Data processing method, computer program product, and data processing system

Abstract

The invention provides a data processing method, a computer program product and a data processing system. The data processing method acquires an output value of a magnetic field from each of the one or more magnetic sensors, and specifies, for each of the one or more magnetic sensors, a magnetic field generated in accordance with a position at which the output value is derived. Then, for each of the one or more magnetic sensors, the data processing method generates a detection value by removing a magnetic field generated according to the position from the output value.

Description

Technical Field

[0001] The invention relates to data processing of a portable magnetic sensor. Background Art

[0002] It is known to use a plurality of electromagnetic sensors arranged on the surface of a subject's body to detect the internal activities of a living body. For example, a plurality of sensors arranged on the subject's head are used to measure the brain magnetic field, a magnetoencephalogram (MEG) is generated using the measured brain magnetic field, and the biological activities are estimated by analyzing the magnetoencephalogram.

[0003] In the past, a system with multiple superconducting quantum interference device (SQUID) sensors was used in the measurement of brain magnetic fields. Each of the multiple SQUID sensors needed to be cooled by liquid helium. Each SQUID sensor was fixed in a dewar flask filled with liquid helium. There are 100 to 300 SQUID sensors arranged on the dewar flask, and a recess for inserting the head is provided on the helmet. During the measurement, the position of each SQUID sensor in the dewar flask needs to correspond to the position of the head. Therefore, the head is fixed in a state of being inserted into the above-mentioned recess. During the measurement, there are problems that the subject cannot move the head and trunk, and will feel uncomfortable and tired.

[0004] In recent years, small portable magnetic sensors that operate at room temperature are being actively developed. Since the magnetic sensor operates at room temperature, liquid helium is not required for cooling in the measurement of the brain magnetic field. Therefore, when using such a sensor, if the sensor is fixed on a helmet, the measurement can be performed without restricting the head wearing the helmet. Regarding the measurement of the brain magnetic field using the portable magnetic sensor described above, various studies have been conducted, for example, in Japanese Patent Gazette No. 2020-151023 and Ryan M. Hill, et.al., "Multi-channel whole-head OPM-MEG: Helmet design and a comparison with a conventional system", Neuroimage, Oct. 01, 2020. Summary of the invention

[0005] Problem that the invention aims to solve

[0006] The operating magnetic field range of the portable magnetic sensor is relatively narrow, about 50nT or less. Therefore, like the measurement using the conventional SQUID sensor, the measurement using the portable magnetic sensor requires a magnetic shielding room. In addition, in the measurement using the portable magnetic sensor, in order to allow the subject to sway (if the measurement is the brain magnetic field, the head swings), it is necessary to use a planar coil or other components to make the magnetic field in the measurement area uniform.

[0007] However, it is difficult to generate a completely uniform magnetic field. Therefore, the main reason for the change in the signal output from the portable magnetic sensor is not only the change in the actual magnetic field of the subject, but also the change in the background magnetic field caused by the swing. Due to such a situation, a technology for accurately measuring the change in the magnetic field of the subject in the measurement of the magnetic field using the portable magnetic sensor is sought.

[0008] Solutions for solving problems

[0009] The present invention has been made in view of the above-mentioned actual situation, and an object of the present invention is to provide a technology for accurately measuring changes in the magnetic field of a subject in the measurement of the magnetic field using a portable magnetic sensor.

[0010] A data processing method in a certain aspect of the present disclosure is a data processing method for one or more magnetic sensors configured in a given manner, and the data processing method comprises the following steps: obtaining output values ​​of a magnetic field from one or more magnetic sensors respectively; for each of the one or more magnetic sensors, determining a magnetic field generated according to a position when the output value is derived; and for each of the one or more OPM sensors, generating a detection value by removing the magnetic field generated according to the position from the output value.

[0011] The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when read in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 1 is a diagram schematically showing the overall structure of a data processing system 1 for a portable magnetic sensor.

[0013] Figure 2 2 is a diagram showing the structure of the helmet 20 .

[0014] Figure 3 It is a perspective view schematically showing the interior of the magnetic shield room.

[0015] Figure 4 It is a front view schematically showing the interior of the magnetic shield room.

[0016] Figure 5It is a diagram schematically showing an example of magnetic field distribution in the measurement region 40 .

[0017] Figure 6 1 is a diagram showing an example of the state of the helmet 20 in the measurement area 40 .

[0018] Figure 7 1 is a diagram showing another example of the state of the helmet 20 in the measurement area 40 .

[0019] Figure 8 It is a diagram showing a specific example of the output value and the detection value of the OPM sensor 2 .

[0020] Fig. 9 4 is a flowchart of a process performed in the data processing system 1 to generate a magnetoencephalogram.

[0021] Fig.10 yes Fig. 9 Flowchart of a variation of the processing of . DETAILED DESCRIPTION

[0022] Hereinafter, the embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In addition, the same reference numerals are given to the same or corresponding parts in the drawings, and their description will not be repeated.

[0023] <Implementation Method 1>

[0024] [Structure of data processing system]

[0025] Figure 1 1 is a diagram schematically showing the overall structure of a data processing system 1 for a portable magnetic sensor. In this embodiment, a case where an OPM (Optically Pumped Magnetometer) sensor 2, a small magnetic sensor that operates at room temperature, is used as an example of a portable magnetic sensor is described. As portable magnetic sensors, in addition to OPM sensors, fluxgate sensors, tunneling magnetoresistance (TMR) sensors, and giant magnetoresistance (GMR) sensors can be cited. In addition, in this embodiment, as an example, the measurement of magnetoencephalography is described, but the measurement object is not limited to magnetoencephalography, and may also be other objects (magnetocardiography).

[0026] The data processing system 1 includes a plurality of OPM sensors 2, an input device 3, an output device 4, and a processing device 10. The data processing system 1 is configured to estimate the position of a biological activity site (current source) in the brain of a subject using detection results obtained by the plurality of OPM sensors 2.

[0027] The plurality of OPM sensors 2 are respectively provided on the helmet 20. When the subject 50 wears the helmet 20 on the head, the plurality of OPM sensors 2 are respectively arranged on the head of the subject 50 in a given manner. Figure 1 In the figure, for the sake of convenience of explanation, the number of OPM sensors 2 shown is set to "4", but the number of OPM sensors 2 used for measurement is not limited to this.

[0028] The input device 3 is a pointing device such as a keyboard or a mouse, and receives input information (such as calculation conditions described later) from the user. The information input to the input device 3 is sent to the processing device 10. The output device 4 is composed of a liquid crystal (LCD: Liquid Crystal Display) panel, for example, and is a display that displays information to the user.

[0029] The processing device 10 includes a sensor interface 11, an input interface 12, an output interface 13, a storage device 14, and a computing device 15 as main hardware elements. The processing device 10 may be implemented by a general-purpose computer or a computer (server, etc.) dedicated to the data processing system 1.

[0030] The sensor interface 11 is an interface for connecting the processing device 10 with a plurality of OPM sensors 2, and realizes the input and output of signals between the processing device 10 and the plurality of OPM sensors 2. The input interface 12 is an interface for connecting the input device 3 with the processing device 10, and realizes the input and output of signals between the processing device 10 and the input device 3. The output interface 13 is an interface for connecting the output device 4 with the processing device 10, and realizes the input and output of data between the processing device 10 and the output device 4.

[0031] The storage device 14 non-transitorily stores information (programs, etc.) used in processing by the calculation device 15 . In addition, input information (calculation conditions, etc., described later) input by a user to the input device 3 is stored in the storage device 14 .

[0032] [helmet]

[0033] Figure 2 2 is a diagram showing the structure of a helmet 20. A plurality of OPM sensors 20 are mounted on the helmet 20. In one embodiment, the plurality of OPM sensors 2 are arranged to be fixed on the helmet 20.

[0034] [Measurement environment]

[0035] Figure 3 It is a perspective view schematically showing the interior of the magnetic shield room. Figure 4 It is a front view schematically showing the interior of the magnetic shield room.

[0036] The brain magnetic field is measured in a magnetic shield room 30. In the magnetic shield room 30, plates 31 and 32 on which planar coils for eliminating noise are mounted are arranged on one side and the other side of the subject 50, respectively.

[0037] In the magnetic shield room 30, a measurement area 40 is defined as an area where the head of the subject 50 is assumed to be located. The measurement area 40 is, for example, a rectangular parallelepiped of 40 cm square. However, the size of the measurement area 40 is not particularly limited.

[0038] [Spatial magnetic field distribution]

[0039] Figure 5 Schematically shows an example of magnetic field distribution in the measurement area 40. Figure 5 In the figure, arrows are used to show the magnetic fields pre-measured for each field in a plurality of places in the measurement area 40. The direction of the arrow indicates the direction of the magnetic field in a three-dimensional space defined by three axes (X-axis, Y-axis, and Z-axis). The length of the arrow indicates the magnitude of the magnetic field. The direction and magnitude of the magnetic field in each of the plurality of places in the measurement area 40 are stored as a "spatial magnetic field distribution" in, for example, the storage device 14. In one example, as a "spatial magnetic field distribution", magnetic fields of 125 places at intervals of 10 cm are stored for a 40 cm square space.

[0040] In one embodiment, the magnetic field of each of the plurality of locations in the measurement area 40 is measured without a subject in the magnetic shield room 30. The computing device 15 generates a spatial magnetic field distribution based on the measurement result and stores the generated spatial magnetic field distribution in the storage device 14.

[0041] [Background magnetic field]

[0042] The data processing system 1 generates a magnetoencephalogram of the subject 50 based on the detection values ​​of each of the plurality of OPM sensors 2. In addition, the position of each OPM sensor 2 may change during the measurement of the brain magnetic field. The data processing system 1 determines the background magnetic field generated according to the position of each OPM sensor 2, and generates a detection value by subtracting the background magnetic field from the output value.

[0043] More specifically, when the data processing system 1 obtains the output value from each OPM sensor 2, it generates a detection value for each OPM sensor 2 based on the output value. Thus, detection values ​​are generated for multiple OPM sensors 2. Then, the data processing system 1 generates a magnetoencephalogram using the detection values ​​generated for multiple OPM sensors 2. The following describes in more detail the change in the position of the OPM sensor 2, the determination of the background magnetic field generated according to the position, and the derivation of the detection value.

[0044] (Change in position of OPM sensor 2)

[0045] In the data processing system 1 , as the head of the subject 50 swings, the helmet 20 swings, and thereby the position of each OPM sensor 2 may change. Figure 6 1 is a diagram showing an example of the state of the helmet 20 in the measurement area 40 . Figure 7 4 is a diagram showing another example of the state of the helmet 20 in the measurement area 40. Figure 6 and Figure 7 In the figure, for the convenience of explanation, three OPM sensors 2 among the plurality of OPM sensors 2 are represented as OPM sensors 2A, 2B, and 2C.

[0046] like Figure 6 and Figure 7 As shown in FIG. 1 , when the head of the subject 50 wearing the helmet 20 is shaken, the position and posture of the helmet 20 are changed. More specifically, Figure 6 In the embodiment, the helmet 20 is located at the upper left of the measurement area 40. Figure 7 In the figure, the helmet 20 is located at the upper left of the measurement area 40.

[0047] And, in Figure 6 and Figure 7 The posture of the helmet 20 changes, and thus the positional relationship between the OPM sensors 2A, 2B, and 2C changes. More specifically, Figure 6 In the figure, OPM sensor 2A is located at the lower left relative to OPM sensor 2B and OPM sensor 2C. Figure 7 , OPM sensor 2A is located at the upper right relative to OPM sensor 2B and OPM sensor 2C.

[0048] (Determination of the Background Magnetic Field of Each OMP Sensor 2)

[0049] The earth's magnetic field is about several microteslas (T), while the change of the brain magnetic field occurs in the range of about several femtoteslas (T). Even if the magnetoencephalogram is measured in the magnetic shielding room 30, it is difficult to fix the magnetic field in the magnetic shielding room 30 to a level that does not affect the brain magnetic field. Therefore, it is assumed that when the position of the OPM sensor 2 changes, the size of the background magnetic field included in the output value of the OPM sensor 2 changes. Therefore, when the output value of the OPM sensor 2 is directly used as the detection value in the generation of the magnetoencephalogram, the magnetoencephalogram sometimes lacks accuracy.

[0050] The data processing system 1 determines the location of each OPM sensor 2 in the measurement area 40. The data processing system 1 determines the magnetic field of the determined location among the magnetic fields of multiple locations in the measurement area 40 registered as the spatial magnetic field distribution as the background magnetic field of each OPM sensor 2. For example, when the magnetic fields of 125 locations are registered as the spatial magnetic field distribution and 20 OPM sensors 2 are installed on the helmet 20, the data processing system 1 determines the magnetic field of the location corresponding to each of the 20 OPM sensors 2 from the magnetic fields of the 125 locations as the background magnetic field of each OPM sensor 2.

[0051] In one embodiment, the data processing system 1 determines the background magnetic field of each OPM sensor 2 using maximum likelihood estimation.

[0052] More specifically, the data processing system 1 obtains output values ​​from the first number of OPM sensors 2. Thus, the data processing system 1 obtains the first number of output values. Then, the data processing system 1 configures the first number of output values ​​according to the configuration of the first number of OPM sensors 2 on the helmet 20.

[0053] In the spatial magnetic field distribution, it is assumed that magnetic fields of a second number of locations (larger than the first number) are registered.

[0054] The data processing system 1 searches for a combination of magnetic fields of the first number of places corresponding to the first number of output values ​​configured as described above, among the magnetic fields of the second number of places constituting the spatial magnetic field distribution. Maximum likelihood estimation is used in the search. In the maximum likelihood estimation, a likelihood function represented by the following equations (1) and (2) is defined.

[0055]

[0056] In the above-mentioned formulas (1) and (2), each OPM sensor 2 is represented as sensor=1~n. Formula (1) represents the measured value y obtained from each magnetic sensor. In formula (1), the measured values ​​of the magnetic field of each OPM sensor 2 in each of the three axial directions are represented as fsx, fsy, and fsz. Formula (2) represents the magnetic field V in an arbitrary sensor configuration in the magnetic field space G. In formula (2), the measured values ​​of the magnetic field of each OPM sensor 2 at the coordinates (x, y, z) in the magnetic field space G are represented as fgx, fgy, and fgz. In addition, the position of the helmet (head) that changes with time due to the swing of the head, etc., that is, the background magnetic field of each OPM sensor is obtained by minimizing the square error between the measured value y and the magnetic field V.

[0057] Furthermore, the data processing system 1 selects the first number of combinations of magnetic fields having the maximum values ​​of the likelihood function among the magnetic fields of the second number of locations registered as the spatial magnetic field distribution as the combination of magnetic fields corresponding to the combination of the first number of OPM sensors 2 .

[0058] The data processing system 1 decomposes the combination of the first number of magnetic fields selected from the spatial magnetic field distribution into background magnetic fields of each OPM sensor 2 according to the configuration of the plurality of OPM sensors 2 on the helmet 20 .

[0059] For example, when there are 20 OPM sensors 2 on the helmet 20, and brain magnetic fields corresponding to biological activities are generated at positions corresponding to 4 of the OPM sensors 2, and brain magnetic fields corresponding to biological activities are not generated at positions corresponding to the remaining 16 OPM sensors 2, the output values ​​of the 16 OPM sensors 2 should be consistent with the value of the background magnetic field. Therefore, by using the maximum likelihood estimation of the likelihood function represented by equation (1), the combination of the output values ​​of the 20 OPM sensors 2 on the helmet 20 can be used to select the combination of the background magnetic fields of the 20 OPM sensors 2 from the combination of multiple magnetic fields registered as the spatial magnetic field distribution.

[0060] In the data processing system 1, the magnetic field of each of the multiple locations in the measurement area 40 is stored as a spatial magnetic field distribution. That is, in the data processing system 1, the movement of the head of the subject 50 is allowed in the measurement area 40. The larger the range of the measurement area 40, the larger the range of movement of the head of the subject 50 is allowed, but the amount of calculation in the maximum likelihood estimation increases. Therefore, the size of the measurement area 40 can be set based on the amount of calculation allowed in the maximum likelihood estimation.

[0061] (Export of test values)

[0062] Figure 8 2 is a diagram showing a specific example of the output value and the detection value of the OPM sensor 2. Figure 8 In the graph G1, the output value is shown as line L11, and in the graph G2, the detection value is shown as line L21. In the graphs G1 and G2, the vertical axis represents the intensity of the magnetic field, and the horizontal axis represents time.

[0063] In graph G1, line L12 represents the background magnetic field. Figure 8 In the example of , the detection value represented by line L21 is calculated by subtracting the value of line L12 from the value of line L11. That is, the detection value is equivalent to the value obtained by removing the background magnetic field from the output value.

[0064] [Processing flow]

[0065] Fig. 9Flow chart of the process performed in the information processing system 1 to generate a magnetoencephalogram. In one embodiment, in the processing device 10, the processing is performed by executing a given program by the computing device 15. Fig. 9 processing.

[0066] In step S10, the operation device 15 determines whether the start of the magnetoencephalogram measurement is instructed. The instruction to start the magnetoencephalogram measurement can be input to the operation device 15 from the input device 3, or can be input to the operation device 15 from an external device via a network. The operation device 15 repeats the control of step S10 (step S10 is "No") until it is determined that the start of the measurement is instructed. When it is determined that the start of the measurement is instructed (step S10 is "Yes"), the control enters step S20.

[0067] In step S20 , the computing device 15 acquires output values ​​from the plurality of OPM sensors 2 .

[0068] In step S30, the computing device 15 determines the background magnetic field component of each OPM sensor in the plurality of OPM sensors 2 according to the spatial magnetic field distribution. In one embodiment, the control of step 30 follows the content described above in [Determination of background magnetic field].

[0069] In step S40 , the calculation device 15 generates a detection value of each of the plurality of OPM sensors 2 by removing each background magnetic field from each of the output values ​​of the plurality of OPM sensors 2 .

[0070] In step S50, the operation device 15 generates a magnetoencephalogram using the detection values ​​of each of the plurality of OPM sensors 2 and outputs the magnetoencephalogram. The output of the magnetoencephalogram is, for example, a display on the output device 4. Then, the operation device 15 returns control to step S10.

[0071] In the first embodiment described above, the computing device 15 generates the detection value of each of the plurality of OPM sensors 2 by removing the background magnetic field from the output value of each of the plurality of OPM sensors 2. Then, the computing device 15 generates the magnetoencephalogram using the detection value of each of the plurality of OPM sensors 2.

[0072] <Implementation Method 2>

[0073] The calculation device 15 may calibrate the magnetic field at a plurality of locations registered as the spatial magnetic field distribution.

[0074] In addition, the plurality of OPM sensors 2 may be mounted on a deformable member such as a headgear instead of a non-deformable member such as a helmet. In this case, the computing device 15 may also implement control for determining the arrangement of the plurality of OPM sensors 2 on the head of the subject 50 wearing the headgear.

[0075] Fig.10 yes Fig. 9 Flowchart of a modified example of the processing of Fig. 9 Compared with the treatment Fig.10 The processing also includes steps S02, S04, and S06.

[0076] Reference Fig.10 In step S02, the computing device 15 corrects the spatial magnetic field distribution.

[0077] More specifically, the computing device 15 measures the magnetic field of one of the multiple places where the magnetic field is registered in the spatial magnetic field distribution. In addition, the computing device 15 compares the measured magnetic field with the magnetic field registered in the spatial magnetic field distribution for the one place. Then, the computing device 15 adds the difference between the measured magnetic field and the registered magnetic field to the magnetic field of all the places registered in the spatial magnetic field distribution. That is, the computing device 15 detects the magnetic field of one place, and uses the result of the detection to correct the magnetic field of both the one place and other places included in the spatial magnetic field distribution.

[0078] As the aforementioned “one location”, it is preferable to select a location with a low probability of the OPM sensor 2 being present during magnetoencephalogram measurement among the multiple locations defined in the measurement area 40. Alternatively, the detection values ​​of the magnetic field at two or more locations may be used for calibration.

[0079] In step S04 , the computing device 15 acquires an image (eg, a 3D image) of the subject wearing the headgear.

[0080] In step S06, the computing device 15 determines the configuration of the plurality of OPM sensors 2 on the subject's head by analyzing the image acquired in step S04. In one embodiment, in the analysis of the image, the portion corresponding to each of the plurality of OPM sensors 2 is determined based on the image, and the configuration of the plurality of OPM sensors 2 on the subject's head is determined based on the configuration of the portion of each OPM sensor 2. Then, the computing device 15 causes the control to enter step S10.

[0081] According to reference Fig.10The processing described above appropriately corrects the magnetic fields of a plurality of locations constituting the spatial magnetic field distribution. By correcting the spatial magnetic field distribution, the accuracy of the value used as the background magnetic field can be ensured, thereby ensuring the accuracy of the detected value of the magnetic field.

[0082] In reference Fig.10 In the described process, even when the subject 50 wears a member made of a flexible material such as a headgear instead of the helmet 20, the data processing system 1 can recognize the arrangement of the plurality of OPM sensors 2 and use it to generate the detection value. Thus, various methods are allowed as the method in which the subject 50 wears the plurality of OPM sensors 2.

[0083] The timing (or conditions) for respectively implementing the correction of the spatial magnetic field distribution in step S02 and / or the determination of the positions of the plurality of OPM sensors 2 in steps S04 and S06 can be appropriately set. For example, when a plurality of magnetoencephalograms are measured continuously for the same subject 50, the correction of the spatial magnetic field distribution in step S02 and / or the determination of the positions of the plurality of OPM sensors 2 in steps S04 and S06 can be implemented each time the magnetoencephalograms are measured, or can be implemented only once before the measurement of the plurality of magnetoencephalograms.

[0084] [Way]

[0085] It will be understood by those skilled in the art that the above-mentioned multiple exemplary embodiments are specific examples of the following aspects.

[0086] (Item 1) A data processing method involved in one embodiment may also be a data processing method for one or more portable magnetic sensors configured in a given manner, the data processing method comprising the following steps: respectively acquiring output values ​​of a magnetic field from the one or more magnetic sensors; determining, for each of the one or more magnetic sensors, a magnetic field generated according to a position at which the output value is derived; and generating, for each of the one or more magnetic sensors, a detection value by removing the magnetic field generated according to the position from the output value.

[0087] According to the data processing method described in Item 1, a technique for accurately measuring changes in the magnetic field of a subject in the measurement of a magnetic field using a magnetic sensor is provided.

[0088] (Item 2) In the data processing method described in Item 1, it may also be that the one or more magnetic sensors derive the output value at the measurement area, determine the magnetic field distribution for the measurement area, and the step of determining the magnetic field generated according to the position includes the following steps: determining a combination of magnetic fields corresponding to a combination of the output values ​​of the one or more magnetic sensors based on the magnetic field distribution in the measurement area; and determining the magnetic field corresponding to the position of each magnetic sensor in the one or more magnetic sensors based on the determined combination of magnetic fields.

[0089] According to the data processing method described in Item 2, the magnetic field distribution in the measurement area can be used as the magnetic field corresponding to the position of each of the one or more magnetic sensors.

[0090] (Item 3) In the data processing method described in Item 2, the step of determining the combination of the magnetic fields may include the following steps: for each of a plurality of combinations of magnetic fields in the magnetic field distribution in the given manner, calculating a value of a likelihood function that the combination is a combination of the output values ​​of the one or more magnetic sensors; and determining a combination having the largest value of the likelihood function from among the plurality of combinations.

[0091] According to the data processing method described in Item 3, it is possible to select a magnetic field appropriate for the position of each of the one or more magnetic sensors from among a plurality of magnetic fields constituting the magnetic field distribution in the measurement region.

[0092] (Item 4) The data processing method described in Item 3 may also include the following steps: measuring the magnetic field of at least one point in the measurement area; and correcting the magnetic field distribution based on the magnetic field of the at least one point.

[0093] According to the data processing method described in Item 4, by correcting the magnetic field distribution in the measurement area, a more accurate value can be used as the magnetic field corresponding to the position of each of the one or more magnetic sensors.

[0094] (Item 5) The data processing method described in any one of Items 1 to 4 may also include the following steps: obtaining position information of each of the one or more magnetic sensors when worn by the subject; and determining the given method based on the position information of each of the one or more magnetic sensors.

[0095] According to the data processing method described in Item 5, various methods are allowed as a method for the subject to wear one or more magnetic sensors.

[0096] (Item 6) A program according to one aspect may be configured such that, when one or more processors of a computer execute the program, the computer implements the data processing method according to any one of Items 1 to 5.

[0097] According to the program described in Item 6, a technique for accurately measuring changes in the magnetic field of a subject in the measurement of a magnetic field using a magnetic sensor is provided.

[0098] (Item 7) A data processing system according to one embodiment may include: a computer; and one or more portable magnetic sensors, wherein the computer includes: one or more processors; and a storage device storing the program according to Item 6.

[0099] According to the data processing system described in Item 7, a technique for accurately measuring changes in the magnetic field of a subject in the measurement of the magnetic field using a magnetic sensor is provided.

[0100] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present disclosure is indicated by the claims rather than by the description of the above-mentioned embodiments, and the scope of the present disclosure is intended to include all changes within the meaning and scope equivalent to the claims. In addition, each technology in the embodiments may be implemented alone or in combination with other technologies in the embodiments as needed to the extent possible.

[0101] Although the embodiments of the present invention have been described, the embodiments disclosed this time should be considered to be illustrative in all aspects and not restrictive. The scope of the present invention is indicated by the claims, and it is intended to include all modifications within the meaning and scope equivalent to the claims.

Claims

1. A data processing method is a data processing method for one or more portable magnetic sensors configured in a given manner, the data processing method comprising the following steps: respectively acquiring output values ​​of the magnetic field from the one or more magnetic sensors; determining, for each of the one or more magnetic sensors, a magnetic field generated according to a position at which the output value is derived; and For each of the one or more magnetic sensors, a detection value is generated by removing a magnetic field generated according to the position from the output value.

2. The data processing method according to claim 1, wherein: The one or more magnetic sensors derive the output value in the measurement area, determining a magnetic field distribution for the measurement area, The step of determining a magnetic field generated according to the position comprises the following steps: determining, based on the magnetic field distribution in the measurement area, a combination of magnetic fields corresponding to a combination of the output values ​​of the one or more magnetic sensors; and A magnetic field corresponding to a position of each of the one or more magnetic sensors is determined based on the determined combination of the magnetic fields.

3. The data processing method according to claim 2, wherein: The step of determining the combination of magnetic fields comprises the following steps: calculating, for each of a plurality of combinations of magnetic fields in the given manner in the magnetic field distribution, a value of a likelihood function that the combination is a combination of the output values ​​of the one or more magnetic sensors; and A combination having the maximum value of the likelihood function is determined from among the plurality of combinations.

4. The data processing method according to claim 3, wherein: The following steps are also included: measuring the magnetic field of at least one point in the measurement area; and The magnetic field distribution is corrected based on the magnetic field of the at least one point.

5. The data processing method according to claim 1, wherein: The following steps are also included: acquiring position information of each of the one or more magnetic sensors when the magnetic sensor is worn by a subject; and The given mode is determined based on the position information of each of the one or more magnetic sensors. 6 . A computer program product comprising a program, wherein when one or more processors of a computer execute the program, the computer is caused to implement the data processing method according to claim 1 .

7. A data processing system comprising: Computers; and One or more portable magnetic sensors, The computer comprises: More than one processor; and A storage device storing the program included in the computer program product according to claim 6.

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