A wristwatch-type pulse and electrocardiogram synchronous acquisition and display device

Abstract

A wristwatch-type pulse and ECG synchronous acquisition and display device, wherein the pulse and ECG synchronous acquisition unit acquires the user's wrist PPG and wrist ECG synchronous signals and converts the data into digital signals through analog-to-digital conversion and sends them to a lower computer; the lower computer signal processing and display unit runs the pulse and ECG synchronous acquisition unit control program, temporary storage of raw data, low-power Bluetooth transmission, low-power filtering and pulse rate algorithm and LCD display control and other program algorithms, real-time low-power wireless transmission of signals and real-time display of signals and pulse rate by the lower computer; the upper computer signal processing and display unit restores the collected synchronous pulse and ECG signals through the filtering algorithm, calculates the corresponding indicators, and displays the restored signals and various indicators on the client terminal in real time. The present invention can realize the wearable synchronous acquisition of wrist pulse and ECG signals, while ensuring comfortable wearing and convenient operation, and is suitable for daily health monitoring of users and auxiliary clinical diagnosis.

Description

Technical Field

[0001] The present invention belongs to the field of wearable vital sign detection and analysis, and relates to wrist photoelectric volumetric pulse wave detection and analysis technology, wrist electrocardiogram signal detection and analysis technology, and multi-signal synchronous acquisition technology, especially for wearable continuous electrocardiogram and pulse signal monitoring, and specifically is a wristwatch-type pulse electrocardiogram synchronous acquisition and display device. Background Art

[0002] The human body's pulse and ECG signals reflect many important physiological information of the human body, such as the hardness and diameter of blood vessels, peripheral resistance, blood viscosity, and other blood vessel and blood characteristics, which will have a complex impact on the pulse and ECG signals. These influencing factors are the root cause of many cardiovascular diseases. Therefore, long-term and accurate collection of pulse and ECG signals can not only serve as a reference for disease diagnosis, but also effectively participate in the regulation of daily physical and mental health.

[0003] For the acquisition of single-lead dynamic ECG signals, the main technical solutions currently include ECG patches with wet electrodes, ECG clothes with dry electrodes, and wristwatch-type acquisition systems. ECG patches are inconvenient to wear, and wet electrodes can cause discomfort or even skin allergies after long-term wearing. However, the method of collecting chest ECG signals with wet electrodes can guarantee the accuracy of the signal to a certain extent and reduce motion artifact interference; ECG clothes with dry electrodes are simpler and more comfortable to wear than ECG patches, but the use of dry electrodes will cause serious artifact interference in the collected ECG signals; the wristwatch-type acquisition system is the most convenient and comfortable to wear. Although it also uses dry electrodes, the problem of motion artifacts will be smaller than that of ECG clothes after being worn firmly, but there is a problem of too low signal-to-noise ratio when collecting single wrist ECG signals, and other parts of the body need to be used as reference electrodes for acquisition. Therefore, it is difficult to achieve the purpose of long-term monitoring.

[0004] The acquisition of wrist pulse signals can be mainly divided into three categories, namely pressure pulse signal acquisition, ultrasonic pulse signal acquisition and photoelectric pulse acquisition. Among them, photoelectric pulse acquisition, namely photoplethysmography (PPG), is widely used in pulse signal analysis due to its low cost and convenient development. PPG sensors usually use red light, near-infrared and green light as light sources. Among them, hemoglobin has a higher absorption rate for green light, which can obtain a higher signal-to-noise ratio and is suitable for dynamic environments. Although infrared and other light sources have a lower signal-to-noise ratio, they are more accurate in static environments. Several light sources can complement each other. PPG signals can be divided into two parts, DC and AC. The AC part is also affected by the pressure between the sensor and the skin. Changes in pressure may cause changes in the AC amplitude, resulting in fluctuations in the waveform. Therefore, the PPG sensor must be firmly connected to the skin to achieve accurate measurement. At the same time, the PPG sensor is a light-sensitive component, and ambient light will have a great impact on the signal collected by the sensor. Therefore, the PPG signal is mainly affected by motion artifacts and ambient light, which is a key issue that needs to be addressed during the design of the acquisition system.

[0005] Both pulse and ECG signals contain a lot of physiological information, and the synchronous acquisition of the two signals can calculate more physiological indicators and reflect more physiological information. Therefore, it is necessary to develop a set of pulse and ECG synchronous acquisition devices. The current technical solutions mainly use ECG stickers or ECG clothes and wrist or finger PPG for synchronous acquisition. The whole solution requires wire connection, which is complicated to wear and not very comfortable. It is necessary to develop a pulse ECG synchronous acquisition system with simpler and faster detection methods and higher comfort.

[0006] Chinese patent CN211934035U discloses a synchronous acquisition and display device for ECG and pulse signals, which realizes the synchronous acquisition of ECG and pulse using a three-lead ECG vest and a wrist vibration pressure sensor, but there are problems with the ease of operation and comfort of wearing the device. This patent uses the dry electrode on the back of the wristwatch body to collect wrist ECG signals, and the PPG sensor to collect wrist pulse signals, without the need for a chest ECG vest or other devices, to achieve synchronous acquisition of ECG and pulse signals, solving the problems of wearing convenience and comfort.

[0007] Chinese patent CN111528813A discloses a portable wrist-mounted multi-physiological information real-time detection wireless system, which realizes the detection of multiple physiological signals such as ECG signals, PPG pulse wave signals and body surface temperature. The patent uses a chest ECG patch and a wrist PPG sensor to collect signals, realizing the simultaneous measurement of multiple physiological signals. This patent uses a wrist dry electrode method to collect ECG, and at the same time requires the synchronization of multi-channel physiological signal collection, which not only improves the comfort of collection, but also can more accurately measure and calculate clinical physiological indicators.

[0008] Chinese patent CN204500675U discloses a portable ECG monitoring system that realizes wearable ECG signal collection, uses Bluetooth to transmit data in real time to an Android phone for real-time display, and compresses the data and transmits it to the server for storage. This patent uses a low-power algorithm to achieve low-power operation on the wristwatch device, and can display basic information such as pulse rate in real time without the need for a client device; the client uses Web Bluetooth and PWA technology to achieve full platform adaptation of client devices without being limited to Android devices; the server uses cloud services and edge computing technology to achieve automated analysis and detection of physiological data, rather than simple data storage functions. Summary of the invention

[0009] In view of the above problems, the present invention proposes a wristwatch-type pulse ECG synchronous acquisition and display device, which synchronously acquires wrist single-lead ECG signals and wrist PPG signals, uploads the original data to the host computer in real time through low-power wireless transmission, performs signal filtering and index calculation and analysis, and finally provides a test report. At the same time, the wristwatch can display the initially processed data on the wristwatch for users to view in real time.

[0010] A wristwatch-type pulse and ECG synchronous acquisition and display device comprises a pulse and ECG synchronous acquisition unit, a lower computer signal processing and display unit and a host computer signal processing and display unit, wherein the output end of the pulse and ECG synchronous acquisition unit is connected to the input end of the lower computer signal processing and display unit, the control output end of the lower computer signal processing and display unit is connected to the control input end of the pulse and ECG synchronous acquisition unit, and the signal output end of the lower computer signal processing and display unit is connected to the input end of the host computer signal processing and display unit;

[0011] The pulse and ECG synchronous acquisition unit is integrated on the back of the wristwatch-type lower computer, and is closely attached to the user's wrist skin when worn, and is used to collect the user's PPG pulse signal and single-lead ECG signal. The signal is transmitted to the lower computer signal processing and display unit through the serial port for further processing;

[0012] The lower computer signal processing and display unit is integrated in the wristwatch-type lower computer, and adopts a 32-bit MCU as the main control chip, which mainly runs pulse and ECG synchronous acquisition unit control, temporary storage of raw data, low-power Bluetooth transmission, low-power filtering and pulse rate algorithm and LCD display control and other program algorithms, realizing the control of pulse and ECG synchronous acquisition unit, real-time low-power wireless transmission of signals and real-time display of signals and pulse rate by the lower computer;

[0013] The host computer signal processing and display unit runs on the client terminal. After establishing a connection with the slave computer via Bluetooth, it can restore the collected synchronous pulse and electrocardiogram signals through a filtering algorithm, calculate the corresponding medical indicators, and display the restored signals and various indicators on the client terminal in real time. After a measurement is completed, a corresponding data report is generated for user and clinical reference.

[0014] As a further improvement of the present invention, the pulse and ECG synchronous acquisition unit includes a multi-channel PPG sensor, an ambient light shielding module, a single-lead ECG acquisition dry electrode, an ECG pre-filter circuit and an ECG and PPG synchronous analog front end.

[0015] As a further improvement of the present invention, the multi-channel PPG sensor includes a green LED, a red LED and a near-infrared LED, which are used to emit light of different bands; the multi-channel PPG sensor includes an infrared cutoff PD and a broadband PD, which are used to receive reflected light of different bands.

[0016] As a further improvement of the present invention, the ambient light shielding module protects the multi-channel PPG sensor through the groove design of the watch case to prevent it from being interfered by ambient light.

[0017] As a further improvement of the present invention, the single-lead ECG acquisition dry electrode is composed of RA electrode, LA electrode and RL electrode to form a capacitively coupled right leg drive differential circuit to realize the acquisition of dynamic ECG signals. Specifically, the RA electrode and LA electrode are distributed on both sides of the back of the lower computer, and the RL electrode is distributed on the side of the wristwatch-type lower computer and is externally connected to other parts of the body through an interface. The ECG pre-filter circuit is an RC low-pass filter circuit to filter out electromagnetic interference in space.

[0018] As a further improvement of the present invention, the lower computer signal processing and display unit adopts STM32 series chips, realizes the storage of algorithms and data by expanding the SRAM chip, runs the motion artifact filtering and pulse estimation algorithm based on spectrum analysis, and sends the calculation results to an external 2-inch TFT LCD screen in real time. At the same time, the BLE Bluetooth module is driven by the serial port to realize low-power wireless transmission of data.

[0019] As a further improvement of the present invention, the host computer signal processing and display unit is developed based on the Node.js framework, and the PWA technology is used to achieve full-platform adaptation of the host computer on Windows, Linux, Android, iOS and other systems. Through cloud computing and edge computing, filtering, signal restoration, and indicator calculation functions are realized, reducing the requirements on the computing power of the user terminal.

[0020] As a further improvement of the present invention, the signal restoration algorithm adopts a method combining wavelet filtering and morphological adaptive filtering to ensure that the signal does not have obvious distortion in the low-frequency and high-frequency parts while filtering out noise.

[0021] As a further improvement of the present invention, the indicator calculation function includes the following indicators: heart rate variability HRV indicators in the time domain and frequency domain of the ECG, including the overall standard deviation SDNN of RR intervals, the percentage of interval differences exceeding 50ms pNN50, the root mean square of the sum of squares of interval differences RMSSD, low-frequency energy LF, high-frequency energy HF, the ratio of low frequency to high frequency LF / HF, sample entropy SampEn, and fuzzy measurement entropy FuzzyMEn; indicators related to pulse, including heart rate HR, pulse transmission time PTT, and pulse wave arrival time PAT; further, three-dimensional indicators of blood pressure, blood oxygen saturation and emotional state are calculated, wherein the blood pressure is calculated using an approximate linear regression model with the pulse wave transmission time PWTT, the blood oxygen saturation is calculated using a linear regression model with the absorption ratio of red light and infrared light, and the emotional state is evaluated using a weighted regression model of the previous HRV indicators, wherein the weighted regression model is trained using a multi-classification support vector machine SVM based on a radial kernel function.

[0022] As a further improvement of the present invention, the linear regression model for calculating blood pressure refers to performing regression operation on the linear model BP=a*PWTT+b through a large number of data samples to obtain suitable parameters a and b, the value range of a is -2.0 to -0.8 mmHg / ms, and the value range of b is 350 to 450 mmHg, which are automatically adjusted according to individual differences; the regression model for calculating blood oxygen saturation obtains two groups of reflected light signals through the red LED and infrared LED of the PPG sensor, and calculates the red light DC amplitude DCR, the red light AC amplitude ACR and the infrared DC amplitude DCIR, the infrared AC amplitude ACIR, respectively, and the linear model is regressed through a large number of data samples. A regression operation is performed to obtain a suitable K parameter, and the value range of K is 95 to 1000.

[0023] Compared with the prior art, the wristwatch-type pulse and electrocardiogram synchronous acquisition and display device provided by the present invention has the following beneficial effects:

[0024] (1) The present invention realizes the synchronous acquisition of wrist pulse and wrist electrocardiogram signals, which can obtain more physiological index parameters with more clinical medical reference value, and help to assist clinical diagnosis and more accurate daily health monitoring.

[0025] (2) The wristwatch-type pulse and ECG synchronous acquisition and display device of the present invention realizes low-power operation and data transmission, greatly improves the battery life of the wearable pulse and ECG synchronous acquisition device, and can realize long-term monitoring.

[0026] (3) The wristwatch-type pulse and electrocardiogram synchronous acquisition and display device of the present invention is comfortable to wear and convenient to measure, and is suitable for users' daily health monitoring and auxiliary clinical diagnosis.

[0027] (4) The present invention adopts cloud computing and edge computing technologies, and is developed using PWA technology. It does not have high performance requirements for client terminal devices and achieves full platform adaptation. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 System flow chart;

[0029] Figure 2 Schematic diagram of the watch's appearance and structure;

[0030] Figure 3 Hardware structure diagram of the lower computer;

[0031] Figure 4 Upper computer software structure diagram. DETAILED DESCRIPTION

[0032] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments:

[0033] like Figure 1 As shown, a wristwatch-type pulse and ECG synchronous acquisition and display device comprises a pulse and ECG synchronous acquisition unit, a lower computer signal processing and display unit and a host computer signal processing and display unit. The output end of the pulse and ECG synchronous acquisition unit is connected to the input end of the lower computer signal processing and display unit, and the control output end of the lower computer signal processing and display unit is connected to the control input end of the pulse and ECG synchronous acquisition unit.

[0034] like Figure 2As shown, the signal output end of the lower computer signal processing and display unit is connected to the input end of the upper computer signal processing and display unit. The pulse and ECG synchronous acquisition unit includes a multi-channel PPG sensor, an ambient light shielding module, a single-lead ECG acquisition dry electrode, an ECG pre-filter circuit and an ECG and PPG synchronization analog front end. The PPG sensor includes two 526nm green LEDs, a 950nm near-infrared LED, a 650nm red LED, an infrared cutoff PD and a broadband PD. The ambient light shielding module is designed to protect the multi-channel PPG sensor through the groove design of the watch case to prevent it from being interfered by ambient light. The single-lead ECG acquisition dry electrode is composed of RA electrode, LA electrode and RL electrode to form a capacitively coupled right leg drive differential circuit to realize the acquisition of dynamic ECG signals. Specifically, the RA electrode and LA electrode are distributed on both sides of the back of the lower computer, and the RL electrode is distributed on the side of the wristwatch-style lower computer, and can also be connected to other parts of the body through an interface.

[0035] like Figure 3 As shown, the ECG pre-filter circuit is an RC low-pass filter circuit with a cut-off frequency of 140kHz to filter out electromagnetic interference in space. The ECG and PPG synchronous analog front end adopts an AFE chip to realize the amplification and synchronous AD conversion of PPG and ECG signals, and transmits the synchronous conversion results to the MCU through the SPI serial port transmission. The lower computer signal processing and display unit adopts an STM32 chip, and realizes the storage of algorithms and data by expanding the SRAM chip, running the motion artifact filtering and pulse estimation algorithm based on FFT spectrum analysis, and sending the calculation results to an external 2-inch TFT LCD screen in real time. At the same time, the BLE Bluetooth module is driven by the serial port to work, realizing low-power wireless data transmission. The system is powered by a 3.7V lithium battery, and the power management is realized by the TPS series chip. The 3.3V voltage regulator powers the Bluetooth module, SRAM, and LCD screen, and the 4.2V and 2.1V voltage regulators power the AFE chip and PPG sensor. The system uses the MCU to perform timing control on the AFE chip and PPG sensor, which means that each LED flashes alternately at a fixed frequency. At the same time, the analog front end samples and transmits the reflected signals of different LEDs at the same frequency, which not only realizes multi-channel signal acquisition but also reduces the power consumption of the system.

[0036] like Figure 4As shown, the host computer signal processing and display unit is developed based on the Node.js framework, and the full-platform adaptation of the host computer in Windows, Linux, Android, iOS and other systems is realized through PWA technology. Through cloud computing and edge computing, functions such as filtering, signal restoration, and index calculation are realized, reducing the requirements for the computing power of the user terminal. The signal restoration algorithm adopts a method combining wavelet filtering and morphological adaptive filtering to ensure that the signal does not show obvious distortion in the low-frequency and high-frequency parts while filtering out noise. The index calculation function is the basis for realizing the index calculation function for the waveform detection of electrocardiogram and pulse. Wavelet transform and convolutional neural network are used to pre-train waveform recognition to obtain a waveform feature recognition model, such as the QRS wave detection model of electrocardiogram. The index calculation function mainly includes the following indicators: ECG time domain and frequency domain HRV indicators, including SDNN, pNN50, RMSSD, LF, HF, LF / HF, SampEn, FuzzyMEn, etc.; pulse-related indicators, including HR, PTT, PAT, etc.; further, blood pressure, blood oxygen saturation and emotional state three-dimensional indicators can be calculated, wherein blood pressure calculation is obtained by using an approximate linear regression model with PWTT, blood oxygen saturation calculation is obtained by using a linear regression model with the absorption ratio of red light and infrared light, and emotional state assessment adopts a weighted regression model for the previous HRV indicators, wherein the weighted regression model is obtained by SVM training based on radial kernel function. The linear regression model for blood pressure calculation refers to the regression operation of the linear model BP=a*PWTT+b through a large number of data samples to obtain appropriate parameters a and b, the value range of a is -2.0~-0.8mmHg / ms, and the value range of b is 350~450mmHg, which is automatically adjusted according to individual differences. The regression model for calculating blood oxygen saturation (SpO2) obtains two sets of reflected light signals through the red LED and infrared LED of the PPG sensor, and calculates the red light DC amplitude DC R , red light AC amplitude R and infrared DC amplitude IR , infrared AC amplitude IR , through a large amount of data to the linear model A regression operation is performed to obtain a suitable K parameter, and the value range of K is 95 to 100.

[0037] The above description is only a preferred embodiment of the present invention and does not constitute any other form of limitation to the present invention. Any modification or equivalent change made based on the technical essence of the present invention still falls within the scope of protection required by the present invention.

Claims

1. A wristwatch-type pulse and electrocardiogram synchronous acquisition and display device, characterized in that: It comprises a pulse and ECG synchronous acquisition unit, a lower computer signal processing and display unit and a host computer signal processing and display unit, wherein the output end of the pulse and ECG synchronous acquisition unit is connected to the input end of the lower computer signal processing and display unit, the control output end of the lower computer signal processing and display unit is connected to the control input end of the pulse and ECG synchronous acquisition unit, and the signal output end of the lower computer signal processing and display unit is connected to the input end of the host computer signal processing and display unit; The pulse and ECG synchronous acquisition unit is integrated on the back of the wristwatch-type lower computer, and is closely attached to the user's wrist skin when worn, and is used to collect the user's PPG pulse signal and single-lead ECG signal. The signal is transmitted to the lower computer signal processing and display unit through the serial port for further processing; The pulse and ECG synchronous acquisition unit comprises a multi-channel PPG sensor, an ambient light shielding module, a single-lead ECG acquisition dry electrode, an ECG pre-filter circuit and an ECG and PPG synchronous analog front end; The multi-channel PPG sensor comprises a green LED, a red LED and a near-infrared LED, and the multi-channel PPG sensor comprises an infrared cut-off PD and a broadband PD; The ambient light shielding module protects the multi-channel PPG sensor through the groove design of the watch case; The single-lead ECG acquisition dry electrode is composed of RA electrode, LA electrode and RL electrode to form a capacitively coupled right leg drive differential loop. Specifically, RA electrode and LA electrode are distributed on both sides of the back of the lower computer, and RL electrode is distributed on the side of the wristwatch-type lower computer and connected to other parts of the body through an interface. The ECG pre-filter circuit is an RC low-pass filter circuit to filter out electromagnetic interference in space. The ECG and PPG synchronous analog front end adopts an AFE chip to achieve amplification and synchronous AD conversion of PPG and ECG signals, and transmits the synchronous conversion results to the MCU via SPI serial port transmission; The lower computer signal processing and display unit is integrated in the wristwatch-type lower computer, and adopts a 32-bit MCU as the main control chip, which mainly operates the pulse and ECG synchronous acquisition unit control, temporary storage of raw data, low-power Bluetooth transmission, low-power filtering and pulse rate algorithm and LCD display control program algorithm, realizing the control of the pulse and ECG synchronous acquisition unit, real-time low-power wireless transmission of signals and the lower computer real-time display of signals and pulse rate functions; The host computer signal processing and display unit runs on the client terminal. After establishing a connection with the lower computer via Bluetooth, it restores the collected synchronous pulse and electrocardiogram signals through a filtering algorithm, calculates the corresponding medical indicators, and displays the restored signals and various indicators on the client terminal in real time. After a measurement is completed, a corresponding data report is generated for user and clinical reference; The host computer signal processing and display unit is developed based on the Node.js framework, and the full-platform adaptation of the host computer on Windows, Linux, Android, and iOS systems is realized through PWA technology. Through cloud computing and edge computing, filtering, signal restoration, and index calculation functions are realized through cloud computing and edge computing, reducing the requirements on the computing power of the user terminal; The signal restoration algorithm adopts a method combining wavelet filtering and morphological adaptive filtering; The index calculation function includes the following indexes: heart rate variability HRV indexes in the time domain and frequency domain of the ECG, including the overall standard deviation SDNN of the RR intervals, the percentage of interval differences exceeding 50ms pNN50, the root mean square of the sum of squares of interval differences RMSSD, low-frequency energy LF, high-frequency energy HF, the ratio of low frequency to high frequency LF / HF, sample entropy SampEn, and fuzzy measurement entropy FuzzyMEn; pulse-related indexes, including heart rate HR, pulse transmission time PTT, and pulse wave arrival time PAT; further, blood pressure, blood oxygen saturation, and emotional state three-dimensional indexes are calculated, wherein the blood pressure is calculated using an approximate linear regression model with the pulse wave transmission time PWTT, the blood oxygen saturation is calculated using a linear regression model with the absorption ratio of red light and infrared light, and the emotional state is evaluated using a weighted regression model of the previous HRV index, wherein the weighted regression model is trained using a multi-classification support vector machine SVM based on a radial kernel function; The linear regression model for calculating blood pressure refers to the regression operation of the linear model BP=a*PWTT+b for calculating blood oxygen saturation SpO2 through a large number of data samples to obtain appropriate two parameters a and b, where the value range of a is -2.0 to -0.8 mmHg / ms, and the value range of b is 350 to 450 mmHg, which are automatically adjusted according to individual differences; the regression model for calculating blood oxygen saturation obtains two groups of reflected light signals through the red LED and infrared LED of the PPG sensor, and calculates the red light DC amplitude DCR, the red light AC amplitude ACR and the infrared DC amplitude DCIR, the infrared AC amplitude ACIR, respectively, and the linear model is regressed through a large number of data samples A regression operation is performed to obtain a suitable K parameter, and the value range of K is 95 to 100.

2. A wristwatch type pulse and electrocardiogram synchronous acquisition and display device according to claim 1, characterized in that: The lower computer signal processing and display unit adopts STM32 series chips, realizes the storage of algorithms and data by expanding SRAM chips, runs motion artifact filtering and pulse estimation algorithms based on spectrum analysis, and sends the calculation results to an external 2-inch TFT LCD screen in real time, while driving the BLE Bluetooth module through the serial port.

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