System for camera-based vital sign measurement

• US 9,943,371 B2
• Filed: 06/11/2013
• Issued: 04/17/2018
• Est. Priority Date: 06/12/2012
• Status: Active Grant

• Current Assignee: Koninklijke Philips N.V.
• Original Assignee: Koninklijke Philips N.V.
• Inventors: Bresch, Erik, Muehlsteff, Jens, Tigges, Timo, Dubielczyk, Alexander, Shan, Caifeng
• Primary Examiner(s): Lamprecht, Joel
• Application Number:
  US14/401,659
• Publication Number:
  US 20150105670A1
• Time in Patent Office: 1,771 Days
• CPC Class Codes: A61B 2090/3937 Visible markers
• 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 5/02427 Details of sensor
• CPC Class Codes: A61B 5/0816 Measuring devices for examining respiratory frequency measuring frequency of electric signals G01R23/00
• CPC Class Codes: A61B 5/1127 using markers
• CPC Class Codes: A61B 5/113 occurring during breathing
• CPC Class Codes: A61B 5/117 Identification of persons methods or arrangements for recognising patterns, e.g. fingerprints, G06F18/00, G06V40/00; identification of persons by analysing their voice or speech G10L17/00
• CPC Class Codes: A61B 5/441 Skin evaluation, e.g. for skin disorder diagnosis
• CPC Class Codes: A61B 5/7207 of noise induced by motion artifacts
• CPC Class Codes: A61B 5/7278 Artificial waveform generation or derivation, e.g. synthesising signals from measured signals A61B5/327 takes precedence
• CPC Class Codes: A61B 90/39 Markers, e.g. radio-opaque or breast lesions markers

Abstract

The present disclosure relates to the measurement of vital signs such as a respiratory rate or a heart rate. In particular, a system (1) for determining a vital sign of a subject (100), comprising an imaging unit (2) for obtaining video data of the subject, a marker (10, 20, 60, 61) directly or indirectly attached to a body of the subject, wherein the marker comprises a graphical pattern (11, 21), an image processing unit (3) for detecting said marker in said video data, and an analysis unit (4) adapted to extract a vital sign parameter related to the vital sign of the subject from said video data and to determine the vital sign from said vital sign parameter. Further aspects of the disclosure relate to a device and a method for determining a vital sign of a subject and a computer program for carrying out said method.

Claims

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

at least one camera configured to obtain video data of the subject,

a marker attachable to a body of the subject, wherein the marker comprises a machine readable graphical pattern, and wherein the graphical pattern comprises encoded data including information about the subject,

at least one processor programmed to:

detect said marker in said video data;

determine said encoded data from said graphical pattern, and

extract in dependence of the encoded data a vital sign parameter of the subject from said video data;

determine a vital sign of the subject from said vital sign parameter; and

output the vital sign.

2. The system according to claim 1,

wherein at least one of:

said vital sign parameter is a respiratory movement of the subject and wherein said vital sign is a respiratory rate of the subject; and

said vital sign parameter is a temporal variation of a skin color of the subject and wherein said vital sign is a heart rate of the subject and/or a concentration of a substance in blood and/or tissue.

3. The system according to claim 1, wherein the marker further comprises:

an orientation indicator separate from the graphical pattern for indicating the orientation of the marker.

4. The system according to claim 1,

wherein the marker is arranged on a fabric that is adapted to contact the subject or a medical item that is adapted to contact the subject.

5. The system according to claim 1,

wherein the at least one processor is further programmed to:

extract the information about the subject from the graphical pattern of the marker;

associate the extracted information about the subject with the extracted vital sign parameter; and

at least one of;

display the extracted information and the extracted vital sign parameter; and

store the extracted information and the extracted vital sign parameter.

6. The system according to claim 1,

wherein the at least one processor is calibrated using a location and/or orientation of the marker.

7. The system according to claim 1, wherein the at least one processor is programmed to determine a measurement quality metric.

8. The system according to claim 1, wherein the at least one camera includes:

a first camera configured to obtain first video data of the subject;

a second camera for obtaining second video data of the subject, and

wherein the at least one processor is programmed to detect said marker in said first and second video data.

9. The system according to claim 8,

wherein the first camera comprises a filter for selectively transmitting light at a first wavelength, and

wherein the second camera comprises a second filter for selectively transmitting light at a second wavelength.

19. The system according to claim 1, wherein the encoded data includes a plurality of structural elements configured for a machine-readable determination of the at least one of the orientation and location of the graphical pattern of the marker.

20. The system according to claim 19, wherein the at least one processor is further programmed to:

determine at least one of a location and orientation of the plurality of structural elements of the graphical pattern of the marker; and

determine a vital sign parameter related to the vital sign of the subject from the determined at least one of a location and orientation of the plurality of structural elements of the graphical pattern of the marker.

10. A device for determining a vital sign of a subject comprising

at least one camera configured to obtain video data of the subject,

at least one processor programmed to:

detect a marker in said video data, wherein said marker is attachable to a body of the subject, wherein the marker comprises a machine readable graphical pattern, and wherein the graphical pattern comprises encoded data including information about the subject, and

determine said encoded data from said graphical pattern, and

extract in dependence of the encoded data a vital sign parameter related to the vital sign of the subject from said video data;

determine a vital sign of the subject from said vital sign parameter; and

output the vital sign.

15. The system according to claim 10, wherein the marker further comprises an orientation indicator separate from the graphical pattern for indicating the orientation of the marker.

16. The system according to claim 10, wherein the at least one processor is calibrated using a location and/or orientation of the marker.

17. The system according to claim 10, wherein the at least one camera includes:

a first camera configured to obtain first video data of the subject;

a second camera for obtaining second video data of the subject, and

wherein the at least one processor is programmed to detect said marker in said first and second video data.

18. The system according to claim 17,

wherein the first camera comprises a filter for selectively transmitting light at a first wavelength, and

wherein the second camera comprises a second filter for selectively transmitting light at a second wavelength.

11. A method for determining a vital sign of a subject, comprising:

attaching a marker to a body of the subject, wherein the marker comprises a machine readable graphical pattern and wherein the graphical pattern comprises encoded data including information about the subject,

with at least one camera, obtaining video data of the subject,

with at least one processor, detecting said marker in said video data and determining said encoded data from said graphical pattern,

with the at least one processor, extracting in dependence of the encoded data a vital sign parameter of the subject from said video data,

with the at least one processor, determining a vital sign of the subject from said vital sign parameter; and

with the at least one processor, outputting the vital sign.

12. A non-transitory computer-readable medium storing instructions for causing a computer to carry out the method as claimed in claim 11 when said computer program is carried out on the computer.

13. The method according to claim 11, further including:

with a first camera, obtaining first video data of the subject;

with a second camera, obtaining second video data of the subject, and

with the at least one processor, detecting said marker in said first and second video data.

14. The system according to claim 13, wherein said vital sign parameter is at least one of:

a respiratory movement of the subject and wherein said vital sign is a respiratory rate of the subject; and

a temporal variation of a skin color of the subject and wherein said vital sign is a heart rate of the subject and/or a concentration of a substance in blood and/or tissue.