Magnetic domain information acquisition device, magnetic domain information acquisition system, magnetic domain information acquisition method, and program

Abstract

This magnetic domain information acquisition device acquires magnetic domain information of a magnetic material, and includes an image acquisition unit that acquires a magnetic domain image of the magnetic material, a feature acquisition unit that acquires magnetic feature quantities of the magnetic material, and an acquisition unit that determines, for each region on the surface of the magnetic material, based on image accuracy related information, whether to use the magnetic domain image or the magnetic feature quantities of the magnetic material to acquire the magnetic domain information, and acquires the magnetic domain information of the magnetic material in accordance with the determination.

Description

[Technical Field]

[0001] The present invention relates to a magnetic domain information acquisition device, a magnetic domain information acquisition system, a magnetic domain information acquisition method, and a program. This application claims priority to Japanese Patent Application No. 2024-119973, filed on July 25, 2024, the contents of which are incorporated herein by reference. [Background technology]

[0002] For example, magnetic materials such as electrical steel sheets are used in social infrastructure, and ensuring the material properties is important for improving social life. Grain-oriented electrical steel sheets, one type of magnetic material, use a technology to reduce iron loss by dividing the magnetic domains using laser irradiation.

[0003] As a technology aimed at achieving both low iron loss and low noise, for example, Patent Document 1 discloses a grain-oriented electrical steel sheet and a manufacturing method thereof that achieves both low iron loss and low noise by having a magnetic domain refinement treated wire in which a magnetic domain control treated wire is partially subjected to magnetic domain refinement treatment.

[0004] Furthermore, for example, Patent Document 2 discloses a method for measuring magnetic properties, which uses a magnetizer large enough to magnetize the entire plate and a detection sensor divided in the width direction to measure the magnetization properties in the width direction.

[0005] Furthermore, Patent Document 3 discloses a magnetic domain discontinuity detection device that uses a magnetizer to DC magnetize a steel sheet when clarifying the contours of magnetic domain discontinuities using a magneto-optical element. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application No. 2022-52343 [Patent Document 2] Japanese Patent Publication No. 2020-180969 [Patent Document 3] Japanese Patent Application Publication No. 2014-70975 Summary of the Invention [Problem to be solved by the invention]

[0007] For quality assurance of irradiated materials whose magnetic domains have been subdivided by laser irradiation, it is necessary to verify that the laser irradiation was performed properly. While methods for achieving this include iron loss measurement and magnetic domain imaging, each method has its own unique characteristics, making it difficult to obtain accurate measurements using only one method. For example, magnetic domain imaging devices using magneto-optical elements are sometimes used for magnetic domain measurement. However, these devices are significantly affected by variations in the distance from the magnetic material being measured, making it difficult to obtain accurate magnetic domain images in environments where the position of the magnetic material fluctuates due to vibrations or other factors. Furthermore, electromagnetic measurements using magnetic sensors are less affected by variations in the distance between the sensor and the object being measured than magnetic domain imaging devices, allowing for more robust measurements. However, because they do not directly measure magnetic domain information, their accuracy is inferior to that of magnetic domain imaging devices.

[0008] The present invention has been made in consideration of the above circumstances, and aims to provide a magnetic domain information acquisition device, a magnetic domain information acquisition system, a magnetic domain information acquisition method, and a program that achieve both accuracy and robustness in acquiring magnetic domain information. [Means for solving the problem]

[0009] The gist of the present invention is as follows. [1] A magnetic domain information acquisition device according to one aspect of the present invention comprises a magnetic domain image acquisition device that acquires a magnetic domain image of a magnetic material, a magnetic feature quantity acquisition device that measures magnetic feature quantities of the magnetic material, and a magnetic domain information acquisition device that acquires magnetic domain information on the surface of the magnetic material, wherein the magnetic domain information acquisition device comprises an acquisition unit that determines, for each region on the surface of the magnetic material, whether to use the magnetic domain image or the magnetic feature quantities of the magnetic material to acquire the magnetic domain information, and acquires the magnetic domain information of the magnetic material in accordance with the determination. [2] In the magnetic domain information acquisition device described in [1] above, the acquisition unit is configured to select at least two options from three options: use of the magnetic domain image, use of the magnetic feature quantity, and use of both the magnetic domain image and the magnetic feature quantity, and to use one of the at least two selected options to acquire the magnetic domain information. When using both the magnetic domain image and the magnetic feature quantity of the magnetic material to acquire the magnetic domain information, the usage ratio of each may be determined, and the magnetic domain information may be acquired based on the magnetic domain information calculated from each and the usage ratio. [3] In the magnetic domain information acquisition device according to [1] or [2] above, the image accuracy related information may be the clarity of the magnetic domain image. [4] In the magnetic domain information acquisition device described in [3] above, the clarity of the recorded magnetic domain image may be represented by the difference between the magnetic domain width calculated from the magnetic domain image and the magnetic domain width calculated from the magnetic feature quantity, and the acquisition unit may calculate the difference, and if the difference is equal to or less than a threshold, decide to use the magnetic domain image to acquire the magnetic domain information, and if the difference is greater than the threshold, decide to use the magnetic feature quantity to acquire the magnetic domain information. [5] The magnetic domain information acquisition device described in any one of [1] to [4] above may further include a displacement amount acquisition unit that acquires a measurement value of the displacement amount in the height direction of the magnetic material, wherein the image accuracy related information is the displacement amount, and the acquisition unit may determine to use the magnetic domain image to acquire the magnetic domain information if the displacement amount is equal to or less than a threshold, and determine to use the magnetic feature amount to acquire the magnetic domain information if the displacement amount is greater than the threshold.

[0010] [6] In addition, a magnetic domain information acquisition system according to another aspect of the present invention comprises an image acquisition device that captures a magnetic domain image of a magnetic material, a magnetic feature acquisition device that acquires magnetic feature quantities of the magnetic material, and a magnetic domain information acquisition device that acquires magnetic domain information of the magnetic material, the magnetic domain information acquisition device having an acquisition unit that determines, for each region on the surface of the magnetic material, whether to use the magnetic domain image or the magnetic feature quantities of the magnetic material to acquire the magnetic domain information based on image accuracy related information, and acquires the magnetic domain information of the magnetic material in accordance with the determination. [7] In the magnetic domain information acquisition system described in [6] above, the magnetic domain image acquisition device may be arranged upstream of the magnetic feature quantity acquisition device in the production line. [8] In the magnetic domain information acquisition system described in [6] or [7] above, the magnetic feature acquisition device may include a plurality of magnetic sensors, and the plurality of magnetic sensors may be arranged across positions corresponding to one end of the magnetic material and the other end. [9] In the magnetic domain information acquisition system described in any one of [6] to [8] above, the magnetic domain image acquisition device may include a plurality of magneto-optical sensors, and the plurality of magneto-optical sensors may be arranged across positions corresponding to one end of the magnetic material and the other end.

[0011]

[10] Furthermore, a magnetic domain information acquisition method according to yet another aspect of the present invention is a magnetic domain information acquisition method for acquiring magnetic domain information on the surface of a magnetic material, comprising: an image acquisition step for acquiring a magnetic domain image of the magnetic material; a feature acquisition step for acquiring magnetic feature quantities of the magnetic material; and an acquisition step for determining, for each region on the surface of the magnetic material, whether to use the magnetic domain image or the magnetic feature quantities of the magnetic material to acquire the magnetic domain information based on image accuracy related information, and acquiring the magnetic domain information of the magnetic material in accordance with the determination.

[0012]

[11] Furthermore, a program according to yet another aspect of the present invention causes a computer to function as an image acquisition unit that acquires a magnetic domain image of a magnetic material, a feature acquisition unit that acquires magnetic feature quantities of the magnetic material, and an acquisition unit that determines, for each region on the surface of the magnetic material, whether to use the magnetic domain image or the magnetic feature quantities of the magnetic material to acquire magnetic domain information based on image accuracy-related information, and acquires the magnetic domain information of the magnetic material in accordance with the determination. [Effects of the Invention]

[0013] According to the above-described embodiment of the present invention, it is possible to obtain magnetic domain information with both accuracy and robustness. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a functional block diagram of a magnetic domain information acquisition system according to an embodiment of the present invention. [Figure 2] FIG. 2 is a schematic diagram showing an example of a hardware configuration of the magnetic domain image acquisition device according to the embodiment. [Figure 3] FIG. 2 is a perspective view showing the main configuration of the magnetic sensor in the embodiment. [Figure 4] 2 is a schematic diagram showing a form in which the magnetic sensor according to the embodiment is used. FIG. [Figure 5] FIG. 2 is a functional block diagram of the magnetic domain image acquisition device according to the embodiment. [Figure 6] FIG. 2 is a schematic diagram showing an example of the arrangement of the magnetic domain information acquisition system according to the embodiment. [Figure 7] FIG. 10 is a block diagram of another example of the magnetic domain information acquisition system according to the embodiment. [Figure 8] 1 is a flowchart showing the flow of a magnetic domain information acquisition method according to an embodiment of the present invention. [Figure 9] FIG. 1 is a contour diagram of the distribution of magnetic domain widths obtained based on a magnetic domain image of a grain-oriented electrical steel sheet in an example. [Figure 10] FIG. 10 is a contour diagram of the distribution of magnetic domain widths obtained based on an unclear magnetic domain image of a grain-oriented electrical steel sheet in an example. [Figure 11] FIG. 10 is a contour diagram of the magnetic domain width distribution obtained by machine learning from the results of magnetic measurements in the examples. DETAILED DESCRIPTION OF THE INVENTION

[0015] Preferred embodiments of the present invention will be described in detail below with reference to the drawings. In the following, this embodiment will be described using grain-oriented electrical steel sheet as an example of a magnetic material. Note that the ratios and dimensions of each component in the drawings do not represent the actual ratios and dimensions of each component. FIG. 1 is a functional block diagram of a magnetic domain information acquisition system according to one embodiment of the present invention. FIG. 2 is a schematic diagram showing an example of the hardware configuration of a magnetic domain image acquisition device in this embodiment.

[0016] <Magnetic domain information acquisition system 1> As shown in FIG. 1, a magnetic domain information acquisition system 1 according to one embodiment of the present invention includes a magnetic domain image acquisition device 10, a magnetic feature amount acquisition device 20, and a magnetic domain information acquisition device 30.

[0017] [Magnetic domain image acquisition device 10] The magnetic domain image acquisition device 10 acquires a magnetic domain image of a magnetic material. The magnetic domain image acquisition device 10 includes, for example, a light source unit 11, a magneto-optical (MO) sensor 12, an image sensor 13, and a signal processing unit 14, as shown in FIG.

[0018] The light source unit 11 has a light source made up of a light emitting diode (LED), and irradiates the MO sensor 12 with light having a uniform polarization plane.

[0019] MO sensor 12 is a device for measuring the magnetic domain structure of a magnetic material and has an observation surface on which a magnetic sample to be measured is placed. Light emitted from light source 11 passes through the interior of MO sensor 12 and is reflected by a reflective layer. The reflected light passes through the interior of MO sensor 12 again and is output from MO sensor 12. When a grain-oriented electrical steel sheet, which serves as a magnetic material, is placed on the observation surface of MO sensor 12, a leakage magnetic field corresponding to the direction of spontaneous magnetization of the grain-oriented electrical steel sheet is generated inside MO sensor 12. This leakage magnetic field rotates the polarization plane of the reflected light.

[0020] The image sensor 13 is a complementary metal-oxide-semiconductor (CMOS) image sensor that forms an image of the reflected light from the MO sensor 12 on its light-receiving surface, photoelectrically converts the light, and outputs the photoelectrically converted analog signal to the signal processing unit 14. By detecting the reflected light with a rotated polarization plane with the image sensor 13, the spatial distribution of the leakage magnetic field can be obtained, and the magnetic domain structure of the magnetic material can be clarified.

[0021] The signal processing unit 14 includes an amplifier, an AD converter, a digital signal processor (DSP), etc. The analog signal output from the image sensor 13 is amplified by the amplifier and converted into a digital signal by the AD converter. This digital signal is subjected to predetermined digital processing by the DSP to generate an image signal. The image signal generated by the signal processing unit 14 is output to the magnetic domain information acquisition device 30 via a cable or by wireless communication.

[0022] In order to improve the image acquisition speed, the magnetic domain image acquisition device 10 preferably includes a plurality of MO sensors 12 according to the size of the magnetic material. In order to acquire magnetic domain images without omission, the plurality of magnetic sensors 21 are preferably arranged from one end of the magnetic material to the other end.

[0023] [Magnetic feature acquisition device 20] The magnetic feature acquisition device 20 acquires magnetic feature values ​​of the surface of a magnetic material. The magnetic feature values ​​are analytical information obtained by magnetic measurement that can estimate the magnetic domain width.

[0024] Magnetic features are information obtained when acquiring the hysteresis loop for each region of a magnetic material, and examples include features of the excitation waveform, features of the magnetic flux density B-external magnetic field H loop, and features of eddy currents.

[0025] The excitation waveform features include, for example, the maximum magnetization voltage V mag , maximum magnetizing current I mag , distortion factor K, third harmonic amplitude A3, and third harmonic phase P3.

[0026] The feature quantity of the BH loop is, for example, the maximum incremental permeability DZ max , average incremental permeability DZ mean , the incremental permeability DZ when the external magnetic field is zero r , maximum incremental permeability DZ max Magnetizing voltage U at cdz , maximum incremental permeability DZ maxMagnetizing voltage DU at 75% of 75dz , maximum incremental permeability DZ max Magnetizing voltage DU at 50% of 50dz , maximum incremental permeability DZ max Magnetizing voltage DU at 25% of 25dz , and the asymmetry of the incremental permeability R em Examples include:

[0027] The feature of the eddy current is, for example, the maximum amplitude Z on the impedance plane. max , the minimum amplitude Z on the impedance plane min , the mean amplitude Z on the impedance plane mean , the maximum phase P on the impedance plane hiZmax , minimum phase P on the impedance plane hiZmin , the average phase on the impedance plane P hiZmean , the maximum amplitude Z on the impedance plane max Impedance width W at 3% of 3Z , and the maximum amplitude Z on the impedance plane max Impedance width W at 10% of 10Z Examples include:

[0028] The magnetic feature acquisition device 20 is realized by a magnetic sensor. For example, a magnetic sensor 21 shown in FIG. 3 can be used as the magnetic sensor. FIG. 3 is a perspective view showing the main components of the magnetic sensor 21 in this embodiment. The magnetic sensor 21 includes a U-shaped yoke 22, an excitation coil 23 wound around the yoke 22, and a detection coil 24 wound around the yoke 22 at a location different from the excitation coil 23. The magnetic sensor 21 may include only the excitation coil 23 without including the detection coil 24. Furthermore, there may be multiple magnetic sensors 21. In the case of multiple magnetic sensors 21, the presence or absence of a magnetic domain refining process line can be determined for each portion on a magnetic domain control process line, which is a virtual line that follows the magnetic domain refining process line (e.g., a groove, thermal distortion, etc.), which is a portion that has been subjected to magnetic domain refining process.

[0029] FIG. 4 shows the configuration of the yoke 22 and the magnetic material when measuring the magnetic material using the magnetic sensor 21. FIG. 4 is a diagram showing the configuration when the magnetic sensor 21 of this embodiment is used. In FIG. 4, the excitation coil 23 and the detection coil 24 are omitted. Also, in FIG. 4, the two end faces 22A of the yoke 22 are arranged in a non-contact state away from the grain-oriented electromagnetic steel plate 50. Also, to stabilize the magnetic sensor 21 on the magnetic material, a plate-shaped guide 25 made of a non-magnetic material and fixed to the yoke 22 is used. Note that the magnetic sensor 21 does not need to abut against the magnetic material. Here, an AC current (or an AC current with a superimposed DC component) is passed through the excitation coil 23, and the output voltage (induced voltage) of the detection coil 24 is measured. The current passed through the excitation coil 23 forms a magnetic path R in FIG. 4. The magnetic properties of the magnetic material are measured from the relationship between the output voltage (waveform) of the detection coil 24 and the input current of the excitation coil 23, or from the output voltage (waveform) of the detection coil 24 when the input current of the excitation coil 23 is fixed. If the magnetic sensor 21 is equipped with only the excitation coil 23, the magnetic properties of the magnetic material are measured from the output current (waveform) of the excitation coil 23 when the input voltage of the excitation coil 23 is fixed.

[0030] The distance between the two end faces 22A of the yoke 22 is determined according to the size of the crystal grains of the magnetic material. For example, the distance between the two end faces 22A is set to a length that includes approximately two or less crystal grains. This allows the magnetic sensor 21 to acquire magnetic feature quantities with high accuracy. Furthermore, the magnetic feature quantity acquisition device 20 preferably includes a plurality of magnetic sensors 21, and the plurality of magnetic sensors 21 are preferably arranged from one end of the magnetic material to the other end of the magnetic material. The information on the measured magnetic properties is output to the magnetic domain information acquisition device 30 via a cable or by wireless communication.

[0031] [Magnetic domain information acquisition device 30] FIG. 5 is a schematic diagram showing the hardware configuration of a magnetic domain image acquisition device in this embodiment. A magnetic domain information acquisition device 30 acquires magnetic domain information on the surface of a magnetic material. As shown in FIG. 5, the magnetic domain information acquisition device 30 includes an acquisition unit 31, a display unit 32, an input unit 33, a storage unit 34, a control unit 35, and a communication I / F (not shown). The magnetic domain information is information on the magnetization direction of a crystal. <100> The magnetic domain width refers to at least one of the magnetic domain width and magnetic domain orientation, which is the direction of the magnetic domain sandwiched between two 180° magnetic domain walls that are approximately parallel to the rolling direction. Here, the magnetic domain width refers to the distance between adjacent magnetic domain walls (magnetic domain wall spacing).

[0032] The acquisition unit 31 determines, for each region on the surface of the magnetic material, whether to use a magnetic domain image or magnetic feature quantities to acquire magnetic domain information based on the image accuracy-related information, and acquires the magnetic domain information of the magnetic material in accordance with the determination. The regions are arbitrarily divided regions, and may be, for example, regions divided by crystal grain boundaries or regions divided by arbitrarily set areas.

[0033] The image accuracy-related information is information indicating the accuracy of the image and information that affects the accuracy of the image. Information indicating the image accuracy is, for example, the clarity of the magnetic domain image, and information that affects the image accuracy is, for example, the amount of displacement of the magnetic material. Therefore, the acquisition unit 31 determines whether to use the magnetic domain image or the magnetic feature quantity of the magnetic material to acquire the magnetic domain information, for example, based on the clarity of the magnetic domain image.

[0034] The clarity of a magnetic domain image is measured, for example, by the following method. The magnetic domain width calculated from the magnetic domain image is compared with the magnetic domain width calculated from the magnetic feature quantity, and the difference between them is calculated. This difference is used as an index of the clarity of the magnetic domain image, and if the difference is equal to or less than a threshold, it is decided to use the magnetic domain image to obtain magnetic domain information. If the difference is greater than the threshold, it is decided to use the magnetic feature quantity to obtain magnetic domain information. The threshold can be calculated in advance for a large number of samples to determine the difference between the magnetic domain width calculated from a clear magnetic domain image and the magnetic domain width calculated from the magnetic feature quantity, and a statistical value such as the maximum value or average value can be used. In other words, if the threshold exceeds the maximum value of the difference in magnetic domain width that can occur in a clear magnetic domain image, the magnetic domain image can be determined to be unclear.

[0035] The acquisition unit 31 may also perform image processing on the magnetic domain image to quantify the image clarity, determining that areas with large quantified values ​​are clear areas and areas with small quantified values ​​are not clear areas. For example, a Sobel filter may be used to create an edge-enhanced image of the magnetic domain image, and the pixel value, in other words, the magnitude of the brightness gradient, may be used to determine the clarity. The threshold for determining whether an image is clear or not may be determined as the brightness gradient value that best classifies clear and not clear magnetic domain images, which may be prepared in advance, for example, by manually classifying them.

[0036] The acquisition unit 31 may also preliminarily label multiple magnetic domain images acquired in the past as to whether they are clear or not, and use the data associating the magnetic domain images with the labels as training data to perform training (machine learning) using, for example, a convolutional neural network, and use the trained model to determine whether the magnetic domain images can be used. That is, the acquisition unit 31 may input the magnetic domain images into the trained model, and obtain whether the magnetic domain images output from the trained model can be used. If the magnetic domain images are unusable, the magnetic feature values ​​are used to acquire magnetic domain information.

[0037] The information output from the trained model is not limited to whether or not the magnetic domain image can be used, but may also be whether or not the magnetic domain image is clear, the degree of clarity, etc. When the degree of clarity is output, for example, if the clarity is equal to or greater than a predetermined threshold, the magnetic domain image is used to acquire the magnetic domain information, and if the clarity is less than the threshold, the magnetic feature amount is used to acquire the magnetic domain information.

[0038] Furthermore, the acquisition unit 31 is preferably configured to use at least two of three predetermined options to acquire magnetic domain information: use of a magnetic domain image, use of a magnetic feature quantity, and use of both a magnetic domain image and a magnetic feature quantity. The at least two options (i.e., two or three options) may be pre-installed in the magnetic domain information acquisition device 30. For example, if only two options, such as use of a magnetic domain image and use of a magnetic feature quantity, are installed, the acquisition unit 31 determines which of the two installed options to use. If three options are installed, the acquisition unit 31 determines which of the three installed options to use. Furthermore, if all three options are installed in the magnetic domain information acquisition device 30, the at least two options may be arbitrarily set by the user. That is, the magnetic domain information acquisition device 30 is configured to allow the user to pre-install one of four options, selecting at least two from the three options, before executing processing, and the acquisition unit 31 determines whether to use a magnetic domain image or a magnetic feature quantity according to this setting.

[0039] Furthermore, when using two of the magnetic domain image and magnetic feature quantities, which is one of the three options described above, it is also possible to determine the usage ratio of the magnetic domain information calculated from each of the magnetic domain image and magnetic feature quantities, and calculate the magnetic domain information based on each of the magnetic domain information and the determined usage ratio. The usage ratio may be determined in advance using a table or function, etc., as a ratio corresponding to an index value of the clarity of the magnetic domain image, and the magnetic domain information may be calculated by taking a weighted average of the calculated values ​​of each piece of magnetic domain information according to the usage ratio associated with the index value.

[0040] The acquisition unit 31 determines whether to use the magnetic domain image or magnetic feature of the magnetic material to acquire magnetic domain information for each region on the surface of the magnetic material. Therefore, when the magnetic domain image is partially damaged, for example, the data for the damaged portion can be supplemented with the magnetic domain width based on the magnetic measurement results.

[0041] Note that magnetic domain information can be obtained from a magnetic domain image by any known method as long as it can be obtained by such a method as line segment method or short interval two-dimensional Fourier transform (see Patent Document 1).

[0042] Acquisition of magnetic domain information based on magnetic feature quantities may be performed by learning (machine learning). Specifically, the acquisition unit 31 may use a trained model that has learned the relationship between magnetic domain widths and magnetic feature quantities to calculate magnetic domain widths according to the measurement results of magnetic feature quantities in the measurement area (measurement position) of the target material. That is, the acquisition unit 31 inputs magnetic feature quantities into the trained model to obtain magnetic domain information output from the trained model.

[0043] The trained model is created by learning multiple data sets (training data) that associate magnetic feature values ​​with corresponding magnetic domain widths. This training data is created by measuring magnetic feature values ​​using the magnetic measurement described above and measuring magnetic domain widths by capturing magnetic domain images for multiple magnetic material samples. The creation of the trained model (machine learning) may be performed by the acquisition unit 31 (magnetic domain information acquisition device 30), or may be created by a device other than the magnetic domain information acquisition device 30, and the created trained model may be acquired by the magnetic domain information acquisition device 30 and used by the acquisition unit 31. In the present disclosure, the trained model is a type of program.

[0044] The acquisition unit 31 is realized by a Central Processing Unit (CPU) and performs the above calculations and determinations according to programs stored in the storage unit. The memory includes a Read Only Memory (ROM) and a Random Access Memory (RAM). The ROM stores programs executed by the CPU of the acquisition unit 31 and data required for executing these programs. The programs and data stored in the ROM are loaded into the RAM and executed. Note that, instead of general-purpose hardware such as a CPU, the acquisition unit 31 may be dedicated hardware such as an application specific integrated circuit (ASIC) or a field programmable gate array (FPGA) specialized for analyzing magnetic domain structures.

[0045] The display unit 32 displays the analysis results of the magnetic domain information acquired by the acquisition unit 31. The display unit 32 also displays the image of the magnetic material acquired by the magnetic domain image acquisition device 10. The display unit 32 is realized by a display such as a liquid crystal display (LCD), a plasma display, or an organic electroluminescence (EL) display.

[0046] The input unit 33 is realized by input devices such as a mouse and a keyboard. By operating the input device, a user can input and process various data to the magnetic domain information acquisition device 30. The communication I / F is an interface for transmitting and receiving data to and from external devices via a network such as a local area network (LAN), a wide area network (WAN), or the Internet.

[0047] The storage unit 34 temporarily or permanently stores programs and various data for operation of the magnetic domain information acquisition device 30. The storage unit 34 is realized by a magnetic memory such as a hard disk drive (HDD) or an optical memory such as an optical disk. Alternatively, a computer-readable recording medium that is detachable from the magnetic domain information acquisition device 30 may be used as the storage unit 34 to store the programs and data. The programs executed by the acquisition unit 31 may be received from a network via a communication I / F.

[0048] FIG. 6 is a schematic diagram showing an example of the arrangement of the magnetic domain information acquisition system 1 according to this embodiment. As shown in FIG. 6, the magnetic domain image acquisition device 10 and the magnetic feature acquisition device 20 are configured to acquire magnetic domain images and magnetic feature quantities in-line for a plate-shaped (strip-shaped) magnetic material that has been subjected to magnetic domain refinement processing (e.g., laser irradiation) and is installed in a strip threading device 60, without temporarily stopping the magnetic material while it is being transported by the strip threading device 60. Note that the magnetic material may be temporarily stopped during the transport. In a production line equipped with such a strip threading device 60, the magnetic domain image acquisition device 10 is preferably disposed upstream of the magnetic feature acquisition device 20 in the traveling direction (RD) of the grain-oriented electrical steel sheet 50 on the production line, as shown in FIG. 6. The magnetic feature acquisition device 20 applies a magnetic field to acquire magnetic information of the magnetic material, so magnetism may remain in the magnetic material after the application of the magnetic field. For magnetic materials with residual magnetism, it may be difficult to accurately estimate the magnetic domain width and magnetic domain orientation based on the magnetic domain image. Therefore, it is preferable that the magnetic domain image acquisition device 10 is disposed upstream of the magnetic feature amount acquisition device 20 and acquires the magnetic domain image before acquiring the magnetic information.

[0049] The magnetic domain information acquisition system 1 preferably acquires magnetic domain information of a grain-oriented electromagnetic steel sheet 50 being transported. The grain-oriented electromagnetic steel sheet 50 may vibrate in the height direction as it is transported. The magnetic domain information acquisition system 1 according to this embodiment can acquire magnetic domain information even if the position of the grain-oriented electromagnetic steel sheet 50 in the height direction fluctuates. Therefore, either magnetic domain information acquired based on the magnetic domain image or magnetic domain information acquired based on the magnetic feature quantities may be displayed on the display unit 32 based on the displacement of the magnetic material, the transport speed of the magnetic material, acceleration information, temperature information of the magnetic material, etc. when the magnetic domain image or magnetic feature quantities are acquired by the magnetic domain image acquisition device 10 or the magnetic feature quantity acquisition device 20.

[0050] Furthermore, as shown in FIG. 7, the magnetic domain information acquisition system 1 preferably includes a displacement measurement device 40 that measures the displacement of the magnetic material in the height direction (hereinafter simply referred to as the displacement). The displacement is the height distance between an arbitrarily determined reference position and the position of the magnetic material. The reference position may be a position that overlaps with an arbitrary position (e.g., the top surface) of the magnetic material when the magnetic material, such as a plate-shaped grain-oriented electromagnetic steel sheet, is placed on a production line in a stationary state. It may also be a position that overlaps with a sensing surface of a sensor that photographs or measures the magnetic material, such as the light-receiving surface of the image sensor 13. The acquisition unit (displacement acquisition unit) 31 of the magnetic domain information acquisition device 30 preferably determines to use a magnetic domain image to acquire magnetic domain information when the displacement is equal to or less than a threshold, and determines to use a magnetic feature value to acquire magnetic domain information when the displacement of the magnetic material exceeds the threshold. The displacement of the magnetic material is measured using various displacement meters. The threshold value for the amount of displacement of the position of the magnetic material is determined as the minimum value of the amount of displacement of the position of the magnetic material relative to the unclear magnetic domain image, for example, using an unclear magnetic domain image classified manually and the amount of displacement of the position of the magnetic material when the magnetic domain image is obtained. In other words, the minimum amount of displacement at which the magnetic domain image becomes unclear is the threshold. The amount of displacement of the magnetic material is one of the image accuracy-related information.

[0051] FIG. 8 is a flowchart showing the flow of a magnetic domain information acquisition method according to one embodiment of the present invention. FIG. 8 shows the flow of the magnetic domain information acquisition method for one region from which a magnetic domain image is acquired. The magnetic domain information acquisition method according to an embodiment of the present invention includes an image acquisition step (S1) for acquiring a magnetic domain image of a magnetic material, a feature acquisition step (S2) for acquiring magnetic feature quantities of the magnetic material, and an acquisition step (S3) for determining, for each region on the surface of the magnetic material, whether to use the magnetic domain image or the magnetic feature quantities to acquire the magnetic domain information based on image accuracy-related information, and acquiring the magnetic domain information of the magnetic material in accordance with the determination. The above operations are performed for the region from which magnetic domain information is to be acquired. Furthermore, a program according to an embodiment of the present invention causes a computer to function as an image acquisition unit that acquires a magnetic domain image of a magnetic material, a feature acquisition unit that acquires the magnetic feature quantities of the magnetic material, and an acquisition unit that determines, based on image accuracy-related information, whether to use the magnetic domain image or the magnetic feature quantities to acquire the magnetic domain information, and acquires the magnetic domain information of the magnetic material in accordance with the determination. This program may be recorded on a readable recording medium. Readable recording media include, for example, portable media such as flexible disks, optical magnetic disks, ROMs, and CD-ROMs (Compact Disc Read Only Memory), and non-transitory recording media such as hard disks and solid state drives (SSDs) built into computer systems.

[0052] The present invention has been described above using the present embodiment. However, the technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

[0053] For example, in the above-described embodiment, grain-oriented electromagnetic steel sheet has been described as an example of the magnetic material, but the magnetic material is not limited to grain-oriented electromagnetic steel sheet. Furthermore, the shape of the magnetic material is not particularly limited, and it may be plate-shaped, rod-shaped, annular, or processed into various shapes. When the magnetic material is not plate-shaped, the displacement amount of the magnetic material refers to the distance between the magnetic domain image acquisition device and the surface of the magnetic material. [Example]

[0054] Figure 9 shows a contour map of the magnetic domain width distribution calculated based on a captured magnetic domain image of a grain-oriented electrical steel sheet. Figure 10 shows a contour map of the magnetic domain width distribution calculated based on a magnetic domain image obtained when a blurred magnetic domain image was acquired due to the displacement of the grain-oriented electrical steel sheet. Figure 11 also shows a contour map of the magnetic domain width distribution obtained by machine learning from the results of magnetic measurement. In Figures 9 to 11, the horizontal axis indicates an arbitrary direction of the grain-oriented electrical steel sheet, and the vertical axis indicates the direction perpendicular to that arbitrary direction. The scale on each axis is in mm. Figures 9 to 11 are normalized by the largest magnetic domain width among the estimated magnetic domain widths. Data correlating magnetic measurement results with magnetic domain widths was used as training data for machine learning, and learning was performed using support vector regression.

[0055] As can be seen from Figures 9 and 10, the contour plot of the magnetic domain width distribution obtained from the unclear magnetic domain image underestimates the magnetic domain width. This is because the outlines of the magnetic domains are blurred by noise. On the other hand, as can be seen from Figures 9 and 11, the magnetic domain width obtained from the magnetic measurement results is sufficiently accurate. Therefore, for example, if the magnetic domain image is partially damaged, the data for that damaged part can be supplemented with the magnetic domain width based on the magnetic measurement results.

[0056] The conditions in the examples are merely examples adopted to confirm the feasibility and effects of the present invention, and the present invention is not limited to the conditions used in the following examples. Various conditions can be adopted in the present invention as long as they do not deviate from the gist of the present invention and the object of the present invention is achieved. [Explanation of symbols]

[0057] 1. Magnetic domain information acquisition system 10 Magnetic domain image acquisition device 11 Light source section 12 MO sensor 13 Image Sensor 14 Signal processing section 20 Magnetic feature acquisition device 21 Magnetic Sensor 22 York 22A end face 23 Excitation coil 24 detection coil 25 Guide 30 Magnetic domain information acquisition device 31 Acquisition Department 32 Display section 33 Input section 34 Storage section 35 Control Unit 40 Displacement measuring device 50 Grain-oriented electrical steel sheet 60 Threading equipment ND: normal direction to the rolling surface RD rolling direction R magnetic path

Claims

1. A magnetic domain information acquisition device for acquiring magnetic domain information of a magnetic material, an image acquisition unit for acquiring a magnetic domain image of a magnetic material; a feature acquisition unit that acquires a magnetic feature of the magnetic material; an acquisition unit that determines, for each region on the surface of the magnetic material, whether to use a magnetic domain image or magnetic feature quantity of the magnetic material to acquire the magnetic domain information, based on image accuracy related information, and acquires the magnetic domain information of the magnetic material in accordance with the determination.

2. The acquisition unit at least two options are selected from three options: use of the magnetic domain image, use of the magnetic feature amount, and use of both the magnetic domain image and the magnetic feature amount; and one of the at least two selected options is used to acquire the magnetic domain information; 2. The magnetic domain information acquisition device according to claim 1, wherein, when both a magnetic domain image and a magnetic feature quantity of the magnetic material are used to acquire the magnetic domain information, a usage ratio of each is determined, and the magnetic domain information is acquired based on the magnetic domain information calculated from each and the usage ratio.

3. 3. The magnetic domain information acquisition device according to claim 1, wherein the image accuracy related information is the clarity of the magnetic domain image.

4. the clarity of the magnetic domain image is represented by a difference between a magnetic domain width calculated from the magnetic domain image and a magnetic domain width calculated from the magnetic feature quantity; 4. The magnetic domain information acquisition device according to claim 3, wherein the acquisition unit calculates the difference, and if the difference is equal to or less than a threshold, determines to use the magnetic domain image to acquire the magnetic domain information, and if the difference is greater than the threshold, determines to use the magnetic feature amount to acquire the magnetic domain information.

5. a displacement amount acquiring unit that acquires a measurement value of a displacement amount in a height direction of the magnetic material; the image accuracy related information is the displacement amount, 3. The magnetic domain information acquisition device according to claim 1, wherein the acquisition unit determines to use the magnetic domain image to acquire the magnetic domain information when the displacement amount is equal to or less than a threshold, and determines to use the magnetic feature amount to acquire the magnetic domain information when the displacement amount is greater than the threshold.

6. an image acquisition device that captures an image of a magnetic domain of a magnetic material; a magnetic feature acquisition device for acquiring a magnetic feature of the magnetic material; a magnetic domain information acquisition device for acquiring magnetic domain information of the magnetic material, the magnetic domain information acquisition device comprising: an acquisition unit that determines, for each region on the surface of the magnetic material, whether to use a magnetic domain image or magnetic feature quantity of the magnetic material to acquire the magnetic domain information based on image accuracy related information, and acquires the magnetic domain information of the magnetic material in accordance with the determination.

7. The magnetic domain information acquisition system according to claim 6 , wherein the image acquisition device is disposed upstream of the magnetic feature acquisition device in a production line.

8. the magnetic feature acquisition device includes a plurality of magnetic sensors, 8. The magnetic domain information acquisition system according to claim 6, wherein the plurality of magnetic sensors are arranged over a range of positions corresponding to one end and the other end of the magnetic material.

9. the image capture device comprises a plurality of magneto-optical sensors; 8. The magnetic domain information acquisition system according to claim 6, wherein the plurality of magneto-optical sensors are arranged over a range of positions corresponding to one end and the other end of the magnetic material.

10. A method for acquiring magnetic domain information on a surface of a magnetic material, comprising: an image acquisition step of acquiring a magnetic domain image of the magnetic material; a feature acquisition step of acquiring a magnetic feature of the magnetic material; an acquisition step of determining, for each region on the surface of the magnetic material, whether to use a magnetic domain image or magnetic feature of the magnetic material to acquire the magnetic domain information, based on image accuracy related information, and acquiring the magnetic domain information of the magnetic material in accordance with the determination.

11. Computer, an image acquisition unit for acquiring a magnetic domain image of a magnetic material; a feature acquisition unit that acquires a magnetic feature of the magnetic material; A program for causing the program to function as an acquisition unit that determines, for each region on the surface of a magnetic material, whether to use a magnetic domain image or magnetic feature of the magnetic material to acquire magnetic domain information based on image accuracy related information, and acquires the magnetic domain information of the magnetic material in accordance with the determination.

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