Magnetic induction assembly and detection device for security gate and security gate

Abstract

The application relates to a magnetic induction assembly and a detection device for a security door and the security door. Based on the application, in a coil arrangement area where a transmitting coil assembly and a receiving coil assembly are located together: a plurality of receiving coils in the receiving coil assembly have a coil shape with beveled edges and are complementarily spliced with adjacent beveled edges parallel to each other to minimize the gap between adjacent receiving coils where weak induction signals are easily generated; on the other hand, the transmitting coil assembly is arranged in a zigzag shape along the joint between adjacent receiving coils, so that the strong area distribution of the physical magnetic field is not limited to the edge of the coil arrangement area, but can be staggered inside the coil arrangement area, and at the same time, the weak area surrounded by the transmitting coil can be reduced. Therefore, the detection blind area of the security door can be reduced due to the overlap of the receiving coil and the weak area, thereby helping to reduce the detection blind area of the security door.

Description

Technical Field

[0001] This application relates to security inspection equipment, and more particularly to a magnetic induction component for a security gate, a detection device using the magnetic induction component, and a security gate using the detection device. Background Technology

[0002] Security gates typically have passageways between their side panels for pedestrians and / or goods to pass through. These side panels are usually equipped with magnetic induction units. The transmitting coil in the magnetic induction unit generates a physical magnetic field covering the passageway. If a pedestrian carrying metal objects or / or an object containing metal objects passes through the passageway, the metal objects in the physical magnetic field will induce a secondary field. Furthermore, the receiving coil in the magnetic induction unit generates an induced signal to the physical magnetic field. If, in addition to the primary field of the physical magnetic field, a secondary field induced by the metal objects also exists within the passageway, the induced signal will change by a certain amplitude. Therefore, the change in the induced signal can be used to indicate the presence of metal objects within the passageway of the security gate. Thus, by observing the change in the induced signal, it is possible to determine whether a target metal object (such as a knife that could threaten personal safety) is present within the passageway of the security gate.

[0003] Typically, the magnetic field generated by the transmitting coil has relatively strong and relatively weak regions. For example, assuming the transmitting coil is deployed in a rectangular area parallel to the XY plane of the door panel, the strong region can include areas with strong magnetic fields in any of the X, Y, and Z directions from the wiring position of the transmitting coil along the edge of the rectangular deployment area. The weak region can include areas with weak magnetic fields in the Z direction perpendicular to the door panel within the rectangular deployment area surrounded by the transmitting coil. Accordingly, multiple receiving coils deployed on the door panel cannot generate induced signals under the same magnetic field strength. Furthermore, since electromagnetic interference and power frequency interference also exist in the physical magnetic field, the weak induced signals generated based on the weak regions of the physical magnetic field (especially the gaps between adjacent receiving coils) may be covered by electromagnetic interference and power frequency interference, resulting in blind spots in the security gate.

[0004] It is evident that reducing the blind spots of security gates is a technical problem that needs to be solved in the existing technology. Summary of the Invention

[0005] In the embodiments of this application, a magnetic induction component for a security gate, a detection device using the magnetic induction component, and a security gate using the detection device are provided, which helps to reduce the detection blind spot of the security gate.

[0006] One embodiment of this application provides a magnetic induction component for a security gate, comprising:

[0007] A transmitting coil assembly is used to generate a physical magnetic field covering the passage area of ​​the security gate based on a transmitted signal;

[0008] A receiving coil assembly is used to generate an inductive signal to the passage area;

[0009] The receiving coil assembly includes multiple receiving coils, each receiving coil having a coil shape with a bevel, and the multiple receiving coils are complementaryly spliced ​​together in such a way that adjacent bevels are parallel to each other;

[0010] Furthermore, the transmitting coil of the transmitting coil assembly is arranged in a zigzag pattern along the seam between adjacent receiving coils.

[0011] In some examples, optionally, a plurality of receiving coils in the receiving coil assembly are arranged as a receiving coil array filling a rectangular deployment area; the transmitting coil assembly bends and meanders along the seams between adjacent receiving coils within the rectangular deployment area.

[0012] In some examples, optionally, at least one row of the receiving coil array includes a pair of symmetrical receiving coils.

[0013] In some examples, optionally, each row of the receiving coil array includes a pair of the symmetrical receiving coils; the symmetrical centerlines of the symmetrical receiving coils in each row of the receiving coil array are aligned; and the symmetrical receiving coils in every two adjacent rows of the receiving coil array are complementaryly spliced ​​in such a way that their adjacent hypotenuses are parallel to each other.

[0014] In some examples, optionally, the bend and meandering shape of the transmitting coil of the transmitting coil assembly is arranged in a mirror image relative to the symmetrical centerline of each row of symmetrical receiving coils.

[0015] In some examples, the coil shape with the beveled side may optionally include at least one of a triangle, a trapezoid, and a rhombus.

[0016] Another embodiment of this application provides a detection device for a security gate, comprising:

[0017] The magnetic induction component as described in the foregoing embodiments;

[0018] A signal transmitting circuit is used to output the transmitting signal to the transmitting coil assembly;

[0019] A signal receiving circuit is used to demodulate the induced signal;

[0020] A processing component for generating a detection result of the passage area based on the sensing signal.

[0021] In some examples, optionally, an LC resonant circuit is also included, connected in series between the signal transmitting circuit and the transmitting coil assembly, and the LC resonant circuit includes an adjustable capacitor module; the processing component is further configured to: set the capacitance value of the adjustable capacitor module to a target capacitance value, wherein when the capacitance value of the adjustable capacitor module reaches the target capacitance value, the signal center frequency of the transmitted signal is at a specified center frequency corresponding to the target metal product.

[0022] In some examples, the adjustable capacitor module may optionally include multiple parallel branches, each of which has a rated capacitor and a branch selection switch connected in series; the processing component is specifically configured to generate a capacitor selection signal for controlling the branch selection switch in each of the parallel branches.

[0023] Another embodiment of this application provides a security gate including a side door panel and a detection device as described in the foregoing embodiments, wherein the transmitting coil assembly and the receiving coil assembly are arranged on the side door panel.

[0024] Based on the above embodiments of this application, within the coil deployment area shared by the transmitting coil assembly and the receiving coil assembly: multiple receiving coils in the receiving coil assembly have a coil shape with beveled edges, and are complementarily spliced ​​using adjacent parallel beveled edges to minimize the gaps between adjacent receiving coils where weak induction signals are easily generated; on the other hand, the transmitting coil assembly is deployed in a zigzag pattern along the seams between adjacent receiving coils, so that the distribution of strong areas of the physical magnetic field is not limited to the edges of the coil deployment area, but can be staggered within the coil deployment area, while also reducing the area of ​​weak areas surrounded by the transmitting coils. Therefore, the overlap between the receiving coils and weak areas can be reduced, thereby helping to reduce the detection blind spot of the security gate. Attached Figure Description

[0025] The following figures are for illustrative purposes only and do not limit the scope of this application:

[0026] Figure 1 This is an exemplary structural diagram of a detection device for a security gate in one embodiment of this application;

[0027] Figure 2 For example Figure 1 A schematic diagram of a first example of the magnetic induction component of the detection device shown.

[0028] Figure 3 For example Figure 2 The diagram shows the wiring method of the magnetic induction component;

[0029] Figure 4 For example Figure 1A schematic diagram of the second example structure and wiring method of the magnetic induction component of the detection device shown;

[0030] Figure 5 For example Figure 1 A schematic diagram of the third example structure and wiring method of the magnetic induction component of the detection device shown;

[0031] Figure 6 For example Figure 1 A schematic diagram of the fourth example structure and wiring method of the magnetic induction component of the detection device shown.

[0032] Figure 7 For example Figure 1 A schematic diagram of the fifth example structure and wiring method of the magnetic induction component of the detection device shown;

[0033] Figure 8 For example Figure 1 A schematic diagram of a first example of the signal transmission circuit of the detection device shown.

[0034] Figure 9 For example Figure 1 A schematic diagram of a second example of the signal transmission circuit of the detection device shown;

[0035] Figure 10 For example Figure 1 A schematic diagram of the third example of the signal transmission circuit of the detection device shown;

[0036] Figure 11 For example Figure 1 A schematic diagram of the fourth example of the signal transmission circuit of the detection device shown;

[0037] Figure 12 For example Figure 1 The diagram shows an optimized structure of the detection device used to adjust the center frequency of the signal.

[0038] Figure 13 For example Figure 12 The diagram shows an example of the optimized structure.

[0039] Figure 14 For example Figure 1 The diagram shows an optimized structure of the detection device used to improve the accuracy of detection results.

[0040] Figure 15 This is an exemplary structural diagram of a security gate according to another embodiment of this application. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided with reference to the accompanying drawings and embodiments.

[0042] Figure 1 This is an exemplary structural diagram of a detection device for a security gate according to one embodiment of this application. Please refer to... Figure 1 In embodiments of this application, the detection device for a security gate may include a processing component 10, a signal transmitting circuit 20, a signal receiving circuit 40, and a magnetic induction component for deployment on the side panel of the security gate, wherein the magnetic induction component includes a transmitting coil component 30 and a receiving coil component 50.

[0043] The signal transmitting circuit 20 is used to generate the transmitting signal S_emit, that is, the signal transmitting circuit 20 can output the transmitting signal S_emit to the transmitting coil assembly 30.

[0044] The transmitting coil assembly 30 is used to generate a physical magnetic field covering the passage area of ​​the security gate based on the transmitting signal S_emit, wherein the passage area of ​​the security gate may refer to the area between a pair of side panels of the security gate, and the transmitting signal S_emit used by the transmitting coil assembly 30 to generate the physical magnetic field has a sinusoidal frequency signal.

[0045] The receiving coil assembly 50 is used to generate a sensing signal S_ind for the passage area of ​​the security gate, wherein the receiving coil assembly 50 may include multiple receiving coils.

[0046] The signal receiving circuit 40 is used to process the induced signal generated by the receiving coil assembly 50. For example, the signal receiving circuit 40 may include a signal amplification circuit 400 for amplifying the induced signal S_ind.

[0047] The processing component 10 may include at least one processing device such as a CPU (Central Processing Unit), and / or at least one logic device such as an MCU (Microcontroller Unit), a CPLD (Complex Programmable Logic Device), or an FPGA (Field Programmable Gate Array). The processing component 10 can be used to drive the signal transmitting circuit 20, control the signal receiving circuit 40, and generate detection results for the passage area of ​​the security gate based on the sensing signal S_ind.

[0048] In embodiments of this application, in order to reduce the blind spot of the security gate and improve the accuracy of the detection results generated by the processing component 10:

[0049] Each receiving coil of the receiving coil assembly 50 may have a coil shape with a bevel, and the multiple receiving coils of the receiving coil assembly 50 are complementaryly spliced ​​in such a way that adjacent bevels are parallel to each other, wherein the bevel mentioned herein refers to a contour edge that has an included angle greater than 0° relative to both the horizontal direction (e.g., the X direction of the side door panel) and the vertical direction (e.g., the Y direction of the side door panel).

[0050] The transmitting coil of the transmitting coil assembly 30 is arranged in a zigzag pattern along the seam between adjacent receiving coils.

[0051] Based on the above embodiments of this application, within the coil deployment area shared by the transmitting coil assembly 30 and the receiving coil assembly 50: the multiple receiving coils in the receiving coil assembly 50 have a coil shape with beveled edges, and are complementarily spliced ​​using adjacent parallel beveled edges to minimize the gaps between adjacent receiving coils where weak induction signals are easily generated; on the other hand, the transmitting coil assembly 30 is deployed in a zigzag pattern along the seams between adjacent receiving coils, so that the strong area distribution of the physical magnetic field is not limited to the edge of the coil deployment area, but can be staggered within the coil deployment area, while also reducing the area of ​​weak areas surrounded by the transmitting coils. Therefore, the overlap between the receiving coils and weak areas can be reduced, thereby helping to reduce the detection blind spot of the security gate.

[0052] In particular, when the target metal product includes small metals, even though the physical magnetic field of the transmitting coil assembly 30 has limited ability to magnetize the small metal (to induce a secondary field in the small metal), the receiving coil assembly 50 has limited ability to sense the secondary field of the dry sound after the small metal is magnetized, and the signal receiving circuit 40 has limited tolerance for the signal-to-noise ratio of the induced signal S_ind, by increasing the area of ​​the strong region (the region with a strong magnetic field in any of the X, Y, and Z directions) and decreasing the area of ​​the weak region (the region with a weak magnetic field in the Z direction), especially by minimizing the gap between the receiving coils in the weak region, the multidimensional magnetic fields in the X, Y, and Z directions can be effectively utilized to ensure that small metals in any orientation can be successfully detected. Note: Minor metals refer to non-ferrous metals that are different from major metals. In some metal classification standards, major metals mainly include metals with relatively large units, such as copper, aluminum, lead, zinc, tin, nickel, manganese, and selenium. Precious metals mainly refer to rare metals such as gold, silver, and platinum. Minor metals can include metals with relatively small units, such as zirconium, gallium, molybdenum, magnesium, niobium, lithium, tantalum, antimony, titanium, tungsten, indium, and germanium.

[0053] To better understand the "coil shape with beveled edges", "complementary splicing with adjacent beveled edges parallel to each other", and "bending and meandering along the seam between adjacent receiving coils", specific examples will be provided below.

[0054] Figure 2 For example Figure 1 A schematic diagram of a first example of the magnetic induction component of the detection device shown. Please refer to [link / reference needed]. Figure 2 Taking a coil shape with a hypotenuse, including a triangle, as an example, the multiple receiving coils of the receiving coil assembly 50 may include triangular receiving coils 511 and 512 of different sizes, with the coil area of ​​triangular receiving coil 511 being smaller than that of triangular receiving coil 512.

[0055] In this configuration, each pair of adjacent triangular receiving coils 511 and 512 are complementaryly spliced ​​with their adjacent hypotenuses parallel to each other, thereby arranging the plurality of triangular receiving coils 511 and 512 in the receiving coil assembly 50 to fill the coil deployment area. Figure 2 The receiving coil array (with the dotted line as the boundary) is arranged so that the gap between adjacent triangular receiving coils 512, where weak induction signals are easily generated, can still be minimized.

[0056] Furthermore, the parallel hypotenuses of every two adjacent triangular receiving coils 511 and 512 are not seamlessly connected. Instead, a wiring gap for deploying the transmitting coil 300 is left between the parallel hypotenuses of every two adjacent triangular receiving coils 511 and 512. The size of this wiring gap is adapted to the line width of the transmitting coil 300, thereby:

[0057] The transmitting coil 300 can first be attached to one side of the coil deployment area in the horizontal direction (e.g. Figure 2 (left side), and in a broken line shape from one end of the coil deployment area in the vertical direction as the starting end (e.g.) Figure 2 (At the top of the middle) traverses each row of the receiving coil array row by row until reaching the other end of the coil deployment area in the vertical direction (e.g., the top of the middle) Figure 2 (at the bottom of the middle), the zigzag shape described here matches the distribution shape of the wiring gaps between the parallel hypotenuses on one side of the coil deployment area in the horizontal direction for each of two adjacent triangular receiving coils 511 and 512.

[0058] The transmitting coil 200 then meanders from the other end of the coil deployment area in the vertical direction to the other side of the coil deployment area in the horizontal direction (e.g. Figure 2 (on the right side of the middle), and then from the coil deployment area in a zigzag pattern at the other end in the vertical direction (e.g., ... Figure 2 The bottom of the coil array is traversed row by row across each row of the receiving coil array until the starting point of the return coil deployment area in the vertical direction. The zigzag shape described here matches the distribution shape of the wiring gaps between the parallel hypotenuses on the other side of the horizontal direction of each pair of adjacent triangular receiving coils 511 and 512 abutting the coil deployment area.

[0059] Thus, by the bending and meandering of the transmitting coil 300 of the transmitting coil assembly 30 along the seam between the adjacent triangular receiving coils 511 and 512, the strong area distribution of the physical magnetic field can be extended from the edge of the coil deployment area to the interior of the coil deployment area, while reducing the area of ​​the weak area surrounded by the transmitting coil.

[0060] To accommodate the shape of the side panel, the coil deployment area can be set as a rectangular deployment area. That is, multiple triangular receiving coils 511 and 512 in the receiving coil assembly 50 can be arranged as a receiving coil array to fill the rectangular deployment area. Correspondingly, the transmitting coil assembly 30 bends and meanders along the seam between adjacent triangular receiving coils 511 and 512 within the rectangular deployment area.

[0061] In addition, Figure 2 Taking a receiving coil array where each row includes a pair of symmetrical triangular receiving coils 511 or 512 as an example, in this case, the symmetrical center lines of the symmetrically arranged triangular receiving coils 511 or 512 in each row of the receiving coil array are aligned. The symmetrically arranged triangular receiving coils 511 and 512 in every two adjacent rows of the receiving coil array are complementaryly joined with their adjacent hypotenuses parallel to each other. Furthermore, the bent and meandering shape of the transmitting coil 300 of the transmitting coil assembly 30 is mirrored relative to the symmetrical center lines of the symmetrically arranged triangular receiving coils 511 and 512 in each row. If the coil deployment area is set as a rectangular deployment area, then the sum of the horizontal width dimensions of the symmetrically arranged triangular receiving coils 511 or 512 in each row of the receiving coil array is the same.

[0062] Figure 3 For example Figure 2 The diagram shows the wiring configuration of the magnetic induction component. Please refer to [link / reference needed]. Figure 3 , Figure 2 Each row of the receiving coil array is configured to include a pair of symmetrical triangular receiving coils 511 or 512. This allows a subtractor (e.g., a differential amplifier) ​​to be connected to the output of each pair of triangular receiving coils 511 or 512. In this case, the induced signal generated by the receiving coil assembly 50 can include the output signal of the subtractor connected to each pair of triangular receiving coils 511 or 512. Since each pair of triangular receiving coils 511 or 512 is in the same magnetic field environment, the magnetic field interference and power frequency interference induced by them are equivalent. Therefore, by connecting a subtractor to the output of each pair of triangular receiving coils 511 or 512, the magnetic field interference and power frequency interference in the output signal of the subtractor used as the induced signal S_ind can be eliminated, thereby improving the signal quality of the induced signal S_ind.

[0063] It is understood that, in the embodiments of this application, even without improving the signal quality of the induced signal by connecting a subtractor to the receiving coils arranged in pairs in each row, the detection blind zone can still be reduced by splicing the receiving coils and the detour of the transmitting coils as described above. That is, the paired symmetrical deployment of the receiving coils should not be construed as a necessary limitation for reducing the detection blind zone in the embodiments of this application.

[0064] Figure 4 For example Figure 1 A schematic diagram of the second example structure and wiring method of the magnetic induction component of the detection device shown. Please refer to [link / reference needed]. Figure 4 and Figure 2 and Figure 3 The comparison, still using the example of a coil shape with a hypotenuse including a triangle, is different. Figure 2 and Figure 3 The thing is, as Figure 4 The receiver coil assembly 50 shown includes multiple receiver coils, each consisting of a single triangular receiver coil 512 of the same size. Specifically, a pair of symmetrical triangular receiver coils 511 located in the first and last rows are replaced by a single triangular receiver coil 512 with a larger coil area. In this case, the gap between adjacent triangular receiver coils 512, which is prone to generating weak inductive signals, can still be minimized. Furthermore, the transmitter coil 300 of the transmitter coil assembly 30 can still bend and meander along the seams between adjacent triangular receiver coils 512 to increase the area of ​​the strong signal region and reduce the area of ​​the weak signal region.

[0065] Therefore, whether or not a paired symmetrical deployment of the receiving coils is adopted only affects the signal quality of the induction signal S_ind, and does not affect the effect of reducing the detection blind zone in the embodiments of this application.

[0066] Although Figure 2 and Figure 3 as well as Figure 4 The examples used are all examples of coil shapes with slanted sides, including triangles. However, in the embodiments of this application, coil shapes with slanted sides are not limited to triangles.

[0067] Figure 5 For example Figure 1 A schematic diagram of the third example structure and wiring method of the magnetic induction component of the detection device shown. Please refer to [link / reference needed]. Figure 5 Taking a coil with a slanted side, including a trapezoidal shape, and a coil deployment area that is a rectangular deployment area as an example, the multiple receiving coils of the receiving coil assembly 50 may include trapezoidal receiving coils 515 and 516 of different sizes. The trapezoidal receiving coil 515 is a right trapezoid, the trapezoidal receiving coil 516 is an isosceles trapezoid, and the coil area of ​​the trapezoidal receiving coil 515 is smaller than the coil area of ​​the trapezoidal receiving coil 516.

[0068] In this configuration, every two vertically adjacent trapezoidal receiving coils 515 and 516 are complementaryly spliced ​​with their adjacent hypotenuses parallel to each other, and every two horizontally adjacent trapezoidal receiving coils 515 and 516 are complementaryly spliced ​​with their respective straight edges parallel to the vertical direction. Thus, the plurality of trapezoidal receiving coils 515 and 516 in the receiving coil assembly 50 are arranged to fill the rectangular deployment area. Figure 5 The receiving coil array (with the dotted line as the boundary) is designed so that the gap between adjacent units in the vertical direction that is prone to generate weak induction signals can still be minimized.

[0069] Furthermore, the parallel hypotenuses of every two vertically adjacent trapezoidal receiving coils 515 and 516, and the straight edges of every two horizontally adjacent trapezoidal receiving coils 515 and 516, are not seamlessly connected. Instead, wiring gaps for deploying the transmitting coil 300 are provided between the parallel hypotenuses of every two vertically adjacent trapezoidal receiving coils 515 and 516, and between the straight edges of every two horizontally adjacent trapezoidal receiving coils 515 and 516. The size of these wiring gaps is adapted to the line width of the transmitting coil 300, thereby:

[0070] The transmitting coil 300 can first be attached to one side of the coil deployment area in the horizontal direction (e.g. Figure 2 (left side), and in a broken line shape from one end of the coil deployment area in the vertical direction as the starting end (e.g.) Figure 2 (At the top of the middle) traverses each row of the receiving coil array row by row until reaching the other end of the coil deployment area in the vertical direction (e.g., the top of the middle) Figure 2 (at the bottom of the middle), the zigzag shape described here matches the distribution shape of the wiring gap between the parallel hypotenuses on one side of the coil deployment area of ​​each pair of vertically adjacent trapezoidal receiving coils 515 and 516 in the horizontal direction, and the wiring gap between the straight sides of adjacent trapezoidal receiving coils 515 and 516 in the horizontal direction.

[0071] The transmitting coil 200 then meanders from the other end of the coil deployment area in the vertical direction to the other side of the coil deployment area in the horizontal direction (e.g. Figure 2 (on the right side of the middle), and then from the coil deployment area in a zigzag pattern at the other end in the vertical direction (e.g., ... Figure 2 The bottom of the coil array is traversed row by row until the starting point of the coil deployment area in the vertical direction. The zigzag shape described here matches the distribution shape of the wiring gaps between the parallel hypotenuses on the other side of the horizontal direction of each pair of vertically adjacent trapezoidal receiving coils 515 and 516, and the wiring gaps between the straight sides of adjacent horizontal trapezoidal receiving coils 515 and 516.

[0072] Thus, by the bending and meandering of the transmitting coil 300 of the transmitting coil assembly 30 along the seam between the adjacent trapezoidal receiving coils 515 and 516, the strong area distribution of the physical magnetic field can be extended from the edge of the coil deployment area to the interior of the coil deployment area, while reducing the area of ​​the weak area surrounded by the transmitting coil.

[0073] and Figure 2 and Figure 3 Similarly, in cases where the coil shape with beveled edges includes a trapezoid, each row of the receiving coil array may include a pair of symmetrical trapezoidal receiving coils 515 or 516. The receiving coil array is aligned along the symmetrical centerline of the symmetrically arranged trapezoidal receiving coils 515 or 516 in each row. The symmetrically arranged trapezoidal receiving coils 515 or 516 in each row of the receiving coil array are joined together with straight edges parallel to the vertical direction. Each pair of adjacent rows of symmetrically arranged trapezoidal receiving coils 515 and 516 are complementaryly joined with adjacent beveled edges parallel to each other. The bent and meandering shape of the transmitting coil 300 of the transmitting coil assembly 30 is mirrored relative to the symmetrical centerline of the symmetrically arranged trapezoidal receiving coils 515 and 516 in each row, and the sum of the width dimensions of the symmetrically arranged trapezoidal receiving coils 515 and 516 in each row of the receiving coil array is the same in the horizontal direction. Thus, with Figure 3 Similarly, the output of each symmetrically arranged trapezoidal receiving coil 515 or 516 in the receiving coil array is connected to a subtractor (e.g., a differential amplifier).

[0074] Figure 6 For example Figure 1 A schematic diagram of the fourth example structure and wiring method of the magnetic induction component of the detection device shown. Please refer to [link / reference needed]. Figure 6 A coil shape with a hypotenuse can include both triangles and trapezoids, that is, Figure 5 The trapezoidal receiving coil 515, symmetrically arranged in the first and last rows of the receiving coil array and having a right-angled trapezoidal shape, can be replaced with, for example... Figure 2 and Figure 3 A triangular receiving coil 511 is symmetrically arranged in the center.

[0075] Figure 7 For example Figure 1 A schematic diagram of the fifth example structure and wiring method of the magnetic induction component of the detection device shown. Please refer to [link / reference]. Figure 7 The shape of the coil with the slant can also include a rhombus, and the receiving coil 513 with a rhombus coil shape in the receiving coil array can coexist with triangular receiving coils 511 or 512 arranged symmetrically in a row, a triangular receiving coil 512 occupying the entire row alone, and / or trapezoidal receiving coils 515 or 516 arranged symmetrically in a row.

[0076] That is, in the embodiments of this application, the coil shape with beveled edges includes at least one of triangle, trapezoid, and rhombus. Moreover, it is understood that any coil shape with beveled edges other than triangle, trapezoid, and rhombus can be applied to the embodiments of this application as long as it satisfies the condition that the receiving coils in the receiving coil assembly 50 are complementaryly spliced ​​with adjacent beveled edges parallel to each other, and allows the transmitting coils in the transmitting coil assembly 30 to be deployed in a zigzag pattern along the seam between adjacent receiving coils. In other words, the embodiments of this application are not intended to impose unnecessary limitations on the coil shape with beveled edges.

[0077] In the embodiments of this application, when the coil deployment area is a rectangular deployment area, the transmitting coil assembly bends and meanders along the seam between adjacent receiving coils within the rectangular deployment area. Furthermore, the coil shape with beveled edges can also be arranged such that: multiple receiving coils in the receiving coil assembly 50 are arranged as a receiving coil array that fills the rectangular deployment area, that is, the sum of the width dimensions of the receiving coils in each row of the receiving coil array of the receiving coil assembly 50 is the same.

[0078] In embodiments of this application, regardless of the shape of the coil with beveled edges, in order to improve the signal quality of the induced signal S_ind, at least one row of the receiving coil array of the receiving coil assembly 50 includes a pair of symmetrical receiving coils. In this case, the output of the symmetrical receiving coils can be connected to a subtractor, and the induced signal S_ind can include the output signal of the subtractor.

[0079] As an optimal solution, each row of the receiving coil array of the receiving coil assembly 50 includes a pair of symmetrical receiving coils. If so, the symmetrical center lines of the symmetrical receiving coils in each row of the receiving coil array of the receiving coil assembly 50 are aligned, and the symmetrical receiving coils in every two adjacent rows of the receiving coil array are complementaryly spliced ​​in such a way that the adjacent hypotenuses are parallel to each other. The bent and meandering shape of the transmitting coil assembly 30 can be arranged in a mirror image relative to the symmetrical center lines of the symmetrical receiving coils in each row. Furthermore, the output terminals of each pair of symmetrical receiving coils in each row of the receiving coil array of the receiving coil assembly 50 can be connected to a subtractor.

[0080] To better understand the hardware configuration and working principle in the above embodiments of this application, the signal transmitting circuit 20 and the signal receiving circuit 40 will be described by example below.

[0081] In embodiments of this application, the signal transmitting circuit 20 can output a transmitting signal S_emit to the transmitting coil assembly 30 based on the driving signal S_drv generated by the processing component 10. The signal transmitting circuit 20 can have various options, and an LC (inductor-capacitor) resonant circuit for frequency selection of the transmitting signal S_emit can be further connected in series between the signal transmitting circuit 20 and the transmitting coil assembly 30. This allows the LC resonant circuit to control the signal center frequency of the transmitting signal S_emit generated by the signal transmitting circuit 20. This is because:

[0082] For each metal element, the effective frequency band that can induce a secondary field is limited. If the center frequency of the emitted signal S_emit that generates the physical magnetic field does not match the effective frequency band suitable for the metal element of the target metal product, it will be difficult to induce a secondary field of sufficient strength in the target metal product in the physical magnetic field, resulting in a weak induced signal S_ind. That is, the introduction of the LC resonant circuit is to improve the signal quality of the induced signal S_ind, and should not be construed as a necessary limitation for improving the detection accuracy of the target metal product in the embodiments of this application.

[0083] Figure 8 For example Figure 1 A schematic diagram of a first example of the signal transmission circuit of the detection device shown. Please refer to [link / reference]. Figure 8 As an optional solution, the signal transmitting circuit 20 may include a push-pull circuit 210, wherein the push-pull circuit 210 may include two transistors M11 and M12 of different polarities, and a transformer T20 connected between the transistors M11 and M12. The transistors M11 and M12 may be MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors) operating in the linear region, and the center tap of the transformer T20 is connected to the power supply VCC. In this case, the processing component 10 can be configured to generate a pulse drive signal to the push-pull circuit 210. That is, the drive signal S_drv generated by the processing component 10 to the signal transmitting circuit 20 can be a pulse drive signal. The pulse drive signal includes two reverse pulses S_drv1 and S_drv2 respectively output to the two transistors M11 and M12, so that the two transistors M11 and M12 are turned on alternately. After being amplified by the transformer T20, a frequency signal with a sine wave is generated as the transmission signal S_emit and output to the transmitting coil component 30. Preferably, the transmission signal S_emit can be output to the transmitting coil component 30 at a specified center frequency after being resonated by the LC resonant circuit 60.

[0084] Figure 9 For example Figure 1 A schematic diagram of a second example of the signal transmission circuit of the detection device shown. Please refer to [link / reference needed]. Figure 9 As an alternative, the signal transmitting circuit 20 may include a half-bridge circuit 220, which may include two switching devices M21 and M22. The two switching devices M21 and M22 may be MOSFETs operating in a switching state. Optionally, the half-bridge circuit 220 may also include a transformer for determining the amplification factor of the drive signal S_drv. In this case, the processing component 10 can be configured to generate a pulse drive signal to the half-bridge circuit 220. That is, the drive signal S_drv generated by the processing component 10 to the signal transmitting circuit 20 can be a pulse drive signal. The pulse drive signal includes two reverse pulses S_drv1 and S_drv2 respectively output to the two switching devices M21 and M22, so that the two switching devices M21 and M22 are alternately turned on. Thus, similar to the push-pull circuit 210, a frequency signal with a sine wave can be generated as a transmission signal S_emit and output to the transmitting coil assembly 30. Preferably, the transmission signal S_emit can be output to the transmitting coil assembly 30 at a specified center frequency after being resonated by the LC resonant circuit 60.

[0085] Figure 10 For example Figure 1 The diagram shows a third example of the signal transmission circuit structure of the detection device. Please refer to [link / reference needed]. Figure 10 As an alternative, the signal transmitting circuit 20 may include an operational amplifier circuit 230. For example, the operational amplifier circuit 230 may include a filter circuit 231, an operational amplifier 232, and a power filter amplifier 233 connected in series between the processing component 10 and the transmitting coil component 50. Furthermore, the operational amplifier circuit 230 may also include a power ground and digital ground isolation circuit 235 connected between the processing component 10 and the LC resonant circuit 60. In this case, the processing component 10 may be configured to generate a frequency drive signal to the operational amplifier circuit 230. That is, the drive signal S_drv generated by the processing component 10 to the signal transmitting circuit 20 may be a frequency drive signal. For example, the processing component 10 may use an integrated DAC (Digital to Analog Converter) to generate a frequency drive signal with a sinusoidal waveform, so that the frequency drive signal is amplified by the operational amplifier circuit 230 and becomes a transmitting signal S_emit, which is output to the transmitting coil component 30. Preferably, the transmitting signal S_emit may be resonated by the LC resonant circuit 60 and output to the transmitting coil component 30 at a specified center frequency.

[0086] Figure 11 For example Figure 1 The diagram shows a fourth example of the signal transmission circuit structure of the detection device. Please refer to [link / reference needed]. Figure 11 As an alternative, the transmitting drive circuit of the signal transmitting circuit 20 may include a power amplifier circuit 240 suitable for an audio power amplifier. For example, the power amplifier circuit 240 may include an RC filter circuit 241, a power amplifier 242, and an LC filter circuit 243 connected in series between the processing component 10 and the transmitting coil component 50. Similar to the operational amplifier circuit 230, the power amplifier circuit 240 may also include a power ground and digital ground isolation circuit 245 connected between the processing component 10 and the LC resonant circuit 60. In this case, the processing component 10 can be configured to generate a frequency drive signal to the power amplifier circuit 240. That is, the drive signal S_drv generated by the processing component 10 to the signal transmitting circuit 20 can be a frequency drive signal. For example, the processing component 10 can use an integrated DAC to generate a frequency drive signal with a sine wave, so that the frequency drive signal is amplified by the power amplifier circuit 240 and output as a transmission signal S_emit to the transmitting coil component 30. Preferably, the transmission signal S_emit can be resonated by the LC resonant circuit 60 and output to the transmitting coil component 30 at a specified center frequency.

[0087] The above are as follows Figures 8 to 11 The example structure of the signal transmitting circuit 20 shown is intended to illustrate that this application can accommodate a variety of choices of the signal transmitting circuit 20, and is not intended to impose unnecessary restrictions on the signal transmitting circuit 20.

[0088] Another matter Figures 8 to 11 The LC resonant circuit 60 shown can control the center frequency of the transmitted signal S_emit generated by the transmitting circuit 20 to a specified center frequency determined by the constraints of the capacitor C20 and the inductor L20. Since the effective frequency bands for generating secondary fields of different metal elements are different, in order to expand the range of applicability to the target metal product categories, when the LC resonant circuit 60 is further introduced as an optimization scheme, the LC resonant circuit 60 can be further improved to support the adjustment of the center frequency of the transmitted signal S_emit in the embodiments of this application.

[0089] Figure 12 For example Figure 1 The diagram shows an optimized structure of the detection device used to adjust the signal center frequency. Please refer to [link / reference needed]. Figure 12 In embodiments of this application, if the detection device further includes an LC resonant circuit 60 connected in series between the signal transmitting circuit 20 and the transmitting coil assembly 30, then, as a preferred embodiment, the LC resonant circuit 60 may include an adjustable capacitor module C_adj, and the processing component 10 may be further used for:

[0090] The capacitance value of the adjustable capacitor module C_adj in the LC resonant circuit 60 is set to the target capacitance value. When the capacitance value of the adjustable capacitor module C_adj reaches the target capacitance value, the signal center frequency of the transmitted signal S_emit is at the specified center frequency.

[0091] Figure 13 For example Figure 12 The diagram shows an example of the optimized structure. Please refer to [link / reference]. Figure 13 In some examples of embodiments of this application, the adjustable capacitor module C_adj may include multiple parallel branches, each of which is connected in series with a rated capacitor c_i and a branch selection switch s_i, where i is a positive integer greater than or equal to 1 and less than or equal to k, k is a positive integer representing the total number of branches in the parallel branches, and k is greater than 1. In this case, the processing component 10 may be specifically configured to generate capacitor selection signals S_Adj[1:k] for controlling the branch selection switches s_1~s_k in each parallel branch.

[0092] Therefore, based on the selection of branch selection switches s_1~s_k using the capacitor selection signal S_Adj[1:k], the adjustable capacitor module C_adj can be adjusted within the range of min{c_i}~∑c_i. For example, assuming that the rated capacitors c_1~c_k in each parallel branch have a set value Δc, then, based on the selection of branch selection switches s_1~s_k using the capacitor selection signal S_Adj[1:k], the adjustable capacitor module C_adj can be adjusted within the range of Δc~k×Δc with granularity.

[0093] In practical use, there may be multiple categories of target metal products with different metal elements, and the effective frequency bands corresponding to these categories of target metal products may not be the same. Furthermore, it is unpredictable which category of target metal product a metal product appears in the passage area of ​​the security gate belongs to. Therefore, the processing component 10 can be further configured to poll and set the capacitance value of the adjustable capacitor module C_adj of the LC resonant circuit 60 to a target capacitance value that is adapted to the specified center frequency of each target metal product based on a specified center frequency that is pre-set for at least two types of target metal products.

[0094] For example, Table 1 shows the results of polling with three specified center frequencies. , as well as The test results were obtained for target metal products A, B, and C, which contain different small metal materials, based on the target capacitance value that was not adapted.

[0095] Table 1

[0096]

[0097] Figure 14 For example Figure 1 The diagram shows an optimized structure of the detection device used to improve the accuracy of detection results. Please refer to [link / reference]. Figure 14 In addition to amplifying the induced signal S_ind, the signal receiving circuit 40 can also be used to demodulate the induced signal generated by the receiving coil assembly 50. Therefore, the signal receiving circuit 40 may include a first demodulation circuit 410 and a second demodulation circuit 420 connected in parallel between the receiving coil assembly 50 and the processing assembly 10 (e.g., between the signal amplification circuit 400 and the processing assembly 10). The first demodulation circuit 410 is used to demodulate the induced signal S_ind using the first demodulation signal S_dem_a, and the second demodulation circuit 420 is used to demodulate the induced signal using the second demodulation signal S_dem_b. The first demodulation circuit 410 and the second demodulation circuit 420 may include, but are not limited to, analog devices such as analog switches and multipliers. The embodiments of this application do not limit this.

[0098] In the embodiments of this application, the first demodulated signal S_dem_a, the second demodulated signal S_dem_b, and the induced signal S_ind are all frequency signals, and there is a phase difference n between the first demodulated signal S_dem_a and the second demodulated signal S_dem_b.

[0099] For example, if the inductive signal S_ind is represented as The first demodulated signal S_dem1_a ​​is represented as The second demodulated signal S_dem1_b can be represented as ,but:

[0100] The first demodulation result S_rec_a obtained by the first demodulation circuit 410 using the first demodulation signal S_dem_a to demodulate the induced signal S_ind can be expressed as follows: ;

[0101] The second demodulation circuit 420 uses the second demodulation signal S_dem_b to demodulate the induced signal S_ind, and the resulting second demodulation result S_rec_b can be expressed as follows: .

[0102] Processing component 10 may include at least one processing device such as a CPU (Central Processing Unit), and / or at least one logic device such as an MCU (Microcontroller Unit), a CPLD (Complex Programmable Logic Device), or an FPGA (Field Programmable Gate Array). Processing component 10 may be used to drive signal transmitting circuit 20 and control signal receiving circuit 40.

[0103] In embodiments of this application, when the signal receiving circuit 40 is used to demodulate the induced signal generated by the receiving coil assembly 50, the processing component 10 can be used to:

[0104] A first demodulated signal S_dem_a and a second demodulated signal S_dem_b are generated, that is, the first demodulated signal S_dem_a is generated to the first demodulation circuit 410 and the second demodulation signal S_dem_b is generated to the second demodulation circuit 420.

[0105] Based on the first demodulation result S_rec_a obtained by the first demodulation circuit 410 using the first demodulation signal S_dem_a to demodulate the sensing signal S_ind, and the second demodulation result S_rec_b obtained by the second demodulation circuit 420 using the second demodulation signal S_dem_b to demodulate the sensing signal S_ind, the target features within the passage area of ​​the security gate are determined. These target features are used to characterize the physical properties within the passage area of ​​the security gate.

[0106] Based on the target features that characterize the physical properties of the passage area of ​​the security gate, the detection results of the passage area of ​​the security gate are generated.

[0107] Based on the above embodiments of this application, two different demodulated signals with a phase difference (i.e., the first demodulated signal S_dem_a and the second demodulated signal S_dem_b) can be used to demodulate the sensing signal S_ind generated by the receiving coil assembly 50 on the passage area of ​​the security gate. Furthermore, by using the two demodulation results obtained from demodulating the sensing signal S_ind (i.e., the first demodulation result S_rec_a and the second demodulation result S_rec_b), target features characterizing the physical properties within the passage area can be determined, thereby generating detection results for the passage area based on the target features. The physical properties within the passage area characterized by the target features not only indicate whether there are metal objects within the passage area, but also, compared to the amplitude of changes in the sensing signal, can to a certain extent reflect the properties of the metal objects within the passage area. Therefore, compared to using changes in the sensing signal to determine whether there are target metal objects within the passage area, the above embodiments can help improve the detection accuracy of target metal objects, thereby reducing or even eliminating the need for security personnel to intervene in the screening, thus improving the passage efficiency of the security gate.

[0108] In some examples of embodiments of this application, the target feature may include a first target feature M associated with the signal amplitude of the sensing signal S_ind, and a second target feature N associated with the phase difference n between the first demodulated signal S_dem_a and the second demodulated signal S_dem_b. The first target feature M can be used to characterize the intensity of the secondary field generated within the passage area of ​​the security gate, and the second target feature N can be used to characterize the material element properties within the passage area of ​​the security gate. When the target feature includes the aforementioned first target feature M and second target feature N, the processing component 10 may be specifically configured as follows:

[0109] Based on the first demodulated signal S_dem_a and the second demodulated signal S_dem_b, a first target feature M and a second target feature N are determined, wherein the first target feature M is associated with the signal amplitude of the sensed signal S_ind, and the second target feature N is associated with the phase difference n between the first demodulated signal S_dem_a and the second demodulated signal S_dem_b; and,

[0110] Based on the first target feature M and the second target feature N, the detection results of the passage area of ​​the security gate are generated.

[0111] In some examples of embodiments of this application, in order to enable the first target feature M to better characterize the intensity of the secondary field generated in the passage area of ​​the security gate, the processing component 10 may be specifically configured to: determine the first target feature M based on the superposition of the first demodulation result S_rec_a and the second demodulation result S_rec_b.

[0112] For example, processing component 10 can determine the square root of the first demodulation result S_rec_a and the second demodulation result S_rec_b as the first target feature M. That is, if the first demodulation circuit 410 uses the first demodulation signal S_dem_a to demodulate the induced signal S_ind, the first demodulation result S_rec_a is expressed as... Furthermore, the second demodulation result S_rec_b obtained by the second demodulation circuit 420 using the second demodulation signal S_dem_b to demodulate the induced signal S_ind can be expressed as: Then, the first target feature M can be expressed as the following expression (1).

[0113] Expression (1)

[0114] In some examples of embodiments of this application, in order to enable the second target feature N to better characterize the material element properties within the passage area of ​​the security gate, the processing component 10 may be specifically configured to: determine the second target feature N based on the ratio of the first demodulation result S_rec_a and the second demodulation result S_rec_b.

[0115] For example, processing component 10 can determine the arctangent function value of the ratio of the first demodulation result S_rec_a and the second demodulation result S_rec_b as the second target feature N. That is, if the first demodulation circuit 410 uses the first demodulation signal S_dem_a to demodulate the induced signal S_ind, the first demodulation result S_rec_a is expressed as... Furthermore, the second demodulation result S_rec_b obtained by the second demodulation circuit 420 using the second demodulation signal S_dem_b to demodulate the induced signal S_ind can be expressed as: Then, the second target feature N can be expressed as the following expression (2).

[0116] Expression (2)

[0117] Therefore, the processing component 10 can use the comparison between the first target feature M and the second target feature N and the pre-set sample feature set to generate the detection result of the passage area of ​​the security gate. Each sample in the sample feature set can be calibrated according to each pre-selected target metal product, and each sample in the sample feature set can have an intensity feature value for characterizing the secondary field intensity induced by the corresponding target metal product, and an attribute feature value for characterizing the elemental properties of the corresponding target metal product.

[0118] For example, the intensity feature values ​​of each sample in the sample feature set can be compared with the first target feature M, and the attribute feature values ​​of each sample in the sample feature set can be compared with the second target feature N. Furthermore, to increase the correlation between the second target feature N and the elemental attributes of the target metal product, the phase difference n between the first demodulated signal S_dem_a and the second demodulated signal S_dem_b can be set according to the elemental attributes of the target metal product. If there are multiple categories of target metal products with different metal elements, and the elemental attributes of these categories of target metal products are not all the same, then the processing component 10 can be further configured to generate a set of second demodulated signals S_dem_b with different phase difference n values ​​by polling the value of the phase difference n pre-set for at least two types of target metal products. This is to obtain a second target feature N that can reflect the metallic properties of all target metal products.

[0119] Furthermore, if a metal object appears in the passage area of ​​the security gate, the detection result generated by comparing the first target feature M and the second target feature N with the pre-set sample feature set can further include alarm information generated when a target metal object similar to the metal object is matched.

[0120] Figure 15 This is an exemplary structural diagram of a security gate according to another embodiment of this application. Please refer to... Figure 15 In another embodiment of this application, a security gate may include side panels (i.e., a first side panel 91 and a second side panel 92) and the detection device described in the foregoing embodiments, wherein the transmitting coil assembly 30 and the receiving coil assembly 50 of the detection device may be arranged on the side panels (i.e., at least one of the first side panel 91 and the second side panel 92). Figure 12 As shown, in some preferred embodiments of this application, the transmitting coil assembly 30 and the receiving coil assembly 50 are simultaneously arranged on the first side panel 91 and the second side panel 92, that is:

[0121] The transmitting coil assembly 30 may include a first transmitting coil assembly 31 and a second transmitting coil assembly 32;

[0122] The receiving coil assembly 50 may include a first receiving coil assembly 51 and a second receiving coil assembly 52;

[0123] The first transmitting coil assembly 31 and the first receiving coil assembly 51 are arranged on the first side door panel 91 such that the first transmitting coil assembly 31 and the first receiving coil assembly 51 are located on the first side of the passage area of ​​the security gate;

[0124] The second transmitting coil assembly 31 and the second receiving coil assembly 52 are arranged on the second side door panel 92 such that the second transmitting coil assembly 31 and the second receiving coil assembly 52 are located on the second side of the passage area of ​​the security gate.

[0125] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A magnetic induction component for a security gate, characterized in that, include: A transmitting coil assembly is used to generate a physical magnetic field covering the passage area of ​​the security gate based on a transmitted signal; A receiving coil assembly is used to generate an inductive signal to the passage area; in: The receiving coil assembly includes multiple receiving coils arranged in a receiving coil array that fills a rectangular deployment area. Each receiving coil has a coil shape with a bevel, and the multiple receiving coils are complementaryly spliced ​​together in such a way that adjacent bevels are parallel to each other. The transmitting coil of the transmitting coil assembly is deployed in a zigzag pattern along the seam between adjacent receiving coils within the rectangular deployment area in the following manner: The transmitting coil, in a zigzag pattern, traverses each row of the receiving coil array from the first vertical end of the rectangular deployment area, meandering along the first horizontal side of the rectangular deployment area, until it reaches the second vertical end of the rectangular deployment area. The transmitting coil also traverses each row of the receiving coil array from the second end of the rectangular deployment area in a meandering, zigzag pattern along the second side of the rectangular area in the horizontal direction, until it returns to the first end of the rectangular deployment area in the vertical direction.

2. The magnetic induction component according to claim 1, characterized in that, The shape of a coil with a slanted side includes at least one of a triangle, a trapezoid, and a rhombus.

3. A magnetic induction component for a security gate, characterized in that, include: A transmitting coil assembly is used to generate a physical magnetic field covering the passage area of ​​the security gate based on a transmitted signal; A receiving coil assembly is used to generate an inductive signal to the passage area; in: The receiving coil assembly includes multiple receiving coils arranged in a receiving coil array that fills a rectangular deployment area. Each receiving coil has a coil shape with a bevel, and the multiple receiving coils are complementaryly spliced ​​together in such a way that adjacent bevels are parallel to each other. The transmitting coil of the transmitting coil assembly is deployed in a zigzag pattern along the seam between adjacent receiving coils within the rectangular deployment area; At least one row of the receiving coil array includes a pair of symmetrical receiving coils, the output of each pair of symmetrical receiving coils is connected to the same subtractor, and the induced signal includes the output signal of the subtractor.

4. The magnetic induction component according to claim 3, characterized in that, Each row of the receiving coil array includes a pair of the symmetrical receiving coils; The center lines of the symmetrical receiving coils in each row of the receiving coil array are aligned. The symmetrical receiving coils in every two adjacent rows of the receiving coil array are complementaryly spliced ​​together in such a way that their adjacent hypotenuses are parallel to each other.

5. The magnetic induction component according to claim 4, characterized in that, The bends and twists of the transmitting coil in the transmitting coil assembly are mirror images of the symmetrical centerlines of the rows of symmetrical receiving coils.

6. The magnetic induction component according to claim 2, characterized in that, The shape of a coil with a slanted side includes at least one of a triangle, a trapezoid, and a rhombus.

7. A detection device for security gates, characterized in that, include: The magnetic induction component as described in any one of claims 1 to 6; A signal transmitting circuit is used to output the transmitting signal to the transmitting coil assembly; A signal receiving circuit is used to demodulate the induced signal; A processing component for generating a detection result of the passage area based on the sensing signal.

8. The detection device according to claim 7, characterized in that, It also includes an LC resonant circuit connected in series between the signal transmitting circuit and the transmitting coil assembly, and the LC resonant circuit includes an adjustable capacitor module; The processing component is further used for: The capacitance value of the adjustable capacitor module is set as the target capacitance value. When the capacitance value of the adjustable capacitor module reaches the target capacitance value, the signal center frequency of the transmitted signal is at the specified center frequency corresponding to the target metal product.

9. The detection device according to claim 8, characterized in that, The adjustable capacitor module includes multiple parallel branches, and each of the parallel branches is connected in series with a rated capacitor and a branch selection switch; The processing component is specifically configured to generate capacitor gate signals for controlling the branch gate switches in each of the parallel branches.

10. A security gate, characterized in that, The device includes a side door panel and a detection device as described in any one of claims 7 to 9, wherein the transmitting coil assembly and the receiving coil assembly are arranged on the side door panel.

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