PROCESSING APPARATUS, PROCESSING METHOD AND SYSTEM FOR PROCESSING A PHYSIOLOGICAL SIGNAL

• US 20160228069A1
• Filed: 09/17/2014
• Published: 08/11/2016
• Est. Priority Date: 09/27/2013
• Status: Active Application

• Current Assignee: Koninklijke Philips N.V.
• Original Assignee: Koninklijke Philips N.V.
• Inventors: JANSE, Cornelis Pieter, DERKX, Rene Martinus Maria
• Application Number:
  US15/024,630
• Publication Number:
  US 20160228069A1
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61B 5/11 Measuring movement of the entire body or parts thereof, e.g. head or hand tremor, mobility of a limb for measuring pulse A61B5/02 ;A61B5/1038 takes precedence; motion detection to correct for motion artifacts in physiological signals A61B5/721
• CPC Class Codes: A61B 5/1102 Ballistocardiography
• CPC Class Codes: A61B 5/113 occurring during breathing
• CPC Class Codes: A61B 5/6823 Trunk, e.g., chest, back, abdomen, hip
• CPC Class Codes: A61B 5/7221 Determining signal validity, reliability or quality A61B5/7207 and A61B5/7217 take precedence
• CPC Class Codes: A61B 5/7246 using correlation, e.g. template matching or determination of similarity
• CPC Class Codes: A61B 5/7278 Artificial waveform generation or derivation, e.g. synthesising signals from measured signals A61B5/327 takes precedence

Abstract

A processing apparatus for processing a physiological signal is presented. The processing apparatus is configured to perform the steps of: obtaining the physiological signal (6) containing at least two wave cycles originating from a physiological process (6b), obtaining a feature signal (12) descriptive of occurrences of a feature (P) in the physiological signal (6), determining an average waveform of the physiological signal (6) around said occurrences of the feature (P) in the physiological signal (6), and determining a model signal (18) comprising amplitude-scaled instances of the average waveform of the physiological signal (6) placed at the occurrences of the feature (P) in the physiological signal (6). Furthermore, a corresponding processing method, a system (1) for determining a vital sign of a subject comprising said processing apparatus and a computer program are presented.

Claims

1. A processing apparatus for processing a physiological signal configured to perform the steps of:

obtaining the physiological signal containing at least two wave cycles originating from a physiological process,

obtaining a feature signal descriptive of occurrences of a feature in the physiological signal,

determining an average waveform of the physiological signal around said occurrences of the feature in the physiological signal, and

determining a model signal comprising amplitude-scaled instances of the average waveform of the physiological signal placed at the occurrences of the feature in the physiological signal.

2. The processing apparatus according to claim 1, wherein the physiological signal is a movement signal descriptive of a physiological movement.

3. The processing apparatus according to claim 1, wherein the feature of the physiological signal is a peak of the physiological signal.

4. The processing apparatus according to claim 1, further configured to perform the step of comparing the model signal with the physiological signal.

5. The processing apparatus according to claim 4, wherein the comparing step comprises the computation of a difference signal between the model signal and the physiological signal.

6. The processing apparatus according to claim 5, wherein the comparing step further comprises the computation of an energy of the difference signal descriptive of the quality of the feature signal or the physiological signal.

7. The processing apparatus according to claim 1, wherein the step of determining the average waveform comprises the step of determining an average relative change between a value of the physiological signal at occurrences of the feature and a value of a neighboring sample of the physiological signal.

8. The processing apparatus according to claim 7, wherein step of determining the average waveform comprises repeating the step of determining an average relative change for different neighboring samples preceding and/or succeeding occurrences of the feature.

9. The processing apparatus according to claim 8, wherein said repeating is performed until reaching a stop criterion, in particular until a relative change has been determined for all samples of the physiological signal between at least one pair of succeeding occurrences of the features having the smallest temporal separation.

10. The processing apparatus according to claim 1, wherein the step of determining the model signal further comprises the step of interpolating the model signal between instances of the average waveform.

11. The processing apparatus according to claim 1, wherein the processing apparatus is further configured to evaluate a variation of a temporal separation of occurrences of a feature in the feature signal.

12. The processing apparatus according to claim 1, wherein the processing apparatus is further configured to evaluate the physiological signal and/or feature signal in time-domain.

15. A system for determining a vital sign of a subject comprising

a sensor for measuring a physiological signal, and

a processing unit comprising a first processing apparatus for determining a feature signal descriptive of occurrences of a feature of the physiological signal, and a second processing apparatus for processing a physiological signal, wherein the second processing apparatus is a processing apparatus according to claim 1 configured to determine a model signal,

wherein the processing unit is further configured to determine the vital sign of the subject based on the physiological signal taking into account the model signal.

13. A processing method for processing a physiological signal comprising the steps of:

obtaining the physiological signal containing at least two wave cycles originating from a physiological process,

obtaining a feature signal descriptive of occurrences of a feature of the physiological signal,

determining an average waveform of the physiological signal around said occurrences of the feature of the physiological signal,

determining a model signal comprising amplitude-scaled instances of the average waveform of the physiological signal placed at the occurrences of the feature of the physiological signal.

14. Computer program comprising program code means for causing a computer to carry out the steps of the method as claimed in claim 13 when said computer program is carried out on the computer.