Dual-sensing vital signs monitoring system and method

Abstract

The application is suitable for the field of vital sign monitoring, and provides a dual-sensing vital sign monitoring system and method, wherein the dual-sensing vital sign monitoring system comprises a dual-sensing module, a filtering and amplifying module, an analog-digital conversion device, a main control chip and a memory; the dual-sensing module comprises a main sensor and an auxiliary sensor; the main sensor is used for receiving a vital sign signal of a human body and a noise signal of environmental micro-vibration; and the auxiliary sensor is used for receiving only the noise signal of environmental micro-vibration. The signals collected by the main sensor and the auxiliary sensor are sequentially filtered and amplified by the filtering and amplifying module, and two digital signals are obtained by the analog-digital conversion device; the main control chip is used for pre-processing the digital signals and a heart rate and respiration algorithm, and storing real-time heart rate and respiration rate values obtained into the memory. The dual-sensing vital sign monitoring system provided by the application has the advantages of high signal-to-noise ratio, low cost, simple structure, strong flexibility and the like.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of vital sign monitoring, and particularly relates to a dual-sensing vital sign monitoring system and method. BACKGROUND

[0002] The vital sign monitoring device mainly monitors the heart rate and respiratory rate of a person as well as body movement, bed leaving and other information. Compared with the traditional electrocardio monitor, the non-contact and non-wearing vital sign monitoring device has the advantages of convenience and long-term monitoring, and the precision can be close to that of the medical-grade monitor. The non-contact vital sign monitoring device mainly uses a sensor to collect the micro-vibration signals of the human body, such as the ballistocardiogram signal of the heartbeat and the chest and abdominal movement during breathing, and then converts them into electrical signals for processing. The commonly used sensors include piezoelectric ceramic, piezoelectric cable, piezoelectric film, optical fiber and radar, etc. The sensitivity of these sensors to weak vibration signals is very high, so that accurate heart rate and respiratory rate values can be obtained.

[0003] However, the disadvantage of high sensitivity is that the sensor is also very sensitive to the interference of the external environment. For example, in some noisy environment, the vibration of the environment itself may even exceed the human body itself, which will drown the real vital sign signal and cause the detection accuracy of the heart rate and respiratory rate to decrease. More seriously, it may cause misjudgment of the presence or absence of a person and mistake the environmental noise as the vital sign signal. Therefore, in order to make the vital sign monitoring device adapt to different environments, it is necessary to improve the signal-to-noise ratio of the system. SUMMARY

[0004] The purpose of the embodiment of the present application is to provide a dual-sensing vital sign monitoring system and method, which is used to solve the problem that the sensor is easily disturbed by the external environmental noise when collecting the micro-vibration signals of the human body, resulting in that the vital sign monitoring device cannot obtain accurate heart rate and respiratory rate.

[0005] The embodiment of the present application is implemented in this way, and a dual-sensing vital sign monitoring system is provided, which comprises 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 comprises a main sensor and an auxiliary sensor. The main sensor is used to receive the vital sign signals and the environmental noise signals of the human body, and the auxiliary sensor is arranged to receive only the environmental noise signals.

[0006] Further, the dual-sensing module is a sensing structure in the form of a film, a sheet or a cable.

[0007] Further, the double-sensing module is a thin film sensing structure, wherein the double-sensing module further comprises a shell, a contact point, a support bridge, a limiting bridge and a main plate, wherein the contact point is located on the shell and in contact with the main sensor, the main sensor and the auxiliary sensor form a bridge structure with the support bridge and the limiting bridge respectively, and the auxiliary sensor is not in contact with the shell or the contact point.

[0008] Further, the double-sensing module is a thin film sensing structure, wherein the double-sensing module further comprises a shell, a contact point, a support bridge, a limiting bridge and a main plate, wherein the contact point is located on the shell and in contact with the main sensor, the main sensor and the auxiliary sensor form a bridge structure with the support bridge and the limiting bridge respectively, and the auxiliary sensor is not in contact with the shell or the contact point.

[0009] Further, the double-sensing module is a cable sensing structure, wherein the double-sensing module further comprises a surface cover, a substrate, a protective cover and a signal line, wherein the protective cover is a hard protective cover arranged to cover the auxiliary sensor to prevent the auxiliary sensor from collecting the vital sign signals of the human body.

[0010] Further, the filter amplification module comprises two filter amplification circuits, the topological structures and circuit parameters of the two filter amplification circuits are the same, and the PCB wiring is symmetrically arranged, so as to minimize the noise introduced by the asymmetry of the circuit.

[0011] Further, the filter amplification module is a differential amplification circuit, directly taking the signals of the main sensor and the auxiliary sensor as positive and negative inputs of the differential amplification circuit, and can directly filter out the environmental common-mode noise through the circuit, and only amplify the vital sign signals (differential signals).

[0012] Another object of the embodiment of the present application is to provide a double-sensing vital sign monitoring method, comprising the following steps:

[0013] Sensor data acquisition: including main sensor data acquisition and auxiliary sensor data acquisition;

[0014] Signal filtering and amplification: including filtering and amplifying the signals collected by the main sensor and the auxiliary sensor respectively;

[0015] Analog-to-digital conversion: including analog-to-digital conversion of the analog signals output by the filtered and amplified signals collected by the main sensor and the auxiliary sensor respectively;

[0016] Presence or absence of person identification;

[0017] Body movement identification; and

[0018] Heart rate and respiration algorithm.

[0019] Further, the presence or absence of person identification step comprises:

[0020] obtaining an array of main sensing signals M[n] and an array of auxiliary sensing signals S[n];

[0021] obtaining a mean value of main sensing signals Mean_M and a mean value of auxiliary sensing signals Mean_S;

[0022] obtaining an average energy of main sensing signals P_M and an average energy of auxiliary sensing signals P_S;

[0023] obtaining an energy difference of the two signals DP by subtracting the average energy of the two signals; and

[0024] comparing the energy difference of the two signals with a set threshold DP_th, and determining that there is a person when DP exceeds the threshold DP_th, otherwise determining that there is no person.

[0025] Further, the body motion recognition step comprises:

[0026] obtaining an array of main sensing signals M[n] and an array of auxiliary sensing signals S[n];

[0027] obtaining a main-auxiliary sensing signal difference DMS[n] by subtracting the two signals;

[0028] calculating a number Cnt_bm that satisfies DMS[n] is greater than a set body motion threshold DMS_th; and

[0029] comparing Cnt_bm with a set threshold Cnt_th, and determining that there is body motion when Cnt_bm exceeds the threshold Cnt_th, otherwise determining that there is no body motion.

[0030] Further, the heart rate and respiration algorithm step comprises:

[0031] obtaining an array of main sensing signals M[n] and an array of auxiliary sensing signals S[n];

[0032] performing frequency domain transformation and spectrum analysis on the array of auxiliary sensing signals S[n];

[0033] constructing an ambient noise filter;

[0034] obtaining a filtered signal of the main sensor M_filter[n];

[0035] performing a heart rate and respiration rate algorithm on M_filter[n]; and

[0036] obtaining a heart rate and a respiration rate.

[0037] Compared with the prior art, the beneficial effects of the present application are that the dual-sensing 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 sign signals of the human body and the noise signals of environmental vibration as the main sensor; the other sensor is only used to receive the noise signals of environmental vibration as the auxiliary sensor. The dual-sensing vital sign monitoring method provided by the present application can improve the signal-to-noise ratio of the vital sign signals of the human body through certain algorithm processing on the two groups of data, and the accuracy of the measured heart rate and respiration rate is high. Compared with the traditional vital sign monitoring system and method, the dual-sensing vital sign monitoring system of the present application also has the advantages of simple structure, strong flexibility, low cost, etc. The wireless communication connection between the mobile terminal can be realized through Bluetooth, wifi and zigbee, etc. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 is a hardware structure diagram of a dual-sensing vital sign monitoring system provided by an embodiment of the present application;

[0039] Figure 2 is a hardware structure diagram of another dual-sensing vital sign monitoring system provided by an embodiment of the present application;

[0040] Figure 3 is a hardware structure diagram of another dual-sensing vital sign monitoring system provided by an embodiment of the present application;

[0041] Figure 4 is a structure schematic diagram of a thin film type dual-sensing module provided by an embodiment of the present application;

[0042] Figure 5 is a structure schematic diagram of a thin sheet type dual-sensing module provided by an embodiment of the present application;

[0043] Figure 6 is a structure schematic diagram of a cable type dual-sensing module provided by an embodiment of the present application;

[0044] Figure 7 is a flowchart of a dual-sensing vital sign monitoring method provided by an embodiment of the present application;

[0045] Figure 8 is a flowchart of a dual-sensing vital sign monitoring method provided by an embodiment of the present application; Figure 7 is a schematic diagram of a human identification algorithm in the dual-sensing vital sign monitoring method;

[0046] Figure 9 is a schematic diagram of a body movement identification algorithm in the dual-sensing vital sign monitoring method; and Figure 7 is a schematic diagram of a body movement identification algorithm in the dual-sensing vital sign monitoring method; and

[0047] Figure 10 is a flowchart of a dual-sensing vital sign monitoring method provided by an embodiment of the present application; Figure 7Schematic diagram of the central rate respiration algorithm.

[0048] In the figure: 1 - housing, 2 - main sensor, 3 - auxiliary sensor, 4 - contact point, 5 - support pier, 6 - limit pier, 7 - main board, 8 - signal line, 9 - surface covering, 10 - substrate, 11 - protective cover. DETAILED DESCRIPTION

[0049] In order to make the technical problems to be solved by the present application, technical solutions and beneficial effects more clear and explicit, the present application will be further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and not used to limit the present application.

[0050] The embodiment of the present application provides a kind of dual sensing vital sign monitoring system, the system includes dual sensing module, filter amplification module, analog-digital conversion device, main control chip, memory and wireless communication module, wherein, dual sensing module includes main sensor and auxiliary sensor, main sensor is used to receive the vital sign signal (main signal) of human body and the noise signal (background signal) of environmental microvibration, auxiliary sensor is only used to receive the noise signal (background signal) of environmental microvibration. Figure 1 It is a kind of hardware structure diagram of dual sensing vital sign monitoring system provided by the embodiment of the present application, from the figure, the original signal collected by main sensor and auxiliary sensor is filtered and amplified by filter amplification module respectively, analog-digital conversion device is used to convert the analog signal output by filter amplification module into digital signal, main control chip is used to pre-process and heart rate respiration rate algorithm to the digital signal, and the real-time heart rate respiration rate value obtained is stored in memory, while main control chip can be connected with customer terminal by wireless communication module.

[0051] Figure 2 It is a kind of hardware structure diagram of dual sensing vital sign monitoring system provided by another embodiment of the present application, from the figure, Figure 1 Filter amplification module in it is replaced by differential amplification circuit, so that the signal of main sensor and auxiliary sensor can be directly used as positive and negative input of differential amplification circuit, the common-mode signal of noise of environment can be directly filtered out by circuit mode, and vital sign signal is amplified as differential mode signal, so as to improve the signal-to-noise ratio of vital sign monitoring system.

[0052] Figure 3 It shows a kind of comprehensive Figure 1 And Figure 2 Hardware structure diagram of dual sensing vital sign monitoring system provided by the embodiment of the present application, from the figure, vital sign monitoring system in this embodiment simultaneously uses filter amplification module and differential amplification circuit, so that the advantages of the two are combined Figure 1The middle algorithm processing mode has low cost, strong flexibility and Figure 2 The obtained signal has high signal-to-noise ratio.

[0053] Specifically, the double-sensing module in the vital sign monitoring system provided by the embodiment of the present application further comprises a film type, sheet type or cable type sensor, such as a piezoelectric film, a piezoelectric ceramic, a piezoelectric cable and a fiber sensor.

[0054] Figure 4 A structure diagram of a film type double-sensing module is shown, and the film can be a piezoelectric film. Figure 4 As shown in the figure, the double-sensing module comprises a shell 1, a main sensor 2, an auxiliary sensor 3, a contact point 4, a support pier 5, a limiting pier 6 and a main board 7, wherein the main sensor 2, the auxiliary sensor 3, the contact point 4, the support pier 5, the limiting pier 6 and the main board 7 are arranged inside the shell 1. The shell 1 can be a hard material such as metal or plastic. The contact point 4 is located on the shell 1 and in contact with the main sensor 2. The vital sign signal of the human body is transmitted to the main sensor 2 through the shell 1 and the contact point 4. The main sensor 2 or the auxiliary sensor 3 and the support pier 5 and the limiting pier 6 respectively form a bridge type sensing structure. The support pier 5 is used to support the sensor, so that the sensor has enough space to produce micro deformation. The 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 shell, the vital sign signal cannot be transmitted to the auxiliary sensor 3, so that the auxiliary sensor 3 can only receive the noise signal of the environment, i.e. the background signal. The sensor can be riveted or connected to the main board 7 through PCB wiring (not shown in the figure) to transmit the signal directly to the main board 7.

[0055] Figure 5 A structure of a sheet type double-sensing module is shown, and the sheet can be a piezoelectric ceramic. The piezoelectric material is attached to the metal sink during preparation to form a sheet type structure. In this embodiment, the double-sensing module comprises a shell 1, a main sensor 2, an auxiliary sensor 3, a contact point 4 and a signal line 8. The shell 1 can be a hard material such as metal or plastic. The contact point 4 is located inside the shell 1 and in contact with the shell 1, and also in contact with the main sensor 2. The auxiliary sensor does not have a contact point 4 and is not in contact with the shell 1, which is the same as the above embodiment. The vital sign signal of the human body is transmitted to the main sensor 2 through the shell 1 and the contact point 4. Since the auxiliary sensor 3 is not in contact with the contact point 4 on the shell, the vital sign signal cannot be transmitted to the auxiliary sensor 3, so that 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 the signal. The signal line 8 is used to connect with the host box.

[0056] Figure 6A structural diagram of a cable type double sensing module is given, that is, the double sensing module comprises a cable type sensor, wherein the cable type sensor can be a piezoelectric cable or an optical fiber sensor. Figure 6 As shown in the figure, the double sensing module comprises 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 be connected with a host box, the surface covering 9 and the substrate 10 are bonded together to form a thin pad-shaped sensing device, and the protective cover 11 is a hard protective cover used to prevent the auxiliary sensor 3 from collecting the vital sign signals of a human body. Figure 6 The signal line 8 is connected with the main sensor 2 and the auxiliary sensor 3 at the same time.

[0057] Specifically, the filter amplification module used in the embodiment of the present application comprises two filter amplification circuits, the topological structures and circuit parameters of the two filter amplification circuits are completely consistent, and the PCB wiring is kept symmetrical, so that the noise introduced by the asymmetry of the circuit can be reduced to the minimum. The filter is usually a band-pass filter, and the frequency band is 0.1Hz-30Hz. This frequency band is the main frequency band of the vital sign signals of a human body, so the noise of other frequency bands can be filtered out.

[0058] Specifically, the memory used in the embodiment of the present application is used to store the results of the vital sign signals calculated each time, such as time, heart rate, respiration rate, off-bed and body movement information, so that the vital sign data of a period of time can be exported regularly, so that the user can query the data and make further analysis.

[0059] Further, the wireless communication module used in the embodiment of the present application can be Bluetooth, wifi or zigbee.

[0060] The embodiment of the present application also provides a double sensing vital sign monitoring method applied to a double sensing vital sign monitoring system, as shown in the figure. Figure 7 The method specifically comprises the following steps:

[0061] S1 data acquisition: 21 represents main sensor data acquisition, and 31 represents auxiliary sensor data acquisition, both of which are performed at the same time;

[0062] S2 signal filtering and amplification: 22 represents filtering and amplification of the signal collected by the main sensor, and 32 represents filtering and amplification of the signal collected by the auxiliary sensor;

[0063] S3 analog-to-digital conversion: 23 corresponds to the analog signal output by the signal collected by the main sensor after filtering and amplification, and 33 corresponds to the analog signal output by the signal collected by the auxiliary sensor after filtering and amplification;

[0064] 40: human presence or absence identification;

[0065] 50: body movement identification;

[0066] 60: Heart rate and respiration algorithm;

[0067] 70: Data storage.

[0068] Specifically, the system first collects data using sensors (including both main and auxiliary sensors simultaneously). Then, the two acquired signals are filtered, amplified, and converted from analog to digital. An algorithm then uses these two digital signals to determine the presence of a person. If a person is detected, body movement is detected. If no body movement is detected, it indicates the person is in a stable state. Next, heart rate and respiratory rate are calculated to obtain accurate heart and respiratory rates. Simultaneously, the system stores the presence / absence information, body movement information, and heart and respiratory rate data for users to query and further analyze.

[0069] Further, refer to Figure 8 , Figure 7 The algorithm for detecting the presence or absence of people in step 40 specifically includes: 411 acquiring the array M[n] of the main sensor signal, and 412 acquiring the array S[n] of the auxiliary sensor signal; 421 and 422 calculating the average of the two arrays respectively to obtain the average values ​​Mean_M and Mean_S of the main sensor signal; 431 and 432 calculating the average energy of the two signals respectively to obtain the average energy P_M of the main sensor signal and the average energy P_S of the auxiliary sensor signal; 44 subtracting the average energy of the two signals to obtain the energy difference DP; 45 comparing the energy difference of the two signals with a set threshold DP_th. If DP exceeds the threshold DP_th, it is determined that someone is present; otherwise, it is determined that no one is present.

[0070] The formula for calculating the signal mean is as follows:

[0071]

[0072]

[0073] The formula for calculating the average energy of a signal is:

[0074]

[0075]

[0076] Where n is the length of the acquired signal array.

[0077] The formula for calculating the energy difference between the two signals is:

[0078] DP = P_M - P_S

[0079] Figure 9 Showing Figure 7The specific steps of the motion recognition algorithm in step 50 are as follows: 511 First, obtain the array M[n] of the main sensor signal; 512 First, obtain the array S[n] of the auxiliary sensor signal; 52 Calculate the difference between the two signals to obtain the difference between the main and auxiliary sensor signals DMS[n]; 53 Then, calculate the number Cnt_bm that satisfies DMS[n] being greater than the set motion threshold DMS_th; 54 Compare Cnt_bm with the threshold Cnt_th. If Cnt_bm exceeds the threshold Cnt_th, it is determined to be motion; otherwise, it is determined to be non-motion.

[0080] The formula for calculating the difference between the primary and secondary sensor signals is as follows:

[0081] DMS[n] = M[n] - S[n],

[0082] Where n is the length of the acquired signal array.

[0083] Figure 10 Showing Figure 7 The specific steps of the heart rate and respiratory rate algorithm in step 60 are as follows: 64 First, obtain the array M[n] of the main sensor signal; 61, obtain the array S[n] of the auxiliary sensor signal; 62, perform frequency domain transformation and spectrum analysis on the array S[n] of the auxiliary sensor 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 band of the environmental noise. Next, 63, construct an environmental noise filter, and pass the array M[n] of the main sensor signal obtained in 64 through this filter to filter out the main noise concentration band in the environment; 65, thus obtaining the filtered signal M_filter[n] of the main sensor. Because the signal M_filter[n] filters out the environmental noise band, the energy of the human vital signs signal is more obvious, that is, the signal-to-noise ratio of the system is improved. Next, 66, perform the heart rate and respiratory rate algorithm on the filtered signal; 67, thus obtaining the heart rate and respiratory rate.

[0084] The dual-sensor vital sign monitoring system and method provided in this invention have advantages over traditional vital sign monitoring systems and methods, such as high signal-to-noise ratio, low cost, simple structure, and high flexibility.

[0085] 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 within the protection scope of the present invention.

Claims

1. A dual-sensing vital sign monitoring system, comprising a dual-sensing module, a filter-amplification module, an analog-digital conversion device, a master control chip and a memory, the dual-sensing module comprising a main sensor and an auxiliary sensor, the main sensor being configured to receive a vital sign signal of a human body and an environmental noise signal, the auxiliary sensor being configured to receive only the environmental noise signal, the filter-amplification module comprising two filter-amplification circuits, the two filter-amplification circuits being configured to filter and amplify the signals collected by the main sensor and the auxiliary sensor respectively, the dual-sensing module being a sensing structure in a film type, a sheet type or a cable type, the dual-sensing module being a sensing structure in a film type, wherein the dual-sensing module further comprises a housing, a contact point, a support pier, a limiting pier and a main board, the contact point being located on the housing and being in contact with the main sensor, the main sensor and the auxiliary sensor forming a bridge structure with the support pier and the limiting pier respectively, and the auxiliary sensor not being in contact with the housing or the contact point.

2. The dual-sensing vital signs monitoring system of claim 1, wherein, The two filter-amplification circuits have the same topology and circuit, and the PCB wiring is symmetrically arranged to minimize the noise introduced by the asymmetry of the circuit, the filter-amplification module is a differential amplification circuit, the signals of the main sensor and the auxiliary sensor are directly used as the positive and negative inputs of the differential amplification circuit, and the environmental common-mode noise is directly filtered out through the circuit, so that only the vital sign signal is amplified. 3.A dual-sensing vital sign monitoring method, which is implemented by using the vital sign monitoring system according to claim 1 or 2, and comprises 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-digital conversion, including analog-digital conversion of the analog signals output by the signals collected by the main sensor and the auxiliary sensor after filtering and amplification; presence or absence of a person identification; body movement identification; and heart rate and respiration algorithm.

4. The dual-sensing vital signs monitoring method of claim 3, wherein, The presence or absence of a person identification step comprises: obtaining an array M[n] of the main sensor signal and an array S[n] of the auxiliary sensor signal; obtaining a mean value Mean_M of the main sensor signal and a mean value Mean_S of the auxiliary sensor signal; obtaining a mean energy P_M of the main sensor signal and a mean energy P_S of the auxiliary sensor signal; obtaining a signal energy difference DP by subtracting the mean energy of the two signals; and comparing the signal energy difference with a set threshold value DP_th, and determining that there is a person when the DP exceeds the threshold value DP_th, otherwise determining that there is no person.

5. The dual-sensing vital signs monitoring method of claim 3, wherein, The body movement identification step comprises: obtaining an array M[n] of the main sensor signal and an array S[n] of the auxiliary sensor signal; obtaining a main-auxiliary sensor signal difference DMS[n] by subtracting the two signals; calculating a number Cnt_bm satisfying DMS[n] being greater than a set body movement threshold value DMS_th; and comparing Cnt_bm with a set threshold value Cnt_th, and determining that there is body movement when Cnt_bm exceeds the threshold value Cnt_th, otherwise determining that there is no body movement.

6. The dual-sensing vital signs monitoring method of claim 3, wherein, The heart rate and respiration algorithm step comprises: obtaining an array M[n] of the main sensor signal and an array S[n] of the auxiliary sensor signal; performing frequency domain transformation and spectral analysis on the array of secondary sensing signals S[n]; constructing an ambient noise filter; obtaining a filtered signal of the primary sensor M_filter[n]; performing a heart rate and respiration rate algorithm on M_filter[n]; and obtaining a heart rate and respiration rate.

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