A magnetic field measurement method based on magnetic rotatory effect and image analysis

Abstract

The application discloses a kind of based on magnetic rotatory effect and image analysis's magnetic field measurement method.The method includes the following steps: construction wedge tip device, based on polarizer and magnetic field measurement method of analyser, and utilize wedge tip device setting based on magnetic rotatory effect and image analysis's magnetic field measurement device;Wedge tip device includes equal-thickness glass sheet and magnetic rotatory crystal;Glass sheet and magnetic rotatory crystal one end parallel interface, glass sheet and magnetic rotatory crystal other end interval filament is arranged, to form the wedge-shaped air film with inclination angle between glass sheet and magnetic rotatory crystal;Using based on magnetic rotatory effect and image analysis's magnetic field measurement device obtains the image gray value of wedge tip interference fringe;Based on the image gray value of wedge tip interference fringe, using magnetic rotatory effect principle calculates magnetic field intensity.The application can accurately measure the subtle change of magnetic field in small range, and in the measurement process, each component is easy to combine, and optical path is easy to build, shorten the measurement time.

Description

Technical Field

[0001] This invention relates to the field of magnetic field measurement, and more specifically to a magnetic field measurement method based on magneto-optical rotation effect and image analysis. Background Technology

[0002] Magnetic field measurement is crucial for many scientific and engineering applications. However, existing magnetic field measurement methods each have their limitations. Magnetic field strength detectors can measure magnetic field strength, but they have limitations in terms of accuracy and stability. Deep learning-based magnetic field detection methods require large datasets. Spinless exchange-relaxation atom spin magnetic field detection methods offer high accuracy but are sensitive to environmental temperature and vibration, requiring complex isolation and stabilization devices. Magnetic field sensors using Hall elements and iron core magnetic field detection methods based on excitation signals are sensitive to temperature and electromagnetic interference. Nuclear magnetic resonance magnetometers offer high accuracy and sensitivity, but their large size makes them unsuitable for use in confined spaces. Summary of the Invention

[0003] To address the aforementioned shortcomings in the existing technology, this invention provides a magnetic field measurement method based on magneto-optical rotation effect and image analysis.

[0004] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows:

[0005] A magnetic field measurement method based on magneto-optical rotation effect and image analysis, characterized by comprising the following steps:

[0006] S1. Construct a wedge device, based on the magnetic field measurement method of polarizer and analyzer, and use the wedge device to set up a magnetic field measurement device based on magneto-optical rotation effect and image analysis.

[0007] The wedge device includes a glass plate of equal thickness and a magneto-optical crystal; one end of the glass plate and the magneto-optical crystal are connected in parallel, and the other end of the glass plate and the magneto-optical crystal is provided with spacer filaments to form a wedge-shaped air film with an inclination angle between the glass plate and the magneto-optical crystal.

[0008] S2. Obtain the image grayscale value of the wedge interference fringes using the magnetic field measurement device based on magneto-optical rotation effect and image analysis in step S1;

[0009] S3. Based on the image grayscale values ​​of the wedge interference fringes in step S2, calculate the magnetic field strength using the principle of magneto-optical rotation.

[0010] Further, in step S1, a magnetic field measurement device based on the polarizer and analyzer is set up using a wedge device to measure the magnetic field based on the magneto-optical rotation effect and image analysis. The specific process is as follows: a sodium lamp, a polarizer, a semi-reflective mirror, a wedge device, an electromagnet, an analyzer, a CCD camera, and a microscope are placed on the operating table; the polarizer and the semi-reflective mirror are placed on the optical path axis of the sodium lamp; the microscope arm is connected to the microscope base via a column; a CCD camera is placed above the microscope arm; an analyzer is placed below the microscope arm; a semi-reflective mirror is placed directly below the analyzer; the microscope base is hollowed out in the middle to accommodate an electromagnet; a wedge device is placed above the electromagnet; the angle between the semi-reflective mirror and the horizontal plane is set to 45°; the CCD camera is connected to a display terminal.

[0011] Further, in step S2, the image grayscale value of the wedge interference fringe includes the image grayscale value of the wedge interference fringe at the first set detection angle when the electromagnet is not energized, the image grayscale value of the wedge interference fringe at the second set detection angle when the electromagnet is not energized, and the image grayscale value of the wedge interference fringe at the second set detection angle when the electromagnet is energized.

[0012] Furthermore, the image grayscale value of the wedge interference fringes at the second set detection angle when the electromagnet is not energized is represented as:

[0013]

[0014] Among them: I a2 I represents the image grayscale value of the wedge interference fringes at the second set detection angle when the electromagnet is not energized. a1 I1 represents the image grayscale value of the first wedge interference fringe when the electromagnet is not energized, and I2 represents the image grayscale value of the second wedge interference light. θ represents the phase difference between the first wedge interference light and the second wedge interference light, and θ is the second set detection angle.

[0015] Furthermore, the image grayscale value of the wedge interference fringes at the second set detection angle when the electromagnet is energized is expressed as:

[0016]

[0017] Among them: I b2 I is the image grayscale value of the wedge interference fringes at the second set detection angle when the electromagnet is energized. a1 I1 represents the image grayscale value of the first wedge interference fringe when the electromagnet is not energized, and I2 represents the image grayscale value of the second wedge interference light. Let θ be the phase difference between the first and second wedge interference beams, and let θ be the second set detection angle. FThe optical rotation angle generated by the magneto-optical crystal.

[0018] Further, step S3 includes the following steps:

[0019] S31. Based on the image grayscale values ​​of the wedge interference fringes in step S2, calculate the optical rotation angle generated by the magneto-optical crystal;

[0020] S32. Based on the optical rotation angle generated by the magneto-optical crystal in step S31, the magnetic field strength is calculated using the principle of magneto-optical effect.

[0021] Further, in step S31, based on the image grayscale values ​​of the wedge interference fringes in step S2, the optical rotation angle generated by the magneto-optical crystal is calculated, expressed as:

[0022]

[0023] Where: θ F I is the optical rotation angle generated by the magneto-optical crystal. b2 I is the image grayscale value of the wedge interference fringes at the second set detection angle when the electromagnet is energized. a1 I represents the image grayscale value of the wedge interference fringes at the first set detection angle when the electromagnet is not energized. a2 θ represents the grayscale value of the wedge interference fringes at the second set detection angle when the electromagnet is not energized.

[0024] The present invention has the following beneficial effects:

[0025] (1) This invention constructs a wedge device, uses a magnetic field measurement method based on a polarizer and an analyzer, and uses the wedge device to set up a magnetic field measurement device based on magneto-optical rotation effect and image analysis. It can accurately measure the subtle changes in magnetic field within a small range. Furthermore, the components are easy to assemble and the optical path is easy to build during the measurement process, which shortens the measurement time.

[0026] (2) The magnetic field measurement device based on magneto-optical effect and image analysis of the present invention obtains the image gray value of wedge interference fringes, which can obtain a large amount of data in a single frame in data processing. At the same time, the use of image analysis technology is beneficial to perform data analysis in the entire frame, and the change trend of the magnetic field in the entire frame range can be clearly seen.

[0027] (3) This invention uses wedge interference to measure magnetic field, which reduces the interference of stray light in the environment on the measurement process and reduces the impact of the measurement environment. Furthermore, the data points of the wedge interference fringes are highly regular and easy to analyze, and the requirements for stable operating environment are relatively low. Attached Figure Description

[0028] Figure 1This is a schematic diagram of a magnetic field measurement method based on magneto-optical rotation effect and image analysis;

[0029] Figure 2 This is a schematic diagram of the wedge device.

[0030] Figure 3 The wedge interferogram was taken in the absence of a magnetic field when the angle between the polarizer and the analyzer is 90°.

[0031] Figure 4 The wedge interferogram was taken in the absence of a magnetic field when the angle between the polarizer and the analyzer is 45°.

[0032] Figure 5 The wedge interferogram was taken when there was a magnetic field and the angle between the polarizer and the analyzer was 45°.

[0033] Figure 6 The graph shows the intensity variation of wedge interference light with and without a magnetic field when the angle between the polarizer and the analyzer is 45°.

[0034] Among them: 1. Glass plate; 2. Magneto-optical crystal; 3. Spacer filaments. Detailed Implementation

[0035] The specific embodiments of the present invention are described below to enable those skilled in the art to understand the present invention. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.

[0036] like Figure 1 As shown, a magnetic field measurement method based on magneto-optical rotation effect and image analysis is characterized by comprising steps S1-S3, as follows:

[0037] S1. Construct a wedge device, based on the magnetic field measurement method of polarizer and analyzer, and use the wedge device to set up a magnetic field measurement device based on magneto-optical rotation effect and image analysis.

[0038] like Figure 2As shown, the wedge device includes a glass plate 1 of equal thickness and a magneto-optical crystal 2; one end of the glass plate and the magneto-optical crystal are connected in parallel, and the other end of the glass plate and the magneto-optical crystal is provided with spacer wires 3 to form a wedge-shaped air film with an inclination angle between the glass plate and the magneto-optical crystal. This invention replaces the upper surface glass plate in traditional wedge interference with a magneto-optical crystal. By placing the device on the magnetic field to be measured, wedge interference fringes are generated on the wedge device using linearly polarized light. By comparing the light intensity changes of the wedge interference fringes under no magnetic field and the wedge interference fringes under a magnetic field, the optical rotation angle generated by the magneto-optical crystal can be obtained.

[0039] In an optional embodiment of the present invention, the present invention is based on the magnetic field measurement method of a polarizer and an analyzer, and utilizes a wedge device to set up a magnetic field measurement device based on magneto-optical rotation effect and image analysis. The specific process is as follows: a sodium lamp, a polarizer, a semi-reflective mirror, a wedge device, an electromagnet, an analyzer, a CCD camera, and a microscope are set on the operating table; the polarizer and the semi-reflective mirror are set on the optical path axis of the sodium lamp; the microscope arm is connected to the microscope base through a column; a CCD camera is set above the microscope arm; an analyzer is set below the microscope arm; a semi-reflective mirror is set directly below the analyzer; the microscope base is hollowed out in the middle to place the electromagnet; a wedge device is set above the electromagnet; the angle between the semi-reflective mirror and the horizontal plane is set to 45°; the CCD camera is connected to a display terminal.

[0040] S2. Use the magnetic field measurement device based on magneto-optical rotation effect and image analysis from step S1 to obtain the image grayscale value of wedge interference fringes.

[0041] In an optional embodiment of the present invention, the image grayscale value of the wedge interference fringe includes the image grayscale value of the wedge interference fringe at a first set detection angle when the electromagnet is not energized, the image grayscale value of the wedge interference fringe at a second set detection angle when the electromagnet is not energized, and the image grayscale value of the wedge interference fringe at a second set detection angle when the electromagnet is energized.

[0042] Specifically, the first set detection angle of the present invention is to set the angle between the polarizer and the analyzer to be 90°, and the second set detection angle is to set the angle between the polarizer and the analyzer to be 45°.

[0043] This invention utilizes a magnetic field measurement device based on magneto-optical rotation effect and image analysis in step S1 to obtain the image grayscale value of wedge interference fringes. The specific process is as follows: The sodium lamp is turned on for preheating. The angle between the polarizer and analyzer is set to 90°. The reflected sodium lamp emits linearly polarized light through the polarizer, allowing it to be incident perpendicularly into the wedge device. The CCD camera lens is adjusted for focusing, ensuring clear wedge interference fringes are visible on the display terminal. Then, with the electromagnet de-energized, the CCD camera captures an image of the light spot interference fringes when the angle between the polarizer and analyzer is 90° to obtain the image grayscale value of the wedge interference fringes at the first set detection angle when the electromagnet is de-energized. The angle between the polarizer and analyzer is changed to 45°, and the wedge interference fringes image is captured again to obtain the image grayscale value of the wedge interference fringes at the second set detection angle when the electromagnet is de-energized. Finally, the electromagnet is energized, and the CCD camera captures another image of the wedge interference fringes under a strong magnetic field to obtain the image grayscale value of the wedge interference fringes at the second set detection angle when the electromagnet is energized.

[0044] like Figure 3 As shown, when the angle between the polarizer and the analyzer is 90°, this invention can capture wedge interferograms in the absence of a magnetic field. Figure 4 As shown, when the angle between the polarizer and the analyzer is 45°, this invention can capture wedge interferograms in the absence of a magnetic field. Figure 5 As shown, when the angle between the polarizer and the analyzer is 45°, this invention acquires a wedge interferogram under a magnetic field. Then, this invention subtracts the background light intensity of the wedge interferogram when the angle between the polarizer and the analyzer is 45°, as shown... Figure 6 As shown, there is a significant difference in the intensity of the blue and orange interference fringes, representing the distribution of interference fringe intensity on the same horizontal line under conditions of no magnetic field and with magnetic field, respectively. Therefore, this invention can acquire all the intensity changes within the entire bright spot image, and thus obtain the magnetic field distribution within the entire bright spot image.

[0045] The grayscale value of the image of the wedge interference fringes at the second set detection angle when the electromagnet is not energized is represented as:

[0046]

[0047] Among them: I a2 I represents the image grayscale value of the wedge interference fringes at the second set detection angle when the electromagnet is not energized. a1 I1 represents the image grayscale value of the first wedge interference fringe when the electromagnet is not energized, and I2 represents the image grayscale value of the second wedge interference light. θ represents the phase difference between the first wedge interference light and the second wedge interference light, and θ is the second set detection angle.

[0048] The grayscale value of the image of the wedge interference fringes at the second set detection angle when the electromagnet is energized is represented as:

[0049]

[0050] Among them: I b2 I is the image grayscale value of the wedge interference fringes at the second set detection angle when the electromagnet is energized. a1 I1 represents the image grayscale value of the first wedge interference fringe when the electromagnet is not energized, and I2 represents the image grayscale value of the second wedge interference light. Let θ be the phase difference between the first and second wedge interference beams, and let θ be the second set detection angle. F The optical rotation angle generated by the magneto-optical crystal.

[0051] S3. Based on the image grayscale values ​​of the wedge interference fringes in step S2, calculate the magnetic field strength using the principle of magneto-optical rotation.

[0052] In an optional embodiment of the present invention, the present invention calculates the optical rotation angle generated by the magneto-optical crystal based on the image grayscale value of the wedge interference fringes, and then calculates the magnetic field strength based on the optical rotation angle generated by the magneto-optical crystal using the principle of magneto-optical effect.

[0053] Step S3 includes the following steps:

[0054] S31. Based on the image grayscale values ​​of the wedge interference fringes in step S2, calculate the optical rotation angle generated by the magneto-optical crystal, expressed as:

[0055]

[0056] Where: θ F I is the optical rotation angle generated by the magneto-optical crystal. b2 I is the image grayscale value of the wedge interference fringes at the second set detection angle when the electromagnet is energized. a1 I represents the image grayscale value of the wedge interference fringes at the first set detection angle when the electromagnet is not energized. a2 θ represents the grayscale value of the wedge interference fringes at the second set detection angle when the electromagnet is not energized.

[0057] S32. Based on the optical rotation angle generated by the magneto-optical crystal in step S31, the magnetic field strength is calculated using the principle of magneto-optical effect, and expressed as:

[0058]

[0059] Where: B is the magnetic field strength, θ F V is the optical rotation angle generated by the magneto-optical crystal, V is the Field constant, and D is the thickness of the magneto-optical crystal.

[0060] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0061] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0062] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0063] Specific embodiments have been used to illustrate the principles and implementation methods of this invention. The descriptions of the embodiments above are only for the purpose of helping to understand the method and core ideas of this invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this invention. Therefore, the content of this specification should not be construed as a limitation of this invention.

[0064] Those skilled in the art will recognize that the embodiments described herein are intended to help the reader understand the principles of the invention, and should be understood that the scope of protection of the invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific modifications and combinations based on the technical teachings disclosed in this invention without departing from the spirit of the invention, and these modifications and combinations are still within the scope of protection of this invention.

Claims

1. A magnetic field measurement method based on magneto-optical rotation effect and image analysis, characterized in that, Includes the following steps: S1. Construct a wedge device, based on the magnetic field measurement method of polarizer and analyzer, and use the wedge device to set up a magnetic field measurement device based on magneto-optical rotation effect and image analysis. The wedge device includes a glass plate of equal thickness and a magneto-optical crystal; one end of the glass plate and the magneto-optical crystal are connected in parallel, and the other end of the glass plate and the magneto-optical crystal is provided with spacer filaments to form a wedge-shaped air film with an inclination angle between the glass plate and the magneto-optical crystal. S2. Obtain the image grayscale value of the wedge interference fringes using the magnetic field measurement device based on magneto-optical rotation effect and image analysis in step S1; S3. Based on the image grayscale values ​​of the wedge interference fringes in step S2, calculate the magnetic field strength using the principle of magneto-optical rotation. In step S2, the image grayscale values ​​of the wedge interference fringes include the image grayscale values ​​of the wedge interference fringes at the first set detection angle when the electromagnet is not energized, the image grayscale values ​​of the wedge interference fringes at the second set detection angle when the electromagnet is not energized, and the image grayscale values ​​of the wedge interference fringes at the second set detection angle when the electromagnet is energized. Step S3 includes the following steps: S31. Based on the image grayscale values ​​of the wedge interference fringes in step S2, calculate the optical rotation angle generated by the magneto-optical crystal; S32. Based on the optical rotation angle generated by the magneto-optical crystal in step S31, calculate the magnetic field strength using the principle of magneto-optical effect. Based on the image grayscale values ​​of the wedge interference fringes in step S2, the optical rotation angle generated by the magneto-optical crystal is calculated and expressed as: in: The optical rotation angle generated by the magneto-optical crystal. The image grayscale value of the wedge interference fringes at the second set detection angle when the electromagnet is energized. The image grayscale value of the wedge interference fringes at the first set detection angle when the electromagnet is not energized. The image grayscale value of the wedge interference fringes at the second set detection angle when the electromagnet is not energized. Set the second detection angle; the detection angle is the angle between the polarizer and the analyzer.

2. The magnetic field measurement method based on magneto-optical rotation effect and image analysis according to claim 1, characterized in that, In step S1, a magnetic field measurement device based on the polarizer and analyzer is set up using a wedge device to measure the magnetic field based on the magneto-optical rotation effect and image analysis. The specific process is as follows: a sodium lamp, a polarizer, a semi-reflective mirror, a wedge device, an electromagnet, an analyzer, a CCD camera, and a microscope are placed on the operating table; the polarizer and the semi-reflective mirror are placed on the optical path axis of the sodium lamp; the microscope arm is connected to the microscope base via a column; a CCD camera is placed above the microscope arm; an analyzer is placed below the microscope arm; a semi-reflective mirror is placed directly below the analyzer; the microscope base is hollowed out in the middle to accommodate the electromagnet; a wedge device is placed above the electromagnet; the angle between the semi-reflective mirror and the horizontal plane is set to 45°; the CCD camera is connected to a display terminal.

3. The magnetic field measurement method based on magneto-optical rotation effect and image analysis according to claim 1, characterized in that, The grayscale value of the image of the wedge interference fringes at the second set detection angle when the electromagnet is not energized is represented as: in: The image grayscale value of the wedge interference fringes at the second set detection angle when the electromagnet is not energized. The image grayscale value of the wedge interference fringes at the first set detection angle when the electromagnet is not energized. The image grayscale value of the first wedge interference light. The image grayscale value of the second wedge interference light. The phase difference between the first wedge interference beam and the second wedge interference beam is denoted as . Set the second detection angle.

4. The magnetic field measurement method based on magneto-optical rotation effect and image analysis according to claim 1, characterized in that, The grayscale value of the image of the wedge interference fringes at the second set detection angle when the electromagnet is energized is represented as: in: The image grayscale value of the wedge interference fringes at the second set detection angle when the electromagnet is energized. The image grayscale value of the wedge interference fringes at the first set detection angle when the electromagnet is not energized. The image grayscale value of the first wedge interference light. The image grayscale value of the second wedge interference light. The phase difference between the first wedge interference beam and the second wedge interference beam is denoted as . To set the second detection angle, The optical rotation angle generated by the magneto-optical crystal.

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