How to compensate for calibration factors

Abstract

The present invention relates to a method for compensating for a calibration factor in a continuous bioinformation measurement system, and more specifically, to a calibration factor compensation method that can accurately compensate for a calibration factor by taking into account sensor characteristics that change in real time by calculating an offset taking into account sensor characteristics that change with the passage of time the sensor is used after it is inserted into the body, and that can accurately calculate an offset in a noise-resistant manner by calculating a reference average value from biosignals from a first time point to a second time point after the sensor is inserted, and calculating an offset from the difference between a comparison average value that changes with the passage of time the sensor is used and the reference average value.

Description

[Technical field]

[0001] The present invention relates to a method for compensating for a calibration factor in a continuous bioinformation measurement system, and more specifically, to a calibration factor compensation method that can accurately compensate for a calibration factor by taking into account sensor characteristics that change in real time by calculating an offset taking into account sensor characteristics that change with the passage of time the sensor is used after it is inserted into the body, and that can accurately calculate an offset in a noise-resistant manner by calculating a reference average value from biosignals measured by the sensor from a first time point to a second time point after the sensor is inserted, and calculating an offset from the difference between a comparison average value that changes with the passage of time the sensor is used and the reference average value. [Background technology]

[0002] Diabetes is a chronic disease that commonly affects modern people, and in Korea, the number of patients has reached more than 2 million, equivalent to 5% of the total population.

[0003] Diabetes mellitus develops when there is an absolute or relative deficiency of insulin produced by the pancreas due to various causes, including obesity, stress, poor eating habits, and congenital genetics, making it impossible to maintain a good sugar balance in the blood, and the absolute amount of sugar in the blood increases.

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

[0005] However, if glucose increases more than necessary, it is not properly stored in the liver, muscles, or fat cells, and instead accumulates in the blood. As a result, diabetic patients 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 that is absolutely necessary for each tissue of the body, causing abnormalities in each tissue of the body.

[0006] Diabetes is characterized by the fact that in the early stages there are almost no noticeable symptoms. However, as the disease progresses, symptoms specific to diabetes appear, such as excessive drinking, eating, and urination, weight loss, general fatigue, itchy skin, and slow healing of wounds on the hands and feet. As the disease progresses further, complications appear, which can progress to vision problems, high blood pressure, kidney disease, stroke, periodontal disease, muscle spasms and neuralgia, and gangrene.

[0007] In order to diagnose this type of diabetes and manage it so that it does not progress to complications, systematic blood glucose monitoring and treatment must be performed in parallel.

[0008] Diabetes requires frequent blood glucose measurement for management, and the demand for blood glucose measurement devices is on the rise. It has been confirmed through various studies that when diabetic patients strictly control their blood glucose, the occurrence of diabetic complications is significantly reduced. Therefore, it is very important for diabetic patients to regularly measure their blood glucose for blood glucose control.

[0009] Generally, blood glucose meters using the finger prick method are used to manage blood glucose levels in diabetic patients, but although such blood glucose meters are useful for managing blood glucose levels in diabetic patients, they have the problem that it is difficult to accurately grasp blood glucose levels that change frequently because they only show the results at the time of measurement.In addition, blood glucose meters require blood to be drawn each time blood glucose is measured multiple times a day, which places a heavy burden on diabetic patients.

[0010] Diabetic patients generally go back and forth between hyperglycemic and hypoglycemic states, but emergencies occur during hypoglycemic states. Hypoglycemic states occur when sugar does not last long, and can lead to loss of consciousness or, in the worst case, loss of life. Therefore, it is very important for diabetic patients to immediately detect hypoglycemic states. However, blood glucose meters that measure blood glucose intermittently have clear limitations.

[0011] To overcome the limitations of blood sampling type blood glucose meters, a Continuous Glucose Monitoring System (CGMS) has been developed that is inserted into the human body to measure blood glucose at intervals of several minutes, making it easier to manage diabetic patients and respond to emergencies.

[0012] The continuous blood glucose measurement system includes a sensor transmitter that is attached to a user's body part to measure and transmit a biosignal indicating a blood glucose level from bodily fluids, and a communication terminal that converts the biosignal transmitted from the sensor transmitter into a blood glucose level and outputs it to the user. The sensor transmitter includes a continuous blood glucose measurement sensor, a part of which is inserted into the human body, and the sensor continues to measure the biosignal while being inserted into the human body for a certain period of use, for example, about 15 days. The sensor transmitter periodically measures the biosignal from bodily fluids, and the communication terminal is installed with a blood glucose management application that periodically receives the biosignal from the sensor transmitter, calculates the blood glucose level from the received biosignal, and outputs it to the user.

[0013] Although the sensor of the sensor transmitter is continuously inserted into the skin for a set period of use, the sensor sensitivity may vary depending on the body part into which the sensor is inserted or for each user wearing the sensor, and even if the sensor is inserted at the same position on the body part, the sensitivity of the sensor changes over time. Therefore, the user's blood glucose level must be calibrated using a calibration factor for calibrating the measured biological information according to the changing sensitivity.

[0014] In order to provide an accurate blood glucose value to a user, the biosignal 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 is calculated from a reference blood glucose value measured by a separate meter at each calibration interval during the use of the sensor transmitter and a biosignal value, e.g., a current value, received from the sensor transmitter, and then the blood glucose value is calculated by applying the calibration factor to the biosignal value received from the sensor transmitter.

[0015] The calibration factor F is the ratio of the reference blood glucose level BG to the current value i received from the sensor transmitter, and can be calculated as follows:

[0016] [Mathematical formula 1] Calibration factor = Reference blood glucose value / Current value

[0017] During a given period of use, the sensor characteristics may change as the sensor is used for a certain period of time. For example, if biomolecules are densely packed around the sensor inserted in the body and encapsulate the sensor, the sensor may generate a biosignal having a lower current value than in a normal state.

[0018] When the sensor characteristics change in this way, the current value measured by the sensor corresponding to the same value of the reference blood glucose level (VBG) drops from i1 to i2 as shown in Figure 1, and the calibration factor calculated as a result becomes a relatively high value. When the slope of the calibration factor is large like this, even if the value of the biosignal measured by the sensor changes slightly, the actual calibrated blood glucose level has a large difference, which can cause the calibrated blood glucose level to be inaccurate. To solve this problem, the calibration factor can be compensated for by using an offset when calculating the calibration factor.

[0019] In order to compensate for the conventional calibration factor, a preset offset is provided based on the magnitude of the calibration factor, for example, when the magnitude of the calibration factor is equal to or greater than a certain value, the calibration factor is compensated with the value of offset O1, and when the magnitude of the calibration factor is equal to or less than a certain value, the calibration factor is compensated with the value of offset O2. However, such a conventional calibration factor compensation method does not take into account real-time changes in sensor characteristics, and further does not take into account sensor characteristics that change differently for each type of sensor, for each part where the sensor is worn, for each user who uses the sensor, or as the sensor is used over time, and therefore has a problem in that the calibration factor cannot be compensated accurately. Summary of the Invention [Problem to be solved by the invention]

[0020] The present invention is intended to solve the problems of the conventional calibration factor compensation method using an offset described above, and an object of the present invention is to provide a calibration factor compensation method that can calculate an offset taking into account sensor characteristics that change over time after a sensor is inserted into a body and accurately compensate for the calibration factor using the offset.

[0021] Another object of the present invention is to provide a calibration factor compensation method that can calculate an offset accurately and with resistance to noise by calculating a reference average value from biosignals measured by the sensor from a first time point to a second time point after insertion of the sensor, and calculating an offset from the difference between the reference average value and a comparative average value that changes as the sensor is used for a certain period of time.

[0022] Yet another object of the present invention is to provide a method for compensating for a calibration factor, which can obtain an accurate offset reference value by varying the period for acquiring biometric information of the sensor after insertion of the sensor in order to calculate the reference average value depending on whether the sensor has stabilized or not. [Means for solving the problem]

[0023] According to the present invention, a method for compensating a calibration factor in a continuous bioinformation measurement system includes a step of receiving a biosignal from a sensor that is inserted into the body and continues to measure a user's bioinformation, a step of calculating a reference average value from the biosignal, and when a reference biovalue for calibrating the biosignal is input, a step of calculating an offset from a difference between a comparison average value up to the time the reference biovalue is input and the reference average value, and a step of determining a calibration factor using the offset and applying the biosignal to the calibration factor to generate a calibrated biovalue.

[0024] Preferably, according to one embodiment of the present invention, the step of calculating the reference average value includes a step of extracting the received vital signs from a first time point to a second time point after the sensor is inserted into the body, and a step of calculating the reference average value from the first time point to the second time point based on the extracted vital signs.

[0025] Here, the second time point is characterized by being after a stabilization determination time has elapsed from the first time point.

[0026] Here, the stabilization determination time is characterized by being already set.

[0027] Preferably, according to the present invention, the step of calculating the reference average value further includes a step of determining whether the sensor has stabilized based on the biosignal at the second time point, and if it is determined that the sensor has stabilized, the reference average value from the first time point to the second time point is calculated based on the biosignal.

[0028] Preferably, according to the present invention, the step of calculating the reference average value further includes a step of determining whether the sensor has stabilized based on the biological signal received from the sensor after the second time point if it is determined that the sensor has not stabilized, and if it is determined that the sensor has stabilized, the reference average value is calculated based on the biological information from the first time point to the time when the sensor stabilized.

[0029] In another embodiment of the present invention, the stabilization determination time is variable depending on whether the sensor has stabilized or not.

[0030] Preferably, according to the present invention, the step of calculating the comparative average value is characterized by including a step of extracting the biological signals received from a first time point after the sensor is inserted into the body to a time point when the reference blood glucose value is input, and a step of calculating the comparative average value from the extracted biological signals.

[0031] Here, whether or not the sensor has stabilized is determined based on at least one of the rate of change of the biosignal, the difference between the reference biovalue and the biosignal, the rate of change of the sensor sensitivity, and the coefficient of variation.

[0032] Preferably, the calibration factor in the present invention is determined by a step of calculating a sensor sensitivity from a reference vital value and the vital signal, and a step of applying the offset to the sensor sensitivity.

[0033] Here, the biological signal is a blood glucose signal of the user. Effect of the Invention

[0034] The method for compensating for the calibration factor in a continuous biological information measuring device according to the present invention has the following advantages.

[0035] First, the calibration factor compensation method according to the present invention calculates an offset taking into account the sensor characteristics that change over time after the sensor is inserted into the body, thereby enabling accurate compensation of the calibration factor by taking into account the sensor characteristics that change in real time according to the type of sensor, the user, the body part into which the sensor is inserted, and the actual use time of the sensor.

[0036] Second, the calibration factor compensation method of the present invention calculates a reference average value from the biosignals measured by the sensor from a first time point to a second time point after the sensor is inserted, and calculates an offset from the difference between the reference average value and the comparative average value that changes as the sensor is used over time, thereby making it possible to calculate an offset that is resistant to noise and accurate.

[0037] Thirdly, the calibration factor compensation method according to the present invention calculates an offset by varying the period for acquiring biometric information from the sensor after insertion depending on whether the sensor has stabilized or not, in order to calculate a reference average value, thereby obtaining an accurate offset reference value and accurately compensating for the calibration factor. [Brief description of the drawings]

[0038] [Figure 1] 1 shows an example of a calibration factor calculated from a reference blood glucose level and a blood glucose signal. [Diagram 2] 1 is a schematic diagram showing a continuous biological information measuring system according to an embodiment of the present invention. [Diagram 3] FIG. 2 is a functional block diagram for explaining a calibration factor compensation device according to the present invention. [Figure 4] FIG. 4 is a functional block diagram for explaining an example of an offset generating unit according to the present invention. [Diagram 5] 1 is a flowchart illustrating a method for compensating a calibration factor in a continuous biological information measurement system according to the present invention. [Figure 6] 10 is a flowchart illustrating an example of a method for calculating an offset in the present invention. [Figure 7] FIG. 11 is a diagram for explaining an example of calculating an offset in the present invention. [Figure 8] 13 is a flowchart illustrating an example of calculating a reference average value. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0039] It should be noted that the technical terms used in the present invention are merely used to describe a particular embodiment and are not intended to limit the present invention. In addition, unless otherwise 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. Furthermore, if 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.

[0040] In addition, singular expressions used in the present invention include plural expressions unless the context clearly indicates a different meaning. In the present invention, the terms "comprise" or "include" should not be interpreted as including all of the components or steps described in the invention, but should be interpreted as including some of the components or steps not included, or including additional components or steps.

[0041] It should be noted that the accompanying drawings are provided for easily understanding the concept of the present invention, and the concept of the present invention should not be construed as being limited by the accompanying drawings.

[0042] The method for compensating for a calibration factor in a continuous vital sign measurement system according to the present invention will be discussed in more detail below with reference to the accompanying drawings.

[0043] FIG. 2 is a schematic diagram showing a continuous biological information measuring system according to one embodiment of the present invention.

[0044] In the following, blood glucose level will be used as an example of biological information and reference blood glucose level will be used as an example of reference biological information, but various biological information other than blood glucose level can be measured depending on the field to which the present invention is applied.

[0045] Referring to FIG. 2, a continuous biological information measuring system according to an embodiment of the present invention includes a sensor transmitter 10 and a communication terminal 30.

[0046] The sensor transmitter 10 is attached to the body, and when the sensor transmitter 10 is attached to the body, one end of the sensor of the sensor transmitter 10 is inserted into the skin and periodically measures a biosignal indicating a blood glucose level, i.e., a blood glucose signal, from the body fluids of the human body.

[0047] 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. A terminal capable of communicating with the sensor transmitter 10, such as a smartphone, a tablet PC, or a notebook computer, can be used. Of course, the communication terminal 30 is not limited thereto, and may be any type of terminal that includes a communication function and can install programs and applications.

[0048] That is, the sensor transmitter 10 generates a blood glucose signal, for example, a current signal, representing 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 the unit to a calibrated blood glucose value. 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 value, and the communication terminal 30 may calibrate the blood glucose value received from the sensor transmitter 10 with the calibration factor. Depending on the field to which the present invention is applied, the sensor transmitter 10 may calibrate the blood glucose signal with a calibration factor and convert the unit to a calibrated blood glucose value, and the communication terminal 30 may receive the calibrated blood glucose value and output it to the user.

[0049] The sensor transmitter 10 transmits a blood glucose signal to the communication terminal 30 periodically or in real time at the request of the communication terminal 30 or at set times. To perform 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 by a wired communication method such as a USB cable or by a wireless communication method such as infrared communication, NFC communication, Bluetooth (registered trademark).

[0050] 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 an initial calibration of the blood glucose signal is performed using the initial calibration factor. Thereafter, the communication terminal 30 calibrates the blood glucose signal received from the sensor transmitter 10 with the initial calibration factor, and outputs and provides the calibrated blood glucose value to the user.

[0051] Here, the initial stabilization may be determined to occur after a certain period of time, for example, 2 hours, has elapsed since the sensor was inserted into the body, or the presence or absence of initial stabilization may be determined based on the blood glucose signal. However, as a minimum stabilization time or condition required to notify the user of the calibrated blood glucose level as soon as possible after the sensor is inserted into the body, additional time, for example, about 3 to 10 days, may be required until the actual sensor stabilization is completed.

[0052] After the initial stabilization, in order to accurately calibrate the blood glucose signal in the sensor transmitter 10, the communication terminal 30 calculates a new calibration factor using a reference blood glucose level measured by a separate blood glucose meter at each calibration cycle during the use of the sensor transmitter 10, calibrates the blood glucose signal received from the sensor transmitter using the new calibration factor to calculate a calibrated blood glucose value, and outputs and provides the calculated calibrated blood glucose value to the user.

[0053] Here, when calculating the initial calibration factor or the new calibration factor, an offset that changes according to the sensor characteristics can be calculated, and the calibration factor can be compensated with the calculated offset. By taking into account the sensor characteristics that change in real time when calculating the offset used to compensate the calibration factor in this way, the offset can be calculated taking into account the sensor characteristics that change according to the type of sensor, the user who uses the sensor, the body part into which the sensor is inserted, and the passage of time after the sensor is inserted into the body and used, as compared to the conventional compensation method that uses a preset offset, thereby making it possible to more accurately compensate the calibration factor.

[0054] FIG. 3 is a functional block diagram for explaining a calibration factor compensation device according to the present invention.

[0055] In the present invention, when the calculation and compensation of the calibration factor is performed in a communication terminal, the compensation device for the calibration factor can be realized in the communication terminal, whereas when the calculation and compensation of the calibration factor is performed in a sensor transmitter, the compensation device for the calibration factor can be realized in the sensor transmitter.

[0056] More specifically, referring to Fig. 3, the transceiver 110 receives a blood glucose signal measured by a sensor transmitter. Here, the blood glucose signal may be a current value measured from bodily fluid by a sensor inserted into the body.

[0057] After the sensor is inserted, the offset generating unit 130 calculates a reference average value from the blood glucose signal from the first time point to the second time point, and then, when the calibration cycle arrives, calculates an offset from the difference between the comparative average value from the first time point to the calibration cycle and the reference average value. More specifically, after the sensor is inserted, the blood glucose signal measured by the sensor from the first time point to the second time point is acquired, and the reference average value is calculated from the blood glucose signal from the first time point to the second time point. The offset generating unit 130 calculates an offset that takes into account the changed sensor characteristics from the difference between the comparative average value calculated from the blood glucose signal measured by the sensor from the first time point to the calibration time point and the reference average value.

[0058] When a calibration cycle arrives or when a reference blood glucose level for calibrating the blood glucose signal is input regardless of the calibration cycle, the calibration factor compensation unit 150 calculates a calibration factor from the ratio of the blood glucose signal received via the transceiver unit 110 to the reference blood glucose level, and applies an offset calculated at the time of calibration to the calibration factor to compensate for the calibration factor.

[0059] When the calibration unit 170 receives a blood glucose signal measured by the sensor after the calibration time point, it converts the blood glucose signal into a unit using the compensated calibration factor to generate a calibrated blood glucose value.

[0060] FIG. 4 is a functional block diagram for explaining an example of the offset generating unit according to the present invention.

[0061] More specifically, with reference to Fig. 4, the reference average calculation unit 135 calculates a reference average value from the blood glucose signal measured by the sensor from the first time point to the second time point. The reference average value is a reference value used to calculate an offset for compensating for a calibration factor during the use period of the sensor, and the blood glucose signal obtained from the first time point to the second time point, for example, the average value, median value, arithmetic mean value, geometric mean value, etc. of the current value measured by the sensor from the first time point to the second time point may be used as the reference average value.

[0062] Preferably, the stabilization determination unit 131 determines whether the sensor has stabilized when a second point that has already been set has elapsed after the insertion of the sensor, and based on the determination result of the stabilization determination unit 131, the reference average value calculation unit 135 can calculate a reference average value from the blood glucose signal measured by the sensor from the first point to the second point if the sensor has stabilized at the second point.

[0063] However, if the sensor is not stabilized at the second time point based on the determination result of the stabilization determination unit 131, the variable unit 133 extends and varies the stabilization determination time from the second time point, and the stabilization determination unit 131 determines whether the sensor is stabilized at the varied stabilization determination time. Depending on the field to which the present invention is applied, the variable unit 133 may continue to extend the stabilization determination time to a set period based on the determination result of the stabilization determination unit 131, and determine whether the sensor is stabilized. If the sensor is stabilized at the varied stabilization determination time, the reference average value calculation unit 135 may calculate a reference average value from the blood glucose signal measured by the sensor from the first time point to the varied stabilization determination time.

[0064] The comparison average value calculation unit 136 calculates a comparison average value from the blood glucose signal measured by the sensor from the first time point to a calibration time point of the calibration cycle or a calibration time point at which the user wishes to perform calibration regardless of the calibration cycle. Here, the comparison average value may be the average value, median value, arithmetic mean value, geometric mean value, etc. of the current values ​​measured by the sensor from the first time point to the calibration time point.

[0065] Preferably, the calibration control unit 137 determines whether the calibration time point is valid based on the blood glucose signal of the sensor measured at the calibration time point or the reference blood glucose level. For example, if the sensor is temporarily unstable or the user's blood glucose level is unstable, such as when the rate of change of the blood glucose signal at the calibration time point is equal to or greater than a critical rate of change, or when the calibrated blood glucose level generated at the calibration time point is outside a critical range, the calibration time point can be delayed. The comparison average value calculation unit 136 calculates a comparison average value at a calibration time point that is determined to be valid, based on the result of the calibration control unit's determination as to whether the calibration time point is valid.

[0066] The offset calculation unit 139 calculates the offset at the time of calibration from the difference between the reference average value and the comparison average value.

[0067] FIG. 5 is a flow chart for explaining a method for compensating a calibration factor in a continuous vital sign measurement system according to the present invention.

[0068] More specifically, with reference to FIG. 5, a blood glucose signal measured by a sensor is received (S110).

[0069] After the sensor is inserted, a reference average value is calculated from the blood glucose signals received from the first time point to the time point when the sensor is stabilized, and then, when the calibration time point arrives, a comparison average value is calculated from the blood glucose signals received from the first time point to the calibration time point, and an offset is calculated from the difference between the reference average value and the comparison average value (S130).

[0070] A calibration factor is calculated from the blood glucose signal measured by the sensor corresponding to the reference blood glucose level measured using a separate blood glucose meter at the time of calibration and the time when the reference blood glucose level was measured, and the calculated calibration factor is compensated for with an offset (S150).

[0071] Preferably, the compensated calibration factor Fc can be calculated as follows:

[0072] Fc = Reference blood glucose level / (blood glucose signal-offset)

[0073] When a blood glucose signal is received from the sensor after the calibration time point, the blood glucose signal is converted into a calibrated blood glucose value using the compensated calibration factor and calibrated (S170). The calibrated blood glucose value can be provided to the user via the communication terminal.

[0074] FIG. 6 is a flowchart illustrating an example of a method for calculating an offset in the present invention.

[0075] 6, after the sensor is inserted, it is determined whether the sensor is stabilized (S131). Here, the determination as to whether the sensor is stabilized can be made when a preset stabilization determination time has elapsed, but the stabilization determination time can be changed depending on the field to which the present invention is applied.

[0076] When the sensor is stabilized, the reference average value is calculated from the blood glucose signal measured from the first time point to the stabilization determination time point, i.e., the second time point after the insertion of the sensor (S133). Here, the first time point may be the same as the time point of the insertion of the sensor, but the first time point may be set to a time point at which a certain time has passed since the insertion of the sensor. For example, the period between the first time point and the second time point can be set in various ways, such as 5 days from the time point of the insertion of the sensor, the time point at which one day has passed since the insertion of the sensor is set as the first time point, the time point at which five days have passed since the insertion of the sensor is set as the second time point, the time point at which three days have passed since the insertion of the sensor is set as the first time point, and the time point at which five days have passed since the insertion of the sensor is set as the second time point.

[0077] If a user command is input to input a reference blood glucose value at a calibration time point according to a calibration cycle or at a calibration time point unrelated to the calibration cycle (S135), a comparative average value is calculated from the blood glucose signal measured from the first time point to the calibration time point (S137).

[0078] An offset is calculated from the difference between the reference average value and the comparison average value (S139).

[0079] FIG. 7 is a diagram for explaining an example of calculating an offset in the present invention.

[0080] As shown in FIG. 7, the time from the first time t0 to the time t when the sensor stabilizes s The average value of the blood glucose signal, i.e., the current value, measured by the sensor up to this point is calculated.

[0081] The offset used to compensate the calibration factor at the first calibration time t1 is calculated as the difference O1 between the reference average value s and the comparison average value at the first calibration time, i.e., the average value of the current values ​​up to the first calibration time. For example, if the difference between the reference average value and the comparison average value is -0.2, then -0.2 is used as the offset at the first calibration time to compensate the calibration factor.

[0082] Similarly, at the second calibration time t2, the third calibration time t3, the fourth calibration time t4, and the fifth calibration time t5, an offset is calculated from the difference between the reference average value and the comparison average value to compensate for the calibration factors at the second calibration time t2, the third calibration time t3, the fourth calibration time t4, and the fifth calibration time t5.

[0083] FIG. 8 is a flowchart for explaining an example of calculating the reference average value.

[0084] 8, after the sensor is inserted, it is determined whether the stabilization determination time has arrived (S211). Here, the stabilization determination time can be set in various ways depending on the sensor characteristics.

[0085] When the stabilization determination time arrives, it is determined whether the sensor has stabilized (S213). Here, whether the sensor has stabilized can be determined based on the tendency of the blood glucose signal measured by the sensor (e.g., rate of change, deviation, etc.), the deviation of the blood glucose signal from the reference blood glucose level, the change in sensitivity, the coefficient of variation, etc.

[0086] If it is determined that the sensor has stabilized, a reference average value is calculated from the blood glucose signal measured by the sensor from the first time point after the insertion of the sensor until the stabilization determination time arrives (S215).

[0087] However, if it is determined that the sensor has not stabilized by the stabilization determination time, the stabilization determination time is extended (S217). It is again determined whether the sensor has stabilized during the extended stabilization determination time, and if it is determined that the sensor has stabilized during the extended stabilization determination time, a reference average value is calculated from the blood glucose signal measured by the sensor from the first time point after insertion of the sensor until the extended stabilization determination time (S215).

[0088] However, if it is determined that the sensor is not stable within the extended stabilization determination time, the stabilization determination time is extended again to determine whether the sensor is stabilized. In this manner, the stabilization determination time is continuously extended to a previously set time point based on whether the sensor is stabilized, and whether the sensor is stabilized is determined. If the sensor is not stabilized until the set time point has passed, the calibrated blood glucose value can be calculated without compensating for the calibration factor calculated at the calibration time. In another embodiment of the present invention, if the sensor is not stabilized until the set time point has passed, a warning can be given to the user to replace the sensor.

[0089] Meanwhile, the above-described embodiments of the present invention can be created as a computer-executable program, and can be realized on a general-purpose digital computer that runs the program using a computer-readable recording medium.

[0090] The above-mentioned computer-readable recording medium includes storage media such as magnetic storage media (e.g., ROM, floppy disk, hard disk, etc.), optically readable media (e.g., CD-ROM, DVD, etc.), and carrier waves (e.g., transmission over the Internet).

[0091] 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. receiving a biometric signal from a sensor that is inserted into the body and continuously measures a biometric information of the user; calculating a reference average value from the biosignal; When a reference vital value for calibrating the vital signal is input, an offset is calculated from a difference between a comparison average value up to the time when the reference vital value is input and the reference average value; determining a calibration factor using said offset, and applying said biometric signal to said calibration factor to generate a calibrated biometric value.

2. The step of calculating the reference average value comprises: extracting a biosignal received from a first time point to a second time point after the sensor is inserted into the body; 2. The method of claim 1, further comprising the step of: calculating a reference average value from the first time point to the second time point based on the extracted biological signal.

3. 3. The method of claim 2, wherein the second point in time is after a sensor stabilization time has elapsed from the first point in time.

4. The method for compensating for a calibration factor of a biological signal according to claim 3, wherein the sensor stabilization time is already set.

5. The step of calculating the reference average value comprises: determining whether a sensor is stabilized based on the biological signal at the second time point; The method for compensating for a calibration factor according to claim 4, further comprising: calculating a reference average value from the first time point to the second time point based on the biological signal when it is determined that the sensor is stabilized.

6. The step of calculating the reference average value comprises: If it is determined that the sensor is not stabilized, the method further includes determining whether the sensor is stabilized based on a biological signal received from the sensor after the second time point; 6. The method for compensating for a calibration factor according to claim 5, further comprising the step of: calculating a reference average value based on biological information from the first time point to a time point at which the sensor is stabilized when it is determined that the sensor is stabilized.

7. 4. The method of claim 3, wherein the sensor stabilization time is variable depending on whether the sensor has stabilized.

8. The step of calculating the comparison average value comprises: extracting a biological signal received from a first time point to a time point when a reference blood glucose level is input after the sensor is inserted into the body; 2. The method of claim 1, further comprising the step of: calculating a comparative average value from the extracted vital signs.

9. Whether the sensor has stabilized or not is determined by The calibration factor compensation method according to any one of claims 5 to 8, characterized in that the calibration factor compensation method is determined based on at least one of the rate of change of the biological signal, the difference between a reference biological value and the biological signal, the rate of change of sensor sensitivity, and a coefficient of variation.

10. The calibration factor is calculating a sensor sensitivity from the reference vital sign and the vital sign; 2. The method of claim 1, wherein the calibration factor is determined by applying the offset to the sensor sensitivity.

11. The method for compensating for a calibration factor according to claim 1 , wherein the biological signal is a blood glucose signal of a user.

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