Apparatus and method for estimating blood glucose

Patent metadata

Field	Value
Publication number	US-11517223-B2
Application number	US-201916506656-A
Country	US
Kind code	B2
Filing date	Jul 9, 2019
Priority date	Dec 13, 2018
Publication date	Dec 6, 2022
Grant date	Dec 6, 2022

Abstract

An apparatus for estimating blood glucose using a photoplethysmography (PPG) signal is provided. The apparatus for estimating blood glucose includes: a pulse wave sensor configured to obtain a pulse wave signal from an object; and a processor configured to obtain at least two points from a waveform of the pulse wave signal, to extract a feature based on time values of the obtained at least two points, and to estimate blood glucose based on the extracted feature.

First claim

What is claimed is:

1. An apparatus for estimating blood glucose, the apparatus comprising:
a pulse wave sensor configured to obtain a pulse wave signal from an object;
a processor configured to:
detect a first local minimum point and a second local minimum point from a second order differential signal, obtained by performing second order differentiation on the pulse wave signal;
obtain a first point in a systolic interval of the pulse wave signal corresponding to the first local minimum point, and obtain a second point in a diastolic interval of the pulse wave signal corresponding to the second local minimum point;
extract, as a feature, a difference between a time value of the first point and a time value of the second point;
estimate a first blood glucose value by applying a blood glucose estimation model to the extracted feature,
estimate a final blood glucose value based on a weighted summation between the first blood glucose value that is estimated based on the extracted feature and a calibration blood glucose value which is measured at a calibration time, and

an output interface configured to provide the estimated final blood glucose value,
wherein the processor is further configured to, based on the estimated final blood glucose value satisfying a calibration condition, calibrate the blood glucose estimation model, the calibration condition comprising at least one of a condition that a total number of times the estimated final blood glucose value falling outside a normal range during a predetermined period of time is greater than or equal to a first threshold value, a condition that a number of times the estimated final blood glucose value continuously falling outside the normal range is greater than or equal to a second threshold value, or a condition that the estimated final blood glucose value deviates from the normal range by more than a third threshold value, and
wherein the processor is further configured to, based on the estimated final blood glucose value satisfying the calibration condition, control the output interface to display (i) information related to a blood glucose measuring device that is connected with the apparatus and/or (ii) an interface for receiving a new calibration blood glucose value from a user.

2. The apparatus of claim 1 , wherein the pulse wave sensor comprises:
at least one light source configured to emit light of at least one wavelength onto the object; and
at least one detector configured to detect the light of the at least one wavelength that is scattered or reflected from the object.

3. The apparatus of claim 2 , wherein the at least one wavelength comprise at least one of a red wavelength, a green wavelength, a blue wavelength, and an infrared wavelength.

4. The apparatus of claim 1 , wherein the processor is further configured to extract, as the feature, a time difference ratio obtained by dividing the difference by the time value of the first point or the time value of the second point.

5. The apparatus of claim 1 , wherein the processor is further configured to obtain a component of a pulse waveform forming a waveform of the pulse wave signal, and obtain the first point and the second point based on the obtained component of the pulse waveform.

6. The apparatus of claim 1 , wherein the feature comprises at least one of pulse rate variability, heart rate variability, heart rate, pulse rate, arterial stiffness, blood pressure, perfusion index, and pulsatile volume.

7. A method of estimating blood glucose, the method comprising:
obtaining, by using a pulse wave sensor, a pulse wave signal from an object;
detecting a first local minimum point and a second local minimum point from a second order differential signal, obtained by performing second order differentiation on the pulse wave signal;
obtaining a first point in a systolic interval of the pulse wave signal corresponding to the first local minimum point, and obtaining a second point in a diastolic interval of the pulse wave signal corresponding to the second local minimum point;
extracting, as a feature, a difference between a time value of the first point and a time value of the second point;
estimating a first blood glucose value by applying a blood glucose estimation model to the extracted feature;
estimating a final blood glucose value based on a weighted summation between the first blood glucose value that is estimated based on the extracted feature and a calibration blood glucose value which is measured at a calibration time;
outputting, via an output interface, the estimated final blood glucose value;
based on the estimated final blood glucose value satisfying a calibration condition, calibrating the blood glucose estimation model, the calibration condition comprising at least one of a condition that a total number of times the estimated final blood glucose value falling outside a normal range during a predetermined period of time is greater than or equal to a first threshold value, a condition that a number of times the estimated final blood glucose value continuously falling outside the normal range is greater than or equal to a second threshold value, or a condition that the estimated final blood glucose value deviates from the normal range by more than a third threshold value; and
based on the estimated final blood glucose value satisfying the calibration condition, controlling the output interface to display (i) information related to a blood glucose measuring device that is connected with an apparatus for estimating blood glucose and/or (ii) an interface for receiving a new calibration blood glucose value from a user.

8. The method of claim 7 , wherein the extracting comprises extracting, as the feature, a time difference ratio obtained by dividing the difference by the time value of the first point or the time value of the second point.

9. The method of claim 7 , wherein the obtaining the first point and the second point further comprises obtaining a component of a pulse waveform forming a waveform of the pulse wave signal, and obtaining the first point and the second point based on the obtained component of the pulse waveform.

10. An apparatus for estimating blood glucose, the apparatus comprising:
a pulse wave sensor configured to obtain a pulse wave signal from an object;
a processor configured to:
detect a first local minimum point and a second local minimum point from a second order differential signal, obtained by performing second order differentiation on the pulse wave signal;
obtain a first point in a systolic interval of the pulse wave signal corresponding to the first local minimum point, and obtain a second point in a diastolic interval of the pulse wave signal corresponding to the second local minimum point;
extract, as a feature, a difference between a time value of the first point and a time value of the second point; and
estimate a first blood glucose value by applying a blood glucose estimation model to the extracted feature;

a metabolism information obtainer configured to obtain metabolism information of a user; and
an output interface,
wherein the processor is further configured to estimate a second blood glucose value based on the metabolism information, and to estimate a final blood glucose value based on a weighted summation between the first blood glucose value, the second blood glucose value, and a calibration blood glucose value which is measured at a calibration time, and
wherein the output interface is configured to provide the estimated final blood glucose value,
wherein the processor is further configured to, based on the estimated final blood glucose value satisfying a calibration condition, calibrate the blood glucose estimation model, the ca

Assignees

• Samsung Electronics Co Ltd

Inventors

• Choi Ka Ram
• Bae Sang Kon
• Lee So Young
• Yoon Seung Keun

Classifications

• A61B5/0205

  Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition · CPC title

• A61B5/02416

  using photoplethysmograph signals, e.g. generated by infrared radiation (A61B5/14552 takes precedence) · CPC title

• A61B5/02007

  Evaluating blood vessel condition, e.g. elasticity, compliance · CPC title

• A61B5/681

  Wristwatch-type devices · CPC title

• A61B5/02125

  of pulse wave propagation time · CPC title