing interference in the set direction. The result of the interference is a beam of high-intensity light in that direction, while the light emitted from each phase-controlled unit in other directions cancels each other out, thereby achieving the deflection of the light beam. When light passes through the grating, the bright fringes of different single slit diffractions will be superimposed at the coherent point. The position of the central bright fringe will be different if the angle of incidence is different. The schematic diagram of the parallel light incident grating is shown in the figure. Figure 8 As shown, according to the grating formula , is the phase difference, is the diffraction wavelength, is the diffraction angle, d is the grating constant, and the phase difference relationship can be obtained. This formula is the root of phased array technology. It can change the emission angle by controlling the phase difference of adjacent emission light through electrical signals. Many such emission units will form an array. By controlling the emission units, we can also achieve 2D and 3D scanning, forming the same effect as mechanical selection.

[0032] TOF, the full name of which is Time of Flight, means that the sensor emits modulated near-infrared light, which is reflected after encountering an object. The sensor calculates the time difference or phase difference between the emission and reflection of the light to convert the distance of the photographed scene to generate depth information. In addition, combined with traditional camera shooting, the three-dimensional outline of the object can be presented in the form of a topographic map with different colors representing different distances. TOF emits a pulsed laser and calculates the time it takes for the pulsed laser to pass through the target and reflect back to the detector, which is the flight time. The flight time is equal to the product of the number of pulses n and the pulse interval t, and the distance is equal to the product of the flight time and the speed of light c. The formula is: , f is the pulse frequency.

[0033] The motion position solution technology is divided into two steps: initial feature extraction and precise matching. Figure 6 As shown in the figure, the initial feature extraction can preliminarily reduce the rotation and translation misalignment of the infrared temperature matrix data and the point cloud data, and the precise matching can minimize the registration error between the two sets of data. The Iterative Closest Point (ICP) algorithm is used for precise registration. The ICP algorithm can merge point cloud data under different coordinates into the same coordinate system. The first step is to find an available transformation. The registration operation is actually to find a rigid transformation from coordinate system 1 to coordinate system 2. The ICP algorithm is essentially an optimal registration method based on the least squares method. The algorithm repeatedly selects corresponding point pairs and calculates the optimal rigid body transformation until the convergence accuracy requirements for correct registration are met. For each target point in the target data set, the algorithm finds the corresponding reference point with the smallest distance from it in the reference data set, and estimates the rotation matrix and translation vector through an iterative algorithm. However, the algorithm has the disadvantages of large computational complexity, low efficiency, high requirements for the initial position, and ignores the scale factor between the two sets of data. The RANSAC algorithm is added to remove mismatched points, reduce the requirements of the original ICP algorithm for the initial position, and reduce the computing power consumption and increase the matching accuracy with the support of the high-performance processor NVIDIA Jetson Nano. Jetson Nano uses a quad-core 64-bit ARM CPU and a 128-core integrated NVIDIA GPU, which can provide 472 GFLOPS of computing performance. It also includes 4GB LPDDR4 memory and adopts an efficient, low-power package with 5W / 10W power mode and 5V DC input.

[0034] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A multi-radar fusion vital signs monitoring device, characterized in that: It includes a mounting frame, a base plate, a first shell, a second shell, a 3D laser radar, an infrared surface array sensor, a rotating structure and a millimeter wave radar, the base plate is connected to the mounting frame, the rotating structure is arranged on the base plate, the first shell is connected to the rotating structure, the 3D laser radar and the infrared surface array sensor are arranged in the first shell, the second shell is connected to the base plate and is located below the first shell, and the millimeter wave radar is arranged in the second shell.

2. The multi-radar fusion vital signs monitoring device according to claim 1, characterized in that: The rotating structure includes an upper rotating shaft, a rotating fixed plate, a lower rotating shaft and a rotating gear, one end of the rotating fixed plate is connected to the bottom plate, one end of the upper rotating shaft is rotatably connected to the rotating fixed plate, the other end of the upper rotating shaft is connected to the top of the first shell, one end of the lower rotating shaft is connected to the bottom of the first shell, the other end of the lower rotating shaft is connected to the first rotating gear, and the first rotating gear is arranged in the second shell.

3. The multi-radar fusion vital signs monitoring device according to claim 1, characterized in that: A radar heat dissipation shell that performs heat conduction is provided in the first shell, and the radar heat dissipation shell is connected to the chip of the 3D laser radar.

4. The multi-radar fusion vital signs monitoring device according to claim 2, characterized in that: A steering gear frame, a driving steering gear and a second rotating gear are arranged in the second housing. The driving steering gear is connected to the steering gear frame. The second rotating gear is connected to the output end of the driving steering gear. The second rotating gear is meshed with the first rotating gear.

5. The multi-radar fusion vital signs monitoring device according to claim 1, characterized in that: A microprocessor and a communication chip are also provided inside the second shell. The microprocessor is communicatively connected to the 3D laser radar, infrared array sensor and millimeter wave radar, and the communication chip is communicatively connected to the microprocessor.

6. The multi-radar fusion vital signs monitoring device according to claim 1, characterized in that: The millimeter wave radar includes an RX antenna, a TX antenna, a synthesizer and a mixer. The synthesizer generates a 60GHz millimeter wave frequency band pulse, which is emitted by the TX transmitting antenna and directly acts on an object. The object generates a reflection of the millimeter wave frequency band pulse, and the RX antenna captures the reflected pulse. The mixer combines the signal of the RX antenna with the signal of the TX antenna to generate an intermediate frequency IF signal and outputs it to the microprocessor.

7. The multi-radar fusion vital signs monitoring device according to claim 1, characterized in that: The mounting frame is tilted, the tilt angle range of the mounting frame is 15-30°, and the tilt angle of the millimeter wave radar is 15°.

8. A monitoring method of the multi-radar fusion vital sign monitoring device according to claims 1-7, characterized in that: The following steps are involved: Step S1: When there is activity in the room, the 3D laser radar and the infrared array sensor are activated, and the 3D laser radar rotates 180 degrees to scan the entire room. The 3D laser radar uses a solid-state laser radar technology based on the time-of-flight principle, generates 3D point cloud data through a single scan, and transmits the point cloud data to the microprocessor; Step S2: The infrared array sensors scan simultaneously and communicate with the microprocessor via I2C to send back the infrared temperature readings; Step S3: The microprocessor compares the human body contour point cloud data of the 3D laser radar with the human body temperature of the infrared array sensor. If the human body contour area coincides with the human body temperature area, it is identified as a real human body. Then, the point cloud changes are used to determine whether the human body is in a falling posture. If it is in a falling posture, the communication chip transmits an alarm signal to the background system and issues an alarm.

9. The monitoring method of the multi-radar fusion vital signs monitoring device according to claim 8, characterized in that: In step S1, the area array solid-state laser radar relies on the reflection or reception of waves to detect the characteristics of the target. An array of photosensitive elements is arranged on the focal plane of the focal plane detector. Infrared rays emitted from an infinite distance are imaged on these photosensitive elements on the focal plane of the system through the optical system. The detector converts the received light signal into an electrical signal and performs integral amplification, sampling and holding. The signal is finally sent to the monitoring system to form an image through the output buffer and multiplex transmission system. The principle of time of flight is that the sensor emits modulated near-infrared light, which is reflected after encountering an object. The sensor converts the distance of the photographed scene by calculating the time difference or phase difference between the emission and reflection of the light. Combined with traditional camera shooting, the three-dimensional outline of the object is presented in the form of a topographic map with different colors representing different distances. The flight time is equal to the product of the number of pulses n and the pulse interval t, and the distance is equal to the product of the flight time and the speed of light c. The formula is: , f is the pulse frequency.

10. The monitoring method of the multi-radar fusion vital signs monitoring device according to claim 8, characterized in that: In step S3, the dot temperature obtained by the infrared array sensor and the human body contour point cloud data of the 3D laser radar are extracted. After the initial features are extracted, they are accurately matched through the ICP algorithm. The ICP algorithm merges the point cloud data under different coordinates into the same coordinate system, finds the rigid transformation between the coordinate systems, and repeatedly selects the corresponding relationship point pairing based on the least squares method, calculates the optimal rigid body transformation, until the convergence accuracy requirement of the correct registration is met, for each target point in the target data set, finds the corresponding reference point with the smallest distance to it in the reference data set, estimates the rotation matrix and translation vector through the iterative algorithm, and then removes the mismatched points through the RANSAC algorithm, and finally outputs the position of the feature point.

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