Method and device for recognising the condition of vehicle occupants

Patent metadata

Field	Value
Publication number	US-10011176-B2
Application number	US-201615519055-A
Country	US
Kind code	B2
Filing date	Jan 14, 2016
Priority date	Jan 20, 2015
Publication date	Jul 3, 2018
Grant date	Jul 3, 2018

Abstract

The physical and/or mental condition of a vehicle occupant can be recognized on the basis of a BCG (ballistocardiograph) signal, which is obtained by means of a BCG sensor. The BCG sensor is an MEM sensor; a cross-correlation of the BCG signal with heartbeat parameters is carried out in an optimum filter, which heartbeat parameters are varied within predefined limits to find a maximum of the cross-correlation function; and probable peaks are located in a cross-correlation function found in this manner and the heart rate is calculated therefrom.

First claim

The invention claimed is:

1. A method for identifying a condition of a vehicle occupant on the basis of ballistocardiograph (BCG) data, comprising:
obtaining the BCG data of the vehicle occupant from a BCG sensor, wherein the BCG sensor is a micro-electrical-mechanical (MEM) sensor;
carrying out a cross-correlation function of a BCG signal with heartbeat parameters in an optimum filter, wherein the heartbeat parameters are varied within predefined limits to find a maximum of the cross-correlation function;
locating probable peaks in the cross-correlation function;
calculating a heart rate from the probable peaks; and
wherein the heartbeat parameters include a plurality of heartbeat patterns that are generated by frequency variation of one or more predefined heartbeat patterns within natural heartbeat limits.

2. The method of claim 1 , wherein the heartbeat parameters include a plurality of heartbeat patterns that are generated by frequency variation of a single predefined heartbeat pattern within natural heartbeat limits.

3. The method of claim 1 , wherein a maximum of the cross-correlation function is found by short-term interval cross-correlation of the BCG signal with the generated heartbeat patterns.

4. The method of claim 1 , wherein, after a maximum of the cross-correlation function has been found and before the probable peaks are located, the BCG signal is subjected to an adaptive window function.

5. The method of claim 1 , wherein, after at least one of (a) the maximum of the cross-correlation function has been found and (b) an adaptive window function has been applied, and before the probable peaks are located, a separate parameter adaptation is carried out to optimize the peak amplitudes.

6. The method of claim 1 , wherein located peaks are filtered to exclude unrecognized peaks from the calculation of the heart rate.

7. The method of claim 1 , wherein the BCG sensor is a seat sensor.

8. The method of claim 1 , further comprising determining a blood pressure of the vehicle occupant in addition to the heart rate.

9. The method of claim 1 , wherein a first seat damping coefficient and a second support coefficient are used to obtain the heart rate.

10. A system, comprising:
a ballistocardiograph (BCG) sensor, wherein the BCG sensor is a micro-electrical-mechanical (MEM) sensor; and
a computing device programmed to
obtain the BCG data of a vehicle occupant from the BCG sensor;
carry out a cross-correlation function of a BCG signal with heartbeat parameters in an optimum filter, wherein the heartbeat parameters are varied within predefined limits to find a maximum of the cross-correlation function;
locate probable peaks in the cross-correlation function;
calculate a heart rate from the probable peaks; and
wherein the computing device is further programmed to include in the heartbeat parameters a plurality of heartbeat patterns that are generated by frequency variation of one or more predefined heartbeat patterns within natural heartbeat limits.

11. The system of claim 10 , the computing device further programmed to include in the heartbeat parameters a plurality of heartbeat patterns that are generated by frequency variation of a single predefined heartbeat pattern within natural heartbeat limits.

12. The system of claim 10 , the computing device further programmed to find a maximum of the cross-correlation function by short-term interval cross-correlation of the BCG signal with the generated heartbeat patterns.

13. The system of claim 10 , the computing device further programmed to, after a maximum of the cross-correlation function has been found and before the probable peaks are located, subject the BCG signal subjected to an adaptive window function.

14. The system of claim 10 , the computing device further programmed to, after at least one of (a) the maximum of the cross-correlation function has been found and (b) an adaptive window function has been applied, and before the probable peaks are located, carry out a separate parameter adaptation to optimize the peak amplitudes.

15. The system of claim 10 , the computing device further programmed to filter located peaks to exclude unrecognized peaks from the calculation of the heart rate.

16. The system of claim 10 , wherein the BCG sensor is a vehicle seat sensor.

17. The system of claim 10 , the computing device further programmed to determine a blood pressure of a vehicle occupant in addition to the heart rate.

18. The system of claim 10 , the computing device further programmed to use a first seat clamping coefficient and a second support coefficient to obtain the heart rate.

19. A method for identifying a condition of a vehicle occupant on the basis of ballistocardiograph (BCG) data, comprising:
obtaining the BCG data of the vehicle occupant from a BCG sensor, wherein the BCG sensor is a micro-electrical-mechanical (MEM) sensor;
carrying out a cross-correlation function of a BCG signal with heartbeat parameters in an optimum filter, wherein the heartbeat parameters are varied within predefined limits to find a maximum of the cross-correlation function;
locating probable peaks in the cross-correlation function;
calculating a heart rate from the probable peaks; and
wherein a maximum of the cross-correlation function is found by short-term interval cross-correlation of the BCG signal with the generated heartbeat patterns.

20. A system, comprising:
a ballistocardiograph (BCG) sensor, wherein the BCG sensor is a micro-electrical-mechanical (MEM) sensor; and
a computing device programmed to
obtain the BCG data of a vehicle occupant from the BCG sensor;
carry out a cross-correlation function of a BCG signal with heartbeat parameters in an optimum filter, wherein the heartbeat parameters are varied within predefined limits to find a maximum of the cross-correlation function;
locate probable peaks in the cross-correlation function;
calculate a heart rate from the probable peaks; and
find a maximum of the cross-correlation function by short-term interval cross-correlation of the BCG signal with the generated heartbeat patterns.

Assignees

• Ford Global Tech Llc
• Ford Werke Gmbh

Inventors

• Gussen Uwe
• Arndt Dr Habil Christoph
• Stefan Frederic

Classifications

• A61B5/725

  using specific filters therefor, e.g. Kalman or adaptive filters (specific diagnostics methods using using bioelectric or biomagnetic signals A61B5/316) · CPC title

• G06F17/15

  Correlation function computation {including computation of convolution operations (arithmetic circuits for sum of products per se, e.g. multiply-accumulators G06F7/5443; digital filters, e.g. FIR, IIR, adaptive filters H03H17/00)} · CPC title

• A61B5/0245

  by using sensing means generating electric signals, {i.e. ECG signals} · CPC title

• B60K28/06 Primary

  responsive to incapacity of driver · CPC title

• B60W2040/0872

  Driver physiology · CPC title