Method for calibrating vital signs in a continuous vital sign measurement system

Abstract

A method for calibrating a vital sign signal in a continuous vital sign measurement system is provided. [Solution] In one aspect of the present invention, when calculating a calibration factor using a reference biovalue, if the calibration parameters are unstable, instead of using the current calibration factor calculated from the reference biovalue as is, a compensation value calculated from the difference between the current calibration factor and a previous calibration factor is applied to the current calibration factor to correct the current calibration factor, thereby making it possible to accurately calibrate the biosignal and calculate the calibrated biovalue even when the calibration parameters are unstable.In addition, the entire usage period of the sensor is divided into a plurality of calibration intervals, and the calibration factor is corrected taking into account the degree of stabilization of the sensor depending on the calibration interval to which the reference biovalue is input, making it possible to accurately calculate the calibrated biovalue from the biosignal of the sensor.

Description

[Technical field]

[0001] The present invention relates to a method for calibrating a biosignal in a continuous bioinformation measuring system, and more particularly, to a method for accurately calibrating a biosignal and calculating a calibrated biosignal even when a calibration parameter is unstable by applying a compensation value calculated from a difference between a current calibration factor and a previous calibration factor to the current calibration factor without using a current calibration factor calculated from a reference biovalue as it is when a calibration parameter is unstable when a calibration factor is calculated using the reference biovalue, and correcting the current calibration factor, thereby accurately calibrating a biosignal and calculating a calibrated biosignal even when a calibration parameter is unstable. The present invention also relates to a method for accurately calculating a calibrated biosignal from a biosignal of a sensor by dividing an entire usage period of a sensor into a plurality of calibration intervals and correcting the calibration factor in consideration of a degree of stabilization of the sensor according to a calibration interval to which a reference biovalue is input. [Background technology]

[0002] Diabetes is a chronic disease that occurs frequently among modern people, affecting more than 2 million people in Korea, or 5% of the total population.

[0003] Diabetes occurs when there is an absolute or relative deficiency of insulin produced by the pancreas due to various causes such as obesity, stress, poor eating habits, and congenital genetics, which causes the blood to not immediately balance the sugar content, resulting in an absolute excess of sugar in the blood.

[0004] Blood normally contains a certain concentration of glucose, from which tissue cells obtain their energy.

[0005] However, if glucose levels increase more than necessary, it cannot be properly stored in the liver, muscles, or fat cells and instead accumulates in the blood. As a result, diabetics maintain blood sugar levels much higher than normal people, and the excess blood sugar passes directly through the tissues and is excreted in the urine, causing a shortage of sugar, which is absolutely necessary for each tissue of the body, and causing abnormalities in each tissue.

[0006] Diabetes is characterized by the fact that in the early stages there are almost no noticeable symptoms, but as the disease progresses, specific symptoms of diabetes such as excessive drinking, eating, urination, weight loss, general fatigue, skin itching, and persistent wounds on the hands and feet that do not heal appear. As the disease progresses further, advanced complications such as vision problems, high blood pressure, kidney disease, stroke, periodontal disease, muscle spasms, neuralgia, and psoriasis appear.

[0007] In order to diagnose and manage diabetes so that it does not progress to complications, systematic blood glucose monitoring and treatment must be carried out simultaneously.

[0008] Diabetes requires constant monitoring of blood glucose levels to be managed, and the demand for blood glucose monitoring and related devices is constantly increasing. It has been confirmed through various studies that when diabetic patients strictly control their blood glucose levels, the occurrence of diabetic complications is significantly reduced. Therefore, it is very important for diabetic patients to regularly monitor their blood glucose levels to control their blood glucose levels.

[0009] Generally, blood glucose measuring devices using the finger prick method are used to manage blood glucose levels of diabetics. Although this method helps diabetics manage blood glucose levels, it has a problem that it is difficult to accurately grasp blood glucose levels that change frequently because it only shows the results at the time of measurement. In addition, blood glucose measuring devices require blood to be drawn every time to measure blood glucose levels at any time throughout the day, which places a heavy burden on diabetics.

[0010] Diabetic patients generally go through periods of hyperglycemia and hypoglycemia, but emergency situations occur during hypoglycemia. Hypoglycemia occurs when sugar is not sustained for a long period of time, and can result in loss of consciousness or, in the worst case, loss of life. Therefore, it is very important for diabetic patients to detect hypoglycemia immediately. However, blood glucose measuring devices that measure blood glucose intermittently have clear limitations.

[0011] To overcome the limitations of blood sampling type blood glucose measuring devices, a Continuous Glucose Monitoring System (CGMS) was developed that is inserted into the human body to measure blood glucose every few minutes, and can be used to easily manage diabetic patients and respond to emergency situations.

[0012] The continuous blood glucose measurement system comprises a sensor transmitter that is attached to a part of the user's body to measure a biometric value from bodily fluids, and a communication terminal that outputs information on the received biometric value to the user. The sensor transmitter has a continuous blood glucose measurement sensor that is partially inserted into the human body, and the sensor is inserted into the human body for a certain period of use, for example, about 15 days, to continuously measure the biometric value. The sensor transmitter periodically measures the biometric value from the bodily fluids, and the communication terminal is installed with a biometric management application that periodically receives the biometric value from the sensor transmitter and outputs information on the received biometric value to the user. The sensor of the sensor transmitter is inserted into the skin for a period of use, but the sensitivity of the sensor may differ depending on the part of the body where the sensor is inserted, and even if the sensor is inserted at the same position on the body, the sensitivity of the sensor changes over time. The biometric value measured by the sensor transmitter has an error with the actual biometric value of the user due to the change in sensitivity, and in order to overcome such an error, the biometric value of the user must be calibrated by applying a calibration factor to the measured biometric value.

[0013] In order to provide accurate biometric values ​​to a user, the biometric values ​​received from the sensor transmitter must be initially calibrated, and then must be continuously calibrated at regular calibration intervals during the use of the sensor transmitter. More specifically, a calibration factor must be calculated from a reference biometric value measured by a separate measuring device and a biometric value received from the sensor transmitter at each calibration interval during the use of the sensor transmitter, and the calibration factor must be applied to calibrate the biometric value received from the sensor transmitter before the next calibration interval.

[0014] However, when the reference vital value is measured in a state where the calibration parameters such as the rate of change and magnitude of vital value measured by the sensor are unstable, and the calibration factor is calculated using the measured reference vital value, there is a problem in that the calibrated vital value cannot be accurately determined.

[0015] Meanwhile, after the sensor is inserted into the body, it takes a certain amount of time for the sensor to stabilize, and before the sensor stabilizes, the reliability of the measured biometric value is relatively low, and the reliability of the measured biometric value increases relatively as the sensor stabilizes thereafter. Therefore, when calculating the calibration factor using the reference biometric value measured while the calibration parameter is unstable, the calibration factor needs to be calculated differently taking into account the degree of stabilization of the sensor. Summary of the Invention [Problem to be solved by the invention]

[0016] The present invention is intended to solve the problems of the conventional calibration factor calculation method mentioned above, and the purpose of the present invention is to provide a method for accurately calculating a calibration factor depending on whether the calibration parameters are unstable when calculating the calibration factor using a reference biological value.

[0017] Another object of the present invention is to provide a method for accurately calculating a calibration factor by dividing the entire usage period of a sensor into a plurality of calibration intervals and taking into account the degree of stabilization of the sensor according to the calibration interval when the calibration parameters are unstable when calculating a calibration factor using a reference biological value. [Means for solving the problem]

[0018] In order to achieve the object of the present invention, a method for calibrating a biosignal of a sensor according to the present invention includes a step of determining whether a reference biosignal is input, a step of extracting calibration parameters at the time when the reference biosignal is input and determining whether the extracted calibration parameters satisfy a correction condition, and a step of calculating a calibration factor according to whether the correction condition is satisfied and calculating a calibrated biosignal from the biosignal measured by the sensor using the calibration factor.

[0019] The method for calibrating a biosignal according to the present invention is characterized in that, when a correction condition is not satisfied, a current calibration factor is calculated from an input reference biosignal value, and a calibrated biosignal value is calculated from the biosignal using the current calibration factor until the next reference biosignal value is input.

[0020] Preferably, a method for calibrating a biometric signal according to an embodiment of the present invention includes, when a correction condition is satisfied, a step of calculating a current calibration factor from an inputted reference biometric value, a step of determining a calibration interval to which the time when the reference biometric value is input belongs, a step of calculating a corrected calibration factor from a current calibration factor that differs depending on the calibration interval to which the time when the reference biometric value is input belongs based on the determined calibration interval, and a step of calculating a calibrated biometric value using the biometric signal measured by the sensor and the corrected calibration factor until the next reference biometric value is input.

[0021] In the method for calibrating a biosignal according to the present invention, the calibration period is characterized in that the entire use period of the sensor is divided into a first period, a second period, and a third period according to the passage of time from the time point when the sensor is inserted into the body.

[0022] Here, the modified calibration factor is characterized in that, when the time point at which the reference biometric value is input belongs to the first interval, the current calibration factor is calculated as the modified calibration factor.

[0023] Here, the modified calibration factor is characterized in that, when the time point at which the reference biometric value is input belongs to the second interval, a first compensation value is calculated from a difference between the current calibration factor and the previous calibration factor, and the first compensation value is applied to the current calibration factor to calculate the modified calibration factor.

[0024] Here, when the time point at which the reference biometric value is input belongs to the third interval, the modified calibration factor is calculated by calculating a second compensation value from the difference between the current calibration factor and the previous calibration factor and applying the second compensation value to the current calibration factor.

[0025] Preferably, the method for calibrating a biosignal according to the present invention further includes the steps of calculating an average value of previously calculated modified calibration factors in a third interval based on a time point when a reference biosignal value is input, and re-modifying the modified calibration factor based on the average value.

[0026] Preferably, in one embodiment of the step of re-adjusting the modified calibration factor in the present invention, the step of calculating a modified critical range based on the average value, the step of determining whether the modified calibration factor falls outside the modified critical range, and the step of re-adjusting the modified calibration factor depending on whether the modified calibration factor falls outside the modified critical range to determine a final calibration factor.

[0027] Here, when the modified calibration factor falls outside the modification critical range, the modified calibration factor is re-modified within the modification critical range to determine the final calibration factor.

[0028] Here, if the modified calibration factor is within the modified critical range, the modified calibration factor is determined to be the final calibration factor.

[0029] Preferably, another embodiment of the step of re-adjusting the modified calibration factor in the present invention is characterized by including the steps of calculating a difference between the modified calibration factor and an average value, calculating a third compensation value from the difference between the modified calibration factor and the average value, and re-adjusting the modified calibration factor with the third compensation value to calculate a final calibration factor.

[0030] Here, the sensor is inserted into the user's body and measures the user's biosignals continuously for a certain period of time from the body fluids.

[0031] Here, the sensor is a sensor for measuring a blood glucose level of a user, and the reference biovalue is a reference blood glucose level measured by a separate blood glucose meter in order to calibrate the measured blood glucose level measured by the sensor. Effect of the Invention

[0032] In the method for calibrating a biosignal according to the present invention, when a calibration factor is calculated using a reference biosignal value, if the calibration parameter is unstable, the current calibration factor calculated from the reference biosignal value is not used as is, but a compensation value calculated from the difference between the current calibration factor and a previous calibration factor is applied to the current calibration factor to correct the current calibration factor, thereby accurately calibrating the biosignal and calculating a calibrated biosignal value even when the calibration parameter is unstable.

[0033] In addition, in the method for calibrating a biosignal according to the present invention, when a calibration parameter is unstable when calculating a calibration factor using a reference biovalue, the entire usage period of the sensor is divided into a plurality of calibration intervals, and the calibration factor is modified taking into account the degree of stabilization of the sensor depending on the calibration interval to which the reference biovalue is input, thereby making it possible to accurately calculate a calibrated biosignal from the biosignal of the sensor.

[0034] In addition, the method for calibrating a biosignal according to the present invention calculates an average value of the calibration factor in a section where the sensor is stabilized, and re-corrects the calibration factor taking into account the difference between the corrected calibration factor and the average value, thereby making it possible to accurately calculate a calibrated biosignal value from the biosignal of the sensor in a section where the sensor is stabilized. [Brief description of the drawings]

[0035] [Figure 1] FIG. 1 is a schematic diagram showing a continuous vital sign measuring system according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a functional block diagram for explaining the blood glucose signal calibration device according to the present invention. [Diagram 3] FIG. 3 is a functional block diagram for explaining the calibration unit according to the present invention. [Figure 4]FIG. 4 is a flow chart illustrating a method for calibrating a blood glucose signal according to the present invention. [Diagram 5] FIG. 5 is a diagram illustrating an example of inputting calibration information according to a calibration period. [Figure 6] FIG. 6 shows an example of a calibration interval for dividing the entire use period of a sensor according to the present invention. [Figure 7] FIG. 7 is a flow chart illustrating an example of a method for calculating a calibration factor in the present invention. [Figure 8] FIG. 8 is a flow chart for explaining an example of the steps for recalibrating the modified calibration factor in the present invention. [Figure 9] FIG. 9 is a flow chart illustrating another example of the step of recalibrating the modified calibration factor in the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0036] It should be noted that the technical terms used in the present invention are merely used to describe a specific embodiment and are not intended to limit the present invention. In addition, unless otherwise specifically defined in the present invention, the technical terms used in the present invention should be interpreted in a way that is generally understood by a person having ordinary knowledge in the technical field to which the present invention belongs, and should not be interpreted in an overly comprehensive or overly narrow sense. In addition, when the technical terms used in the present invention are incorrect technical terms that cannot accurately express the idea of ​​the present invention, they should be replaced and understood by technical terms that can be correctly understood by a person skilled in the art.

[0037] In addition, singular expressions used in the present invention include plural expressions unless the context clearly dictates differently. In the present invention, terms such as "comprise" or "include" should not be interpreted as including all of the components or steps described in the invention, but rather as including some components or steps that may not be included, or may further include additional components or steps.

[0038] In addition, it should be noted that the attached drawings are intended to facilitate understanding of the concept of the present invention, and should not be construed as limiting the concept of the present invention.

[0039] Hereinafter, the method for calibrating a biological signal according to the present invention will be described in more detail with reference to the accompanying drawings.

[0040] FIG. 1 is a schematic diagram showing a continuous vital sign measurement system according to an embodiment of the present invention.

[0041] In the following, blood glucose level will be described as an example of a biological value, and reference blood glucose level will be described as an example of a reference biological value. However, various biological values ​​other than blood glucose level can be measured depending on the field to which the present invention is applied.

[0042] Referring to FIG. 1, a continuous vital sign measuring system 1 according to an embodiment of the present invention includes a sensor transmitter 10 and a communication terminal 30. The sensor transmitter 10 and communication terminal 30 are connected to a communication device.

[0043] The sensor transmitter 10 is attached to the body, and when the sensor transmitter 10 is attached to the body, one sensor end of the sensor transmitter 10 is inserted into the skin to periodically measure a biosignal indicating a blood glucose level, i.e., a blood glucose signal, from bodily fluids of the human body.

[0044] The communication terminal 30 is a terminal that can receive a blood glucose signal from the sensor transmitter 10, calibrate the received blood glucose signal with a calibration factor, convert the unit into a calibrated blood glucose value, and display it to a user, and can be a terminal that can communicate with the sensor transmitter 10, such as a smartphone, a tablet PC, or a notebook. Of course, the communication terminal 30 is not limited thereto, and can be any type of terminal that includes a communication function and can install programs and applications.

[0045] That is, the sensor transmitter 10 generates a blood glucose signal, for example, a current signal, indicative of the user's blood glucose level and transmits the blood glucose signal to the communication terminal 30, which calibrates the blood glucose signal with a calibration factor and converts it into a calibrated blood glucose level. Depending on the field to which the present invention is applied, the sensor transmitter 10 may directly convert the blood glucose signal into a blood glucose level, and the communication terminal 30 may calibrate the blood glucose level received from the sensor transmitter 10 with the calibration factor.

[0046] Hereinafter, in the present invention, the blood glucose signal measured by the sensor transmitter 10 or the unit-converted blood glucose value will be referred to as the measured blood glucose value, and the blood glucose value obtained by calibrating the blood glucose signal or the unit-converted blood glucose value in the communication terminal 30 with a calibration factor will be referred to as the calibrated blood glucose value.

[0047] The sensor transmitter 10 transmits information on the measured blood glucose level to the communication terminal 30 at the request of the communication terminal 30 or periodically at set times. For data communication between the sensor transmitter 10 and the communication terminal 30, the sensor transmitter 10 and the communication terminal 30 may be connected to each other via a wired communication method such as a USB cable, or via a wireless communication method such as infrared communication, NFC communication, or Bluetooth (registered trademark).

[0048] When communication is established between the sensor transmitter 10 and the communication terminal 30, an initial calibration factor is calculated using a reference blood glucose level measured by a separate blood glucose meter (not shown) after initial stabilization of the sensor transmitter 10, and initial calibration of the measured blood glucose level is performed using the initial calibration factor. Thereafter, the communication terminal 30 calibrates the measured blood glucose level received from the sensor transmitter 10 with the initial calibration factor, and outputs the calibrated blood glucose level to the user.

[0049] Here, initial stabilization may be determined as occurring after a certain period of time, e.g., 2 hours, has elapsed after the sensor is inserted into the body, or initial stabilization may be determined based on the measured blood glucose level. However, initial stabilization is the minimum stabilization time or condition required to inform the user of the calibrated blood glucose level as soon as possible after the sensor is inserted into the body, and additional time, e.g., about 3 to 10 days, is required until the sensor is actually stabilized.

[0050] In order to accurately calibrate the measured blood glucose value by the sensor transmitter 10 after the initial stabilization, the communication terminal 30 calculates a new calibration factor using a reference blood glucose value measured by a separate blood glucose meter at each calibration cycle during the period of use of the sensor transmitter 10, calibrates the measured blood glucose value received from the sensor transmitter using the new calibration factor, calculates a calibrated blood glucose value, and outputs the calculated calibrated blood glucose value to the user.

[0051] Preferably, the calibration period can be changed according to the progress of stabilization. For example, after initial stabilization, calibration can be performed at 12 hour intervals, and thereafter, calibration can be performed at 24 hour or 48 hour intervals according to the progress of stabilization.

[0052] FIG. 2 is a functional block diagram illustrating a blood glucose signal calibration device according to the present invention.

[0053] The blood glucose signal calibration device may be implemented as a communication terminal such as a smart terminal that communicates with the sensor transmitter and notifies the user of the calibrated blood glucose level, or may be implemented as a separate receiving device.

[0054] More specifically, referring to FIG. 2, the calibration alarm unit 130 provides a calibration alarm to the user through the user interface unit 110 when the calibration period comes according to the calibration period stored in the memory unit 150 .

[0055] Preferably, when a calibration period comes, the calibration alarm unit 130 extracts the calibration parameters stored in the memory unit 130, compares the extracted calibration parameters with the calibration limiting conditions, and if the calibration limiting conditions are satisfied, does not provide a calibration alarm to the user interface unit 110 or deactivates a calibration icon that allows a calibration command to be input to the user interface unit 110. Here, the calibration parameters may be a calibrated blood glucose value, a rate of change of the calibrated blood glucose value, a rate of change of the calibrated blood glucose value, etc., and the calibration limiting conditions may be whether the calibrated blood glucose value exceeds a critical blood glucose value limit or whether the rate of change of the calibrated blood glucose value exceeds a critical rate of change limit.

[0056] When a reference blood glucose value is input through the user interface unit 110, the calibration unit 170 determines the calibration interval to which the time when the reference blood glucose value is input belongs, or determines whether the calibration parameters at the time when the reference blood glucose value is input satisfy the modification conditions. The calibration unit 170 calculates a calibration factor based on whether the calibration parameters satisfy the modification conditions and the calibration interval to which the time when the reference blood glucose value is input belongs, and calculates a calibrated blood glucose value using the calculated calibration factor.

[0057] When a reference blood glucose value is input, the calibrator 170 determines a measured blood glucose value corresponding to the input time of the reference blood glucose value among the measured blood glucose values ​​received through the transceiver 190, and generates a calibration pair made of the reference blood glucose value and the corresponding measured blood glucose value. The calibrator 170 calculates a calibration factor using the calibration pair. Depending on the field to which the present invention is applied, the calibrator 170 can calculate a calibration factor using a current calibration pair made of the input reference blood glucose value and the corresponding measured blood glucose value, but in order to calculate an accurate calibration factor, the calibrator 170 can calculate a calibration factor in a regressive manner using the current calibration pair and the past calibration pair.

[0058] The calibration unit 170 can use the calculated calibration factor as it is or modify the calculated calibration factor based on whether the calibration parameters satisfy the modification condition at the time when the reference blood glucose value is input and the calibration interval to which the time when the reference blood glucose value is input belongs. The calibration unit 170 calibrates the measured blood glucose value received after the reference blood glucose value is input with the calibration factor to calculate the calibrated blood glucose value, and provides the calculated calibrated blood glucose value to the user through the user interface unit 110.

[0059] FIG. 3 is a functional block diagram for explaining the calibration unit according to the present invention.

[0060] More specifically, with reference to FIG. 3, when a reference blood glucose value is input, the calibration interval determination unit 173 determines the calibration interval to which the reference blood glucose value is input based on the time when the reference blood glucose value is input.

[0061] Meanwhile, the calibration condition determination unit 175 extracts the calibration parameters when the reference blood glucose level is input and determines whether the calibration parameters satisfy the correction conditions, and the calibration factor calculation unit 177 calculates the current calibration factor from the current calibration pair or the past calibration pair.

[0062] The calibration factor determination unit 171 determines the current calibration factor calculated by the calibration factor calculation unit 177 as the calibration factor based on the calibration interval to which the reference blood glucose value is input and whether the calibration parameters satisfy the correction conditions at the time when the reference blood glucose value is input, or determines a corrected calibration factor by correcting the current calibration factor in the calibration factor correction unit 178.

[0063] If the calibration parameters satisfy the modification conditions at the time when the reference blood glucose value is input, the calibration factor determination unit 171 requests the calibration factor modification unit 178 to modify the current calibration factor. When the calibration factor modification unit 178 receives a request to modify the current calibration factor, it calculates a compensation value based on the calibration interval to which the reference blood glucose value is input and the difference between the current calibration factor and the previous calibration factor, and applies the calculated compensation value to the current calibration factor to calculate a modified calibration factor.

[0064] Depending on the degree of stabilization progress, when the degree of stabilization of the sensor is high, it is necessary to maintain the calibration factor so that it does not change significantly. However, when it is determined that the time point when the reference blood glucose level is input is in a calibration period in which the sensor is highly stabilized, the calibration factor correction unit 178 can re-correct the correction calibration factor based on the average value of the previous calibration factors in the calibration period in which the sensor is highly stabilized, calculated by the average value calculation unit 179.

[0065] In this way, the calibration factor determination unit 171 uses the current calibration factor calculated based on whether the calibration parameters at the time when the reference blood glucose value is input satisfy the modification condition, and if the modification condition is not satisfied, it uses the current calibration factor as it is. However, if the calibration parameters at the time when the reference blood glucose value is input satisfy the modification condition, it modifies the current calibration factor by applying a compensation value calculated differently depending on the calibration interval to which the time when the reference blood glucose value is input belongs, or it can re-modify the modified calibration factor based on the average value of the previous calibration factor in the calibration interval where the sensor is highly stabilized.

[0066] FIG. 4 is a flow chart illustrating a method for calibrating a blood glucose signal in accordance with the present invention.

[0067] More specifically, referring to FIG. 4, it is determined whether a calibration period has elapsed or whether a reference blood glucose level is to be input at the request of the user regardless of the calibration period (S110).

[0068] When the reference blood glucose value is input, a calibration period to which the reference blood glucose value is input is determined (S130). Here, the calibration period can be divided into a first period, a second period, and a third period based on the time from the insertion of the sensor into the body. The first period is a period in which the stability of the sensor is low after insertion of the sensor, the second period is a period in which the stability of the sensor is further increased after the first period, and the third period is a period in which the stability of the sensor is higher than that of the second period. The entire use period of the sensor can be divided into a variety of calibration periods depending on the field to which the present invention is applied, and this is within the scope of the present invention.

[0069] A calibration factor is calculated based on the calibration interval to which the reference blood glucose value is input (S150), and the measured blood glucose value is calibrated using the calculated calibration factor to calculate a calibrated blood glucose value, and the calculated calibrated blood glucose value is provided to the user (S170).

[0070] The calibration factor can be calculated differently depending on whether the calibration parameters extracted at the time point when the reference blood glucose value is input satisfy the correction condition in the calibration interval to which the time point when the reference blood glucose value is input belongs.

[0071] FIG. 5 is a diagram for explaining an example of inputting calibration information according to a calibration period. Here, the calibration information is a reference blood glucose level of a user measured with a test strip through a separate blood glucose meter.

[0072] 5, at the time (t1) when the sensor of the sensor transmitter is initially stabilized, initial calibration information is input to the communication terminal. Here, the initial calibration information can be input multiple times to accurately calculate the calibration factor. The communication terminal calculates the initial calibration factor using the initial calibration information and the blood glucose level measured by the sensor transmitter, and calculates the calibrated blood glucose level of the user by calibrating the measured blood glucose level received from the sensor transmitter using the initial calibration factor.

[0073] After the sensor of the sensor transmitter is initially stabilized, new calibration information is input to the communication terminal periodically until the expiration of the usage period of the sensor transmitter, preferably at a calibration period of 12 hours, 24 hours, etc. After the sensor of the sensor transmitter is initially stabilized, new calibration information is input to the sensor at a first calibration period (T1) of 12 hours for a certain period of time, and thereafter new calibration information can be input to the sensor of the sensor transmitter at a second calibration period (T2) of 24 hours, 48 ​​hours, etc.

[0074] When a sensor is manufactured in the same environment and under the same conditions, the sensor will have a certain sensitivity drift after insertion into the body, and based on this sensitivity drift characteristic, the calibration period can be set differently depending on the manufacturing environment of the sensor.

[0075] FIG. 6 shows an example of a calibration interval that divides the entire life of a sensor according to the present invention.

[0076] Referring to FIG. 6, the first section (T is ) is the section where the sensor is less stabilized after the initial stabilization, and the second section (T fs ) is the section where the sensor stabilization information is intermediate after the first section has elapsed, and the third section (T es ) is a section in which the degree of stabilization of the sensor after the second section has elapsed is higher than that of the second section.

[0077] Depending on the field to which the present invention is applied, the first period can be set to 0.5 to 1 day from the time the sensor is inserted into the body, the second period can be set to 3 to 5 days from the time the first period ends, and the third period can be set from the time the second period ends until the remaining period of use of the sensor. Depending on the field to which the present invention is applied, the first, second, and third periods can be set to different times from each other, and this is within the scope of the present invention.

[0078] FIG. 7 is a flow chart illustrating an example of a method for calculating a calibration factor in the present invention.

[0079] 7, it is determined whether the calibration interval to which the reference blood glucose value is input is the first interval (S171). If the calibration interval to which the reference blood glucose value is input is the first interval, a current calibration factor calculated from the reference blood glucose value and the measured blood glucose value corresponding to the time when the reference blood glucose value is input is calculated as a corrected calibration factor (S179).

[0080] On the other hand, if the calibration interval to which the reference blood glucose value is input is not the first interval, it is determined whether the calibration interval to which the reference blood glucose value is input is the second interval (S173). If the calibration interval to which the reference blood glucose value is input is the second interval, it is determined whether the calibration parameters extracted at the time when the reference blood glucose value is input satisfy the modification condition (S175). If the calibration interval to which the reference blood glucose value is input is the second interval and the calibration parameters do not satisfy the modification condition at this time, the current calibration factor is calculated as a modified calibration factor (S179). However, if the calibration interval to which the reference blood glucose value is input is the second interval and the calibration parameters satisfy the modification condition at this time, a first compensation value is calculated from the difference between the current calibration factor and the previous calibration factor, and the first compensation value is applied to the current calibration factor to calculate the modified calibration factor (S179).

[0081] For example, if the calibration interval to which the reference blood glucose level is input belongs is the second interval, and the calibration parameters satisfy the correction condition at this time, the correction calibration factor can be calculated as shown in Equation 1 below.

[0082]

number

[0083] On the other hand, if the calibration interval to which the reference blood glucose value is inputted is not the second interval, the calibration interval to which the reference blood glucose value is inputted is determined to be the third interval, and it is determined whether the calibration parameters extracted at the time when the reference blood glucose value is inputted satisfy the modification condition (S177). If the calibration interval to which the reference blood glucose value is inputted is the third interval and the calibration parameters do not satisfy the modification condition at this time, the current calibration factor is calculated as the modified calibration factor (S179). However, if the calibration interval to which the reference blood glucose value is inputted is the third interval and the calibration parameters satisfy the modification condition at this time, a second compensation value is calculated from the difference between the current calibration factor and the previous calibration factor, and the second compensation value is applied to the current calibration factor to calculate the modified calibration factor (S179).

[0084] For example, if the calibration interval to which the reference blood glucose level is input belongs is the third interval, and the calibration parameters satisfy the correction condition at this time, the correction calibration factor can be calculated as shown in Equation 2 below.

[0085]

number

[0086] Here, the correction condition is a condition for determining whether a calibration parameter falls outside the normal range, and may be set differently or equally depending on the calibration interval.

[0087] For example, an example of the modification condition is as follows: When the reference blood glucose level exceeds the upper critical blood glucose level and the current calibration factor is greater than the previous calibration factor If the reference blood glucose level is lower than the lower critical blood glucose level and the previous calibration factor is higher than the current calibration factor When the rising blood glucose change rate at the time the reference blood glucose value is entered is greater than the critical change rate and the current calibration factor is greater than the previous calibration factor When the blood glucose downward change rate at the time the reference blood glucose value is entered is greater than the critical change rate and the previous calibration factor is greater than the current calibration factor.

[0088] FIG. 8 is a flow chart illustrating an example of the steps for recalibrating the modified calibration factor in the present invention.

[0089] If the calibration interval to which the reference blood glucose level is input is the third interval, the calibration factor needs to be maintained so as not to change significantly since the sensor is highly stable in the third interval. To this end, the corrected calibration factor can be re-corrected to track the average value of the calibration factor calculated in the third interval.

[0090] More specifically, referring to FIG. 8, the average value of the modified calibration factors calculated in the third interval is calculated based on the time when the reference vital sign value is input (S211), and the modified critical range is calculated based on the calculated average value (S213).

[0091] It is determined whether the modified calibration factor falls outside the modification critical range (S215), and the modified calibration factor is re-modified depending on whether the modified calibration factor falls outside the modification critical range to determine the final calibration factor (S217).

[0092] That is, if the modified calibration factor is within the modification critical range, the modified calibration factor is determined as the final calibration factor. However, if the modified calibration factor is outside the modification critical range, the modified calibration factor is re-modified within the modification critical range to determine the final calibration factor (S219). Once the final calibration factor is determined, the final calibration factor is used to calculate the calibrated biometric value.

[0093] For example, if the modified calibration factor exceeds the upper limit of the modified critical range, the modified calibration factor is re-modified at the upper limit of the modified critical range, and if the modified calibration factor exceeds the lower limit of the modified critical range, the modified calibration factor is re-modified at the lower limit of the modified critical range.

[0094] FIG. 9 is a flow chart illustrating another example of the step of recalibrating the modified calibration factor in the present invention.

[0095] More specifically, referring to FIG. 9, the average value of the modified calibration factors calculated in the third interval based on the time when the reference biometric value is input is calculated (S221), and the third compensation value is calculated based on the calculated average value (S223).

[0096] Here, a third compensation value can be calculated by taking into account the difference between the modified calibration factor and the average value so that the modified calibration factor tracks the average value, and the third compensation value can be calculated as shown in Equation 3 below.

[0097]

number

[0098] Meanwhile, the above-described embodiments of the present invention can be created as a program that can be executed by a computer, and can be embodied in a general-purpose digital computer that runs the program using a computer-readable recording medium.

[0099] The computer-readable recording medium includes storage media such as magnetic storage media (e.g., ROM (Read Only Memory), floppy disks, hard disks, etc.), optically readable media (e.g., CD-ROM, DVD, etc.) and carrier waves (e.g., transmission over the Internet).

[0100] The present invention has been described with reference to the embodiments shown in the drawings, but these are merely illustrative, and those skilled in the art will appreciate that various modifications and equivalent embodiments are possible. Therefore, the true technical scope of the present invention should be determined by the technical ideas of the appended claims.

Claims

1. determining whether a reference biovalue is input to be used for calculating a calibrated biovalue from a biosignal measured by the sensor; extracting calibration parameters when the reference biometric values ​​are input, and determining whether a correction condition is satisfied based on the extracted calibration parameters; and calculating a calibration factor according to whether the correction condition is satisfied, and calculating a calibrated vital value from the vital signal measured by the sensor using the calibration factor.

2. The method for calibrating a biological signal includes:

2. The method of claim 1, further comprising: calculating a current calibration factor from the input reference biometric value when the correction condition is not satisfied; and calculating a calibrated biometric value from the biometric signal using the current calibration factor until the next reference biometric value is input.

3. The method for calibrating a biological signal includes: calculating a current calibration factor from the input reference biometric values ​​if the correction condition is satisfied; determining a calibration interval to which the reference biometric value is input; calculating a final calibration factor from a current calibration factor according to a calibration interval to which the reference biometric value is input based on the determined calibration interval; and 2. The method of claim 1, further comprising: calculating a calibration vital sign value using the vital sign measured by the sensor and the final calibration factor until a next reference vital sign value is input.

4. The method for calibrating a biological signal, 4. The method of claim 3, wherein the calibration period is divided into a first period, a second period, and a third period according to the passage of time from a time point when the sensor is inserted into the body.

5. The final calibration factor is 5. The method of claim 4, wherein if the time point at which the reference vital sign value is input is in a first interval, the current calibration factor is calculated using the final calibration factor.

6. The final calibration factor is 5. The method of claim 4, further comprising: calculating a first compensation value from a difference between the current calibration factor and a previous calibration factor when the reference biometric value is inputted at a time point in a second interval; and applying the first compensation value to the current calibration factor to calculate a final calibration factor.

7. The final calibration factor is 5. The method of claim 4, further comprising: calculating a second compensation value from a difference between the current calibration factor and a previous calibration factor when the reference biometric value is inputted at a time point in a third interval; and applying the second compensation value to the current calibration factor to calculate a final calibration factor.

8. The method for calibrating a biological signal includes: calculating an average value of the previous final calibration factors calculated in the third interval based on the time point when the reference biometric value is input; and 8. The method of claim 7, further comprising the step of re-adjusting the final calibration factor based on the average value.

9. The step of recalibrating the final calibration factor comprises: calculating a modified critical range based on the average value; determining whether the final calibration factor falls outside the modified critical range; and re-correcting the final calibration factor depending on whether the final calibration factor falls outside the correction critical range; 9. The method for calibrating a vital sign signal according to claim 8, further comprising the step of calculating a calibrated vital sign value using the final calibration factor after the re-correction.

10. The method of claim 9, further comprising the step of: re-correcting the final calibration factor within the correction critical range if the final calibration factor falls outside the correction critical range.

11. The method of claim 9, further comprising the steps of: if the final calibration factor is within the modified critical range, the final calibration factor is used as is.

12. The step of recalibrating the final calibration factor comprises: calculating the difference between said final calibration factor and said average value; calculating a third compensation value from the difference between the final calibration factor and the average value; and recalibrating the final calibration factor with the third compensation value; 9. The method for calibrating a vital sign signal according to claim 8, further comprising the step of calculating a calibrated vital sign value using the final calibration factor after the re-correction.

13. 13. The method of claim 1, wherein the sensor is inserted into the user's body and measures the user's biosignal continuously from bodily fluids for a certain period of time.

14. The sensor is a sensor for measuring a blood glucose level of a user, The method for calibrating a biological signal according to any one of claims 1 to 12, wherein the reference biological value is a reference blood glucose value measured by a separate blood glucose meter in order to calibrate the measured blood glucose value measured by the sensor.

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