DEVICE AND METHOD FOR EXTRACTING PHYSIOLOGICAL INFORMATION

• US 20140148663A1
• Filed: 11/14/2013
• Published: 05/29/2014
• Est. Priority Date: 11/23/2012
• Status: Active Grant

• Current Assignee: Koninklijke Philips N.V.
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: BRESCH, Erik, VERKRUIJSSE, Willem, BARTULA, Marek Janusz
• Granted Patent: US 9,770,197 B2
• Time in Patent Office: Days
• US Class Current: 600/323
• CPC Class Codes: A61B 2560/0223 of calibration, e.g. protocols for calibrating sensors
• CPC Class Codes: A61B 5/0077 Devices for viewing the surface of the body, e.g. camera, magnifying lens
• CPC Class Codes: A61B 5/02416 using photoplethysmograph signals, e.g. generated by infrared radiation A61B5/14552 takes precedence
• CPC Class Codes: A61B 5/1116 Determining posture transitions
• CPC Class Codes: A61B 5/14542 for measuring blood gases A61B5/14551 takes precedence
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/7225 Details of analog processing, e.g. isolation amplifier, gain or sensitivity adjustment, filtering, baseline or drift compensation A61B5/30, A61B5/316 take precedence; transformers for specific applications H01F38/00; amplifiers H03F
• CPC Class Codes: A61B 5/7246 using correlation, e.g. template matching or determination of similarity

Abstract

The present invention relates to a device and a method for extracting physiological information from detected electromagnetic radiation emitted or reflected by a subject. A data stream derived from detected electromagnetic radiation is received. The data stream comprises a continuous or discrete characteristic signal including physiological information indicative of at least one vital parameter, the characteristic signal comprising at least one indicative signal component representative of a detected spectral portion indicative of the at least one vital parameter. The data stream at least sectionally comprises at least one auxiliary signal component detected along with the at least one indicative signal component, the at least one auxiliary signal component being representative of a distinct spectral portion. A characteristic signal discrepancy between at least one of the at least one indicative signal component and the at least one auxiliary signal component is detected, the signal discrepancy being related to a physiological state of the subject. A signal calibration parameter is determined under consideration of the detected signal discrepancy. Consequently, the at least one vital parameter can be detected under consideration of the calibration parameter.

Claims

1. A device for extracting physiological information from detected electromagnetic radiation emitted or reflected by a subject, comprising:

an interface that receives a data stream derived from detected electromagnetic radiation, the data stream comprising a continuous or discrete characteristic signal including physiological information indicative of at least one vital parameter, the characteristic signal comprising at least one indicative signal component representative of a detected spectral portion indicative of the at least one vital parameter, the data stream at least sectionally comprising at least one auxiliary signal component detected along with the at least one indicative signal component, the at least one auxiliary signal component being representative of a distinct spectral portion,

a signal comparator that detects a characteristic signal discrepancy between at least one of the at least one indicative signal component and the at least one auxiliary signal component, the signal discrepancy being related to a physiological state of the subject, and

a calibration processor that determines a signal calibration parameter under consideration of the detected signal discrepancy.

2. The device as claimed in claim 1, further comprising an analyzing unit that detects the at least one vital parameter under consideration of the calibration parameter.

3. The device as claimed in claim 1, wherein the signal discrepancy is a temporal signal discrepancy representative of an actual posture of the subject.

4. The device as claimed in claim 1, wherein the signal discrepancy is a temporal signal discrepancy representing a time delay between the at least one of the at least one indicative signal component and the at least one auxiliary signal component.

5. The device as claimed in claim 1, wherein the signal discrepancy is a signal form discrepancy representing differences in waveform between the at least one of the at least one indicative signal component and the at least one auxiliary signal component.

6. The device as claimed in claim 1, wherein the at least one vital parameter is a parameter derivable from cardiovascular activity.

7. The device as claimed in claim 1, wherein the at least one vital parameter is chosen from the group consisting of oxygen saturation, heart beat, heart rate, heart rate variability, Traube-Hering-Mayer waves, and respiration rate.

8. The device as claimed in claim 1, wherein the calibration parameter is an adaptive calibration parameter, and wherein the calibration processor computes the calibration parameter under consideration of statistical adjustment computation measures applying the detected signal discrepancy.

9. The device as claimed in claim 1, wherein the signal comparator further detects the signal discrepancy by applying a correlation computation to the at least one of the at least one indicative signal component and the at least one auxiliary signal component.

10. The device as claimed in claim 1, wherein the characteristic signal comprises at least two indicative signal components, wherein a first signal component is representative of a first indicative spectral portion and wherein a second signal component is representative of a second indicative spectral portion.

11. The device as claimed in claim 10, wherein the at least one auxiliary signal component is representative of an auxiliary spectral portion, and wherein the auxiliary spectral portion and at least one of the first indicative spectral portion and the second indicative spectral portion are chosen such that different respective absorption and reflection characteristics appear in an observed tissue of the subject.

12. The device as claimed in claim 1, further comprising a sensor unit, in particular a camera, configured for capturing electromagnetic radiation at a distance, wherein the sensor unit comprises a defined response characteristic adapted to at least two defined spectral distributions.

13. The device as claimed in claim 1, further comprising at least one source of electromagnetic radiation configured for directing radiation to the subject at a distance, in particular a source capable of generating radiation portions comprising visible radiation and infrared radiation.

14. A pulse oximetry device for extracting physiological information, comprising:

an interface that receives a data stream derived from detected electromagnetic radiation, the data stream comprising a characteristic signal including physiological information indicative of at least one vital parameter, the characteristic signal comprising at least two indicative signal components representative of detected spectral portions indicative of the at least one vital parameter, the data stream at least sectionally comprising at least one auxiliary signal component, the at least one auxiliary signal component being representative of a distinct spectral portion,

a signal comparator that detects a characteristic signal discrepancy between at least one of the at least two indicative signal components and the at least one auxiliary signal component, and

a calibration processor that determines an adaptive signal calibration parameter under consideration of the detected signal discrepancy.

15. The device as claimed in claim 14, further comprising an analyzing unit that detects the at least one vital parameter under consideration of the adaptive calibration parameter.

16. The device as claimed in claim 14, wherein the signal discrepancy is a temporal signal discrepancy representing a time delay between the at least one of the at least two indicative signal components and the at least one auxiliary signal component.

17. The device as claimed in claim 14, wherein the calibration processor computes the calibration parameter under consideration of statistical adjustment computation measures applying the detected signal discrepancy

18. A method for extracting physiological information, comprising the steps of:

receiving a data stream derived from detected electromagnetic radiation, the data stream comprising a characteristic signal including physiological information indicative of at least one vital parameter, the characteristic signal comprising at least one indicative signal component representative of a detected spectral portion indicative of the at least one vital parameter, the data stream at least sectionally comprising at least one auxiliary signal component representative of a distinct spectral portion,

detecting a characteristic signal discrepancy between at least one of the at least one indicative signal component and the at least one auxiliary signal component, and

determining a signal calibration parameter under consideration of the detected signal discrepancy.

19. The method as claimed in claim 18, further comprising the steps of:

computing the calibration parameter under consideration of statistical adjustment computation measures applying the detected signal discrepancy, and

detecting the at least one vital parameter under consideration of the calibration parameter.

20. A computer readable non-transitory medium having instructions stored thereon which, when carried out on a computer, cause the computer to perform the steps of the method as claimed in claim 18.