PHYSIOLOGICAL PROPERTY DETERMINATION APPARATUS

• US 20170172435A1
• Filed: 02/13/2015
• Published: 06/22/2017
• Est. Priority Date: 03/06/2014
• Status: Active Grant

• Current Assignee: Koninklijke Philips N.V.
• Original Assignee: Koninklijke Philips N.V.
• Inventors: Presura, Cristian Nicolae
• Granted Patent: US 11,134,854 B2
• Time in Patent Office: Days
• CPC Class Codes: A61B 5/02416 using photoplethysmograph signals, e.g. generated by infrared radiation A61B5/14552 takes precedence
• CPC Class Codes: A61B 5/02427 Details of sensor
• CPC Class Codes: A61B 5/02438 with portable devices, e.g. worn by the patient
• CPC Class Codes: A61B 5/681 Wristwatch-type devices
• CPC Class Codes: A61B 5/721 using a separate sensor to detect motion or using motion information derived from signals other than the physiological signal to be measured

Abstract

The invention relates to a physiological property determination apparatus (1) for determining a physiological property like a pulse rate of a person. The apparatus may be configured to be worn on the wrist like a watch. A controller (8) separately controls at least two light sources (3, 4, 5) for emitting at least two light beams having different wavelengths into tissue of the person and a light detector (6) having a two-dimensional detection surface (12) detects light, which has travelled through the tissue, wavelength-dependently and generates a wavelength-dependent two-dimensional image based on the detected light. Based on the generated wavelength-dependent two-dimensional image the physiological property is determined. The separate control of the light sources allows for an independent optimization of the illumination and detection processes for each wavelength, which in turn can lead to an improved determination of the physiological property based on the wavelength-dependent two-dimensional image.

Claims

1. A physiological property determination apparatus for determining a physiological property of a person, the physiological property determination apparatus comprising:

at least two light sources for emitting at least two light beams having different wavelengths into tissue of the person,

a light detector having a two-dimensional detection surface for detecting light, which has travelled through the tissue, wavelength-dependently and for generating a wavelength-dependent two-dimensional image based on the detected light, wherein the two-dimensional detection surface comprises a two-dimensional arrangement of detection elements, each detection element generating wavelength-dependent detection signals for generating the wavelength-dependent two-dimensional image,

a controller for separately controlling the intensities of the light beams of the different light sources such that the light detector is not overloaded, and

a physiological property determination unit for determining the physiological property based on the generated wavelength-dependent two-dimensional image, wherein the physiological property by linearly combining the detection signals, wherein, before linearly combining the detection signals, the detection signals are weighted, wherein the detection signals, which correspond to tissue regions where the perfusion is larger, obtain a larger weight than detection signals which correspond to tissue regions where the perfusion is smaller.

2. The physiological property determination apparatus as defined in claim 1, wherein the at least two light sources include three light sources emitting three different light beams having different wavelengths.

3. The physiological property determination apparatus as defined in claim 2, wherein the light sources are adapted to emit blue, green and red light beams.

4. The physiological property determination apparatus as defined in claim 1, wherein the apparatus further comprises a spacer being transparent for the light beams, wherein the spacer is arranged in front of the detection surface.

5. The physiological property determination apparatus as defined in claim 1, wherein the two-dimensional detection surface comprises a two-dimensional arrangement of detection elements, each detection element generating a wavelength-dependent detection signal for generating the wavelength-dependent two-dimensional image, wherein the physiological property determination unit is adapted to determine the physiological property a) by individually processing the detection signal generated by different detection elements or b) by determining for different groups of detection elements group detection signals based on the detection signals generated by the respective group of detection elements and by individually processing the group detection signals.

6. The physiological property determination apparatus as defined in claim 5, wherein the physiological property determination unit is adapted to determine a degree of disturbance of the respective detection signal or group detection signal by motion and to determine the physiological property based on detection signals or group detection signals having a degree of disturbance being smaller than a disturbance threshold.

7. The physiological property determination apparatus as defined in claim 6, wherein the physiological property determination apparatus further comprises a motion sensor for generating a motion signal being indicative of a motion of the physiological property determination apparatus and wherein the physiological property determination unit is adapted to determine the degree of disturbance of the respective detection signal or group detection signal based on the motion signal.

9. The physiological property determination apparatus as defined in claim 1, wherein the at least two light sources and the light detector are adapted to generate the wavelength-dependent two-dimensional image such that it is temporally dependent and comprises at least two two-dimensional image frames for different times, wherein the physiological property determination unit is adapted to determine corresponding regions in different image frames and to determine the physiological property based on these corresponding regions in the different image frames.

10. The physiological property determination apparatus as defined in claim 1, wherein the controller is adapted to control the light sources such that the intensities of the light beams are varied.

11. The physiological property determination apparatus as defined in claim 1, wherein the physiological property determination apparatus further comprises an attaching element for attaching at least the light sources and the light detector to the wrist of the person.

12. The physiological property determination apparatus as defined in claim 1, wherein the physiological property determination unit is adapted to determine the pulse rate as the physiological property.

8. (canceled)

13. A physiological property determination method for determining a physiological property of a person, the physiological property determination method comprising:

emitting at least two light beams having different wavelengths into tissue of the person by at least two light sources,

detecting light, which has travelled through the tissue, wavelength-dependently and generating a wavelength-dependent two-dimensional image based on the detected light by a light detector having a two-dimensional detection surface, wherein the two-dimensional detection surface comprises a two-dimensional arrangement of detection elements, each detection element generating wavelength-dependent detection signals for generating the wavelength-dependent two-dimensional image,

separately controlling the intensities of the light beams of the different light sources by a controller such that the light detector is not overloaded, and

determining the physiological property based on the generated wavelength-dependent two-dimensional image by a physiological property determination unit, wherein the physiological property determination unit determines the physiological property by linearly combining the detection signals, wherein, before linearly combining the detection signals, the detection signals are weighted, wherein the detection signals, which correspond to tissue regions where the perfusion is larger, obtain a larger weight than detection signals which correspond to tissue regions where the perfusion is smaller.

14. (canceled)