Method and apparatus for determining respiration state based on plurality of biological indicators calculated using bio-signals

Patent metadata

Field	Value
Publication number	US-11064906-B2
Application number	US-201916260364-A
Country	US
Kind code	B2
Filing date	Jan 29, 2019
Priority date	Jan 29, 2018
Publication date	Jul 20, 2021
Grant date	Jul 20, 2021

Abstract

A method and apparatus for determining a respiration state on the basis of a plurality of biological indicators calculated using bio-signals. The method for determining a respiration state on the basis of a plurality of biological indicators calculated using bio-signals includes collecting a photoplethysmography (PPG) signal measured by a PPG sensor and a cutaneous electric signal measured by an electrodermal activity (EDA) sensor; analyzing the collected PPG signal and cutaneous electric signal and calculating a plurality of biological indicators including a respiration rate; and comprehensively evaluating the plurality of biological indicators to determine a user's respiration state.

First claim

What is claimed is:

1. A method of determining a respiration state on the basis of a plurality of biological indicators calculated using bio-signals, the method comprising:
collecting a photoplethysmography (PPG) signal measured by a PPG sensor and a cutaneous electric signal measured by an electrodermal activity (EDA) sensor;
analyzing the collected PPG signal and the cutaneous electric signal and calculating a plurality of biological indicators including a respiration rate; and
comprehensively evaluating the plurality of biological indicators to determine a user's respiration state,
wherein the plurality of biological indicators further comprises a blood oxygen saturation and a cutaneous electric conductivity,
wherein the determining of the user's respiration state comprises determining the respiration state as “normal respiration state” when the respiration rate falls within a predetermined threshold range, the blood oxygen saturation is greater than a minimal critical oxygen saturation, and the cutaneous electric conductivity is less than a predetermined neutral critical cutaneous conductivity.

2. The method of claim 1 , wherein the calculating of the plurality of biological indicators comprises:
performing bandpass filtering on the PPG signal to extract a respiration signal; and
performing frequency analysis on the extracted respiration signal on a segment basis to calculate a respiration rate.

3. The method of claim 2 , wherein the performing of the frequency analysis to calculate the respiration rate comprises determining an optimal size of sample data shared by continuous segments.

4. The method of claim 3 , wherein when a number of samples is N and a size of each segment is α·N, the optimal size (β·N) of sample data is determined to satisfy a relationship corresponding to the following equation:
α· N+x·y=N

where, y =(α· N )−(β·α· N )

x =1/α·((1−α))/((1−β)).

5. The method of claim 1 , wherein the PPG signal is a signal obtained by light with wavelengths of 660 nm and 940 nm being reflected.

6. The method of claim 5 , wherein the calculating of the plurality of biological indicators comprises:
normalizing a 660-nm wavelength signal and a 940-nm wavelength signal of the PPG signal at a ratio of an alternating current signal to a direct current signal; and
calculating the blood oxygen saturation using a ratio between the normalized 660-nm wavelength signal and the normalized 940-nm wavelength signal.

7. The method of claim 1 , wherein the determining of the user's respiration state comprises determining the respiration state as “abnormal physical or psychological state” when the respiration rate falls within the predetermined threshold range and the blood oxygen saturation is less than a minimal critical oxygen saturation or the cutaneous electric conductivity is greater than the predetermined neutral critical cutaneous conductivity.

8. The method of claim 1 , wherein the determining of the user's respiration state comprises determining the respiration state as “dyspnea accompanied by oxygen deficiency symptoms due to hyperpnea” when the respiration rate is greater than a maximum value of the predetermined threshold range and the blood oxygen saturation is less than a minimal critical oxygen saturation.

9. The method of claim 1 , wherein the determining of the user's respiration state comprises determining the respiration state as “dyspnea accompanied by a sticky skin symptom due to hyperpnea” when the respiration rate is greater than a maximum value of the predetermined threshold range and the cutaneous electric conductivity is greater than the predetermined neutral critical cutaneous conductivity.

10. The method of claim 1 , wherein the determining of the user's respiration state comprises determining the respiration state as “urgent respiration state” when the respiration rate lies outside the predetermined threshold range, the blood oxygen saturation is less than a minimal critical oxygen saturation, and the cutaneous electric conductivity is greater than the predetermined neutral critical cutaneous conductivity.

11. An apparatus for determining a respiration state on the basis of a plurality of biological indicators calculated using bio-signals, the apparatus comprising:
at least one processor; and
a memory configured to store instructions for instructing the at least one processor to:
collect a photoplethysmography (PPG) signal measured by a PPG sensor and a cutaneous electric signal measured by an electrodermal activity (EDA) sensor;
analyze the collected PPG signal and cutaneous electric signal and calculate a plurality of biological indicators including a respiration rate; and
comprehensively evaluate the plurality of biological indicators to determine a user's respiration state,

wherein the plurality of biological indicators further comprises a blood oxygen saturation and a cutaneous electric conductivity,
wherein the instructions for instructing the at least one processor to comprehensively evaluate the plurality of biological indicators to determine the user's respiration state comprise instructions for instructing the at least one processor to determine the respiration state as “normal respiration state” when the respiration rate falls within a predetermined threshold range, the blood oxygen saturation is greater than a minimal critical oxygen saturation, and the cutaneous electric conductivity is less than a predetermined neutral critical cutaneous conductivity.

12. The apparatus of claim 11 , wherein the instructions for instructing the at least one processor to calculate the plurality of biological indicators comprise instructions for instructing the at least one processor to:
perform bandpass filtering on the PPG signal to extract a respiration signal; and
perform frequency analysis on the extracted respiration signal on a segment basis to calculate a respiration rate.

13. The apparatus of claim 12 , wherein the instructions for instructing the at least one processor to perform the frequency analysis to calculate the respiration rate comprise instructions for instructing the at least one processor to determine an optimal size of sample data shared by continuous segments.

14. The apparatus of claim 13 , wherein when a number of samples is N and a size of each segment is α·N, the optimal size (β·N) of sample data is determined to satisfy a relationship corresponding to the following equation:
α· N+x·y=N

where, y =(α· N )−(β·α· N )

x =1/α·((1−α))/((1−β)).

15. The apparatus of claim 11 , wherein the instructions for instructing the at least one processor to determine the user's respiration state comprises instructions for instructing the at least one processor to determine the respiration state as “abnormal physical or psychological state” when the respiration rate falls within the predetermined threshold range and the blood oxygen saturation is less than a minimal critical oxygen saturation or the cutaneous electric conductivity is greater than the predetermined neutral critical cutaneous conductivity.

16. A method of calculating a number of breaths per minute using bio-signals, the method comprising:
collecting a photoplethysmography (PPG) signal measured by a PPG sensor;
performing bandpass filtering on the PPG signal to extract a respiration signal;
acquiring a blood oxygen saturation and a cutaneous electric conductivity;
performing frequency analysis on the extracted respiration signal on a segment basis to calculate a respiration rate; and
determining a user's respiration state as “normal respiration state” when

Assignees

• Electronics & Telecommunications Res Inst

Inventors

• Shin Hyun Soon
• Kang Do Hyung
• Hahm Chan Young
• Nam Seung Yoon
• Lorenzo John

Classifications

• A61B5/0533 Primary

  Measuring galvanic skin response · CPC title

• A61B5/7225

  Details of analogue processing, e.g. isolation amplifier, gain or sensitivity adjustment, filtering, baseline or drift compensation (input circuits for detecting, measuring, or recording bioelectric or biomagnetic signals A61B5/30; specific diagnostic methods using bioelectric or biomagnetic signals A61B5/316) · CPC title

• A61B5/165

  Evaluating the state of mind, e.g. depression, anxiety · CPC title

• A61B5/7278

  Artificial waveform generation or derivation, e.g. synthesizing signals from measured signals · CPC title

• A61B5/7203

  for noise prevention, reduction or removal · CPC title