Method for ascertaining magnetocardiogram signals of organism

Abstract

The invention relates to a method for determining a magnetocardiogram signal of an organism, comprising the following steps: detecting a magnetic reference field intensity by means of a sensor unit in order to measure a magnetic field, detecting a magnetic measurement field intensity by means of the sensor unit when an organism appears in the environment of the sensor unit, and obtaining a magnetocardiogram signal of the living body based on the magnetic reference field intensity and the magnetic measurement field intensity. The invention also relates to a device, a computer program and a machine-readable storage medium for determining a magnetocardiogram signal of a living organism.

Description

Technical Field

[0001] The present invention relates to a method for obtaining a magnetocardiogram of a biological body, a device for obtaining a magnetocardiogram of a biological body, a computer program and a machine-readable storage medium. Background Art

[0002] The magnetocardiogram is the recording and description of the magnetic field of the heart, which is generated by the electrophysiological activity of the cardiomyocytes. The recording is usually performed with the aid of highly sensitive magnetic field sensors.

[0003] Quantum-based magnetic sensors are known, for example, from the publications DE 10 2018 220 234 A1 and DE 10 2018 214 617 A1. Summary of the invention

[0004] The object of the present invention is to provide a method for efficiently determining magnetocardiographic signals of a living body.

[0005] This object is achieved by means of the respective subject matter of the independent claims. Advantageous embodiments of the invention are the subject matter of the respective dependent claims.

[0006] According to a first aspect, a method for obtaining a magnetocardiogram signal of a biological body is provided, comprising the following steps:

[0007] The magnetic reference field strength is detected by a sensor unit for measuring the magnetic field,

[0008] When a biological body is present in the environment of the sensor unit, the magnetic field strength is detected by the sensor unit.

[0009] The magnetocardiogram signal of the biological body is obtained based on the magnetic reference field strength and the magnetic measurement field strength.

[0010] According to a second aspect, there is provided a device for obtaining a magnetocardiogram signal of a biological body, comprising:

[0011] a sensor unit for measuring a magnetic field, wherein the sensor unit is configured to detect a magnetic reference field strength and to detect a magnetic measurement field strength when a living being is present in the environment of the sensor unit, and

[0012] An ascertainment device is provided for ascertaining a magnetocardiogram signal of the living body based on a magnetic reference field strength and a magnetic measurement field strength.

[0013] According to a third aspect there is provided a computer program comprising instructions which, when executed by a computer (eg by an apparatus according to the second aspect), cause the computer to carry out the method according to the first aspect.

[0014] According to a fourth aspect, there is provided a machine-readable storage medium having stored thereon a computer program according to the third aspect.

[0015] The invention is based on and includes the following finding, which solves the above-mentioned object by detecting a magnetic field strength by means of a sensor unit, wherein it is determined that this magnetic field strength is a reference field strength, i.e. a reference value. Subsequently, when a living being is present in the environment of the sensor unit, the magnetic measurement field strength is detected by means of the sensor unit. Based on this detected magnetic measurement field strength and the previously determined or determined reference value, a magnetocardiogram signal of the living being is determined.

[0016] Typically, the magnetic measurement field strength detected by the sensor unit when a biological body is present in the environment of the sensor unit originates not only from the magnetic field of the heart, but also from other magnetic fields, such as the earth's magnetic field or, for example, electronic devices, such as household appliances. These magnetic fields form interference magnetic fields for the measurement of the magnetic field of the heart. Therefore, before the actual magnetocardiogram measurement, a reference value is determined, which is taken into account in the subsequent magnetocardiogram measurement, so that the magnetocardiogram signal can be effectively determined. In particular, the interference magnetic field can be effectively taken into account.

[0017] Thus, a long-term magnetocardiogram can be created in an advantageous manner. Long-term means, for example, several hours, such as a night.

[0018] Therefore, a technical advantage is achieved, in particular, by providing a method for efficiently determining magnetocardiographic signals of a living body.

[0019] The living organism is, for example, a human being or, for example, an animal.

[0020] In the following, the abbreviation “MKG” may be used for the term “magnetocardiogram”.

[0021] In one specific embodiment of the method, it is provided that a background signal is ascertained based on the magnetic reference field strength, which background signal represents the magnetic background of the environment of the sensor unit, wherein the magnetocardiogram signal is ascertained based on the background signal.

[0022] This results in technical advantages, for example, that the magnetocardiogram signal can be efficiently ascertained. According to this embodiment, it is also provided that the magnetic background of the environment of the sensor unit is ascertained based on the magnetic reference field strength and is also taken into account when ascertaining the magnetocardiogram signal.

[0023] The magnetic background may, for example, be caused by or be based on the Earth's magnetic field.

[0024] In one specific embodiment of the method, it is provided that an interference signal is ascertained based on the magnetic reference field strength, which interference signal represents magnetic interferences in the environment of the sensor unit, wherein the magnetocardiogram signal is ascertained based on the interference signal.

[0025] This results in, for example, technical advantages for the efficient determination of magnetocardiogram signals. According to this embodiment, it is also provided that magnetic disturbances in the sensor unit environment are determined based on the magnetic reference field strength, which are taken into account when determining the magnetocardiogram signals. Magnetic disturbances can be caused, for example, by the operation of electronic devices in the sensor unit environment. Such electronic devices are, for example, electric household appliances or, for example, drive motors for electric roller shutters.

[0026] If, for example, the sensor unit is located in a vehicle, such as a motor vehicle or an aircraft, such magnetic interferences may be caused by the operation of the vehicle.

[0027] For example, such magnetic interference can be caused by electrically driven rail vehicles that travel in the vicinity of the sensor unit. The current consumption of such rail vehicles can generate magnetic fields that can interfere with the measurement of the MKG.

[0028] In one specific embodiment of the method, it is provided that a signal ascertained based on the magnetic reference field strength, ie a background signal and / or a interference signal, is ascertained using a sample recognition method, in particular a machine learning method.

[0029] This results in a technical advantage, for example, that background signals or interfering signals can be efficiently ascertained.

[0030] In one embodiment of the method, it is provided that signals ascertained based on the magnetic reference field strength, i.e. background signals and / or interference signals, are filtered out from a measurement signal representing the detected magnetic measurement field strength to obtain a filtered measurement signal, wherein a magnetocardiogram signal is ascertained based on the filtered measurement signal.

[0031] This results in the technical advantage that, for example, magnetocardiographic signals can be efficiently ascertained. According to this embodiment, it is also provided that magnetic background and / or magnetic interferences are filtered out of the detected magnetic measurement field strengths.

[0032] In one specific embodiment of the method, it is provided that at least one time interval is ascertained, in particular estimated, within which a magnetic disturbance occurs and / or will occur, wherein only magnetic measurement field strengths detected outside the at least one time interval are used to ascertain the magnetocardiogram signal.

[0033] Thus, for example, a technical advantage is achieved in that the magnetocardiogram signal can be efficiently determined. According to this embodiment, it is also provided that detected magnetic interferences are not taken into account when determining the magnetocardiogram signal. Thus, on the one hand, measurements can be performed only outside the time interval, i.e., magnetocardiogram measurements can be performed. On the other hand, in addition or as an alternative, MKG measurements performed within the time interval can be not taken into account when determining the magnetocardiogram signal.

[0034] In one specific embodiment of the method, it is provided that at least one vital parameter of the living being is ascertained based on the magnetocardiographic signal.

[0035] This results in a technical advantage, for example, in that at least one vital parameter of a living organism can be efficiently ascertained.

[0036] In one embodiment of the method, it is provided that at least one vital parameter is an element selected from the following group of vital parameters: heart rate, heart rate variability, duration and / or amplitude of changes in EKG equivalent signals, such as P waves, QRS complexes, T waves and corresponding combinations.

[0037] This results in a technical advantage, for example, in that particularly suitable vital parameters can be efficiently ascertained.

[0038] In one embodiment of the method, it is provided that the measuring range includes a section of the object, which section is an element selected from the following group of objects: mattress, pillow, bed, chair, sofa, armchair, headrest, seat, vehicle seat, aircraft seat, airplane seat, motor vehicle seat.

[0039] This results in a technical advantage, for example, in that a particularly suitable measuring range can be set.

[0040] In one embodiment of the device, it is provided that the measuring range includes a section of the object, which section is an element selected from the following group of objects: mattress, pillow, bed, chair, sofa, armchair, headrest, seat, vehicle seat, aircraft seat, airplane seat, motor vehicle seat.

[0041] This results in technical advantages, for example, in that a particularly suitable measuring range can be used.

[0042] The technical functions of the device are similarly derived from the corresponding technical functions of the method, and vice versa. This also means that the features of the device are derived in particular from the features of the method, and vice versa.

[0043] For example, it is provided that the apparatus is configured to carry out all steps of the method according to the first aspect.

[0044] For example, it is provided that the method according to the first aspect is carried out or executed by means of the device according to the second aspect.

[0045] The method is a computer-implemented method according to an embodiment.

[0046] The expression "at least one" means "one or more".

[0047] The embodiments described here can be combined with one another in any desired manner, even if not specifically stated.

[0048] The detection of the magnetic reference field strength is performed by the sensor unit, for example, when the biological body is absent and / or present in the environment of the sensor unit.

[0049] When a biological body is present in the environment of the sensor unit, the detected magnetic measurement field strength can be used, for example, as a magnetic reference field strength for a MKG measurement later in time. This means that an MKG measurement can also be used as a reference value for a MKG measurement later in time. Magnetic disturbances that occur irregularly or, for example, do not occur during the detection of the magnetic reference field strength, can also be detected in time in an advantageous manner and taken into account for the MKG measurement.

[0050] The measurement of MKG comprises detecting the magnetic measurement field strength by the sensor unit when a living being is present in the environment of the sensor unit and comprises determining a magnetocardiogram signal. The output or result of the MKG measurement is a magnetocardiogram signal.

[0051] For example, multiple magnetocardiogram signals may be determined. Embodiments implemented in connection with one magnetocardiogram signal are similarly applicable to multiple magnetocardiogram signals, and vice versa.

[0052] In one embodiment of the method, a temporal and / or spectral distribution of the interference signal is ascertained, wherein the magnetocardiogram signal is ascertained based on the respective distribution.

[0053] Therefore, for example, a technical advantage is achieved and magnetocardiographic signals can be efficiently obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] The present invention is further explained below according to a preferred embodiment. It is shown here:

[0055] Figure 1 A flow chart of a method for obtaining a magnetocardiogram signal of a biological body,

[0056] Figure 2 A device for obtaining magnetocardiogram signals of a living body,

[0057] Figure 3 a machine-readable storage medium, and

[0058] Figure 4 Multiple interference signals measured sequentially over multiple nights. DETAILED DESCRIPTION

[0059] Figure 1 A flow chart showing a method for obtaining a magnetocardiogram signal of a biological body is shown, comprising the following steps:

[0060] detecting 101 a magnetic reference field strength by a sensor unit for measuring a magnetic field,

[0061] When a biological body is present in the environment of the sensor unit, the magnetic measurement field strength is detected 103 by the sensor unit,

[0062] A magnetocardiogram signal of the biological body is obtained 105 based on the magnetic reference field strength and the magnetic measurement field strength.

[0063] Figure 2 A device 201 for obtaining a magnetocardiogram signal of a biological body is shown, comprising:

[0064] a sensor unit 203 for measuring a magnetic field, wherein the sensor unit 203 is configured to detect a magnetic reference field strength and to detect a magnetic measurement field strength when a biological body is present in the environment of the sensor unit 203, and

[0065] A determination device 205 is provided for determining a magnetocardiogram signal of the living body based on the magnetic reference field strength and the magnetic measurement field strength.

[0066] Figure 3 A machine-readable storage medium 301 is shown, on which a computer program 303 is stored. The computer program 303 comprises instructions which, when the computer program 303 is executed by a computer, cause the computer to carry out a method for determining a magnetocardiogram signal of a living body.

[0067] Figure 4 Shown are a first timeline 401, a second timeline 403, a third timeline 405 and a fourth timeline 407. These four timelines identify four directly following nights, which are also labeled as Night 1, Night 2, Night 3 and Night 4 in the following.

[0068] A device for determining magnetocardiogram signals is proposed. For example, the sensor unit is integrated into the mattress of a bed. The determination device can be arranged, for example, outside the mattress or can also be located inside the mattress.

[0069] It is proposed that, in order to detect the reference field strength, the sensor unit performs a measurement of the magnetic field, ie detects the magnetic field strength, during night 1 when no living organism is in the environment of the sensor unit, ie when no living organism is present in the environment of the sensor unit.

[0070] This means that a magnetic field can be recorded or detected by means of the device during night 1. Such a magnetic field describes the magnetic interference field for the later MKG measurement in the nights of night 2 to night 4.

[0071] For example, three magnetic interference fields are measured in Night 1: a first interference signal 409, a second interference signal 411, and a third interference signal 413. The second interference signal 411 appears twice in Night 1, as shown in the first time axis 401.

[0072] In addition, an oval with reference numeral 415 encloses interference signals 409 , 411 , 413 to indicate that these interference fields or interference signals have not yet been filtered out of the MKG measurement signal.

[0073] In the following nights 2 to 4, however, these interference signals can be filtered out from the measured measurement field strength. This is indicated in the diagram by an X symbol with reference mark 417. This means that in the following nights 2 to 4, the biological body (for example a human) is on the mattress. In addition, it is provided that during the subsequent nights 2 to 4, the sensor unit detects or measures the magnetic field strength, i.e. the magnetic measurement field strength. The measurement signal corresponding to this measurement can be used as the basis for the magnetocardiogram signal of the biological body. In this provision, in night 1 (i.e. the reference night), the interference signals determined are filtered out from the measurement signal, which is detected in the following nights 2 to 4.

[0074] As shown, for example, a fourth magnetic interference field 419 is detected in night 2 , which can also be filtered out in the following nights 3 and 4 .

[0075] Such interference fields can be identified, for example, by applying a machine learning algorithm or by applying artificial intelligence. For example, a pattern recognition method can be applied to recognize patterns in the magnetic reference field strength, which are filtered out, for example, from the existing measurement signals in the following nights 2 to 4.

[0076] In summary, the scheme described here is based on, for example, reference measurement and sample identification of the reference measurement, so that the identified sample can be taken into account when obtaining the magnetocardiogram signal of the organism. For example, it is set to also obtain background signals and / or interference signals based on the magnetic measurement field strength, and the measurement field strength can be used for other MKG measurements to filter out the corresponding magnetic background and / or corresponding magnetic interference from the measurement signal. This means that obtaining the magnetic background and / or obtaining the magnetic interference can be performed similarly to the magnetic reference field strength for the magnetic measurement field strength. The corresponding implementation method is also applicable in this regard. Therefore, when applying a sample identification method, especially a machine learning method, the magnetic measurement field strength can be evaluated to obtain background signals and / or interference signals. Therefore, this obtained signal can be used for subsequent MKG measurements to obtain the corresponding magnetocardiogram signal of the organism based on this signal.

[0077] For example, effective noise suppression can be achieved in an advantageous manner. Thus, feedback can continue to be given in an advantageous manner whether the device is operating unrestricted or only restrictedly and, for example, how long this state lasts. In particular, the temporal distribution of the interfering signal and / or the spectral distribution of the interfering signal are taken into account.

[0078] For example, it is provided that background signals or interfering signals are measured in order to identify them. For this purpose, for example, a reference measurement is performed, i.e., for example, the magnetic reference field strength is measured, for example, for one night, without any organisms in the environment of the sensor unit. The environment of the sensor unit can also generally be referred to as a measurement range.

[0079] Magnetocardiographic measurements can then be performed on the living being in the measuring range during the following night. This means that the magnetic measuring field strength is detected by means of the sensor unit while the living being is in the environment of the sensor unit.

[0080] By way of example, the reference measurement can be performed over a night. A shorter time period, for example a few minutes, can also be provided. For example, a few minutes are sufficient during a self-calibration of the sensor unit and / or the device. This means, for example, that an embodiment of the method is performed during a self-calibration of the sensor unit and / or the device. This means, in particular, that the method steps are carried out during a self-calibration of the sensor unit and / or the device. A few minutes are also sufficient, for example, when the method is used or is to be used in a vehicle, for example a motor vehicle, or in a hospital.

[0081] It is usually provided, for example, that the magnetic reference field strength is subtracted from the measured magnetic measurement field strength. This is in particular the synchronization of the diurnal cycle, usually the clock time synchronization. For example, a reference signal is subtracted from the measurement signal, wherein, for example, a magnetocardiogram signal is obtained based on the corresponding subtracted measurement signal. For example, it is provided that at the time point or time interval at which an interference signal and / or a background signal occurs according to the magnetic reference field strength, a corresponding filter is provided, which filters out the interference signal and / or the background signal from the measurement signal. For example, interference signals that always occur at the same time point can be effectively filtered out. For example, magnetic interference caused by the drive motor of an electric rolling door can be effectively filtered out. For example, it can be obtained based on the magnetic reference field strength that the rolling door rises or falls at a certain time point, so that the interference signal needs to be calculated at this time point, so that this interference signal can be correspondingly filtered out in the measurement signal at this time point.

[0082] For example, samples can be identified in the magnetic reference field strength. Such samples can also be trained when the interference signal occurs at the time point. This means that when it is known that a disturbance always occurs at the same time point, the time curve of the magnetic reference field strength at this time point can be identified as a sample to be filtered. An example is when an electrically driven rail vehicle travels in the environment of the sensor unit at approximately the same or similar time points and thus interferes with the MKG measurement through the current consumption of the drive motor. Therefore, the filter used for data evaluation can be adjusted in an effective manner, especially for specific daytime or nighttime times.

[0083] In this case, classical sample recognition methods and / or machine learning can be applied. For example, characteristic noise samples can be identified in the reference data, i.e. in the detected magnetic reference field strength, such as the passage of a rail vehicle, such as a tram, or the operation of an elevator. For noise suppression, the identified noise samples can be subtracted from the measured signal (i.e. the measurement signal), for example, or corresponding filter criteria can be trained.

[0084] By continuously analyzing the measurement data (ie the magnetic measurement field strength), further samples can be identified and the data quality can be optimized in an advantageous manner.

[0085] By identifying time points or samples with particularly high noise, it is possible, for example, to identify time periods with reduced functionality with respect to the MKG measurement. This allows this time period to be disregarded for other analyses or to provide feedback about the non-functionality of the device with respect to the MKG measurement. It is particularly advantageous that a prediction of the expected duration and extent of the disturbance can be given here by identifying the samples. The data weighted according to the described samples can be managed, for example, in a database, for example online, and can be used in data evaluation and the functions that accompany it (for example alarms for limiting functions).

Claims

1. A method for obtaining a magnetocardiogram signal of a biological body, comprising the following steps: detecting (101) a magnetic reference field strength by a sensor unit for measuring a magnetic field, When a biological body is present in the environment of the sensor unit, the magnetic measurement field strength is detected (103) by the sensor unit, A magnetocardiogram signal of the biological body is obtained (105) based on the magnetic reference field strength and the magnetic measurement field strength.

2. The method according to claim 1, wherein: A background signal is ascertained based on the magnetic reference field strength, the background signal representing the magnetic background of the environment of the sensor unit, wherein the magnetocardiogram signal is ascertained based on the background signal.

3. The method according to claim 1 or 2, wherein: An interference signal (409, 411, 413, 419) is determined based on the magnetic reference field strength, the interference signal representing magnetic interference in the environment of the sensor unit, wherein the magnetocardiogram signal is determined based on the interference signal (409, 411, 413, 419).

4. The method according to claim 2 or 3, wherein: Using a sample recognition method, in particular a machine learning method, a signal ascertained based on the magnetic reference field strength, namely the background signal and / or the interference signal, is ascertained (409, 411, 413, 419).

5. The method according to any one of claims 2 to 4, wherein: A signal determined based on the magnetic reference field strength, i.e., the background signal and / or the interference signal (409, 411, 413, 419) is filtered out from a measurement signal representing the detected magnetic measurement field strength to obtain a filtered measurement signal, wherein the magnetocardiogram signal is determined based on the filtered measurement signal.

6. A method according to any one of the preceding claims and as dependent on claim 3, wherein: At least one time interval is ascertained, in particular estimated, within which a magnetic disturbance occurs and / or will occur, wherein only magnetic measurement field strengths detected outside the at least one time interval are used to ascertain the magnetocardiogram signal.

7. A method according to any one of the preceding claims, wherein: At least one vital parameter of the biological subject is obtained based on the magnetocardiogram signal.

8. The method according to claim 7, wherein: The at least one vital parameter is an element selected from the following group of vital parameters: heart rate, heart rate variability, duration and / or amplitude of changes in EKG equivalent signals, such as P wave, QRS complex, T wave and corresponding combinations.

9. A device (201) for obtaining a magnetocardiogram signal of a biological body, comprising: A sensor unit (203) for measuring a magnetic field, wherein the sensor unit is configured to detect a magnetic reference field strength and to detect a magnetic measurement field strength when a biological body is present in the environment of the sensor unit (203), and An ascertainment device (205) is configured to ascertain a magnetocardiogram signal of the biological subject based on the magnetic reference field strength and the magnetic measurement field strength.

10. The device (201) according to claim 9, wherein: The measurement range comprises a section of the object, said section being an element selected from the following group of objects: mattress, pillow, bed, chair, sofa, armchair, headrest, seat, vehicle seat, aircraft seat, airplane seat, motor vehicle seat.

11. A computer program (303) comprising instructions which, when the computer program (303) is executed by a computer, cause the computer to implement the method according to any one of claims 1 to 8.

12. A machine-readable storage medium (301) on which a computer program (303) according to claim 11 is stored.

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