System and method for capturing and decontaminating photoplethysmopgraphy (PPG) signals in a vehicle

• US 10,153,796 B2
• Filed: 04/27/2015
• Issued: 12/11/2018
• Est. Priority Date: 04/06/2013
• Status: Active Grant

• Current Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Original Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Inventors: Fung, Kin C., Dick, Timothy J., Palande, Dhanashree
• Primary Examiner(s): Yi, Roy Y
• Assistant Examiner(s): Aiello, Jeffrey
• Application Number:
  US14/697,593
• Publication Number:
  US 20150229341A1
• Time in Patent Office: 1,324 Days
• CPC Class Codes: A61B 5/0059 using light, e.g. diagnosis by transillumination, diascopy, fluorescence A61B5/0093, A61B5/1455, A61B5/02416 and A61B5/0261 take precedence
• CPC Class Codes: A61B 5/18 for vehicle drivers or machine operators
• CPC Class Codes: A61B 5/7207 of noise induced by motion artifacts
• CPC Class Codes: B60R 25/25 using biometry
• CPC Class Codes: G06F 2218/10 by analysing the shape of a waveform, e.g. extracting parameters relating to peaks
• CPC Class Codes: G06F 2218/12 Classification; Matching
• CPC Class Codes: G06V 40/15 Biometric patterns based on physiological signals, e.g. heartbeat, blood flow
• CPC Class Codes: H04B 1/10 Means associated with receiver for limiting or suppressing noise or interference

Abstract

A system and method for processing photoplethysmography (PPG) signals in a vehicle. The system and method include receiving a PPG waveform signal from an optical sensor. The system and method also include processing a PPG measurement signal based on the PPG waveform signal. The system and method additionally include receiving a noise waveform signal from at least one of: a seat assembly sensor, a vehicle sensor, and a vehicle system. Additionally, the system and method include processing a motion artifacts measurement signal based on the noise waveform signal. The system and method further include processing a refined PPG signal to suppress the motion artifacts measurement signal from the PPG measurement signal.

Claims

1. A computer-implemented method for processing photoplethysmography (PPG) signals in a vehicle, comprising:

receiving a plurality of PPG waveform signals from a plurality of optical sensors;

processing a PPG measurement signal based on the plurality of PPG waveform signals, wherein processing the PPG measurement signal includes aggregating the plurality of PPG waveform signals that are received from the plurality of optical sensors into the PPG measurement signal;

receiving a noise waveform signal from at least one of;

a seat assembly sensor, a vehicle sensor, and a vehicle system;

processing a motion artifacts measurement signal based on the noise waveform signal;

processing a refined PPG signal to suppress the motion artifacts measurement signal from the PPG measurement signal, wherein processing the refined PPG signal includes filtering a segment of the PPG measurement signal that is attributed to motion artifacts represented within the motion artifacts measurement signal; and

determining at least one driver state associated with a driver of the vehicle based on the refined PPG signal and controlling at least one vehicle system of the vehicle based on the driver state associated with the driver.

2. The computer-implemented method of claim 1, wherein the plurality of optical sensors are included within at least one sensor assembly that is mechanically coupled to a vehicle seat in the vehicle.

3. The computer-implemented method of claim 2, wherein receiving the plurality of PPG waveform signals from the plurality of optical sensors includes the plurality of optical sensors emitting a plurality of light sources at a plurality of frequencies, wherein the plurality of optical sensors is also configured to increase or decrease the intensity of light emitted from the plurality of light sources in order to emit a plurality of wavelengths based on the location of the plurality of optical sensors and the type of measurement that is being output by the plurality of optical sensors.

4. The computer-implemented method of claim 1, wherein processing the PPG measurement signal includes aggregating the plurality of PPG waveform signals that represent a consistent measurement of PPG readings associated with the driver, wherein at least one PPG waveform signal is discarded that is determined to be inconsistent with the plurality of PPG waveform signals.

5. The computer-implemented method of claim 1, wherein processing the PPG measurement signal includes determining an optimum PPG waveform signal and converting the optimum PPG waveform signal into the PPG measurement signal, wherein the optimum PPG waveform signal is determined to be a PPG waveform signal of the plurality of PPG waveform signals that is output by the plurality of optical sensors that emits a lowest amount of LED light intensity.

6. The computer-implemented method of claim 1, wherein processing the motion artifacts measurement signal includes aggregating a plurality of noise waveform signals received from at least one of:

the seat assembly sensor, the vehicle sensor, and the vehicle system into the motion artifacts measurement signal.

7. The computer-implemented method of claim 6, wherein aggregating the plurality of noise waveform signals includes assigning a weight to each noise waveform signal received from at least one of:

the seat assembly sensor, the vehicle sensor, and the vehicle system, and aggregating the plurality of noise waveform signals to each impact the motion artifacts measurement signal based on an assigned weight.

8. The computer-implemented method of claim 1, wherein processing the refined PPG signal includes filtering the PPG measurement signal, wherein filtering the PPG measurement signal includes determining a segment of the PPG measurement signal that includes data that is attributed to the motion artifacts measurement signal, filtering the segment of the PPG measurement signal that is attributed to the motion artifacts as representing the motion artifacts measurement signal, and outputting the refined PPG signal, wherein the refined PPG signal is indicative of a measurement of the driver'"'"'s blood volume and blood composition that is decontaminated from the one or more motion artifacts associated with the driver of the vehicle and the vehicle.

9. A system for processing photoplethysmography (PPG) signals in a vehicle, comprising:

a memory storing instructions when executed by a processor cause the processor to;

receive a plurality of PPG waveform signals from a plurality of optical sensors;

process a PPG measurement signal based on the plurality of PPG waveform signals, wherein processing the PPG measurement signal includes aggregating the plurality of PPG waveform signals that are received from the plurality of optical sensors into the PPG measurement signal;

receive a noise waveform signal from at least one of;

a seat assembly sensor, a vehicle sensor, and a vehicle system and processes a motion artifacts measurement signal based on the noise waveform signal;

process a refined PPG signal to suppress the motion artifacts measurement signal from the PPG measurement signal, wherein processing the refined PPG signal includes filtering a segment of the PPG measurement signal that is attributed to motion artifacts represented within the motion artifacts measurement signal; and

determine at least one driver state associated with a driver of the vehicle based on the refined PPG signal and control at least one vehicle system of the vehicle based on the driver state associated with the driver.

10. The system of claim 9, wherein the plurality of optical sensors are included within at least one sensor assembly that is mechanically coupled to a vehicle seat in the vehicle.

11. The system of claim 10, wherein the plurality of optical sensors is configured to emit a plurality of light sources at a plurality of frequencies, wherein the plurality of optical sensors is also configured to increase or decrease the intensity of light emitted from the plurality of light sources in order to emit a plurality of wavelengths based on the location of the plurality of optical sensors and the type of measurement that is being output by the plurality of optical sensors.

12. The system of claim 9, wherein processing the PPG measurement signal includes aggregating the plurality of PPG waveform signals that represent a consistent measurement of PPG readings associated with the driver, wherein at least one PPG waveform signal is discarded that is determined to be inconsistent with the plurality of PPG waveform signals.

13. The system of claim 9, wherein processing the PPG measurement signal includes determining an optimum PPG waveform signal and converting the optimum PPG waveform signal into the PPG measurement signal, wherein the optimum PPG waveform signal is determined to be a PPG waveform signal of the plurality of PPG waveform signals that is output by the plurality of optical sensors that emits a lowest amount of LED light intensity.

14. The system of claim 9, wherein processing the motion artifacts measurement signal includes aggregating a plurality of noise waveform signals received from at least one of:

the seat assembly sensor, the vehicle sensor, and the vehicle system into the motion artifacts measurement signal.

15. The system of claim 14, wherein aggregating the plurality of noise waveform signals includes assigning a weight to each noise waveform signal received from at least one of:

the seat assembly sensor, the vehicle sensor, and the vehicle system, wherein the motion artifacts determinant module aggregates the plurality of noise waveform signals to each impact the motion artifacts measurement signal based on an assigned weight.

16. The system of claim 9, wherein processing the refined PPG signal includes filtering the PPG measurement signal, wherein filtering the PPG measurement signal includes determining a segment of the PPG measurement signal that includes data that is attributed to the motion artifacts measurement signal, filtering the segment of the PPG measurement signal that is attributed to the motion artifacts as representing the motion artifacts measurement signal, and outputting the refined PPG signal, wherein the refined PPG signal is indicative of a measurement of the driver'"'"'s blood volume and blood composition that is decontaminated from the one or more motion artifacts associated with the driver of the vehicle and the vehicle.

17. A non-transitory computer readable storage medium storing instructions that when executed by a computer, which includes a processor perform a method comprising:

receiving a plurality of PPG waveform signals from a plurality of optical sensors;

processing a PPG measurement signal based on the plurality of PPG waveform signals, wherein processing the PPG measurement signal includes aggregating the plurality of PPG waveform signals that are received from the plurality of optical sensors into the PPG measurement signal;

receiving a noise waveform signal from at least one of;

a seat assembly sensor, a vehicle sensor, and a vehicle system;

processing a motion artifacts measurement signal based on the noise waveform signal;

processing a refined PPG signal to suppress the motion artifacts measurement signal from the PPG measurement signal, wherein processing the refined PPG signal includes filtering a segment of the PPG measurement signal that is attributed to motion artifacts represented within the motion artifacts measurement signal; and

determining at least one driver state associated with a driver of the vehicle based on the refined PPG signal and controlling at least one vehicle system of the vehicle based on the driver state associated with the driver.

18. The computer readable storage medium of claim 17, wherein receiving the plurality of PPG waveform signals from the plurality of optical sensors includes the plurality of optical sensors emitting a plurality of light sources at a plurality of frequencies, wherein the plurality of optical sensors is also configured to increase or decrease the intensity of light emitted from the plurality of light sources in order to emit a plurality of wavelengths based on the location of the plurality of optical sensors and the type of measurement that is being output by the plurality of optical sensors.

19. The computer readable storage medium of claim 17, wherein processing the PPG measurement signal includes aggregating the plurality of PPG waveform signals that represent a consistent measurement of PPG readings associated with the driver, wherein at least one PPG waveform signal is discarded that is determined to be inconsistent with the plurality of PPG waveform signals.

20. The computer readable storage medium of claim 17, wherein processing the refined PPG signal includes filtering the PPG measurement signal, wherein filtering the PPG measurement signal includes determining a segment of the PPG measurement signal that includes data that is attributed to the motion artifacts measurement signal, filtering the segment of the PPG measurement signal that is attributed to the motion artifacts as representing the motion artifacts measurement signal, and outputting the refined PPG signal, wherein the refined PPG signal is indicative of a measurement of the driver'"'"'s blood volume and blood composition that is decontaminated from the one or more motion artifacts associated with the driver of the vehicle and the vehicle.