Search

CN-122004813-A - Continuous cuff-free blood pressure monitoring method and system based on photoconductive film

CN122004813ACN 122004813 ACN122004813 ACN 122004813ACN-122004813-A

Abstract

The invention discloses a cuff-free blood pressure continuous monitoring method and system based on a photoconductive film, which collects multiband reflected light signals of fingertip skin through the photoconductive film attached to a terminal screen, the light guide film realizes directional light guide and stray light filtering through the micro-nano grating array, is aligned with screen pixel hardware, and has obviously improved signal to noise ratio compared with a common camera scheme. The invention extracts multi-dimensional characteristics such as time difference, rise time, enhancement index and the like among wave peaks of the dual-band pulse, and calculates systolic pressure and diastolic pressure by combining a personalized baseline model of a user. The system supports the double modes of active measurement and night passive monitoring, motion artifacts are removed through the acceleration sensor, the ambient light interference is restrained through the ambient light sensor, the system is linked with the applicant spectrum identification patent to realize the exclusive monitoring of one machine for multiple persons, the data is stored in a local encryption mode, and the user manages the system independently. The invention does not need cuff inflation, does not need electrocardiograph reference and has no compression feeling, can realize non-perception continuous blood pressure monitoring in the daily use process of the mobile phone of a user, and has the advantages of no wound, continuity, low cost, high precision and privacy safety.

Inventors

  • CHANG LE

Assignees

  • 常乐

Dates

Publication Date
20260512
Application Date
20260321

Claims (5)

  1. 1. The cuff-free blood pressure continuous monitoring method based on the photoconductive film is characterized by comprising the following steps of: s0, responding to active authorization of a user, acquiring personal physiological parameters of the user, and constructing or calling a personalized blood pressure calculation model, wherein the blood pressure monitoring supports an active user measurement mode and a passive night monitoring mode; The method comprises the steps of S1, collecting spectral reflection data of the skin of a user fingertip in at least two different wavebands by using controllable multiband light emitted by a terminal screen as a light source through a passive light guide film with a micro-nano grating structure, wherein the light guide film realizes directional light guide and stray light filtering through a micro-nano grating array, environmental light interference resistance and a signal to noise ratio are obviously improved compared with a common camera collecting scheme, the micro-nano grating array of the light guide film realizes hardware level alignment with screen pixels through a photoetching process, and an alignment error is less than 0.01 pixel, and the collecting position is a finger abdomen area of an index finger or a middle finger; S2, extracting pulse wave signals from collected spectral reflection data, detecting motion artifacts in an auxiliary mode through a terminal built-in acceleration sensor, automatically removing a current data segment when finger movement acceleration exceeding 0.1g is detected, detecting ambient light mutation in an auxiliary mode through an ambient light sensor, automatically triggering signal compensation or removing an interfered data segment when ambient light intensity change exceeds a preset threshold value, calculating multi-dimensional pulse wave characteristic parameters, wherein the multi-dimensional pulse wave characteristic parameters comprise at least one of pulse wave crest time difference, pulse wave rise time, reflection wave enhancement index and pulse wave area integral of dual-band, and the time difference between the pulse wave crest time is defined as the time difference between the main peak and peak time of a green wave signal and the main peak and peak time of a red wave signal, and the time difference and the systolic pressure are in negative correlation, and are different from the traditional electrocardio-pulse wave conduction time; s3, inputting the extracted multi-dimensional pulse wave characteristic parameters into a personalized blood pressure calculation model, wherein the personalized blood pressure calculation model takes the time difference between wave peaks of the pulse wave in two wavebands, the heart rate, the age and the body quality index as necessary input parameters, takes the rise time of the pulse wave, the reflected wave enhancement index and the ambient temperature as optional input parameters, and outputs estimated systolic pressure and diastolic pressure; S4, carrying out Kalman filtering fusion on the continuous multiple measurement results, outputting smoothed blood pressure trend data, triggering abnormal early warning when the continuous multiple measurement results deviate from the personal baseline by more than a preset threshold value, and pushing early warning information to a user terminal and authorized contacts; S5, encrypting and storing the blood pressure measurement result by adopting a terminal local AES-128, storing a secret key in a terminal safety area, not uploading the secret key to any cloud server, enabling a user to autonomously select whether to synchronize to an authorized cloud, and generating a long-term blood pressure trend report.
  2. 2. The method according to claim 1, wherein in step S1, the at least two different wavelength bands comprise a combination of green wavelength band 520-580nm and red wavelength band 640-700nm, or a combination of green wavelength band 520-580nm and near infrared wavelength band 800-950 nm.
  3. 3. The method according to claim 1, wherein in the night passive monitoring mode, the continuous contact state of the fingertip is judged by the change of the reflected light intensity, and the stable contact is judged and the measurement is started when the reflected light intensity is kept stable for 5 continuous seconds and is higher than a preset threshold value, and the measurement is suspended when the contact is interrupted.
  4. 4. The method according to claim 1, wherein the personalized blood pressure calculation model is established by fitting a standard blood pressure value of a first calibration of a user with a regression of pulse wave characteristics collected synchronously, wherein the first calibration uses a cuff-type sphygmomanometer to synchronously measure 3 times in a resting state to take an average value as a reference value, and the user is recommended to recalibrate every 3-6 months later.
  5. 5. A continuous cuff-less blood pressure monitoring system based on a photoconductive film, comprising: the micro-nano grating array is aligned with screen pixels in hardware level through a photoetching process, the alignment error is smaller than 0.01 pixel, and the micro-nano grating array is used for collecting multiband reflected light signals of the skin of a user fingertip through directional light guiding and stray light filtering; The signal acquisition module is used for continuously acquiring reflected light signals at a sampling frequency of more than 100Hz by taking controllable multiband light emitted by a terminal screen as a light source and extracting pulse wave original data; The characteristic extraction module is used for calculating multidimensional characteristic parameters such as time difference between wave peaks of the dual-band pulse, rise time of the pulse wave, reflected wave enhancement index, area integral of the pulse wave and the like from the pulse wave signals; The blood pressure calculation module is internally provided with a personalized blood pressure calculation model, takes the time difference between the wave peaks of the pulse in two wavebands, the heart rate, the age and the body mass index as necessary input parameters, takes the rising time of the pulse wave and the reflected wave enhancement index as optional input parameters, and outputs estimated systolic pressure and diastolic pressure; The calibration management module is used for managing the first calibration and the regular calibration processes of the user and maintaining the personalized model coefficients of the user; The data storage and display module is used for encrypting and storing blood pressure history data by adopting a terminal local AES-128, storing a secret key in a terminal safety area and not uploading the secret key to any cloud server, and enabling a user to autonomously select whether to synchronize to an authorized cloud to generate a trend report so as to support abnormal early warning and data sharing; The identity recognition module is used for collecting the optical spectrum characteristics of the human body of the user through the light guide film, comparing the optical spectrum characteristics with the pre-stored spectrum characteristic codes, verifying the identity of the user, measuring the blood pressure of the user after the verification is passed, refusing the measurement and prompting the unauthorized user when the verification fails, and realizing the exclusive monitoring and privacy isolation of multiple persons.

Description

Continuous cuff-free blood pressure monitoring method and system based on photoconductive film Technical Field The invention relates to the technical fields of optical acquisition, biological feature monitoring and health management, in particular to a cuff-free blood pressure continuous monitoring method and system based on a light guide film, which are used for acquiring reflected light signals of fingertip skin through the light guide film attached to a terminal screen, the method extracts the time difference between the pulse wave peaks of the dual-band and the characteristic parameters of the multi-dimensional pulse wave, combines the personal baseline data of the user, realizes the blood pressure monitoring without cuff, perception and continuity, and can be widely applied to daily terminal equipment such as mobile phones, flat plates and the like. Citation application The application is based on the technical construction of the prior application patent not previously disclosed by the applicant, and is specifically cited as follows: 1. the prior application 1 is application number 2026102814971, application day 2026-03-10, and the invention name is a light guide toughened film-based non-authority AI interaction implementation method; 2. the prior application patent 3 is application number 2026103269949, application date 2026-03-17, and the invention name is a control method and a control system of an unlicensed eyeball tracking touch terminal based on a light guide interaction layer; 3. The prior application patent is application number 2026103505829, application date 2026-03-20, and the invention name is a unique identification method and system for human body optical spectrum characteristics based on a photoconductive film. The application date of the above prior basic patent is earlier than the present application, and has not been disclosed before the application date of the present application, and the core technical features of the prior art are not included in the present application by reference. Background The existing blood pressure measurement technology has the following defects: The cuff type sphygmomanometer is characterized in that the cuff is required to be worn for inflation and pressurization, the operation is complex, continuous monitoring cannot be performed, the sleeping is influenced by night measurement, and the measurement deviation is caused by tension of a user due to the pressure feeling of the cuff; the wrist electronic sphygmomanometer still needs to be inflated and pressurized, has high requirements on measuring postures, and has larger error when the wrist position is not level with the heart; The wearable equipment is used for measuring blood pressure, relies on a photoelectric sensor and an electrocardio sensor, needs special hardware, needs to be calibrated regularly, and is high in cost and difficult to popularize; The existing photoplethysmography technology can only measure heart rate, can not accurately measure blood pressure, or needs to combine electrocardiosignals (dual sensors), so that hardware complexity is increased; The existing mobile phone camera blood pressure measuring scheme relies on a camera to collect fingertip videos, is greatly interfered by ambient light and has low signal to noise ratio, weak pulse wave characteristics cannot be stably extracted, and the measurement accuracy cannot meet clinical reference requirements. The applicant's previous patents have realized passive optical collection techniques for photoconductive films that can collect the reflected light signals from the skin surface with high accuracy. On the basis of the invention, the directional light guide and clutter filtering characteristics of the light guide film are further utilized to extract the time difference between the pulse wave peaks of the dual wave band and the multi-dimensional pulse wave characteristics, and the single sensor continuous blood pressure monitoring without a cuff and without electrocardiographic reference is realized by combining a personalized baseline model of a user. Disclosure of Invention The invention aims to provide a cuff-free blood pressure continuous monitoring method and system based on a light guide film, which are used for collecting multi-band reflected light signals of fingertip skin by using the light guide film, extracting multi-dimensional characteristics such as time difference between wave peaks of a dual-band pulse wave, rise time of the pulse wave, reflected wave enhancement index and the like, and realizing noninvasive, noninductive and continuous blood pressure monitoring by combining a personalized baseline model constructed by age, height, weight and historical blood pressure data of a user, so that daily management of a hypertensive patient and early warning of cardiovascular diseases can be assisted. S0, responding to active authorization of a user, acquiring personal physiological parameters of the user, and constructin