WO2020186454A1

WO2020186454A1 - Dual sensing life signs monitoring system and method

Info

Publication number: WO2020186454A1
Application number: PCT/CN2019/078712
Authority: WO
Inventors: 卢坤涛; 刘众; 乐勇
Original assignee: 深圳市格兰莫尔科技有限公司
Priority date: 2019-03-19
Filing date: 2019-03-19
Publication date: 2020-09-24

Abstract

A dual sensing life signs monitoring system and a method, the system comprising: a dual sensing module, a filtering and amplification module, an analog-to-digital conversion apparatus, a main control chip and a memory, the dual sensing module comprising a primary sensor (2) and an auxiliary sensor (3), the primary sensor (2) being used to receive a life signs signal of a body and an ambient micro-vibration noise signal, and the auxiliary sensor (3) only being used to receive an ambient micro-vibration noise signal. The signals collected by the primary sensor (2) and the auxiliary sensor (3), respectively, then successively passing through the filtering and amplification module to be filtered and amplified, passing through the analog-to-digital conversion apparatus to obtain two digital signals, the main control chip executing pre-processing and a heart rate and breathing rate algorithm on the digital signals, and storing the obtained real-time heart rate and breathing rate values in the memory. The present dual sensing life signs monitoring system has advantages including a high signal-to-noise ratio, low costs, a simple structure and strong flexibility.

Description

Dual-sensor vital signs monitoring system and method

Technical field

The present invention belongs to the technical field of vital signs monitoring, and specifically relates to a dual-sensor vital signs monitoring system and method.

Background technique

The vital sign monitoring device mainly monitors the person's heart rate and breathing rate, body movement, getting out of bed and other information. Compared with traditional ECG monitors, the current non-contact, non-wearable vital signs monitoring devices have the advantages of convenience and long-term monitoring, and the accuracy can be close to that of medical-level monitors. This non-contact vital sign monitoring device mainly uses sensors to collect human body micro-vibration signals, such as cardiocardiogram signals of heartbeat and chest and abdomen movements during breathing, and then convert them into electrical signals for processing. Commonly used sensors include piezoelectric ceramics, piezoelectric cables, piezoelectric films, optical fibers, radars, etc. These sensors are very sensitive to weak vibration signals, so they can obtain accurate heart rate and respiratory rate values.

But the disadvantage of high sensitivity is that the sensor is also very sensitive to interference from the external environment. For example, in some noisy environments, the vibration of the environment itself even exceeds the signal of the human body itself, submerging the real vital signs signals, resulting in a decrease in the detection accuracy of heart rate and respiration rate. What's more serious is that it will cause misjudgment by no one, and mistakenly regard environmental noise as vital signs. Therefore, in order to adapt the vital sign monitoring device to different environments, it is necessary to improve the signal-to-noise ratio of the system.

Summary of the invention

The purpose of the embodiments of the present invention is to provide a dual-sensor vital sign monitoring system and method, which is used to solve the problem that the sensor in the prior art is easily disturbed by external environmental noise when collecting micro-vibration signals of the human body, causing the vital sign monitoring device to fail Get accurate heart rate and breathing rate and other issues.

The embodiment of the present invention is implemented in this way. A dual-sensing vital signs monitoring system is provided, which includes a dual-sensing module, a filter amplification module, an analog-to-digital conversion device, a main control chip, and a memory. The dual-sensing module includes The main sensor and the auxiliary sensor, the main sensor is used to receive the vital sign signal of the human body and the environmental noise signal, and the auxiliary sensor is set to receive only the environmental noise signal.

Further, the dual sensor module is a film type, sheet type or cable type sensing structure.

Further, the dual sensor module is a thin-film sensor structure, wherein the dual sensor module further includes a housing, a contact point, a supporting pier, a limit bridge pier, and a main board, wherein the contact point is located on the housing and In contact with the main sensor, the main sensor and the auxiliary sensor form a bridge structure with the supporting pier and the limit pier, respectively, and the auxiliary sensor does not contact the housing or the contact point.

Further, the dual sensor module is a sheet-type sensing structure, wherein the dual sensor module further includes a housing, a contact point and a signal line, wherein the contact point is located on the housing and is in contact with the main sensor , The auxiliary sensor is not in contact with the housing or the contact point.

Further, the dual sensor module is a cable-type sensing structure, wherein the dual sensor module further includes a surface covering, a substrate, a protective cover and a signal line, wherein the protective cover is a rigid protective cover, To cover the auxiliary sensor to prevent the auxiliary sensor from collecting vital signs signals of the human body.

Further, the filtering and amplifying module includes two filtering and amplifying circuits, the topological structure and circuit parameters of the two filtering and amplifying circuits are the same, and the PCB wiring is arranged symmetrically, so as to minimize the noise introduced by the asymmetry of the circuit .

Further, the filtering and amplifying module is a differential amplifying circuit, which directly uses the signals of the main sensor and the auxiliary sensor as the positive and negative inputs of the differential amplifying circuit, and can directly filter the environmental common mode noise through the circuit, but only for vital signs The signal (differential signal) is amplified.

Another object of the embodiments of the present invention is to provide a dual-sensor vital signs monitoring method, including the following steps:

Sensor data collection: including main sensor data collection and auxiliary sensor data collection;

Signal filtering and amplification: including filtering and amplifying the signals collected by the main sensor and the auxiliary sensor respectively;

Analog-to-digital conversion: including analog-to-digital conversion of the analog signal output by filtering and amplifying the signal collected by the main sensor and the auxiliary sensor;

No one recognizes;

Body movement recognition; and

Heart rate breathing algorithm.

Further, the step of identifying presence or absence includes:

Acquire the array M[n] of the main sensor signal and the array S[n] of the auxiliary sensor signal;

Calculate the mean value Mean_M of the main sensor signal and the mean value Mean_S of the auxiliary sensor signal;

Calculate the average energy P_M of the main sensor signal and the average energy P_S of the auxiliary sensor signal;

Make the difference between the average energy of the two signals to obtain the energy difference DP of the signal; and

Compare the energy difference of the two signals with the set threshold DP_th. When the DP exceeds the threshold DP_th, it is judged as human, otherwise it is judged as unmanned.

Further, the body movement recognition step includes:

Make difference between the two signals to get the difference DMS[n] of the main and auxiliary sensing signals;

Calculate the number Cnt_bm that satisfies DMS[n] greater than the set body movement threshold DMS_th; and

Compare Cnt_bm with the set threshold Cnt_th, when Cnt_bm exceeds the threshold Cnt_th, it is judged as body movement, otherwise it is judged as non-body movement.

Further, the steps of the heart rate breathing algorithm include:

Perform frequency domain transformation and spectrum analysis on the array S[n] of auxiliary sensing signals;

Build environmental noise filter;

Obtain the filtered signal M_filter[n] of the main sensor;

Perform heart rate and breathing rate algorithm on M_filter[n]; and

Get heart rate and breathing rate.

Compared with the prior art, the present invention has the beneficial effect that the dual-sensor vital sign monitoring system adopts a dual-sensing structure to improve the signal-to-noise ratio of the vital sign monitoring system. One of the sensors is used to receive the vital signs signals of the human body and the noise signals of the environmental vibration as the main sensor; the other sensor is only used to receive the noise signals of the environmental vibration as the auxiliary sensor. The dual-sensor vital sign monitoring method provided by the present invention processes two sets of data through a certain algorithm, which can improve the signal-to-noise ratio of the vital sign signals of the human body, and the measured heart rate and respiration rate have high accuracy. Compared with traditional vital signs monitoring systems and methods, the dual-sensor vital signs monitoring system of the present invention also has the advantages of simple structure, strong flexibility, and low cost. The wireless communication connection with the mobile terminal can be through Bluetooth, Realization of wifi and zigbee.

Description of the drawings

FIG. 1 is a hardware structure diagram of a dual-sensor vital signs monitoring system provided by an embodiment of the present invention;

2 is a hardware structure diagram of another dual-sensor vital signs monitoring system provided by an embodiment of the present invention;

3 is a hardware structure diagram of another dual-sensor vital signs monitoring system provided by an embodiment of the present invention;

4 is a schematic structural diagram of a thin-film dual sensor module provided by an embodiment of the present invention;

FIG. 5 is a schematic structural diagram of a sheet type dual sensor module provided by an embodiment of the present invention;

6 is a schematic structural diagram of a cable-type dual sensor module provided by an embodiment of the present invention;

FIG. 7 is a flowchart of a dual-sensor vital signs monitoring method provided by an embodiment of the present invention;

FIG. 8 is a schematic diagram of an unmanned recognition algorithm in FIG. 7 provided by an embodiment of the present invention;

FIG. 9 is a schematic diagram of a body movement recognition algorithm in FIG. 7 according to an embodiment of the present invention; and

Fig. 10 is a schematic diagram of a heart rate breathing algorithm of Fig. 7 provided by an embodiment of the present invention.

In the figure: 1——Shell, 2——Main sensor, 3——Auxiliary sensor, 4——Contact point, 5——Support pier, 6——Limit bridge pier, 7——Main board, 8——Signal line, 9—surface covering, 10—substrate, 11—protective cover.

detailed description

In order to make the technical problems, technical solutions, and beneficial effects to be solved by the present invention clearer, the following further describes the present invention in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, but not to limit the present invention.

The embodiment of the present invention provides a dual-sensing vital signs monitoring system. The system includes a dual-sensing module, a filter amplification module, an analog-to-digital conversion device, a main control chip, a memory, and a wireless communication module. The dual-sensing module It includes a main sensor and an auxiliary sensor. The main sensor is used to receive the vital signs signal (main signal) of the human body and the noise signal (background signal) of environmental micro-vibration, and the auxiliary sensor is only used to receive the noise signal (background signal) of the environmental micro-vibration. Figure 1 is a hardware structure diagram of a dual-sensor vital signs monitoring system provided by an embodiment of the present invention. It can be seen from the figure that the original signals collected by the main sensor and the auxiliary sensor are filtered and amplified by the filtering and amplifying module respectively. The digital conversion device is used to convert the analog signal output by the filtering and amplifying module into a digital signal. The main control chip is used to preprocess the digital signal and heart rate and respiration rate algorithm, and store the obtained real-time heart rate and respiration rate value in the memory, At the same time, the main control chip can be connected to the client terminal through the wireless communication module.

Figure 2 is a hardware structure diagram of a dual-sensor vital signs monitoring system provided by another embodiment of the present invention. It can be seen from the figure that the filter amplifier module in Figure 1 is replaced with a differential amplifier circuit, so that the main The signals of the sensor and the auxiliary sensor are used as the positive and negative inputs of the differential amplifier circuit, which can directly filter the common mode signal of the environmental noise through the circuit, and the vital sign signal is amplified as the differential mode signal, thereby improving the vital sign monitoring system The signal-to-noise ratio.

Figure 3 shows a hardware structure diagram of a dual-sensor vital sign monitoring system that integrates Figures 1 and 2 provided by an embodiment of the present invention. It can be seen from the figure that the vital signs monitoring system in this embodiment uses both The filter amplifying module and the differential amplifying circuit combine the advantages of the algorithm in Figure 1 with low cost, strong flexibility and high signal-to-noise ratio obtained in Figure 2.

Specifically, the above-mentioned dual sensor module in the vital signs monitoring system provided by the embodiment of the present invention also includes thin film, sheet or cable sensors, such as piezoelectric films, piezoelectric ceramics, piezoelectric cables, and optical fiber sensors. .

Figure 4 shows a schematic diagram of the structure of a thin-film dual-sensing module. The thin film can be a piezoelectric thin film. As shown in Figure 4, the dual sensor module includes housing 1, main sensor 2, auxiliary sensor 3, contact point 4, supporting pier 5, limit bridge pier 6 and main board 7, in which main sensor 2, auxiliary sensor 3, contact point 4. The supporting pier 5, the limiting pier 6 and the main board 7 are all arranged inside the housing 1. The housing 1 can be made of hard material, such as metal or plastic. The contact point 4 is located on the housing 1 and is in contact with the main sensor 2. The vital signs of the human body are transmitted to the main sensor 2 through the contact point 4 through the housing 1. The main sensor 2 or the auxiliary sensor 3, the supporting pier 5 and the limit pier 6 respectively constitute a bridge-type sensing structure. The supporting pier 5 is used to support the sensor so that the sensor has enough space to produce micro-deformation. Limiting pier 6 is used for limiting to prevent damage to the sensor caused by excessive external impact. Since the auxiliary sensor 3 is not in contact with the contact point 4 on the housing, the vital signs signal cannot be transmitted to the auxiliary sensor 3, so the auxiliary sensor 3 can only receive the noise signal of the environment, that is, the background signal. The sensor can be rivet or PCB routing (not shown in the figure) to directly transmit the signal to the main board 7.

Figure 5 shows the structure of a sheet-like dual sensor module, which may be piezoelectric ceramic. During preparation, the piezoelectric material is attached to the metal sink to form a sheet-like structure. In this embodiment, the dual sensor module includes a housing 1, a main sensor 2, an auxiliary sensor 3, a contact point 4, and a signal line 8. The housing 1 can be made of hard material, such as metal or plastic. The contact point 4 is located inside the housing 1 and is in contact with the housing 1 and at the same time is in contact with the main sensor 2. The auxiliary sensor is not provided with the contact point 4 and does not contact the housing 1. This aspect is the same as the above-mentioned embodiment. The vital signs of the human body are transmitted to the main sensor 2 through the contact point 4 through the housing 1. Since the auxiliary sensor 3 is not in contact with the contact point 4 on the housing, the vital sign signal cannot be transmitted to the auxiliary sensor 3, so the auxiliary sensor 3 can only receive the noise signal (background signal) of the environment. The sensor can be connected to the signal line 8 through wiring to output signals. The signal line 8 is used to connect with the main box.

Figure 6 shows a schematic structural diagram of a cable-type dual sensor module, that is, the dual sensor module includes a cable-type sensor, where the cable-type sensor may be a piezoelectric cable or an optical fiber sensor. As shown in FIG. 6, the dual sensor module includes a main sensor 2, an auxiliary sensor 3, a signal line 8, a surface covering 9, a substrate 10 and a protective cover 11. The signal line 8 is used to connect with the main box, the surface cover 9 and the substrate 10 are glued together to form a thin pad-shaped sensing device, and the protective cover 11 is a rigid protective cover to prevent the auxiliary sensor 3 Collect the vital signs signals of the human body. The signal line 8 in FIG. 6 is connected to the main sensor 2 and the auxiliary sensor 3 at the same time.

Specifically, the filter amplifying module used in the embodiment of the present invention includes two filter amplifying circuits. The topology and circuit parameters of the two filter amplifying circuits are completely the same, and the PCB wiring is symmetrical, so the noise introduced by the asymmetry of the circuit can be reduced. Reduce to a minimum. The filter is usually a band-pass filter with a frequency range of 0.1 Hz to 30 Hz. This frequency band is the main frequency band of the human body's vital signs signals, so the noise in other frequency bands will be filtered out.

Specifically, the memory used in the embodiment of the present invention is used to store the results of the vital sign signals calculated each time, such as time, heart rate, respiration rate, getting out of bed, body movement, etc., so that the vital sign data for a period of time can be periodically collected. Export so that users can query the data and do further analysis.

Further, the wireless communication module used in the embodiment of the present invention may be Bluetooth, wifi or zigbee.

The embodiment of the present invention also provides a dual-sensor vital sign monitoring method, which is applied to a dual-sensor vital sign monitoring system. As shown in FIG. 7, the method specifically includes the following steps:

S1 data collection: 21 represents the main sensor data collection, and 31 represents the auxiliary sensor data collection, both of which are performed simultaneously;

S2 signal filtering and amplifying: 22 represents filtering and amplifying the signal collected by the main sensor, 32 represents filtering and amplifying the signal collected by the auxiliary sensor;

S3 analog-to-digital conversion: 23 corresponds to the analog signal output by filtering and amplifying the signal collected by the main sensor), 33 corresponds to the analog signal output by filtering and amplifying the signal collected by the auxiliary sensor;

40: No one recognizes;

50: Body movement recognition;

60: Heart rate breathing algorithm;

70: Data storage.

Specifically, first the sensor (including the main sensor and the auxiliary sensor at the same time) performs data collection, and then filters and amplifies the collected two signals and performs analog-to-digital conversion, and then uses an algorithm to determine whether the two digital signals are unmanned. If it is determined that there is a person, the body movement recognition is performed. When the recognition result is non-body movement, it indicates that the person is in a stable state, and then the heart rate and respiration rate calculation is performed, and finally the accurate heart rate and respiration rate are obtained. At the same time, the memory stores data such as presence information, body movement information, heart rate and respiration rate in the process, so that users can query the data and make further analysis of the data.

Further, referring to FIG. 8, the unmanned recognition algorithm in step 40 in FIG. 7 specifically includes: 411 obtains the array M[n] of the main sensor signal, and at the same time 412 obtains the array S[n] of the auxiliary sensor signal, 421 and 422 respectively average the two arrays to obtain the mean values of the main sensor signal Mean_M and Mean_S. 431 and 432 respectively calculate the energy average of the two signals to obtain the average energy P_M of the main sensor signal and the auxiliary sensor signal. The average energy P_S, 44 is the difference between the average energy of the two signals to obtain the energy difference DP of the signal. 45 is to compare the energy difference of the two signals with the set threshold DP_th. When the DP exceeds the threshold DP_th, it is judged as human, otherwise it is judged as unmanned.

Among them, the calculation formula of the signal mean value is:

The calculation formula of the average energy of the signal is:

Where n is the length of the collected signal array.

The formula for calculating the energy difference between the two signals is:

DP=P_M-P_S

Figure 9 shows the specific steps of the body movement recognition algorithm in step 50 in Figure 7. The algorithm specifically includes: 511 first acquiring the array M[n] of the primary sensor signal, 512 acquiring the array S[n] of the secondary sensor signal , 52 makes the difference between the two signals to get the difference DMS[n] of the main and auxiliary sensing signals. 53 Then calculate the number Cnt_bm that satisfies DMS[n] greater than the set body movement threshold DMS_th, 54 compares Cnt_bm with the threshold Cnt_th, when Cnt_bm exceeds the threshold Cnt_th, it is judged as body movement, otherwise it is judged as non-body movement.

Among them, the calculation formula for the difference between the main and auxiliary sensing signals is:

DMS[n]=M[n]-S[n],

Where n is the length of the collected signal array.

Fig. 10 shows the specific steps of the heart rate and respiration rate algorithm in step 60 in Fig. 7. The specific steps are: 64 first obtain the array M[n] of the main sensor signal, 61 obtain the array S[n] of the auxiliary sensor signal, 62 Then perform frequency domain transformation and spectrum analysis on the array S[n] of the auxiliary sensing signal to obtain the spectrum of environmental noise, and then analyze it to obtain the peak of the spectrum, which is the main energy concentration frequency band of environmental noise. Next, 63 completes the construction of an environmental noise filter, and passes the array M[n] of the main sensor signal obtained by 64 through this filter to filter out the main noise concentration frequency bands in the environment, 65 thus obtains the filtered signal of the main sensor M_filter[n]. Because the signal M_filter[n] filters out the noise frequency band of the environment, the energy of the vital signs signal of the human body is more obvious, that is, the signal to noise ratio of the system is improved. Next, 66 performs the heart rate and respiration rate algorithm on the filtered signal, and 67 obtains the heart rate and respiration rate.

Compared with the traditional vital sign monitoring system and method, the dual-sensor vital sign monitoring system and method provided by the embodiments of the present invention have the advantages of high signal-to-noise ratio, low cost, simple structure, and strong flexibility.

The above descriptions are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modification, equivalent replacement and improvement made within the spirit and principle of the present invention shall be included in the protection of the present invention. Within range.

Claims

A dual-sensing vital signs monitoring system, including dual-sensing modules, a filtering and amplifying module, an analog-to-digital conversion device, a main control chip and a memory. The dual-sensing module includes a main sensor and an auxiliary sensor. In order to receive the vital signs signals of the human body and the environmental noise signals, the auxiliary sensor is set to receive only the environmental noise signals.
The dual-sensing vital signs monitoring system according to claim 1, wherein the dual-sensing module is a thin-film, sheet-type or cable-type sensing structure.
The dual-sensing vital signs monitoring system of claim 2, wherein the dual-sensing module is a thin-film sensing structure, wherein the dual-sensing module further includes a housing, contact points, supporting bridge piers, Limit bridge pier and main board, wherein the contact point is located on the housing and contacts the main sensor, and the main sensor and the auxiliary sensor form a bridge structure with the supporting bridge pier and the limit bridge pier, respectively, The auxiliary sensor is not in contact with the housing or the contact point.
The dual-sensing vital signs monitoring system according to claim 2, wherein the dual-sensing module is a sheet-type sensing structure, wherein the dual-sensing module further includes a housing, contact points and signal lines, The contact point is located on the housing and is in contact with the main sensor, and the auxiliary sensor is not in contact with the housing or the contact point.
The dual-sensing vital signs monitoring system of claim 2, wherein the dual-sensing module is a cable-type sensing structure, wherein the dual-sensing module further comprises a surface covering, a substrate, The protective cover and the signal line, wherein the protective cover is a rigid protective cover and is arranged to cover the auxiliary sensor to prevent the auxiliary sensor from collecting vital signs signals of the human body.
The dual-sensor vital signs monitoring system according to claim 1, wherein the filter amplifying module includes two filter amplifying circuits, the topological structure and circuits of the two filter amplifying circuits are the same, and the PCB wiring Symmetrical setting, in order to minimize the noise introduced by the asymmetry of the circuit, the filter and amplifying module is a differential amplifier circuit, which directly uses the signals of the main sensor and the auxiliary sensor as the positive and negative inputs of the differential amplifier circuit, and directly passes through the circuit. The environmental common mode noise is filtered out, thus only the vital signs signals are amplified.
A dual-sensor vital sign monitoring method includes the following steps:

Sensor data collection: including main sensor data collection and auxiliary sensor data collection;

Signal filtering and amplification: including filtering and amplifying the signals collected by the main sensor and the auxiliary sensor respectively;

Analog-to-digital conversion: including analog-to-digital conversion of the analog signal output by filtering and amplifying the signal collected by the main sensor and the auxiliary sensor;

No one recognizes;

Body movement recognition; and

Heart rate breathing algorithm.
8. The dual-sensor vital signs monitoring method according to claim 7, wherein the step of identifying whether there is no person comprises:

Acquire the array M[n] of the main sensor signal and the array S[n] of the auxiliary sensor signal;

Calculate the mean value Mean_M of the main sensor signal and the mean value Mean_S of the auxiliary sensor signal;

Calculate the average energy P_M of the main sensor signal and the average energy P_S of the auxiliary sensor signal;

Make the difference between the average energy of the two signals to obtain the energy difference DP of the signal; and

Compare the energy difference of the two signals with the set threshold DP_th. When the DP exceeds the threshold DP_th, it is judged as human, otherwise it is judged as unmanned.
8. The dual-sensor vital signs monitoring method according to claim 7, wherein the body movement recognition step comprises:

Acquire the array M[n] of the main sensor signal and the array S[n] of the auxiliary sensor signal;

Make difference between the two signals to get the difference DMS[n] of the main and auxiliary sensing signals;

Calculate the number Cnt_bm that satisfies DMS[n] greater than the set body movement threshold DMS_th; and

Compare Cnt_bm with the set threshold Cnt_th, when Cnt_bm exceeds the threshold Cnt_th, it is judged as body movement, otherwise it is judged as non-body movement.
8. The dual-sensor vital signs monitoring method of claim 7, wherein the heart rate breathing algorithm step comprises:

Acquire the array M[n] of the main sensor signal and the array S[n] of the auxiliary sensor signal;

Perform frequency domain transformation and spectrum analysis on the array S[n] of auxiliary sensing signals;

Build environmental noise filter;

Obtain the filtered signal M_filter[n] of the main sensor;

Perform heart rate and breathing rate algorithm on M_filter[n]; and

Get heart rate and breathing rate.