Non-wearable method and device for measuring blood pressure and heart rate and medium

Abstract

The invention discloses a non-wearable method for measuring blood pressure and heart rate, which comprises the following steps: using a sensor to contact skin to emit LED light to collect the change of blood flow in a blood vessel in unit volume, converting the change into ADC values, reading the ADC values collected by the sensor every several milliseconds, preprocessing the collected original data and normalizing the wave height to obtain PPG data, respectively calculating first-order derivative VPG data and second-order derivative APG data of the PPG data; the characteristic values of the VPG and the APG are obtained through judgment according to the detected peak point of the PPG, when it is judged that the PPG is the peak, the required characteristic values of the VPG and the APG are stored, multiple sets of blood pressure calculation data can be obtained in many times, and multiple sets of blood pressure and heart rate data are calculated. By means of the method, the blood pressure and the heart rate can be rapidly and accurately measured, the calculation speed is high, and judgment is accurate.

Description

Technical Field

[0001] The present invention relates to the technical field of blood pressure and heart rate measurement, and in particular to a method, device and medium for non-wearable blood pressure and heart rate measurement. Background Art

[0002] At present, health has become more and more concerned by humans, and the level of blood pressure is closely related to health, so it is very necessary to measure blood pressure frequently. The current mainstream sphygmomanometers, whether traditional mercury sphygmomanometers, upper arm electronic sphygmomanometers or wrist electronic sphygmomanometers, need to be worn, which is inconvenient to measure. If a non-wearable blood pressure and heart rate measurement method can be provided, it will be very portable and fast to measure blood pressure and heart rate, and the scope of application will be wider.

[0003] Photoplethysmography is a continuous measurement method that uses the fact that the absorption of light by arteries varies while the absorption of light by other tissues remains basically unchanged. The obtained signal is divided into a direct current (DC) signal and an alternating current (AC) signal. The AC signal is extracted to reflect the characteristics of blood flow. This method does not require complex and expensive instruments and equipment, and is simple to operate, stable in performance, non-invasive, and adaptable. Therefore, it is widely valued by the medical community at home and abroad.

[0004] The comprehensive information of the morphology (wave shape), intensity (wave amplitude), rate (wave speed) and rhythm (wave period) of the photoplethysmograph (PPG) signal can reflect many physiological and pathological characteristics of the human cardiovascular system. Therefore, it is necessary to accurately identify and obtain the position of each characteristic point of the PPG signal. However, compared with the electrocardiograph (ECG) signal, its characteristics are less obvious, and the extraction and judgment of the waveform characteristics such as the peaks and troughs of the PPG signal are accompanied by more difficulties and challenges. Therefore, it is urgent to provide a new non-wearable method for measuring blood pressure and heart rate to solve the above problems. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a non-wearable method, device and medium for measuring blood pressure and heart rate, which can quickly and accurately measure blood pressure and heart rate, with fast calculation speed and accurate judgment.

[0006] In order to solve the above technical problems, the first technical solution adopted by the present invention is to provide a non-wearable method for measuring blood pressure and heart rate, comprising the following steps:

[0007] S1: Use the sensor to contact the skin to emit LED light to collect the change of blood flow in the blood vessel per unit volume, and convert it into ADC value. Read the ADC value collected by the sensor every several milliseconds, and pre-process the collected raw data to form a heart rate waveform graph;

[0008] S2: normalize the preprocessed data to obtain PPG data, and calculate the first-order derivative VPG data and the second-order derivative APG data of the PPG data respectively;

[0009] S3: Determine whether the received PPG data is a peak or a trough. If the PPG data is a peak or a trough, save the data and calculate the normalization coefficient of the wave height;

[0010] If the PPG data at this moment is judged to be a trough, then the time starts to be accumulated after the trough data, and the accumulated time t1 from the trough data to 10% to 100% of the next peak data is calculated;

[0011] If the PPG data at this moment is determined to be a peak, then determine whether its VPG data is a peak. If the VPG data is determined to be a peak, save the VPG peak data p1, and start accumulating time after the VPG peak data to calculate the accumulated time t2 from the VPG peak data to the next zero moment;

[0012] If the PPG data at this moment is judged to be a peak, then judge whether its APG data is a peak or a trough. If the APG data is judged to be a peak, then save the APG peak data p2, and calculate the cumulative time t3 from the APG peak data to the next APG trough data. If the APG data is judged to be a trough, then save the APG trough data v1, and calculate the absolute value pv1 of the difference between the APG peak data p2 and the APG trough data v1.

[0013] S4: Calculate the required x1, x2, x3, x4, x5, x6, x7 according to the wave height normalization coefficient according to formula (1) (2);

[0014]

[0015] S5: Calculate the blood pressure data Y according to the blood pressure algorithm formula (3);

[0016]

[0017] Among them, x0 is a constant 379.7194774;

[0018] S6: Calculate the heart rate W=3000 / t4 according to the time difference t4 between two consecutive adjacent peaks of the PPG data.

[0019] In a preferred embodiment of the present invention, in step S1, the step of preprocessing the collected raw data includes:

[0020] First, the collected raw data is filtered;

[0021] Then delete the filtered data of the previous few seconds and keep the stable data.

[0022] In a preferred embodiment of the present invention, after the blood pressure data is calculated, outlier data calculation is performed on several groups of calculated blood pressure data, and the last calculated blood pressure data is taken as the final blood pressure value.

[0023] To solve the above technical problems, the second technical solution adopted by the present invention is: to provide an electronic device, comprising: one or more processors, a memory and one or more programs stored in the memory, wherein the one or more programs include instructions for executing the non-wearable method for measuring blood pressure and heart rate as described in any of the above items.

[0024] To solve the above technical problems, the third technical solution adopted by the present invention is: to provide a computer-readable storage medium, including one or more programs executed by one or more processors of an electronic device, and the one or more programs include instructions for executing the non-wearable method for measuring blood pressure and heart rate as described in any of the above items.

[0025] The beneficial effects of the present invention are:

[0026] (1) The present invention directly collects blood flow change signals through sensors, pre-processes the collected raw data and normalizes the wave height to obtain PPG data, which not only removes erroneous data collected due to the influence of noise and ambient light, but also eliminates amplitude differences, reduces the influence of deviations, simplifies calculations, and reduces the amount of calculation required for processing data;

[0027] (2) Compared with the existing blood pressure algorithms, the present invention only needs to detect the peaks, valleys and zero crossings of the PPG data during the calculation process, and obtain the characteristic values ​​of VPG and APG based on the detected peak points of the PPG. When the PPG is judged to be a peak, the characteristic values ​​required by VPG and APG are saved. After the characteristic values ​​of PPG (t1, p1, t2, p2, -v1, t3 and pv1 data) are obtained, the required VPG and APG characteristic values ​​are saved, and multiple groups of blood pressure calculation data can be obtained in multiple time periods, so as to calculate multiple groups of blood pressure and heart rate data;

[0028] (3) The present invention removes the data of the first few seconds before the sensor contacts and saves relatively stable data. After removing the unstable data, the blood pressure data of several groups calculated are calculated through a mean averaging filtering algorithm, thereby reducing the jitter of the calculated blood pressure data and calculating relatively accurate data. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a flow chart of the method for non-wearable blood pressure and heart rate measurement of the present invention;

[0030] Figure 2 is a waveform diagram of the original data;

[0031] Figure 3 is a waveform diagram of the PPG data;

[0032] Figure 4 yes Figure 3 A schematic diagram of the waveform of the first-order derivative VPG data of the PPG data shown;

[0033] Figure 5 yes Figure 3 Schematic diagram of the waveform of the second derivative APG data of the PPG data shown. DETAILED DESCRIPTION

[0034] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0035] See also Figure 1 , the embodiment of the present invention includes:

[0036] A non-wearable method for measuring blood pressure and heart rate, comprising the following steps:

[0037] S1: Use the sensor to contact the skin to emit LED light. According to the absorption of LED light in the blood, the light that is not absorbed is captured by the sensor after reflection and converted into electrical signals, that is, the change of blood flow in the unit volume in the blood vessel is collected and converted into ADC value. The ADC value collected by the sensor is read every several milliseconds, and the collected raw data is pre-processed to form a heart rate waveform graph;

[0038] In this example, the ADC value collected by the sensor is set to be read every 20ms, which is the raw data. The waveform is as follows: Figure 2 As shown in the figure. The collected raw data is filtered using the ARM FIR low-pass filter function, and the coefficients of the function and the waveform correction coefficients are set according to the frequency of the raw data. The FIR filter function designed by Matlab saves the 0.5Hz-8Hz signal and removes the erroneous data collected due to the influence of noise and ambient light.

[0039] S2: Normalize the preprocessed data to obtain PPG data, and save and plot the normalized data. Figure 3As shown in the figure, wave height normalization can eliminate amplitude differences, reduce the impact of deviations, simplify calculations, and reduce the amount of data processing. Then, the rate of change of PPG is calculated, that is, the first-order derivative of the acquired PPG data is taken to obtain VPG data. The calculated data is saved and plotted as shown in the figure. Figure 4 As shown, after obtaining the VPG data, the rate of change of VPG is calculated, that is, the first-order derivative of VPG is calculated to obtain the APG data. The calculated data is saved and plotted as shown in Figure 5 shown.

[0040] The following specific operations are performed on the read data:

[0041] S3: Determine whether the received PPG data is a peak or a trough. If the PPG data is a peak or a trough, save the data and calculate the normalization coefficient of the wave height, normal = 65535 / (peak data - trough data).

[0042] If the PPG data at this moment is judged to be a trough, then the time starts to be accumulated after the trough data, and the accumulated time t1 from the trough data to 10% to 100% of the next peak data is calculated;

[0043] If the PPG data at this moment is determined to be a peak, then determine whether its VPG data is a peak. If the VPG data is determined to be a peak, save the VPG peak data p1, and start accumulating time after the VPG peak data to calculate the accumulated time t2 from the VPG peak data to the next zero moment;

[0044] If the PPG data at this moment is judged to be a peak, then judge whether its APG data is a peak or a trough. If the APG data is judged to be a peak, then save the APG peak data p2, and calculate the cumulative time t3 from the APG peak data to the next APG trough data. If the APG data is judged to be a trough, then save the APG trough data v1, and calculate the absolute value pv1 of the difference between the APG peak data p2 and the APG trough data v1.

[0045] S4: Calculate the required x1, x2, x3, x4, x5, x6, x7 according to the wave height normalization coefficient according to formula (1) (2);

[0046]

[0047] S5: Calculate the blood pressure data Y according to the blood pressure algorithm formula (3);

[0048]

[0049] Among them, x0 is a constant 379.7194774;

[0050] S6: Calculate the heart rate W=3000 / t4 according to the time difference t4 between two consecutive adjacent peaks of the PPG data.

[0051] The calculated blood pressure data contains unusable data. The data calculated in the first few seconds of the calculated blood pressure data are removed, and the relatively stable data are retained. The retained data are then used for outlier data calculation, and the remaining data with large differences from other data are removed to ensure that the average data fluctuations are relatively smooth, the data are relatively accurate, and the difference between the calculated data and the actual blood pressure is small. In the specific example, the first 15% to the last 15% of the saved data are removed. The last calculated blood pressure data is taken as the final blood pressure value. For example, when the number of blood pressure data after the outlier is 6 or 7, the 6th or 7th is used as the final result of the calculation.

[0052] Compared with the existing blood pressure algorithms, the present invention only needs to detect the peaks, valleys and zero crossings of the PPG data during the calculation process, and obtain the characteristic values ​​of VPG and APG based on the detected PPG peak points. That is, after the PPG characteristic values ​​are obtained, that is, after the PPG is determined to be a peak, the characteristic values ​​of VPG and APG are also determined, that is, if the PPG data is determined not to be a peak, it is determined whether the VPG and APG are peaks, and if so, the data are retained and used when the PPG is determined to be a peak. In this way, after the characteristic values ​​of PPG (t1, p1, t2, p2, -v1, t3 and pv1 data) are obtained, the required VPG and APG characteristic values ​​are saved, and multiple groups of blood pressure calculation data can be obtained in multiple time periods, so as to calculate multiple groups of blood pressure and heart rate data.

[0053] An embodiment of the present invention also provides an electronic device, comprising: one or more processors, a memory, and one or more programs stored in the memory, wherein the one or more programs include instructions for executing the non-wearable method for measuring blood pressure and heart rate as described in any of the above items.

[0054] An embodiment of the present invention also provides a computer-readable storage medium, including one or more programs executed by one or more processors of an electronic device, wherein the one or more programs include instructions for executing the non-wearable method for measuring blood pressure and heart rate as described in any of the above items.

[0055] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0056] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0057] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0058] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A non-wearable method for measuring blood pressure and heart rate, characterized in that: The following steps are involved: S1: Use the sensor to contact the skin to emit LED light to collect the change of blood flow in the blood vessel per unit volume, and convert it into ADC value. Read the ADC value collected by the sensor every several milliseconds, and pre-process the collected raw data to form a heart rate waveform graph; S2: normalize the preprocessed data to obtain PPG data, and calculate the first-order derivative VPG data and the second-order derivative APG data of the PPG data respectively; S3: Determine whether the received PPG data is a peak or a trough. If the PPG data is a peak or a trough, save the data and calculate the normalization coefficient of the wave height; If the PPG data at this moment is judged to be a trough, then the time starts to be accumulated after the trough data, and the accumulated time t1 from the trough data to 10% to 100% of the next peak data is calculated; If the PPG data at this moment is determined to be a peak, then determine whether its VPG data is a peak. If the VPG data is determined to be a peak, save the VPG peak data p1, and start accumulating time after the VPG peak data to calculate the accumulated time t2 from the VPG peak data to the next zero moment; If the PPG data at this moment is judged to be a peak, then judge whether its APG data is a peak or a trough. If the APG data is judged to be a peak, then save the APG peak data p2, and calculate the cumulative time t3 from the APG peak data to the next APG trough data. If the APG data is judged to be a trough, then save the APG trough data v1, and calculate the absolute value pv1 of the difference between the APG peak data p2 and the APG trough data v1. S4: Calculate the required x1, x2, x3, x4, x5, x6, x7 according to the wave height normalization coefficient according to formula (1) (2); S5: Calculate the blood pressure data Y according to the blood pressure algorithm formula (3); Among them, x0 is a constant 379.7194774; S6: Calculate the heart rate W=3000 / t4 according to the time difference t4 between two consecutive adjacent peaks of the PPG data.

2. The non-wearable method for measuring blood pressure and heart rate according to claim 1, characterized in that: In step S1, the step of preprocessing the collected raw data includes: First, the collected raw data is filtered; Then delete the filtered data of the previous few seconds and keep the stable data.

3. The non-wearable method for measuring blood pressure and heart rate according to claim 1, characterized in that: After the blood pressure data is calculated, outlier data is calculated for several groups of blood pressure data, and the last calculated blood pressure data is taken as the final blood pressure value.

4. An electronic device, characterized in that: include: One or more processors, a memory and one or more programs stored in the memory, wherein the one or more programs include instructions for executing the non-wearable method for measuring blood pressure and heart rate as described in any one of claims 1 to 3.

5. A computer-readable storage medium, characterized in that: The device comprises one or more programs executed by one or more processors of an electronic device, wherein the one or more programs include instructions for executing the method for non-wearable measurement of blood pressure and heart rate as described in any one of claims 1 to 3.

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