Method and Device for Determining the Vital Functions of a Vehicle Occupant

Abstract

A method for determining the vital functions of a vehicle occupant enables precise measurements and is easy to use without negatively affecting the vehicle occupant. The method includes determining the vital functions of the vehicle occupant using a sensor device integrated in a vehicle seat of a motor vehicle, and acquiring measurement signals of the vehicle occupant from which cardiogram signals are acquired. The method further includes using an evaluation unit to ascertain the vital functions of the vehicle occupant from the cardiogram signals. The sensor device is a magnetic field sensor device, and the cardiogram signals are magnetic cardiogram signals.

Claims

1. A method for determining vital functions of a vehicle occupant, comprising: acquiring measurement signals of the vehicle occupant using a sensor device integrated in a vehicle seat of a motor vehicle; acquiring cardiogram signals from the measurement signals; and ascertaining the vital functions of the vehicle occupant from the cardiogram signals using an evaluation unit, wherein the sensor device is a magnetic field sensor device, and wherein the cardiogram signals are magnetic cardiogram signals.

2. The method according to claim 1, wherein: the magnetic field sensor device is a gradiometer comprising at least two magnetic field sensors disposed at spaced-apart positions, the at least two magnetic field sensors measure a magnetic field at the spaced-apart positions and generate the measurement signals, and the cardiogram signals are ascertained as a difference signal of the measurement signals of the at least two magnetic field sensors.

3. The method according to claim 1, wherein a plurality of the magnetic field sensor devices are provided, and/or the magnetic field sensor device is automatically positioned in proximity to a heart of the vehicle occupant.

4. The method according to claim 2, wherein: the at least two magnetic field sensors are nitrogen vacancy sensors, and each of the nitrogen vacancy sensors comprises a diamond, optical filters, photodetectors, and a microwave resonator and/or a laser.

5. The method according to claim 2, wherein: the magnetic cardiogram signals are filtered by the evaluation unit with a high-pass filter and/or a low-pass filter, and/or the evaluation unit ascertains a bias drift of the at least two magnetic field sensors by averaging the magnetic cardiogram signals over a period of time that is greater than a heart rate of the vehicle occupant.

6. The method according to claim 1, wherein the evaluation unit ascertains vital parameters from the magnetic cardiogram signals including a heart rate, a heart rate variability, and/or a duration and/or amplitude of ECG-equivalent signal changes including P wave, QRS complex, T wave, and corresponding combinations.

7. The method according to claim 6, wherein: the evaluation unit determines the vital functions of the vehicle occupant based on the vital parameters using a statistical classification method, and the evaluation unit creates an assessment of whether the vehicle occupant is tired or awake, stressed or relaxed, whether an acute or chronic abnormality in cardiac function is present or imminent, and/or whether there are underlying diseases that impair cardiac function of the vehicle occupant.

8. The method according to claim 7, wherein: further measures are taken based on the assessment, and the further measures include an emergency stop of the motor vehicle, placing an emergency call, and/or transmitting the vital functions to medical personnel.

9. The method according to claim 7, wherein: the evaluation unit sends the vital functions and/or the assessment to other motor vehicle systems including an infotainment system, a driver assistance system, and/or a comfort system.

10. A device for determining vital functions of a vehicle occupant, comprising: a sensor device installed in a vehicle seat of a vehicle, and configured to ascertain measurement signals of a vehicle occupant, the sensor device embodied as a magnetic field sensor device; and an evaluation unit configured to ascertain the vital functions of the vehicle occupant from cardiogram signals obtained from the measurement signals, wherein the cardiogram signals are magnetic cardiogram signals.

11. The device according to claim 10, wherein the evaluation unit is disposed in the vehicle seat.

12. A motor vehicle comprising: a vehicle seat; and a device for determining vital functions of an occupant of the motor vehicle, the occupant sitting in the vehicle seat, the device comprising (i) a sensor device installed in the vehicle seat and configured to ascertain measurement signals of the occupant, the sensor device embodied as a magnetic field sensor device, and (ii) an evaluation unit configured to ascertain the vital functions of the occupant from cardiogram signals obtained from the measurement signals, and wherein the cardiogram signals are magnetic cardiogram signals.

Description

[0044] The figures show:

[0045] FIG. 1 a vehicle seat comprising a magnetic field sensor device,

[0046] FIG. 2 a magnetic field sensor device, and

[0047] FIG. 3 a flowchart of the method.

[0048] A method 100 for determining the vital functions of a vehicle occupant 10 is explained in more detail in the following with reference to the figures.

[0049] According to the method, a vehicle seat 11 of a not further depicted motor vehicle is provided and is shown in FIG. 1. A sensor device 13 is disposed in the vehicle seat 11, in particular in the backrest 12. The sensor device 13 is configured as a magnetic field sensor device 14 and acquires measurement signals of a heart 15 of the vehicle occupant 10 (FIG. 3, Step 110). The magnetic field sensor device 14 comprises two magnetic field sensors 16a, 16b which are disposed at spaced-apart positions. A first magnetic field sensor 16a is disposed closer to the heart 15 of the vehicle occupant 10 than a second magnetic field sensor 16b. The two magnetic field sensors 16a, 16b thus measure the magnetic field at the spaced-apart positions and respectively generate the measurement signals. The measurement signals acquired by the magnetic field sensors 16a, 16b are transmitted to an evaluation unit 19 by radio or wire (FIG. 3, Step 120). By calculating the difference between the measurement signals of the two magnetic field sensors 16a, 16b, interference fields, such as the Earth's natural magnetic field or magnetic fields occurring in the motor vehicle, can be eliminated. The difference signal of the measurement signals is a magnetic cardiogram signal. The evaluation unit 19 ascertains vital parameters from the magnetic cardiogram signals (FIG. 3, Step 130). For this purpose, the magnetic cardiogram signals are first filtered with a low-pass filter. A bias drift of the magnetic field sensors 16a, 16b is then ascertained by averaging the magnetic cardiogram signals over a period of time that is greater than the heart rate. The bias drift of the magnetic field sensors 16a, 16b is subtracted from the magnetic cardiogram signals. From the vital parameters, which can be a heart rate and/or a heart rate variability for instance, the evaluation unit 19 ascertains the vital functions of the vehicle occupant 10 and creates an assessment of a current state or a mental or physical condition of the vehicle occupant (Step 140). This state can, for instance, include an assessment of whether the vehicle occupant 10 is tired or awake, stressed or relaxed, whether an acute or chronic abnormality in cardiac function is present or imminent, or whether there are underlying diseases that impair cardiac function. If the evaluation unit 19 determines that there is a vital function that impairs the driving ability of the vehicle occupant 10, the evaluation unit 19 sends the vital functions and/or the assessment to other motor vehicle systems, such as a driver assistance system (Step 150). The driver assistance system is preferably configured to carry out further measures depending on the information received from the evaluation unit about the condition of the vehicle occupant, for example placing an automatic emergency call (e-call) to a control center, bringing the vehicle to a controlled stop, or initiating other helpful or meaningful measures based on the state of the vehicle occupant (Step 160). The two magnetic field sensors 16a, 16b have a distance of 0.5 cm to 2 cm from one another. The magnetic field sensor device 14 is configured as a gradiometer and is height adjustable by means of a guide system 17 in the backrest 12, so that the magnetic field sensor device 14 can always be positioned in proximity to the heart 15 of the vehicle occupant 10. The two magnetic field sensors 16a, 16b are configured as nitrogen vacancy sensors 18a, 18b and comprise a diamond, optical filters, and photodetectors that are not shown in detail.

[0050] FIG. 2 shows a detail view of the magnetic field sensor device 14 of FIG. 1. The magnetic field sensor device 14 comprises two magnetic field sensors 16a, 16b which are configured as nitrogen vacancy sensors 18a, 18b. The two magnetic field sensors 16a, 16b are disposed at a distance of 0.5 cm to 2 cm from one another and each comprise a nitrogen vacancy doped diamond, optical filters, and photodetectors. The magnetic field sensor device 14 further comprises a laser 20 and a microwave resonator 21. The two nitrogen vacancy sensors 18a, 18b are exposed to light by the laser 20 and a fiber splitter 22 is provided in the beam path. The microwave resonator 21 furthermore radiates microwave radiation onto the nitrogen vacancy sensors 18a, 18b, wherein a microwave splitter 23 is disposed in the beam path.