Dynamic construction system and method of magnetic map of spatial magnetic foreign object change

Abstract

The application relates to the field of dynamic construction of magnetic maps, and discloses a system and a method for dynamically constructing magnetic maps of space magnetic foreign object changes. The system for dynamically constructing magnetic maps of space magnetic foreign object changes comprises a signal front-end processing module and a data back-end processing module; the signal front-end processing module is used for detecting different magnetic foreign objects in space and comprises a signal control module, a signal preprocessing module, a signal emission module, a signal acquisition module, an analog-digital conversion module, a data storage module and a power module; the data back-end processing module is used for generating a magnetic field image of the magnetic foreign objects in space and displaying the magnetic map on a screen, and comprises a data processing module and a display module. The application has the advantages of low cost, high precision, high sensitivity, good reliability, the ability to observe the scattering distribution of the magnetic foreign objects to the magnetic field, the ability to observe the disturbance of the magnetic foreign objects to the magnetic field in a computer system, and the ability to realize adaptive adjustment of the magnetic map when the number and position of the objects change.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of magnetic map dynamic construction, in particular to a magnetic map dynamic construction system and method for spatial magnetic foreign object change. BACKGROUND

[0002] People have entered the information age, and the development of wireless communication technology has become popular. The demand for location-based services is growing, and in complex environments such as schools, shopping malls, airports, and underground parking lots, accurate location information is often needed. Current positioning technologies include GPS technology, WIFI, Bluetooth, ultrasonic waves, infrared, geomagnetic positioning, etc. GPS signals can be affected by indoor walls, blocking the propagation of satellite signals, and cannot provide accurate location services indoors. WIFI and Bluetooth technology have high positioning accuracy, but they rely on existing infrastructure in buildings and are greatly affected by visibility and positioning distance in the environment. Ultrasonic and infrared signals require additional signal emitting devices, and the positioning effect is greatly affected by environmental visibility. Geomagnetic positioning has low cost and high precision, but it cannot identify the specific physical properties of magnetic foreign objects. SUMMARY

[0003] In view of this, the purpose of the present application is to provide a magnetic map dynamic construction system and method for spatial magnetic foreign object change, which can sensitively identify magnetic foreign objects and adaptively adjust the generated image of the magnetic foreign object through a noise reduction algorithm. By constructing a magnetic map of the magnetic foreign object in the magnetic field space, the disturbance of the magnetic foreign object to the magnetic field can be dynamically observed.

[0004] In order to achieve the above-mentioned purpose, the technical solutions adopted are as follows:

[0005] The magnetic map dynamic construction system for spatial magnetic foreign object change comprises a signal front-end processing module and a data back-end processing module.

[0006] The signal front-end processing module is used to detect different magnetic foreign objects in space and comprises a signal control module, a signal preprocessing module, a signal emitting module, a signal collecting module, an analog-to-digital conversion module, and a data storage module connected in sequence. It also includes a power module for powering each module.

[0007] The data back-end processing module is used to generate a magnetic field image of the magnetic foreign object in space and visualize the magnetic map through the screen. It comprises a data processing module and a display module connected in sequence, and the data processing module is used to optimize the signal data of the magnetic foreign object stored in the data storage module.

[0008] The magnetic map dynamic construction method for spatial magnetic foreign object change comprises the following steps:

[0009] S1: The signal control module selects a suitable frequency by scanning the frequency and controls the signal transmission module to generate a sinusoidal signal to detect different magnetic anomalies in space. The signal preprocessing module amplifies the signal to generate a signal with sufficient energy to detect objects at a sufficiently long distance and make them respond to the magnetic field signal. When a magnetic anomaly is detected, the signal acquisition module can acquire the signal. If no signal is detected, the scanning and detection are repeated. The analog-to-digital conversion module converts the detected signal into a digital signal for easy subsequent storage and processing. The data storage module can store data in a timely manner, clean up redundant data periodically, and has an interface for exporting data. The data processing module can optimize the signal data of magnetic anomalies, and the display module can visualize the signal of magnetic anomalies, displaying magnetic field images for easy analysis.

[0010] S2: The signal magnitude of the acquired magnetic anomaly is related to the conductivity, permeability, and distance of the magnetic anomaly from the object being measured. Meanwhile, due to the large indoor space, the acquired signal is subject to noise interference. Therefore, fast filtering of the signal noise is the key to dynamic construction of the magnetic map.

[0011]

[0012] In the formula, As a scale factor, It is the displacement factor. For preprocessing signals, For wavelet basis functions, For continuous wavelet transform, this formula demonstrates that it has a significant correlation with wavelet basis functions under specific scale and shift factors;

[0013] S3: The signal is initially processed by wavelet analysis. The characteristics of the magnetic anomaly are judged based on the signal features. The physical characteristics such as conductivity and permeability of the magnetic anomaly are described by data analysis. The signal is stored in the database. Based on the characteristics of the system, an improved magnetic image filtering algorithm is proposed as follows.

[0014]

[0015] In the formula, For the size of the grid, for The number of surrounding grids, As the product factor, For a constant value, The grayscale value of the magnetic field image. For a certain structure size and shape of the structural element, x, y are the coordinate values of the pixel points before processing, i, j are the coordinate values of the adaptive structural element, and s is the number of grid points whose difference value with the center pixel point exceeds 50;

[0016] S4: When a magnetic foreign object is detected in the space, the detection coil of the magnetic field map will receive a continuous signal, and the grid near the magnetic foreign object will be determined according to the size of the signal gradient modulus value;

[0017] S5: After the size and number of the grid are determined, the value of the grid is judged, if the value is 0, the surrounding grid points are traversed, if the difference value of the point with the surrounding 2 / 3 grid number is greater than 50, the point is judged as a void particle, and the inflation operation is performed, the size is the maximum value of the surrounding points;

[0018] If the value is not 0, the surrounding grid points are traversed, if the surrounding grid points are all 0, the point is judged as a disturbance particle, and the smoothing processing is performed, the size is the minimum value of the surrounding points;

[0019] S6: After the data processing is completed, the data is stored in the database, the magnetic map is visualized, and the disturbance of the magnetic foreign object to the space magnetic field can be dynamically observed through the display module.

[0020] The beneficial effects of the present application are: the magnetic foreign object detection principle is used to detect and detect the magnetic permeability and conductivity information of the magnetic foreign object, analyze and process the collected electric signal, describe the magnetic foreign object conductivity and magnetic permeability signal in the form of data information, and the scattering characteristics of the magnetic foreign object to the magnetic field; the noise signal in the detection space can be smoothed according to the noise reduction algorithm, the data is processed through the magnetic map filtering algorithm, so as to realize the dynamic construction of the magnetic map; after the magnetic map is constructed, the disturbance of the magnetic foreign object to the magnetic field can be dynamically displayed. The system is used for detecting the magnetic foreign object, has the advantages of low cost, high precision and high sensitivity, and has good reliability. BRIEF DESCRIPTION OF DRAWINGS

[0021] The drawings constituting a part of the present application are used to provide further understanding of the present application, the illustrative embodiments of the present application and the description thereof are used to explain the present application, and do not constitute improper limitation on the present application. In the drawings:

[0022] Figure 1 It is a block diagram of the magnetic map dynamic construction system of the magnetic foreign object in the space of the present application;

[0023] Figure 2 It is a schematic diagram of detecting the magnetic foreign object of the present application;

[0024] ​​​​​Figure 3 Flow chart of magnetic foreign object detection steps of the present application;

[0025] Figure 4 Flow chart of the dynamic construction method of the magnetic map of spatial magnetic foreign object changes. DETAILED DESCRIPTION

[0026] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The technical solutions in the embodiments of the present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0027] In order to enable persons skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by persons skilled in the art without creative labor should belong to the scope of protection of the present application.

[0028] As shown in the block diagram of the dynamic construction system of the magnetic map of spatial magnetic foreign object changes. Figure 1

[0029] The dynamic construction system of the magnetic map of spatial magnetic foreign object changes is a handheld detection system of magnetic foreign objects, which comprises a signal front-end processing module and a data back-end processing module.

[0030] The signal front-end processing module is used for detecting different magnetic foreign objects in space, and comprises a signal control module, a signal preprocessing module, a signal transmitting module, a signal collecting module, an analog-digital conversion module and a data storage module connected in sequence, and further comprises a power module for supplying power to each module.

[0031] The data back-end processing module is used for generating a magnetic field image of magnetic foreign objects in space and displaying the magnetic map through a screen, and comprises a data processing module and a display module connected in sequence, wherein the data processing module is used for optimizing the signal data of magnetic foreign objects stored in the data storage module.

[0032] The dynamic construction method of the magnetic map of spatial magnetic foreign object changes comprises the following steps:

[0033] ​S1: Adopt the magnetic map dynamic construction system as described above, the signal control module selects a suitable frequency by scanning the frequency, controls the signal emitting module to generate a sinusoidal signal to detect different magnetic foreign objects in space, and the signal pre-processing module amplifies the signal to generate a signal with sufficient energy to detect a sufficient distance and make the magnetic foreign object respond to the magnetic field signal; When the magnetic foreign object is detected, the signal acquisition module can acquire the signal; If no signal is detected, re-scan detection; The analog-to-digital conversion module converts the detected signal into a digital signal for subsequent storage and processing; Through the data storage module, data can be stored in time, and redundant data can be cleaned regularly, and an interface is provided to export the data; Through the data processing module, the signal data of the magnetic foreign object can be optimized, and through the display module, the signal of the magnetic foreign object can be visualized and processed to display the magnetic field image for analysis;

[0034] S2: The signal size of the collected magnetic foreign object is related to the electrical conductivity, magnetic permeability of the magnetic foreign object, and the distance from the measured object, and at the same time, due to the large indoor space, the collected signal will be disturbed by noise, and fast filtering of signal noise is the key to magnetic map dynamic construction;

[0035]

[0036] In the formula, is a scale factor, is a displacement factor, is a preprocessed signal, is a wavelet basis function, is a continuous wavelet transform, which indicates that under a certain scale factor and displacement factor, the wavelet basis function has a large correlation;

[0037] S3: The signal is preliminarily processed by wavelet analysis, the characteristics of the magnetic foreign object are judged according to the signal characteristics, the physical characteristics such as electrical conductivity and magnetic permeability of the magnetic foreign object are described in the form of data analysis, and the signal is stored in the database, according to the characteristics of the system, and a magnetic map filtering algorithm is improved as follows;

[0038]

[0039] In the formula, is the size of the grid, is the number of surrounding grids, is a product factor, is a constant value, is the gray value of the magnetic field image, For a certain structure size and shape of the structural elements, x, y are the coordinate values of the pixel points before processing, i, j are the coordinate values of the adaptive structural elements, s is the number of grid points whose difference with the center pixel point exceeds 50;

[0040] S4: When a magnetic foreign object is detected in the space, the detection coil of the magnetic field map will receive a continuous signal, and the grid near the magnetic foreign object will be determined according to the size of the signal gradient modulus;

[0041] S5: After determining the size and number of the grid , the value of the grid is determined. If the value is 0, the surrounding grid points are traversed. If the difference between the point and 2 / 3 of the surrounding grid points is greater than 50, the point is determined to be a void particle, and the inflation operation is performed, with the size being the maximum value of the surrounding points.

[0042] If the value is not 0, the surrounding grid points are traversed. If all the surrounding grid points are 0, the point is determined to be a disturbance particle, and the smoothing operation is performed, with the size being the minimum value of the surrounding points.

[0043] S6: After the data processing is completed, the data is stored in the database, and the magnetic map is visualized. Through the display module, the disturbance of the magnetic foreign object to the space magnetic field can be dynamically observed.

[0044] As shown in Figure 2 , it is a schematic diagram for detecting magnetic foreign objects.

[0045] The handheld device system can generate a sinusoidal excitation signal with stable amplitude and continuous frequency scanning. The signal is amplified through signal preprocessing to detect magnetic foreign objects in space. When there is no magnetic foreign object in space, the induced signal is the size of the default geomagnetic induction strength. When a magnetic foreign object is placed in space, the magnetic induction strength changes. The magnetic foreign object will gather or diffuse the surrounding space magnetic field, and there is a sinusoidal excitation signal. The magnetic foreign object will respond to the signal, which will respond to the acquisition module. Through processing and analysis of the response signal, a visual magnetic map is displayed on the display module.

[0046] As shown in Figure 3 , it is a flow chart of the magnetic foreign object detection steps.

[0047] Step 1: Generate a sinusoidal excitation signal with stable amplitude and frequency scanning through the signal control module, and the frequency can be fixed by manual input;

[0048] ​​​Step 2: The signal generated by the signal control module is amplified by the signal preprocessing module to generate enough energy to detect magnetic anomalies in space, so that the magnetic anomalies respond to the signal.

[0049] Step 3: Transmit the signal through the signal transmission module;

[0050] Step 4: Collect the response signal of the magnetic anomaly through the signal acquisition module. If no response signal is detected, return to step 1.

[0051] Step 5: The detected response signal is converted into a digital signal by an A / D converter module to facilitate subsequent data processing.

[0052] Step 6: Store the signal through the data storage module, and equip it with an interface to export the data, and clean up redundant data regularly;

[0053] Step 7: Visualize the magnetic anomaly image signal using the data processing module and display the magnetic map using the display module, then return to Step 1.

[0054] like Figure 4 The diagram shown is a flowchart of the method for dynamically constructing a magnetic map of spatial magnetic anomalies according to the present invention. The present invention will be further illustrated with examples.

[0055] Magnetic sensors are placed in the four corners of the indoor space. Each magnetic sensor has a built-in coil. By applying an excitation electric field, an induced magnetic field is generated to detect magnetic anomalies in the space. The detected signals are filtered, and the magnetic map is automatically processed according to a grid partitioning algorithm to realize the dynamic construction of the magnetic map. The constructed magnetic map can clearly observe the disturbance of the magnetic field by magnetic anomalies.

[0056] Objects in space influence the magnetic field, and the magnetic field strength varies in different directions. This system uses a signal control module to generate different input currents for four magnetic sensors, selecting an appropriate current to collect the magnetic field signal, and finally performing normalization processing to ensure the accuracy of the magnetic field signal. When there are no magnetically anomalous objects in space, the magnetic sensors collect spatial data and initialize the spatial magnetic map.

[0057] Put a magnetic foreign object, such as a metal block, rubber stick, when the magnetic foreign object is put into it, the magnetic field of the surrounding space will change, the metal block inside the magnetic domain is affected by the magnetic field, the magnetic domain rotates to the same direction, when the magnetic domain direction tends to be consistent, the metal block shows magnetic, and further enhances the magnetic field strength of the surrounding space, the rubber stick is contrary. At this time, due to the change of the equivalent impedance of the circuit, the signal detected by the magnetic sensor also changes, and the white noise in the space and the noise generated by human factors are also attached, which needs to be filtered.

[0058]

[0059] In the formula, is a scale factor, is a displacement factor, is a preprocessed signal, is a wavelet base function, is a continuous wavelet transform, which shows that it has a large correlation with the wavelet base function under a certain scale factor and displacement factor;

[0060] After filtering, the magnetic permeability, electrical conductivity, dielectric constant information of the object can be judged according to the characteristics of the detection signal, and the object is judged to be a metal block or a rubber stick. The four sensor signals are normalized and fused. And store the signal, process the stored signal again, calculate the magnetic field gradient value near each point.

[0061]

[0062] In the formula, is the size of the grid, is the number of surrounding grids, is a product factor, is a constant value, is the gray value of the magnetic field image, is a structure element with a certain structure size and shape, x and y are the coordinate values of the pixel points before processing, i and j are the coordinate values of the adaptive structure element, and s is the number of grids whose difference value with the center pixel point exceeds 50;

[0063] According to the magnetic map filtering algorithm, the grid is divided, and the disturbance particles or cavity particles in the magnetic map are processed, and then the magnetic field image is generated. The gradient near the metal block and the rubber stick is larger than the gradient value of the surrounding space, the grid is smaller, the number is more, and the imaging accuracy of the magnetic map is higher. When the value of a certain point in the detection signal is greatly different from the surrounding value, it means that the point signal has error, which is processed by the magnetic map filtering algorithm, and the noise points are smoothed.

[0064] If the number of magnetic foreign objects changes or the position of the magnetic foreign objects changes, such as increasing the number of metal blocks in the space by one and moving the rubber stick, the detection signal will also change. Then, the signal is processed according to the above steps to generate a new magnetic map, so as to achieve the purpose of dynamic construction of the magnetic foreign objects in the space.

[0065] The application can observe the scattering distribution of the magnetic foreign objects to the magnetic field, can observe the disturbance of the magnetic foreign objects to the magnetic field in the computer system, and can realize adaptive adjustment of the magnetic map when the number and position of the objects change. The system has the advantages of low cost, high precision, strong sensitivity and good reliability.

[0066] The above only describes the preferred embodiments of the application and is not used to limit the application. For those skilled in the art, the application can have various changes and variations. Any modification, equivalent replacement, improvement, component splitting or combination, etc. made within the spirit and principle of the application shall be included in the protection scope of the application.

Claims

1. A method for dynamically constructing a magnetic map of spatial magnetic foreign object changes, characterized in that, Comprise the following steps: S1: signal control module by scanning frequency selection a suitable frequency, control signal emitting module produces a sinusoidal signal, to detect different magnetic foreign objects in space, through the signal preprocessing module to signal power amplifier, to produce a large enough energy signal, can detect far enough distance, and make the magnetic foreign objects to the magnetic field signal response; When detecting magnetic foreign objects, signal acquisition module can collect signal; If no signal is detected, re-scan detection; Analog-to-digital conversion module will detect the signal analog-to-digital conversion, conversion into digital signal, convenient for subsequent storage and processing; Through the data storage module can store data in time, and regularly clean up redundant data, and equipped with interface, export data; Through the data processing module can optimize the signal data of magnetic foreign objects, through the display module can be visualized processing of magnetic foreign objects signal, display magnetic field image, for analysis; S2: the signal size of the collected magnetic foreign objects is related to the conductivity, magnetic permeability of the magnetic foreign objects and the distance from the measured object, at the same time, due to the large indoor space, the collected signal will be disturbed by noise, the signal noise is quickly filtered, which is the key to dynamic construction of magnetic map; ； wherein is a scale factor, is a shift factor, is a pre-processed signal, is a wavelet basis function, is a continuous wavelet transform; S3: through wavelet analysis to signal preliminary processing, according to the signal characteristics to judge the characteristics of magnetic foreign objects, using data analysis form to describe the conductivity and magnetic permeability of magnetic foreign objects, and store the signal into the database, according to the characteristics of the system, magnetic map filtering algorithm as follows; ； wherein, is the size of the grid, is is the number of surrounding grids, is the product factor, is a constant value, is the gray value of the magnetic field image, is a structure element of a certain structure size and shape, x and y are the coordinate values of the pixel point before processing, i and j are the coordinate values of the adaptive structure element, and s is the number of grids whose difference value with the center pixel point exceeds 50. S4: when the space detects magnetic foreign objects, the detection coil of the magnetic field map will receive continuous signal, the grid near the magnetic foreign objects will be determined according to the signal gradient modulus value; S5: After determining the size and number of the grid, judge the grid value, if 0, traverse the surrounding grid points, if the difference between the point and the surrounding 2 / 3 grid number is greater than 50, judge that the point is a void particle, and perform an inflation operation with a size of the maximum value around the point; ​ If Not 0, traverse The grid points around the point, if the grid around the point is 0, it is determined that the point is a disturbance particle, and the smoothing process is performed, and the size is the minimum value around the point. S6: after data processing, store the data into the database, visualize the magnetic map, through the display module can dynamically observe the disturbance of magnetic foreign objects to the space magnetic field.

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