METHOD FOR EXTRACTING THE FEATURE OF AN ABDOMINAL BREATHING AND A SYSTEM USING THE SAME

• US 20140142453A1
• Filed: 01/27/2014
• Published: 05/22/2014
• Est. Priority Date: 08/08/2011
• Status: Abandoned Application

• Current Assignee: National Chiao Tung University (Government of The Republic of China)
• Original Assignee: National Chiao Tung University (Government of The Republic of China)
• Inventors: HSIAO, Tzu-Chien, HSU, Ju-Hsin
• Application Number:
  US14/165,433
• Publication Number:
  US 20140142453A1
• Time in Patent Office: Days
• US Class Current: 600/529
• CPC Class Codes: A61B 5/08 Detecting, measuring or recording devices for evaluating the respiratory organs A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/0816 Measuring devices for examining respiratory frequency measuring frequency of electric signals G01R23/00
• CPC Class Codes: A61B 5/087 Measuring breath flow
• CPC Class Codes: A61B 5/113 occurring during breathing
• CPC Class Codes: A61B 5/1135 by monitoring thoracic expansion
• CPC Class Codes: A61B 5/6823 Trunk, e.g., chest, back, abdomen, hip
• CPC Class Codes: G16H 50/50 for simulation or modelling of medical disorders

Abstract

A method for extracting the feature of an abdominal breathing is disclosed, capable of extracting the feature of an abdominal breathing, without the requirement of a standard model of an abdominal breathing and the execution of a learning process being executed prior to the method for extracting the feature of an abdominal breathing. By means of computing a plurality of intrinsic mode functions corresponding to the abdominal breathing signal received, an Euler angle function and an instantaneous frequency function of each of the plurality of intrinsic mode functions, and comparing the plurality of instantaneous frequency function with a pre-determined zero-point threshold region, the method for extracting the feature of an abdominal breathing defines one of the plurality of instantaneous frequency function as an abdominal breathing feature function, which contains the feature of the abdominal breathing. In this way, the feature of an abdominal breathing is extracted.

Claims

1. A method for extracting the feature of an abdominal breathing, comprising the following steps of:

receiving an abdominal breathing signal;

executing an empirical mode decomposition process on the abdominal breathing signal, for computing a plurality of intrinsic mode functions;

basing on the plurality of intrinsic mode functions and the results obtained after the execution of a Hilbert transform on the plurality of intrinsic mode functions, computing an Euler angle function of each of the plurality of intrinsic mode functions;

taking the partial derivative of the Euler angle function of each of the plurality of intrinsic mode functions, with respect to time, for computing an instantaneous frequency function of each of the plurality of intrinsic mode functions, and extracting a plurality of maximum values of each of the plurality of instantaneous frequency functions; and

according to a pre-determined sequence, comparing the plurality of maximum values of each of the plurality of instantaneous frequency functions with a zero-point threshold region, respectively, and when a result that all of the plurality of maximum values of one of the plurality of instantaneous frequency functions falling into the zero-point threshold region is obtained, the instantaneous frequency function having the plurality of maximum values is defined as an abdominal breathing feature function.

2. The method as claimed in claim 1, wherein the Euler angle function is a function describing the functional relation between the Euler angle and time in an Euler formula, and the Euler formula is represented as:

re^jθ

=r(cos θ

+j sin θ

)

where, r represents the magnitude, and θ

represents the Euler angle.

3. The method as claimed in claim 1, wherein the plurality of maximum values of each of the plurality of instantaneous frequency functions is local maximum values.

4. The method as claimed in claim 1, wherein the number of the plurality of intrinsic mode functions is between 1 and 16, and each of the plurality of intrinsic mode functions has a characteristic frequency, and the values of the characteristic frequency of different intrinsic mode functions are different from each other.

5. The method as claimed in claim 4, wherein the pre-determined sequence is a sequence staring from the intrinsic mode function having a higher characteristic frequency value thereof, and terminating with the intrinsic mode function having a lower characteristic frequency value.

6. The method as claimed in claim 1, wherein the zero-point threshold region is a region where the value of the instantaneous frequency function is between −

0.5 and 0.5.

7. The method as claimed in claim 1, wherein the distribution of the plurality of minimum values of the abdominal breathing feature function in the time dimension is the frequency of the abdominal breathing.

8. An abdominal breathing feature extracting system, comprising:

a sensing module, for sensing an abdominal breathing signal;

a computing module, coupled with the sensing module, for extracting an abdominal breathing feature function; and

an abdominal breathing feature output module, coupled with the computing module, for outputting the abdominal breathing feature function;

wherein, the computing module extracts the abdominal breathing feature function from the abdominal breathing signal by means of executing an abdominal breathing feature extracting method, and the abdominal breathing feature extracting method comprises the following steps of;

receiving the abdominal breathing signal;

executing an empirical mode decomposition process on the abdominal breathing signal, for computing a plurality of intrinsic mode functions;

basing on the plurality of intrinsic mode functions and the results obtained after the execution of a Hilbert transform on the plurality of intrinsic mode functions, computing an Euler angle function of each of the plurality of intrinsic mode functions;

taking the partial derivative of the Euler angle function of each of the plurality of intrinsic mode functions, with respect to time, for computing an instantaneous frequency function of each of the plurality of intrinsic mode functions, and extracting a plurality of maximum values of each of the plurality of instantaneous frequency functions; and

according to a pre-determined sequence, comparing the plurality of maximum values of each of the plurality of instantaneous frequency functions with a zero-point threshold region, respectively, and when a result that all of the plurality of maximum values of one of the plurality of instantaneous frequency functions falling into the zero-point threshold region is obtained, the instantaneous frequency function having the plurality of maximum values is defined as the abdominal breathing feature function.

9. The system as claimed in claim 8, wherein the sensing module is integrated to a belt, and the sensing module includes a piezoelectric unit and an analog-to-digital converting unit.

10. The system as claimed in claim 8, wherein the sensing module is a system on chip.

11. The system as claimed in claim 8, wherein the abdominal breathing feature output module includes a wireless transmission unit.

12. The system as claimed in claim 8, wherein the Euler angle function is a function describing the functional relation between the Euler angle and time in an Euler formula, and the Euler formula is represented as:

re^jθ

=r(cos θ

+j sin θ

)

where, r represents the magnitude, and θ

represents the Euler angle.

13. The system as claimed in claim 8, wherein the number of the plurality of intrinsic mode functions is between 1 and 16, and each of the plurality of intrinsic mode functions has a characteristic frequency, and the values of the characteristic frequency of different intrinsic mode functions are different from each other.

14. The system as claimed in claim 8, wherein the pre-determined sequence is a sequence staring from the intrinsic mode function having a higher characteristic frequency value thereof, and terminating with the intrinsic mode function having a lower characteristic frequency value.

15. The system as claimed in claim 8, wherein the zero-point threshold region is a region where the value of the instantaneous frequency function is between −

0.5 and 0.5.

16. The system as claimed in claim 8, wherein the distribution of the plurality of minimum values of the abdominal breathing feature function in the time dimension is the frequency of the abdominal breathing.