CN118557168A

CN118557168A - Capillary refill time measurement method, device, medium and equipment

Info

Publication number: CN118557168A
Application number: CN202411046771.4A
Authority: CN
Inventors: 陈大强; 何文俊; 梁锋; 黄大兴; 成娟林
Original assignee: GUANGZHOU MEDSOFT SYSTEM Ltd
Current assignee: GUANGZHOU MEDSOFT SYSTEM Ltd
Priority date: 2024-08-01
Filing date: 2024-08-01
Publication date: 2024-08-30
Anticipated expiration: 2044-08-01
Also published as: CN118557168B

Abstract

The application provides a capillary refill time measuring method, device, medium and equipment, and belongs to the technical field of data processing. The method comprises the following steps: acquiring a detection data subset acquired by laser in a single capillary refill time CRT measurement period of a detected body; conducting derivation on the detection data subsets to form corresponding derivative data subsets; identifying minimum data from the subset of derivative data; identifying two zero crossing data in the derivative data subset adjacent to the minimum data; and determining a first CRT duration corresponding to a single CRT measurement period based on the acquisition time corresponding to the two zero crossing data. The application can quickly and accurately obtain the CRT time length of the user.

Description

Capillary refill time measurement method, device, medium and equipment

Technical Field

The present application relates to the field of data processing technologies, and in particular, to a method, an apparatus, a medium, and a device for measuring capillary refill time.

Background

Capillary refill time (CAPILLARY REFILL TIME, CRT) refers to the time of pressing the skin or mucous membrane of the superficial part of the human body, which after being squeezed, temporarily blocks the blood flow and the pressed part appears pale; after compression is removed, the capillaries may be rapidly filled, from the time compression is removed to capillary refill.

CRT is the most intuitive monitoring index of the peripheral circulation blood flow state, and accurately measuring the time length of CRT has important reference significance for analyzing the health state of users. The normal range of adult CRTs remains controversial. Most studies indicate that CRT is considered normal for < 2 seconds, with CRT for most children and young people being less than 2 seconds, but CRT for healthy women being 2.9 seconds and CRT for elderly people being 4.5 seconds. The normal CRT for children may be between 2-3 seconds and the normal CRT for newborns may be up to 3 seconds.

In a conventional CRT detection method based on laser, a fast fourier transform FFT analysis or a wavelet analysis is generally performed on a CRT waveform of a user measured by laser, and based on these analyses, a compression contact time and a filling recovery time of a subject of the user during CRT measurement are found out, so as to obtain a CRT value of the user. However, such conventional FFT analysis or wavelet analysis requires a large amount of computational resources.

Disclosure of Invention

Based on this, it is an object of the present application to provide a capillary refill time measurement method, device, medium and apparatus to reduce the resource consumption of CRT duration measurement.

In a first aspect of the present application, there is provided a method of measuring capillary refill time, the method comprising:

Acquiring a detection data subset acquired by laser in a single capillary refill time CRT measurement period of a detected body;

conducting derivation on the detection data subsets to form corresponding derivative data subsets;

identifying minimum data from the subset of derivative data;

Identifying two zero crossing data in the derivative data subset adjacent to the minimum data;

And determining a first CRT duration corresponding to a single CRT measurement period based on the acquisition time corresponding to the two zero crossing data.

In one embodiment, the identifying two zero crossing data adjacent to the minimum data in the derivative data subset includes:

Identifying first derivative data corresponding to detection data with the largest numerical value in the detection data subset in the derivative data subset, and taking the first derivative data as one zero crossing point data;

identifying a first maximum data of the derivative data subset that is located after the minimum data and has a value greater than 0;

And taking the zero crossing data in the minimum value data and the first maximum value data as another zero crossing data adjacent to the minimum value data.

In one embodiment, the identifying minimum data from the subset of derivative data includes:

calculating a second difference between the minimum data and the neighboring data in the derivative data subset;

When the second difference exceeds a second difference threshold, the minimum value data is used as the minimum value data;

And when the second difference value does not exceed the second difference value threshold value, correcting the minimum value data, and re-identifying minimum value data from the corrected derivative data subset.

In one embodiment, the modifying the minimum data includes: and removing the minimum value data.

In one embodiment, the modifying the minimum data includes: and correcting the amplitude of the minimum value data based on the adjacent data of the minimum value data.

In one embodiment, the acquiring the subset of test data acquired by the laser during a single capillary refill time CRT measurement period includes: acquiring a detection data set of the detected body obtained by laser acquisition in a measurement time length; the subset of detection data is extracted from the set of detection data.

In one embodiment, the extracting the subset of detection data from the set of detection data includes: identifying maximum data from the set of detection data; and determining the starting time and the stopping time corresponding to the single CRT measurement period based on the maximum value data, and taking the data acquired during the starting time and the stopping time in the detection data set as the detection data subset.

In one embodiment, the extracting the subset of detection data from the set of detection data includes: identifying maximum data from the set of detection data; and determining starting detection data and cut-off detection data corresponding to the starting single CRT measurement period based on the maximum value data, and taking data between the starting detection data and the cut-off detection data in the detection data set as the detection data subset.

In one embodiment, the method further comprises: and generating a graph according to the acquisition time of the data by the detection data set and displaying the graph.

In one embodiment, the detection data set includes a plurality of detection data subsets, and the method further includes: and determining a second CRT duration of the tested object according to the plurality of first CRT durations.

In one embodiment, the subset of detection data is data acquired by green photoplethysmography, PPG.

In one embodiment, the method further comprises: acquiring a third CRT duration of the object analyzed by photographed image recognition during CRT measurement; and determining a fourth CRT duration of the tested object based on the first CRT duration and the third CRT duration.

In a second aspect of the present application, there is provided a capillary refill time measurement device, the device comprising:

The measuring data acquisition module is used for acquiring a detecting data subset acquired by laser in a CRT measuring period of the refilling time of a single capillary vessel;

The derivative data acquisition module is used for deriving the detection data subset to form a corresponding derivative data subset;

A reference data identification module for identifying minimum data from the subset of derivative data; identifying two zero crossing data in the derivative data subset adjacent to the minimum data;

and the CRT duration determining module is used for determining a first CRT duration corresponding to a single CRT measurement period based on the acquisition time corresponding to the two zero crossing data.

In a third aspect, the present application provides a computer readable storage medium having stored thereon executable instructions which, when executed by a processor, cause the processor to perform a method according to any of the embodiments of the present application.

In a fourth aspect of the present application, there is provided an electronic apparatus comprising: one or more processors; a memory for storing one or more programs that, when executed by the one or more processors, cause the one or more processors to perform the method of any of the embodiments of the application.

According to the capillary refill time measuring method, device, medium and equipment, the detection data of the user is collected by utilizing the laser, the derivative data subset is obtained by deriving the detection data, the minimum value data in the derivative data subset is identified, the CRT time of the user is determined based on the collection time corresponding to the two zero crossing point data adjacent to the minimum value data, and the CRT time of the user can be quickly and accurately obtained under the condition of not consuming computing resources.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope of the present application.

FIG. 1 is a flow chart of a method of measuring capillary refill time in one embodiment;

FIG. 2 is a flow diagram of identifying minimum data from the subset of derivative data in one embodiment;

FIG. 3 is a graph formed from sensed data in one embodiment;

FIG. 4 is a graph formed from detection data according to another embodiment;

FIG. 5 is a graph formed from sensed data in yet another embodiment;

FIG. 6 is a graph formed from sensed data in yet another embodiment;

FIG. 7 is a graph formed from derivative data in one embodiment;

FIG. 8 is a graph formed from derivative data in another embodiment;

FIG. 9 is a graph formed from derivative data in yet another embodiment;

FIG. 10 is a flowchart showing a process of calculating a third CRT period of the object by using the image in one embodiment;

FIG. 11 is a block diagram of a capillary refill time measurement device in one embodiment;

FIG. 12 is a block diagram of a capillary refill time measurement device in another embodiment;

FIG. 13 is a block diagram of an image recognition module in one embodiment;

fig. 14 is a block diagram of an electronic device in one embodiment.

Detailed Description

The present application will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present application more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the application.

All terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art unless otherwise defined. It should be noted that the terms used herein should be construed to have meanings consistent with the context of the present specification and should not be construed in an idealized or overly formal manner.

The terms "first," "second," and the like, as used herein, may be used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another element.

Also as used herein, the terms "comprises," "comprising," and/or the like, specify the presence of stated features, steps, operations, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, or components.

In one embodiment, as shown in fig. 1, a method for measuring capillary refill time is provided, the method comprising:

Step 102, acquiring a detection data subset acquired by laser in a single capillary refill time CRT measurement period of the detected body.

In this embodiment, the subject may be a finger, toe or any other suitable location for CRT detection of the user. The single capillary refill time CRT measurement cycle includes various phases of CRT such as compression, compression release of the subject to capillary refill, etc. The single CRT measurement cycle represents the period of time during which the subject takes one CRT measurement, and corresponds to the period from compression release to capillary refill in a single compression. The duration of a single CRT measurement cycle is greater than the maximum duration of a typical user's CRT, typically comprising only 5 seconds, 8 seconds, 10 seconds, 20 seconds, etc.

During the measurement period, the electronic equipment continuously scans the tested object according to the preset scanning frequency by calling the laser module to form a large amount of detection data. The scanning frequency may be any suitable number of times per second, 5 times, 10 times, 20 times, 50 times, 100 times, 200 times, etc. The duration of the continuous scan is typically greater than the maximum duration of the CRT for the average user and may include one or more CRT measurement cycles. Such as for example, half a minute, 1 minute, 10 minutes, 15 minutes, 20 minutes, 30 minutes, etc.

Wherein, before the tested body is pressed, the capillary vessel of the tested body is in a fully filled state; in compression, the capillary vessel of the subject is in a compression state; after the compression is released, the capillary vessel of the subject is in a state of transition from the state of filling recovery to a state of full recovery. In addition to performing CRT measurements during the measurement, the electronic device may perform other measurements on the user, such as pulse measurements on the user, which may be performed simultaneously with or alternatively, so that the measured set of test data may include both a subset of test data corresponding to a single CRT measurement period and other sets of test data within a non-CRT measurement period, such as the other sets of test data including pulse test data of the subject. At the same time, the device can also detect the human tissue temperature of the CRT detection section in real time during the measurement, so that the medical staff can record the patient's body temperature, while the measured temperature data set can be stored or used for calibration of the CRT value. The other measurement may be performed by laser light, or by other means such as image.

For example, pulse measurement may be performed simultaneously in one or more stages of pre-compression, during compression, or during compression release, and the time of each stage of CRT measurement may be corrected based on the pulse measurement, thereby improving the accuracy of CRT measurement. The measurement period may comprise a number of measurements of the object, for example 30 minutes, within which 30 minutes 5 CRT measurements are performed on the object at a frequency of once every 5 minutes, i.e. 5 CRT measurement cycles are included in the test data set, which has 5 subsets of test data. All data in the detection data set and the detection data subset are sequentially ordered according to the sequence of the acquisition time, and the acquisition time of the data ordered before is also the front.

In one embodiment, the electronic device also forms a graphic for the acquired subset of detection data or set of detection data and presents the corresponding graphic. Specifically, the formed detection data subsets or detection data sets (subjected to corresponding preprocessing) are time ordered according to the acquisition time of the data, time is taken as an abscissa, and the amplitude of the detection data (or the preprocessed detection data) is taken as an ordinate, so that a corresponding graph is formed and displayed. Based on the waveform diagram, the scanning amplitude of the measured object at each moment can be intuitively reflected. The waveform diagram corresponding to the CRT measuring period is the first waveform diagram of the CRT.

In one embodiment, the laser module may be a module for emitting green photoplethysmography PPG, and the detection data set or the detection data subset is data acquired by green PPG. The data acquisition is carried out through the green light PPG, so that the acquired data can more accurately show the CRT characteristic information of the user.

In one embodiment, step 102 further comprises: acquiring a detection data set of the detected body obtained by laser acquisition in a measurement time length; the subset of detection data is extracted from the set of detection data.

In this embodiment, the measurement duration may be the duration of the continuous scan described above, which may include one or more CRT measurement periods. The electronic device may extract from the set of detection data a subset of detection data corresponding to a single CRT measurement cycle. The CRT first waveform map is formed directly based on the subset of detected data. Optionally, the detection data set includes a plurality of detection data subsets. The electronics can identify a plurality of CRT measurement cycles from the measurement duration, with the data collected for each measurement cycle being a corresponding subset of the sensed data. Or the electronic device can select from the detection data set to perform analysis by optimizing the detection data in the respective CRT measurement period, so that the calculated CRT time length is the most accurate. Wherein the performance optimization may include identifying that no jitter or detected data anomalies are present within the corresponding CRT measurement period and/or that CRT features are most apparent in the corresponding detected data subset.

Optionally, the electronic device may further generate a graph from the detection data set according to the data acquisition time, and correspondingly extract a graph corresponding to a single CRT measurement period from the graph, where the extracted graph is the first waveform chart of the CRT. Further, the graph and/or the CRT first waveform diagram may be displayed so that the user may intuitively see the corresponding CRT characteristics. As shown in fig. 5 and 6, which are graphs displayed based on (part of the data in) the detection data set. The graph in fig. 3 is a graph displayed by (part of) the subset of the detected data, specifically, a graph displayed by the data collected during the time T ₃~T₄, and T ₀、T₁、T₂ is a time during the time T ₃~T₄. In fig. 3 to 9, the abscissa represents time, and the ordinate represents the magnitude (amplitude) of the corresponding detection data. When the graph in fig. 3 is a graph corresponding to a complete CRT detection cycle, the time T ₃ is the start time of the cycle, and the time T ₄ is the stop time of the cycle. Here, the unit of time in fig. 4, 6, 8, and 9 is 10ms.

Since the graph corresponding to the detection data set includes multiple CRT detections, and/or graphs presented for other measurements (such as pulse measurements) performed by the user. The electronic device may separate the CRT first waveform map corresponding to one or more CRT measurement cycles from the initial waveform map for processing.

Wherein the CRT measurement cycle may be determined from characteristics of the data in the sensed data set and/or may be determined based on the time of start or end of a user's press as sensed by the associated sensor. The sensor may be a pressure sensor or an image sensor or the like.

Specifically, the subject may be placed on a pressing portion of an electronic apparatus for CRT detection, which may be provided with a corresponding pressure sensor, and after detecting that the subject starts pressing and ends pressing, a corresponding timing is recorded. Based on the recorded time of starting pressing and time of ending pressing, a corresponding single CRT measurement period is determined, and a waveform chart formed by a detection data subset corresponding to the single CRT measurement period is further acquired as the CRT first waveform chart.

For example, the electronic device may set a first time period threshold T _A and a second time period threshold T _B, and when the time T ₁₀ at which the subject starts pressing and the time T ₂₀ at which the pressing ends are detected, the first time period threshold T _A may be preceded from the time T ₁₀ as the start time of the single CRT measurement period to be analyzed; from this time T ₂₀, a second time period threshold T _B is set downstream as the cut-off time of the individual CRT measurement cycles to be analyzed. The data measured in the starting time and the stopping time are the detection data subsets, and the formed graph is the CRT first waveform graph.

Wherein, T _A and T _B can be preset values with any suitable duration, and the sizes of the two values can be the same or different. For example, the T _A may be any suitable duration greater than the duration of a conventional CRT, such as 0.1 seconds, 1 second, 2 seconds, 5 seconds, 8 seconds, 10 seconds, 30 seconds, etc.; t _B may be any suitable duration greater than the duration of a conventional CRT, 8 seconds, 10 seconds, 20 seconds, etc.

Similarly, the electronic device may preset a first number threshold N _A and a second data amount threshold N _B, and when detecting the first reference detection data Y ₁ corresponding to the time T ₁₀ when the subject starts to press and the second reference detection data Y ₂ corresponding to the time T ₂₀ when the subject ends to press, may use, from the detection data set, detection data corresponding to a position of the first number threshold N _A before the first reference detection data Y ₁ as the start detection data Y _A; the detection data corresponding to the position of the second number threshold N _B preceding the second reference detection data Y ₂ is taken as cut-off detection data Y _B. All data between data Y _A and data Y _B are the subset of detected data, and the formed graph is the first waveform of the CRT.

The first number threshold N _A and the second data amount threshold N _B may be preset values of any suitable size. Similar to T _A and T _B, N _A and N _B are sized such that the extracted subset of detection data contains all detection data for a complete CRT detection cycle and does not introduce data for other CRT detection cycles. Such as the N _A and N _B, may be determined with reference to T _A and T _B and the scanning frequency of the laser module. For example, with the scanning frequency of the laser module being 100 times per second, the N _A may be set to 200, the N _B may be set to 1000, and the electronic device may select 200 data before the detection data Y ₁, the data during the detection data Y ₁ to the detection data Y ₂, and 1000 data after the detection data Y ₂ to form the detection data subset.

In one embodiment, the electronic device may further determine a portion of the graph where the first waveform of the CRT is located according to a predetermined reference waveform of the CRT. The CRT reference waveform can be a reference graph reflected by data presented in a single CRT measurement in the process of user history measurement. By comparing the CRT reference waveform with the initial waveform, a portion of the waveform having a similarity with the CRT reference waveform exceeding a corresponding similarity threshold is identified from the CRT waveform, and the portion of the waveform exceeding the similarity threshold is extracted as the CRT first waveform.

In one embodiment, the electronic device may also identify relatively large magnitude data from the set of detection data, and determine a corresponding subset of detection data based on the large magnitude data.

Wherein the larger data is the larger data in the corresponding data in a part of continuous time period or all time periods in the detection data set. The larger data may be, for example, data exceeding a preset amplitude threshold, or maximum data within the time period. The larger data or maximum data is usually the data detected when the user is performing CRT measurement, for example, the time corresponding to the maximum data is usually the user pressing time or the pressing release time, or the time near the pressing release or the pressing start. And carrying out forward expansion and backward expansion based on the larger data, determining the starting time and the stopping time under the corresponding CRT measurement period, and/or selecting a part of data from the starting detection data and the stopping detection data in the forward direction and the backward direction respectively to form a detection data subset, thereby forming a CRT first waveform diagram.

The forward and backward selected data amounts may be data amounts of a predetermined length or data amounts adaptively determined according to the acquisition frequency. Such as the number determined from the first time period threshold T _A and the second time period threshold T _B described above, or directly N _A and N _B described above.

For example, as shown in fig. 6, the preset amplitude threshold may be 15000, and for a continuous data set with an amplitude exceeding 15000 in fig. 6, the data with the largest amplitude is selected, and the data with the largest amplitude is selected forward and backward to form a corresponding detection data subset, for example, the data corresponding to the purple interval is the detection data subset.

In one embodiment, a user selection operation for a CRT measurement cycle may also be received, and a corresponding CRT measurement cycle determined based on the operation. For example, as shown in fig. 6, the data set represented by the purple interval is a CRT measurement cycle accordingly. The electronic device may receive a user selection of a start time and an end time of a CRT measurement cycle in the presented graph, and take a time period between the selected start time and end time as one CRT measurement cycle. Alternatively, the user may select other suitable interval data from the graph as a CRT measurement cycle. By selecting an appropriate CRT measurement cycle by the user, the flexibility of CRT measurement cycle selection can be improved.

And 104, deriving the detection data subset to form a corresponding derivative data subset.

In this embodiment, the derivative mode may be to perform a difference processing on the amplitude of a certain data in the corresponding data set (for example, the detected data set or the detected data subset) and the amplitude of the adjacent data, so as to implement derivative. For example, the amplitude of the current data is subjected to difference processing with the amplitude of the previous data or with the amplitude of the next data, and the obtained difference value is used as the amplitude of the derivative data corresponding to the current data. The derived data corresponding to the detection data Y _i may be data Z _i, and the collection time corresponding to the data Z _i is the collection time corresponding to the detection data Y _i.

Alternatively, the CRT second waveform diagram may be formed and displayed for the derivative data subset formed after the derivative. The electronic equipment can conduct derivation on all data in the detection data set to form a corresponding derivative data set, and the corresponding graphs are generated and displayed according to the collection time of the detection data before derivation. The derivative data set includes the subset of derivative data. As shown in fig. 9, the second waveform diagram of the CRT is formed by taking the derivative data subset (or part of the derivative data subset) and taking the derived value (amplitude) as the ordinate according to the acquisition time of the corresponding detection data as the abscissa.

And 106, identifying minimum value data from the derivative data subsets.

The electronic device may identify data corresponding to minima within each segment of continuous data or curve in the second waveform diagram or derivative data subset of the CRT. And selecting the smallest data from all the minimum data as the minimum data. Or directly finding out the minimum amplitude data from the derivative data subset or the CRT second waveform diagram, and taking the minimum amplitude data as minimum value data. The minimum data can be used to measure the compression release time and the filling recovery time of the tested body in the CRT measurement period, so that the CRT time of the user can be determined.

Step 108, identifying two zero crossing data adjacent to the minimum data in the derivative data subset.

For the determined minimum value data, the electronic device can identify the point with zero or near zero value after derivation from the corresponding derivative data subset or the CRT second waveform diagram, and the data corresponding to the point is zero crossing data. Adjacent zero-crossing data refers to zero-crossing data that first appears before or after the collection time of the minimum value data. One of the two zero crossing point data is positioned in front of the minimum value data, namely, the acquisition time is positioned before the acquisition time of the minimum value, and the acquisition time corresponds to the compression release time of the tested body; the other is located at the back of the minimum value data, that is, the collection time is located after the collection time of the minimum value, and the collection time corresponds to the filling recovery time of the tested body.

For data near zero, when the derivative data subset or the CRT second waveform diagram has two continuous data magnitudes, one of which is positive and the other of which is negative, one of the continuous data may be selected as zero-crossing data. For example, the zero-crossing point data may be selected from the two derivative data having smaller absolute values.

Step 110, determining a first CRT duration corresponding to a single CRT measurement period based on the acquisition time corresponding to the two zero crossing data.

In this embodiment, the electronic device may directly use the collection time corresponding to the previous zero-crossing data as the compression release time, use the collection time corresponding to the subsequent zero-crossing data as the filling recovery time, and use the filling recovery time-compression release time as the CRT duration of the user detected in the measurement period, that is, the first CRT duration.

As shown in fig. 7, the derivative data corresponding to the time T ₀ in the graph is the minimum value data, and the derivative data corresponding to the time T ₁ and the time T ₂ are two adjacent zero-crossing point data in the minimum value data. The duration formed by the time T ₁ and the time T ₂ is the first CRT duration. As shown in fig. 9, derivative data corresponding to a green origin is first zero-crossing data, and a corresponding time is 230ms; the derivative data corresponding to the blue origin is the second zero crossing data, the corresponding time is 1630ms, and the first CRT time calculated based on the two zero crossing data is 1.4s.

According to the capillary refill time measuring method, the detection data of the user is collected by utilizing the laser, the derivative data subset is obtained by deriving the detection data, the minimum value data in the derivative data subset is identified, the CRT time of the user is determined based on the collection time corresponding to the two zero crossing point data adjacent to the minimum value data, and the CRT time of the user can be quickly and accurately obtained under the condition that the calculation resource is not consumed too much.

In one embodiment, as shown in FIG. 2, step 106 includes:

step 202, calculating a second difference between the minimum data and the neighboring data in the derivative data subset.

In this embodiment, since the measured object may have jitter or other interference conditions during the CRT measurement, the measured data may not be accurate when the interference conditions exist. Particularly, when the wrong minimum value is determined due to jitter, a large error occurs in the CRT time measured by the subject. It is necessary to verify the minimum value identified.

Specifically, the minimum derivative data may be identified from the subset of derivative data or the CRT second waveform map, and the difference between the magnitude thereof and the magnitude of the neighboring data (i.e., the second difference) may be calculated. The proximity data may be one or more of the data spaced apart from the third number threshold N _C adjacent to the minimum. For example, N _C may be any suitable number, such as 1, 2, 3, 4, 5, 8, 10, etc. Taking N _C =3 as an example, a difference (i.e., a second difference) between the minimum value data and one or more data among three data adjacent thereto may be calculated. Wherein the data adjacent thereto includes data preceding it and data following it. For example, in the derivative data subset or CRT second waveform, there is sequential data Z _i-3、Z_i-2、Z_i-1、Z_i、Z_i+1、Z_i+2、Z_i+3 in sequence. The minimum data identified is the derivative data Z _i, then the electronics can calculate the difference (i.e., the second difference) between the magnitude of data Z _i and the magnitude of one or more of data Z _i-3、Z_i-2、Z_i-1、Z_i+1、Z_i+2、Z_i+3. The second difference may be an absolute value of a difference between the minimum data and the neighboring data.

And 204, when the second difference exceeds a second difference threshold, taking the minimum value data as the minimum value data.

The second difference threshold is a preset critical value for measuring whether the calculated minimum value data is accurate or not. When the second difference exceeds the second difference threshold, it indicates that jitter does not exist at the acquisition time corresponding to the minimum value data, and the minimum value data may be used as the minimum value data.

When the second differences calculated in step 202 include a plurality of second differences, it is compared whether each of the second differences exceeds the second difference threshold, and if yes, the minimum value data is determined to be the minimum value data. If any of the second differences does not exceed the second difference threshold, step 206 is entered.

And step 206, when the second difference value does not exceed the second difference value threshold value, correcting the minimum value data, and re-identifying minimum value data from the corrected derivative data subset.

In this embodiment, when one or more second differences do not exceed the second difference threshold, it is considered that jitter may occur at the acquisition time corresponding to the minimum data, and the minimum data may be found again from the second waveform diagram or the CRT.

Specifically, the minimum value data may be corrected by removing the minimum value data, or removing both the minimum value data and its neighboring data. And re-searching the corresponding minimum value data from the derivative data subset after the corresponding data is removed in the manner of the step 202, and detecting whether the re-searched minimum value data can be used as the minimum value data.

Or the amplitude of the minimum data may also be modified in combination with the neighborhood data of the minimum data. Such as by correcting the magnitude of the minimum data to the average of the magnitudes of its immediate neighbors. For the modified derivative data subset, the minimum data may be re-found from all of its data, or from data other than the minimum data and its neighbors. And detecting whether the newly found minimum value data can be used as the minimum value data.

According to the capillary refill time measuring method, the second difference value between the found minimum value data and the adjacent data is calculated, whether the minimum value data can be used as reference point data (namely, minimum value data) for measuring the CRT duration or not is judged according to the size between the second difference value and the preset second difference value threshold, and the problem that the whole CRT duration calculation is wrong due to the fact that the reference point data is wrong in recognition caused by jitter can be avoided.

In one embodiment, extracting the subset of detection data from the set of detection data comprises: identifying maximum data from the set of detection data; and determining the starting time and the stopping time corresponding to the single CRT measurement period based on the maximum value data, and taking the data acquired during the starting time and the stopping time in the detection data set as the detection data subset.

In one embodiment, extracting the subset of detection data from the set of detection data comprises: and identifying maximum value data from the detection data set, determining initial detection data and cut-off detection data corresponding to the initial single CRT measurement period based on the maximum value data, and taking data between the initial detection data and the cut-off detection data in the detection data set as the detection data subset.

The maximum value data may be the data with the largest value in the whole detection data set, or may be the data with the largest value in the detection data set and in the data set within a certain acquisition time period. The acquisition period may be a partially continuous period as described above. The partial continuous time period may be the time period determined by the duration thresholds T _A and T _B, or may be a time period corresponding to a data set corresponding to the amplitude threshold exceeding the preset value.

Alternatively, the above-mentioned acquisition time periods may include one or more, each corresponding to a different number of CRT detection cycles.

After maximum value data is determined, first detection data of a first data interval before the maximum value data and second detection data of a second data interval after the maximum value data are acquired, and data in the first detection data and the second detection data interval are taken as the detection data subset. The first data interval may be of a size of the first number threshold N _A and the second data interval may be of a size of the second number threshold N _B. For example, after the maximum value data is identified, the maximum value data, the first N _A pieces of data in the maximum value data and the last N _B pieces of maximum value data are taken to form the detection data subset.

Or after the maximum value data is determined, determining the reference acquisition time corresponding to the maximum value data; identifying third detection data corresponding to the starting moment before the reference acquisition moment and fourth detection data corresponding to the cut-off moment after the reference acquisition moment; and taking the data in the third detection data and the fourth detection data interval in the detection data set as the detection data subset. Optionally, taking the acquisition time corresponding to the maximum value data as a reference acquisition time, subtracting a third time threshold from the reference acquisition time to obtain a starting time, and adding a fourth time threshold to the reference acquisition time to obtain a cut-off time. The third and fourth time thresholds may be similar to the first and second time thresholds T _A and T _B, and are not described in detail herein.

In one embodiment, step 108 includes: identifying first derivative data corresponding to detection data with the largest numerical value in the detection data subset in the derivative data subset, and taking the first derivative data as one zero crossing point data; identifying a first maximum data of the derivative data subset that is located after the minimum data and has a value greater than 0; and taking the zero crossing data in the minimum value data and the first maximum value data as another zero crossing data adjacent to the minimum value data.

The derivative data subset is data formed by deriving the detection data subset, so that the value of the derivative data (namely, first derivative data) corresponding to the detection data with the largest value in the detection data subset is 0 or close to zero, and the first derivative data is one zero crossing data of two adjacent zero crossing data. The zero crossing data is located before the minimum data, for example, the data corresponding to the time T ₁ in fig. 3 is the detection data with the largest value in the detection data subset, and the first derivative data corresponding to the data in the derivative data subset is the data which is also located at the time T ₁ in fig. 7. The graph in fig. 4 is an enlarged view of the graph in the purple box in fig. 6, with the moments in fig. 4 reordered. The data at time 160 in fig. 4 has the largest value, 17665. FIG. 8 is a graph of derivative data formed from partial detection data, with time instances reordered, in one embodiment.

For another zero-crossing data, the electronic device may first identify maximum data in the derivative data subset, where the maximum data may include a plurality of maximum data, and one or more of the maximum data may be greater than 0, or may be less than or equal to 0, and its corresponding acquisition time may be before or after the acquisition time of the minimum data. For the identified plurality of maximum data, the data (i.e., the first maximum data) having a value greater than 0 after the minimum data at the acquisition time can be further identified, and for the zero crossing data before the first maximum data and the minimum data, the data is another zero crossing data adjacent to the minimum data. For example, in fig. 7, the first maximum value data after the acquisition time T ₂ is the maximum value data with the value greater than 0, and the derivative data corresponding to the acquisition time T ₂ is the second zero crossing data. Wherein the first maximum value data is also derivative data closest to the minimum value and having a value greater than 0 in the detection data subset. In fig. 9, the data corresponding to the green origin is the derivative data corresponding to the first zero crossing data, and the data corresponding to the blue origin is the derivative data corresponding to the second zero crossing data. As shown in fig. 4, the data corresponding to the green line represents the detection data corresponding to the first zero-crossing data (the time is 1600ms, the value is 17665), the data corresponding to the red line represents the detection data corresponding to the second zero-crossing data (the time is 2020ms, the value is 10634), and the duration of the first CRT obtained based on the two detection data is 0.4s.

By this method, two zero-crossing data can be identified quickly and accurately as well.

In one embodiment, for the displayed first waveform diagram and second waveform diagram of the CRT, the first zero-crossing data and the second zero-crossing data may be marked thereon, and the time and amplitude corresponding to the two zero-crossing data and the corresponding first CRT duration are displayed, so that the relevant user may intuitively learn the detection result.

And further, an adjustment instruction of a user for the first zero crossing data and the second zero crossing data can be received, the first zero crossing data and the second zero crossing data are adjusted based on the adjustment instruction, and the first CRT duration is recalculated based on the time corresponding to the two adjusted zero crossing data.

The relevant user may consider that the calculated time corresponding to the two zero crossing data is inaccurate, that is, the time of releasing compression and/or the time of starting compression in the CRT measurement process are not accurate enough, at this time, an adjustment operation for the first zero crossing data and/or the second zero crossing data may be received, for example, the lines in fig. 4 and 9 may be adjusted, two zero crossing data are redetermined based on the data indicated by the adjusted lines, and the first CRT duration is determined based on the redetermined zero crossing data, so that the accuracy of calculating the first CRT duration is improved.

In one embodiment, the detection data set includes a plurality of detection data subsets from which a plurality of first CRT durations may be measured. The capillary refill time measuring method further comprises the following steps: and determining a second CRT duration of the tested object according to the plurality of first CRT durations.

The final CRT duration of the user may be determined from the plurality of first CRT durations after calculating the corresponding first CRT duration for each measurement period. The second CRT duration is expressed as a final CRT duration of the user calculated from the plurality of first CRT durations. The second CRT duration may be a duration obtained by performing weighted summation on the plurality of first CRT durations, or directly be an average value of the plurality of first CRT durations, or a value obtained after weighted summation, or may be set according to a selection of a relevant user, directly use one of the first CRT durations as the second CRT duration.

In one embodiment, the first CRT duration is not referenced for the second CRT duration calculation when a second difference between the minimum data and the adjacent data in the corresponding derivative data subset does not exceed the second difference threshold during the first CRT duration calculation. In the process of calculating the second CRT duration, the first CRT duration calculated by the subset data suspected to have interference is removed, so that the accuracy of calculating the second CRT duration is further improved.

In the application, besides the CRT duration detection by using laser, the CRT duration detection can be performed by combining the shot images, and the CRT duration (namely, the first CRT duration and the third CRT duration) of the tested body can be finally determined by combining the CRT durations (namely, the fourth CRT duration) measured by the two detection means. The photographed image may specifically be an RGB image or an HSV image.

The number of third CRT durations may also include one or more similar to the first CRT duration, wherein each CRT measurement period may correspond to a third CRT duration. The electronic device may select one or more first CRT durations and one or more third CRT durations to determine a fourth CRT duration.

Similar to the calculation of the second CRT duration, for example, the average of one or more first CRT durations and one or more third CRT durations may be used as the fourth CRT duration, or the value obtained after the weighted summation may be used as the fourth CRT duration. The first CRT duration or the third CRT duration measured under the condition that jitter or other interference is suspected to exist can be removed according to the selection of the plurality of first CRT durations and the plurality of third CRT durations, and the fourth CRT duration is calculated by only reserving the first CRT duration and the third CRT duration measured without interference. To improve accuracy of CRT duration calculations.

Specifically, before acquiring the third CRT duration of the subject analyzed by captured image recognition during CRT measurement, the method further includes: and calculating a third CRT time length of the object by the image. Taking the photographed image as an RGB image as an example, as shown in fig. 10, the process includes:

Step 602, a first image sequence of a measured object taken during a measurement is acquired.

The measurement period may be a period corresponding to the measurement period described above, or a period corresponding to a single CRT measurement period. When the period corresponding to the measurement duration is a period corresponding to the measurement duration, a plurality of CRT measurement periods may be included, and a corresponding third CRT duration may be a plurality of CRTs. And in the measurement period, continuously shooting the tested object according to a preset shooting frequency by calling the shooting module to form a first image sequence. The shooting time of the first image and the acquisition time of the measurement data have a corresponding relation.

Step 604, decomposing the G channel image sequence from the first image sequence, and taking the G channel image sequence as a second image sequence.

Step 606, a channel mean value of the detection area of each frame of the second image in the second image sequence is calculated.

The detection region represents a reference region for CRT detection, which represents a blood color change of the subject. The gray average value may be an average value of gray values of respective pixel points within the detection region. The electronic device may sum the gray values of all the pixels in the detection area and remove the number of pixels in the detection area, so as to use the obtained value as a gray average value.

Step 608 compares whether the rate of change of the channel mean of the adjacent multiframe second image exceeds the first speed threshold.

In this embodiment, after the electronic device calculates the channel mean value of the second image, the channel mean values corresponding to the adjacent multi-frame images may be subtracted, and the value obtained by the subtraction may represent the rate of change of the channel mean value. The adjacent multi-frame images may be two or more adjacent frames. Specifically, the number of adjacent frames may be an integer multiple of 2, such as 2 frames, 4 frames, 6 frames, 8 frames, 10 frames, or any other suitable number of frames. In the adjacent multi-frame images, channel mean values of the images in the first half can be added according to the shooting time sequence to obtain a channel mean value y ₁, channel mean values of the images in the second half are added to obtain a channel mean value P ₂, and then |y ₂-y₁ | is used as a change rate. The change rate may be a change rate dy of the channel mean value at a time at which the adjacent multi-frame images are captured.

The first speed threshold is a critical threshold for measuring the stage of compression release or compression start of CRT.

By comparing the change rate at each time with the first speed threshold value, whether the change rate at each time exceeds the first speed threshold value is obtained, and based on the comparison result, it can be determined at which time the tested body is just at the start of compression or at which time the compression is released, so that CRT timing can be started accurately.

Step 610, determining a compression release time corresponding to the capillary refill time in the second image sequence according to the comparison result.

In this embodiment, when the absolute value of the rate of change at a certain time reaches or exceeds the first speed threshold, this indicates that the time may be at the time when compression of the subject starts or is released. The electronic device obtains a time set corresponding to each time when the change rate reaches or exceeds the first speed threshold, and analyzes the change condition of the change rate or the channel mean value at each time, or combines the detection results of the related sensors, so that a specific time which is the compression release time T ₅ is determined in the time set.

Step 612, determining that the channel mean value after the compression release time is at the filling recovery time corresponding to the second image under the second mean value threshold.

The second average threshold of the measured object may be a preset appropriate threshold, or may be a value adaptively calculated according to the channel average value measured by the measured object before being pressed in the current CRT measurement period. When it is detected that the channel mean value of the second image is at the time corresponding to the second mean value threshold value for the first time after the compression release time, the time is taken as the filling recovery time T ₆. For example, the second average threshold may be set to 0, or a redundant value near 0, for example, the second average threshold may be a related value of 1, 2, etc.

Step 614, a third CRT duration is determined based on the compression release time and the filling restoration time.

When the compression release time T ₅ and the filling recovery time T ₆ are calculated, the filling recovery time T ₆ in the same detection cycle may be subtracted from the compression release time T ₅, and the obtained difference is the capillary refill time CRT.

In one embodiment, after the measured compression release time T ₅ and filling restoration time T ₆, the difference between time T ₅ and time T ₁ may be compared, And a difference between time T ₆ and time T ₂, when the difference is less than a corresponding first difference threshold, indicating that the CRT time measured by the laser and the CRT time measured by the image are substantially identical, if the difference exceeds the corresponding first difference threshold, determining that one or both of the two have larger errors, correcting the measurement result of one or both of the two, Or a CRT duration (such as a first CRT duration and/or a third CRT duration) obtained from other CRT measurement periods as the second CRT duration or the fourth CRT duration of the user. The difference between the corresponding time T ₁ and time T ₅, and the difference between time T ₂ and time T ₆ are all within the corresponding first difference threshold range for this other CRT measurement cycle. The accuracy of CRT duration measurement can be further improved by comparing the time obtained by the two measurement modes. Wherein the first difference threshold corresponding to the difference between time T ₁ and time T ₅ may be the same as the first difference threshold corresponding to the difference between time T ₂ and time T ₆, or may be different.

In one embodiment, as shown in fig. 11, there is provided a capillary refill time measuring device comprising:

a measurement data acquisition module 702, configured to acquire a subset of detection data acquired by the laser during a single capillary refill time CRT measurement period of the subject.

And the derivative data acquisition module 704 is configured to derive the detection data subset to form a corresponding derivative data subset.

A reference data identification module 706 for identifying minimum minima data from the subset of derivative data; two zero crossing data adjacent to the minimum data in the derivative data subset are identified.

A CRT duration determining module 708, configured to determine a first CRT duration corresponding to a single CRT measurement cycle based on the acquisition moments corresponding to the two zero crossing data.

In one embodiment, the reference data identifying module 706 is further configured to identify, from the subset of derivative data, first derivative data corresponding to the detection data having the largest value in the subset of detection data, and use the first derivative data as one of zero-crossing data; identifying a first maximum data of the derivative data subset that is located after the minimum data and has a value greater than 0; and taking the zero crossing data in the minimum value data and the first maximum value data as another zero crossing data adjacent to the minimum value data.

In one embodiment, the baseline data identification module 706 is further configured to calculate a second difference between the minimum data and the neighboring data in the subset of derivative data; when the second difference exceeds a second difference threshold, the minimum value data is used as the minimum value data; and when the second difference value does not exceed the second difference value threshold value, correcting the minimum value data, and re-identifying minimum value data from the corrected derivative data subset.

In one embodiment, the reference data identification module 706 is further configured to remove the minimum data.

In one embodiment, the reference data identification module 706 is further configured to modify the magnitude of the minimum data based on the vicinity data of the minimum data.

In one embodiment, the measurement data acquisition module 702 is further configured to acquire a detection data set obtained by collecting the measured object through laser in a measurement duration; the subset of detection data is extracted from the set of detection data.

In one embodiment, the measurement data acquisition module 702 is further configured to identify maximum value data from the set of detection data; and determining the starting time and the stopping time corresponding to the single CRT measurement period based on the maximum value data, and taking the data acquired during the starting time and the stopping time in the detection data set as the detection data subset.

In one embodiment, the measurement data acquisition module 702 is further configured to determine, based on the maximum value data, start detection data and stop detection data corresponding to the start single CRT measurement period, and use data, which is located between the start detection data and the stop detection data, in the detection data set as the detection data subset.

In one embodiment, the detection data set includes a plurality of detection data subsets, as shown in fig. 12, the apparatus further includes: and the display module 710 is used for generating and displaying a graph of the detection data set according to the acquisition time of the data.

In one embodiment, the CRT duration determination module 708 is further configured to determine a second CRT duration for the subject based on the plurality of first CRT durations.

In one embodiment, the subset of detection data is data acquired by green photoplethysmography, PPG. The apparatus further comprises:

an image recognition module 712 for acquiring a third CRT time period of the subject analyzed by photographed image recognition during CRT measurement.

The CRT duration determination module 708 is further configured to determine a fourth CRT duration of the subject based on the first CRT duration and the third CRT duration.

In one embodiment, as shown in FIG. 13, the image recognition module 712 includes:

an image capturing unit 902 is configured to acquire a first image sequence captured by the subject during measurement.

An image decomposition unit 904, configured to decompose a G-channel image sequence from the first image sequence, and use the G-channel image sequence as the second image sequence.

And a mean value calculating unit 906, configured to calculate a channel mean value of the detection area of each frame of the second image in the second image sequence.

A compression release timing determining unit 908 that compares whether or not the rate of change of the channel mean value of the adjacent multi-frame second image exceeds a first speed threshold; and determining the compression release time corresponding to the capillary refill time in the second image sequence according to the comparison result.

The filling recovery time determining unit 910 determines a filling recovery time corresponding to the second image in which the channel mean value after the compression release time is at the second mean value threshold.

A third CRT duration determination unit 912 that determines the third CRT duration based on the compression release time and the filling restoration time.

In one embodiment, a computer-readable storage medium is provided having stored thereon executable instructions that, when executed by a processor, cause the processor to perform the steps of the method embodiments described above.

In one embodiment, there is also provided an electronic device comprising one or more processors; and a memory, wherein the memory stores one or more programs, and the one or more programs, when executed by the one or more processors, cause the one or more processors to perform the steps in the method embodiments described above.

In one embodiment, an electronic device is provided, which may be specifically a CRT meter as described above. As shown in fig. 14, the electronic apparatus 1000 includes a Central Processing Unit (CPU) 1001 that can perform various appropriate actions and processes according to a program stored in a Read Only Memory (ROM) 1002 or a program loaded from a storage section 1008 into a Random Access Memory (RAM) 1003. In the RAM1003, various programs and data necessary for the operation of the electronic apparatus 1000 are also stored. The CPU1001, ROM1002, and RAM1003 are connected to each other by a bus 1004. An input/output (I/O) interface 1005 is also connected to bus 1004.

The following components are connected to the I/O interface 1005: an input section 1006 including a keyboard, a mouse, and the like; an output portion 1007 including a Cathode Ray Tube (CRT), a Liquid Crystal Display (LCD), etc., and a speaker, etc.; a storage portion 1008 including a hard disk or the like; and a communication section 1009 including a network interface card such as a LAN card, a modem, or the like. The communication section 1009 performs communication processing via a network such as the internet. The drive 1010 is also connected to the I/O interface 1005 as needed. A removable medium 1011, such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, or the like, is installed as needed in the drive 1010, so that a computer program read out therefrom is installed as needed in the storage section 1008.

In particular, according to embodiments of the present application, the processes described above with reference to flowcharts may be implemented as computer software programs. For example, embodiments of the application include a computer program product comprising a computer-readable medium carrying instructions that, in such embodiments, may be downloaded and installed from a network via communication portion 1009 and/or installed from removable medium 1011. When executed by a Central Processing Unit (CPU) 1001, performs the various method steps described in the present application.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present application, and not for limiting the same; although the application has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the application.

Furthermore, those skilled in the art will appreciate that while some embodiments herein include some features but not others included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the application and form different embodiments. For example, in the claims below, any of the claimed embodiments may be used in any combination. The information disclosed in this background section is only for enhancement of understanding of the general background of the application and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

Claims

1.A method of measuring capillary refill time, the method comprising:

identifying minimum data from the subset of derivative data;

2. The method of claim 1, wherein the identifying two zero crossing data in the derivative data subset that are adjacent to the minimum data comprises:

3. The method of claim 1, wherein identifying minimum data from the subset of derivative data comprises:

4. The method of claim 1, wherein the acquiring a subset of test data acquired by the laser during a single capillary refill time CRT measurement period comprises:

Acquiring a detection data set of the detected body obtained by laser acquisition in a measurement time length;

the subset of detection data is extracted from the set of detection data.

5. The method of claim 4, wherein the extracting the subset of detection data from the set of detection data comprises:

identifying maximum data from the set of detection data;

Determining starting time and stopping time corresponding to the single CRT measurement period based on the maximum value data, and taking data acquired during the starting time and the stopping time in the detection data set as the detection data subset; or (b)

And determining starting detection data and cut-off detection data corresponding to the starting single CRT measurement period based on the maximum value data, and taking data between the starting detection data and the cut-off detection data in the detection data set as the detection data subset.

6. The method of claim 5, wherein the set of detection data includes a plurality of subsets of detection data, the method further comprising:

Generating a graph according to the acquisition time of the data from the detection data set and displaying the graph;

and determining a second CRT duration of the tested object according to the plurality of first CRT durations.

7. The method according to any one of claims 1 to 6, wherein the subset of detection data is data acquired by green photoplethysmography, PPG; the method further comprises the steps of:

acquiring a third CRT duration of the object analyzed by photographed image recognition during CRT measurement;

and determining a fourth CRT duration of the tested object based on the first CRT duration and the third CRT duration.

8. A capillary refill time measurement device, the device comprising:

9. A computer readable storage medium having stored thereon executable instructions which when executed by a processor cause the processor to perform the method of any of claims 1 to 7.

10. An electronic device, comprising:

one or more processors;

A memory for storing one or more programs that, when executed by the one or more processors, cause the one or more processors to perform the method of any of claims 1-7.