Device, system and method for detection and processing of heartbeat signals

• US 10,285,602 B2
• Filed: 10/20/2017
• Issued: 05/14/2019
• Est. Priority Date: 01/24/2013
• Status: Active Grant

• Current Assignee: Empatica SRL (Empatica, Inc. (Massachusetts))
• Original Assignee: Empatica SRL (Empatica, Inc. (Massachusetts))
• Inventors: Tognetti, Simone, Cenci, Ivan, Resnati, Daniele, Garbarino, Maurizio, Lai, Matteo
• Primary Examiner(s): Manuel, George
• Application Number:
  US15/789,220
• Publication Number:
  US 20180214040A1
• Time in Patent Office: 571 Days
• CPC Class Codes: A61B 2562/0219 Inertial sensors, e.g. accelerometers, gyroscopes, tilt switches
• CPC Class Codes: A61B 5/0002 Remote monitoring of patients using telemetry, e.g. transmission of vital signals via a communication network A61B5/07 takes precedence; transmission systems for measured values G08C; transmission H04B; transmission of digital information H04L; wireless communication networks H04W
• CPC Class Codes: A61B 5/0071 by measuring fluorescence emission
• CPC Class Codes: A61B 5/02416 using photoplethysmograph signals, e.g. generated by infrared radiation A61B5/14552 takes precedence
• CPC Class Codes: A61B 5/0531 Measuring skin impedance
• CPC Class Codes: A61B 5/0533 Measuring galvanic skin response
• CPC Class Codes: A61B 5/7203 for noise prevention, reduction or removal
• CPC Class Codes: A61B 5/7214 using signal cancellation, e.g. based on input of two identical physiological sensors spaced apart, or based on two signals derived from the same sensor, for different optical wavelengths

Abstract

A heart beat detection device comprises at least one optical reflection sensor to be positioned on the skin of a person. The sensor unit is provided with a light emitter and a corresponding light receiver which converts the light reflected by the skin into an electric signal and comprises electrically adjustable optical filters connected to the emitter, to the receiver or to both of them in order to select, upon operation, a desired light wavelength and perform processing of the signals thus obtained in order to reinforce the heart beat signal. A system with this device and a detection method are also described.

Claims

1. A heart beat detection device comprising:

at least one optical reflection sensor unit configured to be placed on a person'"'"'s skin, the at least one optical sensor unit including a light emitter and a corresponding light receiver, the light emitter configured for emitting light onto the person'"'"'s skin, the light receiver configured to receive the light reflected by the skin and to convert it into an electric signal, characterized in that the at least one optical sensor unit further includes electrically adjustable optical filters connected to the emitter, to the receiver, or to both, in order to select, upon operation, a desired wavelength of the light emitted onto the person'"'"'s skin, of the light receivable by the light receiver, or both, wherein the electrically adjustable filters comprise Fabry-Perot monochromators.

2. The heart beat detection device according to claim 1, further comprising a processing block configured for receiving the electric signal from the light receiver and to control the electrically adjustable optical filters so as to select alternatively a first mode wherein the electric signal is a first electric signal depending on the variation in blood volume using the physical principles of absorption;

and a second mode wherein the electric signal is a second electric signal depending on the variation in blood volume using the physical principles of fluorescence, the processing block further configured for processing the first electric signal and the second electric signal to obtain a signal representing the heart rate.

3. The heart beat detection device according to claim 1, further comprising a processing block configured for receiving the electric signal from the light receiver and for controlling the electrically adjustable optical filters for optimizing the amplitude of the electric signal.

4. The heart beat detection device according to claim 1, comprising two optical sensor units arranged at a distance from each other, and a signal processing block connected to the optical sensor units, the signal processing block configured for estimating a blood pulse propagation time between the two optical sensor units, the signal processing block configured for modifying the signal detected by the at least one of the two optical sensor units depending on the variations in the estimated blood pulse propagation time.

5. The heart beat detection device according to claim 1, further comprising:

an electrical detection system configured for measuring the galvanic response of the skin; and

a processing block configured to obtain, from the measurement of galvanic response of the skin, a signal depending on the person'"'"'s heart beat, and to combine this signal with the signal detected by the at least one optical sensor unit.

6. The heart beat detection device according to claim 1, further comprising a processing block configured for receiving and processing the electric signal from the receiver, and a power supply element for the emitter of the at least one optical sensor unit, the power supply element configured for receiving commands from the processing block to vary the luminosity of the emitter for keeping the light received from the skin above a predefined minimum threshold.

7. A method for detecting the heart beat of a person comprising:

placing at least one optical reflection unit on the person'"'"'s skin, the at least one optical sensor unit including a light emitter and a corresponding light receiver, the light emitter configured for emitting light onto the person'"'"'s skin, the light receiver configured to convert the light reflected by the skin into an electric signal;

emitting, by the light emitter, light onto the person'"'"'s skin;

receiving, by the light receiver, light reflected by the skin;

converting, by the light receiver, the received light into an electric signal; and

receiving, by a processing block of a heart beat detection device comprising the at least one optical sensor unit, the electric signal from the light receiver, characterised in that

the device further comprises;

a first electrically adjustable optical filter connected to the light emitter, in order to select, upon operation, a wavelength of the light emitted onto the skin; and

a second electrically adjustable optical filter connected to the light receiver, in order to select, upon operation, a wavelength of the light receivable by the light receiver; and

the method further comprises;

controlling, by the processing block, the electrically adjustable optical filters so as to select alternatively an absorption mode wherein the electric signal is a first electric signal depending on the variation in blood volume using the physical principles of absorption, and a fluorescence mode, wherein the electric signal is a second electric signal depending on the variation in blood volume using the physical principles of fluorescence; and

processing, by the processing block, the first electric signal and the second electric signal so as to obtain a signal representing the heart beat.

8. The method according to claim 7, further comprising dynamically tuning the wavelengths of the electrically adjustable optical filters to maximize the first electric signal in the absorption mode and the second electric signal in the fluorescence mode, respectively.

9. The method according to claim 7, wherein:

placing the at least one optical reflection sensor unit comprises arranging two optical sensor units at a distance from each other; and

the method further comprises;

receiving, by a signal processing block, the signals from both optical sensor units;

estimating, by the signal processing block, a blood pulse propagation time between the two optical sensor units; and

modifying, by the signal processing block, the signal received from at least one of the optical sensor units depending on variations in the estimated blood pulse propagation time.

10. The method according to claim 7, further comprising:

measuring, by a system configured for measuring the acceleration of the device, a three-dimensional acceleration signal; and

modifying, via an adaptive numerical filter, the electric signal detected by the at least one optical sensor unit, based on the three-dimensional acceleration signal.

11. The method according to claim 7, further comprising:

measuring a galvanic response of the person'"'"'s skin;

obtaining a signal depending on the person'"'"'s heart beat based on the measured galvanic response; and

combining the signal depending on the person'"'"'s heart beat with the signal detected by the at least one optical sensor unit.

12. The method according to claim 7, further comprising using the signal representing the heart beat of the person to estimate one or more of the following physiological parameters of the person:

stress state, level of physical activity, physical condition, quality of sleep, and excitation level.

13. A heart beat detection device comprising:

at least one optical reflection sensor unit configured to be placed on a person'"'"'s skin, the at least one optical sensor unit including a light emitter and a corresponding light receiver, the light emitter configured for emitting light onto the person'"'"'s skin, the light receiver configured to receive the light reflected by the skin and to convert it into an electric signal, the at least one optical sensor unit further includes electrically adjustable optical filters connected to the emitter, to the receiver, or to both, in order to select, upon operation, a desired wavelength of the light emitted onto the person'"'"'s skin, of the light receivable by the light receiver, or both; and

a processing block configured for receiving the electric signal from the light receiver and to control the electrically adjustable optical filters so as to select alternatively a first mode wherein the electric signal is a first electric signal depending on the variation in blood volume using the physical principles of absorption; and

a second mode wherein the electric signal is a second electric signal depending on the variation in blood volume using the physical principles of fluorescence, the processing block further configured for processing the first electric signal and the second electric signal to obtain a signal representing the heart rate.

14. The heart beat detection device according to claim 13, wherein the electrically adjustable filters comprise Fabry-Perot monochromators.

15. The heart beat detection device according to claim 13, wherein the processing block is configured for receiving the electric signal from the light receiver and for controlling the electrically adjustable optical filters for optimizing the amplitude of the electric signal.

16. The heart beat detection device according to claim 13, further comprising:

two optical sensor units arranged at a distance from each other; and

a signal processing block connected to the optical sensor units, the signal processing block configured for estimating a blood pulse propagation time between the two optical sensor units, the signal processing block configured for modifying the signal detected by the at least one of the two optical sensor units depending on the variations in the estimated blood pulse propagation time.

17. The heart beat detection device according to claim 13, further comprising:

an electrical detection system configured for measuring the galvanic response of the skin, wherein the processing block is configured to obtain, from the measurement of galvanic response of the skin, a signal depending on the person'"'"'s heart beat, and to combine this signal with the signal detected by the at least one optical sensor unit.

18. The heart beat detection device according to claim 13, further comprising:

a system configured for measuring the acceleration of the device, wherein the processing block is configured for, based on the measured acceleration, modifying the signal detected by the at least one optical sensor unit.

19. The heart beat detection device according to claim 13, wherein the processing block is configured for receiving and processing the electric signal from the receiver, the device further comprising:

a power supply element for the emitter of the at least one optical sensor unit, the power supply element configured for receiving commands from the processing block to vary the luminosity of the emitter for keeping the light received from the skin above a predefined minimum threshold.

20. A heart beat detection device comprising:

at least one optical reflection sensor unit configured to be placed on a person'"'"'s skin, the at least one optical sensor unit including a light emitter and a corresponding light receiver, the light emitter configured for emitting light onto the person'"'"'s skin, the light receiver configured to receive the light reflected by the skin and to convert it into an electric signal, characterized in that the at least one optical sensor unit further includes electrically adjustable optical filters connected to the emitter, to the receiver, or to both, in order to select, upon operation, a desired wavelength of the light emitted onto the person'"'"'s skin, of the light receivable by the light receiver, or both; and

a processing block configured for receiving the electric signal from the light receiver and for controlling the electrically adjustable optical filters for optimizing the amplitude of the electric signal.

21. A heart beat detection device according to claim 20, wherein the electrically adjustable filters comprise Fabry-Perot monochromators.

22. The heart beat detection device according to claim 20, wherein the processing block is configured for receiving the electric signal from the light receiver and to control the electrically adjustable optical filters so as to select alternatively a first mode wherein the electric signal is a first electric signal depending on the variation in blood volume using the physical principles of absorption;

and a second mode wherein the electric signal is a second electric signal depending on the variation in blood volume using the physical principles of fluorescence, the processing block further configured for processing the first electric signal and the second electric signal to obtain a signal representing the heart rate.

23. The heart beat detection device according to claim 20, further comprising:

two optical sensor units arranged at a distance from each other; and

a signal processing block connected to the optical sensor units, the signal processing block configured for estimating a blood pulse propagation time between the two optical sensor units, the signal processing block configured for modifying the signal detected by the at least one of the two optical sensor units depending on the variations in the estimated blood pulse propagation time.

24. The heart beat detection device according to claim 20, further comprising:

an electrical detection system configured for measuring the galvanic response of the skin, wherein the processing block is configured to obtain, from the measurement of galvanic response of the skin, a signal depending on the person'"'"'s heart beat, and to combine this signal with the signal detected by the at least one optical sensor unit.

25. The heart beat detection device according to claim 20, further comprising:

a system configured for measuring the acceleration of the device, wherein the processing block is configured for, based on the measured acceleration, modifying the signal detected by the at least one optical sensor unit.

26. The heart beat detection device according to claim 20, wherein the processing block is configured for receiving and processing the electric signal from the receiver, the device further comprising:

a power supply element for the emitter of the at least one optical sensor unit, the power supply element configured for receiving commands from the processing block to vary the luminosity of the emitter for keeping the light received from the skin above a predefined minimum threshold.

27. A heart beat detection device comprising:

at least one optical reflection sensor unit configured to be placed on a person'"'"'s skin, the at least one optical sensor unit including a light emitter and a corresponding light receiver, the light emitter configured for emitting light onto the person'"'"'s skin, the light receiver configured to receive the light reflected by the skin and to convert it into an electric signal, characterized in that the at least one optical sensor unit further includes electrically adjustable optical filters connected to the emitter, to the receiver, or to both, in order to select, upon operation, a desired wavelength of the light emitted onto the person'"'"'s skin, of the light receivable by the light receiver, or both;

an electrical detection system configured for measuring the galvanic response of the skin; and

a processing block configured to obtain, from the measurement of galvanic response of the skin, a signal depending on the person'"'"'s heart beat, and to combine this signal with the signal detected by the at least one optical sensor unit.

28. A heart beat detection device according to claim 27, wherein the electrically adjustable filters comprise Fabry-Perot monochromators.

29. The heart beat detection device according to claim 27, wherein the processing block is configured for receiving the electric signal from the light receiver and to control the electrically adjustable optical filters so as to select alternatively a first mode wherein the electric signal is a first electric signal depending on the variation in blood volume using the physical principles of absorption;

and a second mode wherein the electric signal is a second electric signal depending on the variation in blood volume using the physical principles of fluorescence, the processing block further configured for processing the first electric signal and the second electric signal to obtain a signal representing the heart rate.

30. The heart beat detection device according to claim 27, wherein the processing block is configured for receiving the electric signal from the light receiver and for controlling the electrically adjustable optical filters for optimizing the amplitude of the electric signal.

31. The heart beat detection device according to claim 27, further comprising:

an electrical detection system configured for measuring the galvanic response of the skin, wherein the processing block is configured to obtain, from the measurement of galvanic response of the skin, a signal depending on the person'"'"'s heart beat, and to combine this signal with the signal detected by the at least one optical sensor unit.

32. The heart beat detection device according to claim 27, further comprising:

a system configured for measuring the acceleration of the device, wherein the processing block is configured for, based on the measured acceleration, modifying the signal detected by the at least one optical sensor unit.

33. The heart beat detection device according to claim 27, wherein the processing block is configured for receiving and processing the electric signal from the receiver, the device further comprising:

a power supply element for the emitter of the at least one optical sensor unit, the power supply element configured for receiving commands from the processing block to vary the luminosity of the emitter for keeping the light received from the skin above a predefined minimum threshold.

34. A heart beat detection device comprising:

at least one optical reflection sensor unit configured to be placed on a person'"'"'s skin, the at least one optical sensor unit including a light emitter and a corresponding light receiver, the light emitter configured for emitting light onto the person'"'"'s skin, the light receiver configured to receive the light reflected by the skin and to convert it into an electric signal, characterized in that the at least one optical sensor unit further includes electrically adjustable optical filters connected to the emitter, to the receiver, or to both, in order to select, upon operation, a desired wavelength of the light emitted onto the person'"'"'s skin, of the light receivable by the light receiver, or both;

an electrical detection system configured for measuring the galvanic response of the skin; and

a processing block configured to obtain, from the measurement of galvanic response of the skin, a signal depending on the person'"'"'s heart beat, and to combine this signal with the signal detected by the at least one optical sensor unit.

35. A heart beat detection device according to claim 34, wherein the electrically adjustable filters comprise Fabry-Perot monochromators.

36. The heart beat detection device according to claim 34, wherein the processing block is configured for receiving the electric signal from the light receiver and to control the electrically adjustable optical filters so as to select alternatively a first mode wherein the electric signal is a first electric signal depending on the variation in blood volume using the physical principles of absorption;

and a second mode wherein the electric signal is a second electric signal depending on the variation in blood volume using the physical principles of fluorescence, the processing block further configured for processing the first electric signal and the second electric signal to obtain a signal representing the heart rate.

37. The heart beat detection device according to claim 34, wherein the processing block is configured for receiving the electric signal from the light receiver and for controlling the electrically adjustable optical filters for optimizing the amplitude of the electric signal.

38. The heart beat detection device according to claim 34, further comprising:

two optical sensor units arranged at a distance from each other; and

a signal processing block connected to the optical sensor units, the signal processing block configured for estimating a blood pulse propagation time between the two optical sensor units, the signal processing block configured for modifying the signal detected by the at least one of the two optical sensor units depending on the variations in the estimated blood pulse propagation time.

39. The heart beat detection device according to claim 34, further comprising:

a system configured for measuring the acceleration of the device, wherein the processing block is configured for, based on the measured acceleration, modifying the signal detected by the at least one optical sensor unit.

40. The heart beat detection device according to claim 34, wherein the processing block is configured for receiving and processing the electric signal from the receiver, the device further comprising:

a power supply element for the emitter of the at least one optical sensor unit, the power supply element configured for receiving commands from the processing block to vary the luminosity of the emitter for keeping the light received from the skin above a predefined minimum threshold.

41. A heart beat detection device comprising:

at least one optical reflection sensor unit configured to be placed on a person'"'"'s skin, the at least one optical sensor unit including a light emitter and a corresponding light receiver, the light emitter configured for emitting light onto the person'"'"'s skin, the light receiver configured to receive the light reflected by the skin and to convert it into an electric signal, characterized in that the at least one optical sensor unit further includes electrically adjustable optical filters connected to the emitter, to the receiver, or to both, in order to select, upon operation, a desired wavelength of the light emitted onto the person'"'"'s skin, of the light receivable by the light receiver, or both;

a system configured for measuring the acceleration of the device; and

a processing block configured for, based on the measured acceleration, modifying the signal detected by the at least one optical sensor unit, wherein the electrically adjustable filters comprise Fabry-Perot monochromators.

42. The heart beat detection device according to claim 41, wherein the processing block is configured for receiving the electric signal from the light receiver and to control the electrically adjustable optical filters so as to select alternatively a first mode wherein the electric signal is a first electric signal depending on the variation in blood volume using the physical principles of absorption;

and a second mode wherein the electric signal is a second electric signal depending on the variation in blood volume using the physical principles of fluorescence, the processing block further configured for processing the first electric signal and the second electric signal to obtain a signal representing the heart rate.

43. The heart beat detection device according to claim 41, wherein the processing block is configured for receiving the electric signal from the light receiver and for controlling the electrically adjustable optical filters for optimizing the amplitude of the electric signal.

44. The heart beat detection device according to claim 41, further comprising:

two optical sensor units arranged at a distance from each other; and

a signal processing block connected to the optical sensor units, the signal processing block configured for estimating a blood pulse propagation time between the two optical sensor units, the signal processing block configured for modifying the signal detected by the at least one of the two optical sensor units depending on the variations in the estimated blood pulse propagation time.

45. The heart beat detection device according to claim 41, further comprising:

an electrical detection system configured for measuring the galvanic response of the skin, wherein the processing block is configured to obtain, from the measurement of galvanic response of the skin, a signal depending on the person'"'"'s heart beat, and to combine this signal with the signal detected by the at least one optical sensor unit.

46. The heart beat detection device according to claim 41, wherein the processing block is configured for receiving and processing the electric signal from the receiver, the device further comprising:

a power supply element for the emitter of the at least one optical sensor unit, the power supply element configured for receiving commands from the processing block to vary the luminosity of the emitter for keeping the light received from the skin above a predefined minimum threshold.