Foot metal detector and millimeter wave security door

Abstract

The utility model discloses a foot metal detector and a millimeter wave security door, the millimeter wave security door comprises the foot metal detector, and the foot metal detector comprises a fixing plate, a transmitting coil, a receiving coil assembly and a signal processing assembly. Wherein the transmitting coil is arranged on the fixing plate, a polygonal structure is defined by the transmitting coil, the receiving coil assembly is arranged on the fixing plate, the receiving coil assembly is located in the polygonal structure, and the receiving coil assembly comprises a left pin receiving coil assembly and a right pin receiving coil assembly which are arranged at an interval; the left foot receiving coil assembly and the right foot receiving coil assembly are electrically connected through a connecting wire, a detection area for standing of feet of a human body is formed above the left foot receiving coil assembly and the right foot receiving coil assembly, and the left foot receiving coil assembly and the right foot receiving coil assembly are electrically connected with the signal processing assembly. The problem that a foot metal detector is low in metal detection precision is solved.

Description

Technical Field

[0001] The present application relates to the field of security detection, and more particularly, to a foot metal detector and a millimeter wave security door. Background Art

[0002] The millimeter wave linear array scanning devices on the market are usually used in security doors. Due to the physical blind spots of the linear array scanning devices and their imaging principles, synthetic aperture radar has the inherent problem of weak bottom imaging. In addition, when a person wears leather shoes, millimeter waves cannot penetrate the surface of the shoes, making it difficult to conduct security inspections on the feet through millimeter waves.

[0003] In order to avoid the above situation, existing millimeter wave security doors are provided with a foot metal detector at the bottom of the security door. The foot metal detector generates a changing magnetic field at the bottom of the security door. When the metal in the foot enters the security door, the foot metal detector can detect the metal, thereby improving the overall detection accuracy of the millimeter wave security door.

[0004] However, the existing foot metal detectors have the defect of low detection accuracy for the metal in the shoes. How to improve the metal detection accuracy has become an urgent problem to be solved. Summary of the Utility Model

[0005] The main purpose of the present application is to provide a foot metal detector and a millimeter wave security door, so as to at least solve the problem of low detection accuracy of the foot metal detector for metal in the prior art.

[0006] According to one aspect of the present application, a foot metal detector is provided, including:

[0007] A fixing plate;

[0008] A transmitting coil, the transmitting coil is arranged on the fixing plate, and the transmitting coil encloses a polygonal structure;

[0009] A receiving coil assembly, the receiving coil assembly is arranged on the fixing plate, and the receiving coil assembly is located inside the polygonal structure. The receiving coil assembly includes a left foot receiving coil group and a right foot receiving coil group arranged at intervals. The left foot receiving coil group and the right foot receiving coil group are electrically connected through a connecting wire. A detection area for a human foot to stand is formed above the left foot receiving coil group and the right foot receiving coil group;

[0010] A signal processing component, the left foot receiving coil group and the right foot receiving coil group are respectively electrically connected to the signal processing component.

[0011] Further, the positive pole of one of the left foot receiving coil group and the right foot receiving coil group is connected to the negative pole of the other through the connecting wire.

[0012] Further, the fixed plate is an octagonal plate, and the transmitting coil extends along the edge of the fixed plate and encloses an octagonal structure similar to the fixed plate; or,

[0013] The transmitting coil encloses an octagonal structure on the surface of the fixed plate.

[0014] Further, the minimum distance L between the receiving coil assembly and the transmitting coil satisfies the relation: 3 mm ≤ L ≤ 7 mm.

[0015] Further, the foot metal detector further includes a support assembly, the support assembly is located on the outer periphery of the foot metal detector, and an identification area corresponding to the detection area is provided at the top of the support assembly.

[0016] Further, the identification area includes a heel accommodating portion for accommodating the human heel. Along the height direction of the foot metal detector, at least the projection plane of the heel accommodating portion of the identification area is located within the projection plane of the detection area; and / or,

[0017] The identification area includes a left foot identification and a right foot identification, the left foot identification is correspondingly arranged with the left foot receiving coil group, and the right foot identification is correspondingly arranged with the right foot receiving coil group.

[0018] Further, the included angle A between the center dividing line of the left foot identification and the center dividing line of the right foot identification satisfies the relation: 45° ≤ A ≤ 65°.

[0019] Further, the support assembly includes a support frame and a non-metallic pedal. The non-metallic pedal is fixed on the top of the support frame, and the identification area is arranged on the non-metallic pedal.

[0020] The fixed plate is arranged on the support frame, and the transmitting coil is located at the center position of the support frame.

[0021] Further, the receiving coil assembly further includes a positive wire and a negative wire. One of the left foot receiving coil group and the right foot receiving coil group is electrically connected to the signal processing component through the positive wire, and the other is electrically connected to the signal processing component through the negative wire.

[0022] On the other hand, the present application also provides a millimeter wave security door, and the millimeter wave security door includes the above-mentioned foot metal detector.

[0023] In the present application, the transmitting coil is arranged to form a polygonal structure. This means that when the transmitting coil is connected to the power supply, the transmitting coil can generate magnetic fields in multiple different directions, thereby improving the detection accuracy of the foot metal detector. That is to say, there are at least multiple multi-dimensional magnetic fields formed by coupling in different directions in the detection channel, so as to avoid the situation that when the metal on the human foot does not cut the magnetic induction line in the magnetic field, the receiving coil assembly does not generate an electrical signal, which ultimately leads to errors in the detection of the foot metal detector. At the same time, in the present application, the receiving coil assembly is arranged to form a detection area for the human foot to stand on. That is to say, when the human body needs to stand in the detection area in the present application, the foot metal detector will detect the human foot, thereby preventing the human foot from being away from the magnetic field range generated by the transmitting coil and the detection range of the receiving coil assembly, and further improving the detection accuracy. Further, in the present application, the receiving coil assembly includes a left-foot receiving coil group and a right-foot receiving coil group arranged at intervals. The left-foot receiving coil group and the right-foot receiving coil group are electrically connected (reverse butt joint) through a connecting wire. Compared with the situation where the left-foot receiving coil group and the right-foot receiving coil group are not electrically connected, this solution enables the left-foot receiving coil group and the right-foot receiving coil group to generate an electromotive force balance under the magnetic field action of each other, and there will be no situation where the magnetic flux change amounts generated in the magnetic field regions corresponding to the left-foot receiving coil group and the right-foot receiving coil group cancel each other out. Therefore, there will be no metal detection blind area on the left foot or the right foot (especially in the middle position of the foot), effectively improving the detection accuracy of the foot metal detector. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The schematic embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation to the present application. In the drawings:

[0025] Figure 1 is a schematic structural diagram of the millimeter-wave security inspection door disclosed in the present application;

[0026] Figure 2 is an exploded structural diagram of the foot metal detector disclosed in the present application;

[0027] Figure 3 is a structural diagram of the fixing plate, the transmitting coil and the receiving coil assembly disclosed in the present application;

[0028] Figure 4 is the foot metal detector (removing the non-metallic pedal) disclosed in the present application;

[0029] Figure 5 is a signal schematic diagram in the signal processor disclosed in the present application;

[0030] Figure 6 is a detection logic flow chart of the foot metal detector disclosed in the present application;

[0031] Figure 7 For Figure 3 Schematic diagram of the enlarged I area in the middle.

[0032] Among them, the above-mentioned drawings include the following reference numerals:

[0033] 10. Door body; 11. Support assembly; 12. First side plate; 13. Second side plate; 14. Top plate; 101. Detection channel; 15. Shielding assembly; 21. Foot metal detector; 111. Non-metallic pedal; 112. Support frame; 113. Ramp block; 211. Fixed plate; 212. Transmitting coil; 213. Receiver coil assembly; 1111. Identification area; 1112. Left foot identification; 1113. Right foot identification; 1114. Heel accommodation part; 2111. Conical rubber plug; 2131. Left foot receiver coil group; 2132. Right foot receiver coil group; 2133. Positive connection wire; 2134. Negative connection wire; 2135. Connecting wire; 21311. First left foot coil; 21312. Second left foot coil; 21321. First right foot coil; 21322. Second right foot coil. Detailed implementation manners

[0034] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments may be combined with each other. The following will describe the present application in detail with reference to the drawings and in combination with the embodiments.

[0035] It should be noted that the terms used herein are only for describing the specific implementation manners and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "include" and / or "comprise" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0036] Unless otherwise specifically stated, the relative arrangements of the components and steps, numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present application. At the same time, it should be understood that, for the sake of convenience of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and devices should be regarded as part of the authorized specification. In all the examples shown and discussed here, any specific value should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that: similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0037] See Figures 1 to 4 and Figure 7 As shown, according to an embodiment of the present application, a millimeter-wave security door is provided, which includes a door body 10 and a foot metal detector 21.

[0038] Among them, a detection channel 101 is provided in the door body 10, and a millimeter-wave transceiver is provided in the detection channel 101. The millimeter-wave transceiver is used to send millimeter waves to the detection channel 101 and receive the millimeter waves reflected back to the millimeter-wave transceiver. The foot metal detector 21 includes a fixing plate 211, a transmitting coil 212, a receiving coil assembly 213, and a signal processing component (not shown in the figure). The transmitting coil 212 is arranged on the fixing plate 211 and encloses a polygonal structure. The receiving coil assembly 213 is arranged on the fixing plate 211, and the receiving coil assembly 213 is located inside the polygonal structure. The receiving coil assembly 213 includes a left-foot receiving coil group 2131 and a right-foot receiving coil group 2132 arranged at intervals. The left-foot receiving coil group 2131 and the right-foot receiving coil group 2132 are electrically connected through a connecting wire 2135. A detection area for a human foot to stand is formed above the left-foot receiving coil group 2131 and the right-foot receiving coil group 2132. The left-foot receiving coil group 2131 and the right-foot receiving coil group 2132 are respectively electrically connected to the signal processing component.

[0039] Specifically, after the millimeter waves emitted by the millimeter wave transceiver in the detection channel 101 come into contact with the human body, some of the millimeter waves are reflected back to the millimeter wave transceiver. The millimeter wave transceiver receives the millimeter waves, and then the control system of the security gate generates a graph to determine whether there is metal on the human body. Since the penetration ability of millimeter waves is weak, when a person wears shoes, it is difficult for millimeter waves to penetrate the shoes to detect the human feet. At the same time, since the millimeter wave transceiver is usually installed on the side wall of the door body 10, there are many blind spots when detecting the human feet. Therefore, a foot metal detector 21 is provided to make up for the blind spots brought by the millimeter wave transceiver. In the foot metal detector 21, an alternating current is passed through the transmitting coil 212 to generate a changing magnetic field at the bottom of the detection channel. When the human foot with metal enters the detection channel 101, the metal is affected by the changing magnetic field, and then a changing electrical signal is generated inside the metal. After the receiving coil assembly 213 senses the electrical signal in the magnetic field, a corresponding electrical signal is generated on the receiving coil assembly 213. When the value of the electrical signal generated on the receiving coil assembly 213 is higher than the detection threshold, the signal processing component determines that there is metal on the human foot. When there is no metal on the human foot, the electrical signal generated on the receiving coil assembly 213 is lower than the detection threshold, and the signal processing component determines that there is no metal on the human foot. It is worth mentioning that it is not necessary for there to be metal in the magnetic field for the receiving coil assembly 213 to generate an electrical signal. When a human body enters the magnetic field, since the human body contains various substances, some substances can also cause an electrical signal to be generated on the receiving coil assembly 213. However, the substances carried by the human body have a weak impact on the receiving coil assembly 213. Therefore, a detection threshold needs to be set.

[0040] In the present application, the transmitting coil 212 is arranged to form a polygonal structure. This means that when the transmitting coil 212 is connected to a power source, the transmitting coil 212 can generate magnetic fields in multiple different directions, thereby improving the detection accuracy of the foot metal detector 21. That is to say, there are at least multiple multi-dimensional magnetic fields formed by coupling in different directions in the detection channel 101. Furthermore, when the metal on the human foot does not cut the magnetic induction line in the magnetic field, the receiving coil assembly 213 does not generate an electrical signal, which ultimately leads to errors in the detection of the foot metal detector 21. At the same time, in the present application, the receiving coil assembly 213 is arranged to form a detection area for the human foot to stand on. That is to say, in the present application, when the human body needs to stand in the detection area, the foot metal detector 21 will detect the human foot, thereby preventing the magnetic field range generated by the human foot from being far away from the transmitting coil 212 and the detection range of the receiving coil assembly 213, and further improving the detection accuracy. Further, the receiving coil assembly 213 in the present application includes a left-foot receiving coil group 2131 and a right-foot receiving coil group 2132 that are arranged at intervals. The left-foot receiving coil group 2131 and the right-foot receiving coil group 2132 are electrically connected (reverse butt-jointed) through a connecting wire 2135. Compared with the situation where the left-foot receiving coil group 2131 and the right-foot receiving coil group 2132 are not electrically connected, this solution enables the left-foot receiving coil group 2131 and the right-foot receiving coil group 2132 to generate an electromotive force balance under the magnetic field action of each other, and there will be no situation where the magnetic flux change amounts generated in the magnetic field regions corresponding to the left-foot receiving coil group 2131 and the right-foot receiving coil group 2132 cancel each other out. Therefore, there will be no metal detection blind spots in the feet (especially the middle position of the feet) of the left foot or the right foot, effectively improving the detection accuracy of the foot metal detector 21.

[0041] Further, the positive electrode of one of the left-foot receiving coil group 2131 and the right-foot receiving coil group 2132 is connected to the negative electrode of the other through the connecting wire 2135.

[0042] When the positive electrode of the left-foot receiving coil group 2131 is connected to the negative electrode of the right-foot receiving coil group 2132 through the connecting wire 2135, the induced electromotive force generated by the left-foot receiving coil group 2131 under the magnetic field action of the right-foot receiving coil group 2132 cancels out the induced electromotive force generated by the right-foot receiving coil group 2132 under the magnetic field action of the left-foot receiving coil group 2131, thereby avoiding the influence of the electromotive force generated by mutual inductance on the magnitude of the induced electromotive force generated by metal induction. Similarly, when the negative electrode of the left-foot receiving coil group 2131 is connected to the positive electrode of the right-foot receiving coil group 2132 through the connecting wire 2135, the electromotive force generated by their mutual inductance can also be cancelled out.

[0043] In an alternative embodiment, the number of sides of the polygonal structure can be greater than or equal to 7, which means that the magnetic field directions generated by each of at least 7 sides are different, and the magnetic fields in at least 7 directions are coupled to form a multi-dimensional magnetic field, thereby further improving the detection accuracy of the foot metal detector 21.

[0044] In a specific embodiment, the fixing plate 211 is an octagonal plate, and the transmitting coil 212 extends along the edge of the fixing plate 211 and encloses an octagonal structure similar to the fixing plate 211; or, the transmitting coil 212 encloses an octagonal structure on the surface of the fixing plate 211. At this time, the shape of the fixing plate 211 is not particularly limited and can be reasonably set according to requirements.

[0045] Exemplarily, the transmitting coil 212 is fixed into an octagonal structure by a plurality of conical rubber plugs 2111, so as to form a multi-dimensional magnetic field in the octagonal area. The multi-dimensional magnetic field is used to improve the detection accuracy of metals, thereby avoiding the situation where metals do not cut magnetic induction lines in the magnetic field, resulting in the receiving coil assembly 213 being unable to sense the change in the electrical signal in the magnetic field. Of course, in some embodiments, the fixing plate 211 can also be set as an equilateral triangle plate, a square plate, and a regular hexagon plate, and the transmitting coil 212 can enclose an equilateral triangle structure, a square structure, and a regular hexagon structure adapted to the fixing plate 211.

[0046] Furthermore, the minimum distance L between the receiving coil assembly 213 and the transmitting coil 212 satisfies the relation: 3 mm ≤ L ≤ 7 mm.

[0047] In this embodiment, the minimum distance L between the receiving coil assembly 213 and the transmitting coil 212 should be reduced as much as possible. If L is greater than 7, the magnetic field intensity in the detection area enclosed by the receiving coil assembly 213 is low, which may cause metals in the detection area to not be detected normally, affecting the detection accuracy of the foot metal detector 21. And the value of L should not be too low either, as too low may cause the receiving coil assembly 213 to generate a large magnetic field by itself, thereby affecting the determination of the signal processing component. The value of L can be 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, 5.5 mm, 6 mm, 6.5 mm, and 7 mm.

[0048] In addition, the foot metal detector further includes a support assembly 11. The support assembly 11 is located on the outer periphery of the foot metal detector, and a marking area 1111 corresponding to the detection area is provided at the top of the support assembly 11.

[0049] In this embodiment, the support component 11 is used to support the human body so that the human body can stand in the detection channel 101. In addition, the identification area 1111 on the support component 11 corresponds to the detection area, that is, when the human foot stands on the identification area 1111, the receiving coil assembly 213 can better detect whether there is metal on the human foot.

[0050] Further, the identification area 1111 includes a heel accommodating portion 1114 which is used to accommodate the human heel. Along the height direction of the foot metal detector 21 (such as the Z direction in the appendix), at least the projection plane of the heel accommodating portion 1114 of the identification area 1111 is located within the projection plane of the detection area. As Figure 1 shown, the heel accommodating portion 1114 can be completely located within the receiving coil assembly 213. Figure 4 shown, the heel accommodating portion 1114 can be completely located within the receiving coil assembly 213.

[0051] Specifically, the transmitting coil 212 of this embodiment can generate a magnetic field with a height of at least 20 cm in the height direction of the millimeter-wave security gate. Considering some special situations, for example, when a person stands, the height of the back heel is slightly higher than that of the front foot when standing. If the distance between the back heel and the receiving coil assembly 213 is too high, it may reduce the detection accuracy of whether there is metal on the back heel by the foot metal detector 21. At the same time, if the projection plane of the heel accommodating portion 1114 of the identification area 1111 is not located within the projection plane of the detection area, that is, the heel accommodating portion 1114 is too far from the detection area, this will cause the current generated by the metal due to the eddy current effect to be difficult to make the receiving coil assembly 213 generate an induced electromotive force when there is metal on the human foot, and finally the signal processing component cannot accurately judge the situation of the human back heel. Therefore, in order to improve the detection accuracy of whether the human back heel carries metal, at least the projection plane of the heel accommodating portion 1114 of the identification area 1111 in this embodiment is located within the projection plane of the detection area.

[0052] Further, the identification area 1111 includes a left-foot identification 1112 and a right-foot identification 1113. The left-foot identification 1112 is correspondingly arranged with the left-foot receiving coil group 2131, and the right-foot identification 1113 is correspondingly arranged with the right-foot receiving coil group 2132.

[0053] In this embodiment, the left - foot receiving coil group 2131 is used to detect whether there is metal on the left foot of a human body, and the right - foot receiving coil group 2132 is used to detect whether there is metal on the right foot of a human body. When the left foot of a human body stands on the left - foot identifier 1112 and the right foot stands on the right - foot identifier 1113, if there is metal on the left foot of the human body, eddy currents are generated under the action of the magnetic field. The eddy currents cause an induced electromotive force to be generated in the left - foot receiving coil group 2131. When the value of the induced electromotive force is greater than the detection threshold, the signal - processing component determines that there is metal on the left foot; similarly, if there is metal on the right foot of the human body, eddy currents are generated under the action of the magnetic field. The eddy currents cause an induced electromotive force to be generated in the right - foot receiving coil group 2132. When the value of the induced electromotive force is greater than the detection threshold, the signal - processing component determines that there is metal on the left foot.

[0054] As shown in the Figure 4 attachment, the included angle A between the center - dividing line of the left - foot identifier 1112 and the center - dividing line of the right - foot identifier 1113 satisfies the relation: 45° ≤ A ≤ 65°.

[0055] In this embodiment, the center - dividing line of the left - foot identifier 1112 is the center - dividing line along the extending direction of the left - foot identifier 1112, and the center - dividing line of the right - foot identifier 1113 is the center - dividing line along the extending direction of the right - foot identifier 1113. When A satisfies the above - mentioned relation, the opening - closing angle between the left - foot identifier 1112 and the right - foot identifier 1113 is more in line with the opening - closing angle between the left and right feet when a human body stands naturally. When A is less than 45° or A is greater than 65°, the opening - closing angle between the left - foot identifier 1112 and the right - foot identifier 1113 is too small or too large. When a human body stands between the left - foot identifier 1112 and the right - foot identifier 1113, it is easy to feel discomfort. The value of A can be 45°, 50°, 55°, 60°, and 65°.

[0056] Further, the left - foot receiving coil group 2131 includes a first left - foot coil 21311 and a second left - foot coil 21312, and the first left - foot coil 21311 is arranged inside the second left - foot coil 21312; the right - foot receiving coil group 2132 includes a first right - foot coil 21321 and a second right - foot coil 21322, the first right - foot coil 21321 is arranged inside the second right - foot coil 21322, and the second right - foot coil 21322 is electrically connected to the second left - foot coil 21312 through a connecting wire 2135.

[0057] Specifically, the first left - foot coil 21311 is used to detect whether there is metal in the magnetic field in the detection area corresponding to the left - foot identifier 1112, and the first right - foot coil 21321 is used to detect whether there is metal in the magnetic field in the detection area corresponding to the right - foot identifier 1113. In addition, when the metal is between the second left - foot coil 21312 and the second right - foot coil 21322, eddy currents are generated in the changing magnetic field, causing electromotive forces to be generated on the second right - foot coil 21322 and the second left - foot coil 21312. As a result, different magnetic fields are generated between the second left - foot coil 21312 and the second right - foot coil 21322. Under the action of the magnetic field, the detection accuracy of the first left - foot coil 21311 and the first right - foot coil 21321 may be reduced. Therefore, in this embodiment, the connecting wire 2135 is used to electrically connect the second right - foot coil 21322 and the second left - foot coil 21312, so that the electromotive forces on the second right - foot coil 21322 and the second left - foot coil 21312 are balanced with each other, avoiding the generation of a large magnetic field by the second right - foot coil 21322 and the second left - foot coil 21312.

[0058] As shown in the Figure 3 attachment, the receiving coil assembly 213 further includes a positive - pole connection wire 2133 and a negative - pole connection wire 2134. One of the left - foot receiving coil group 2131 and the right - foot receiving coil group 2132 is electrically connected to the signal processing component through the positive - pole connection wire 2133, and the other is electrically connected to the signal processing component through the negative - pole connection wire 2134.

[0059] In this embodiment, the left - foot receiving coil group 2131 and the right - foot receiving coil group 2132 are butted in the opposite direction. As a result, the electrical signals generated in the left - foot receiving coil group 2131 and the right - foot receiving coil group 2132 are opposite, and the left - foot signal and the right - foot signal can be distinguished based on this. In one implementation, as Figure 3 shown, after the left - foot receiving coil group 2131 and the right - foot receiving coil group 2132 are butted in the opposite direction, the left - foot receiving coil group 2131 is connected to the positive pole of the signal processing component through the positive - pole connection wire 2133; the right - foot receiving coil group 2132 is connected to the negative pole of the signal processing component through the negative - pole connection wire 2134. As shown in the Figure 5 attachment, the signal processing component receives the signal generated by the left - foot receiving coil group 2131 as a positive signal, and the signal generated by the right - foot receiving coil group 2132 as a negative signal, facilitating the distinction between whether the metal is carried on the left foot or the right foot of the human body.

[0060] Furthermore, the support component 11 includes a support frame 112 and a non - metallic pedal 111. The non - metallic pedal 111 is fixed on the top of the support frame 112. The identification area 1111 is arranged on the non - metallic pedal 111. The fixing plate 211 is arranged on the support frame 112, and the transmitting coil 212 is located at the center position of the support frame 112.

[0061] Specifically, the non-metal pedal 111 provides support for the human body. To prevent the non-metal pedal 111 from being easily deformed after being stepped on, a support frame 112 is provided at the bottom of the non-metal pedal 111. The support frame 112 is usually a metal frame to improve the structural strength of the support assembly 11. The non-metal pedal 111 can be made of a fiberglass epoxy resin pedal or a polyoxymethylene pedal with relatively high strength. Since the support frame 112 is usually a metal frame, when the foot metal detector 21 is working, eddy currents are generated in the metal frame in the changing magnetic field, and the metal frame itself generates a magnetic field and interferes with the foot metal detector 21, thereby affecting the detection accuracy of the foot metal detector 21. In this embodiment, to solve the above problems, the transmitting coil 212 is located at the center position of the support frame 112. That is to say, when the transmitting coil 212 is located at the center position of the support frame 112, the eddy currents generated by the left metal frame under the action of the magnetic field are the same in magnitude as those generated by the right metal frame under the action of the magnetic field, but in opposite directions. Therefore, the currents on the left and right sides will cancel each other out, thereby avoiding the magnetic field intensity generated by the metal frame from being too large and interfering with the detection of the foot metal detector 21.

[0062] In addition, the support assembly 11 further includes ramp blocks 113. In this embodiment, there are two ramp blocks 113, and the two ramp blocks 113 are respectively arranged on both sides of the non-metal pedal 111 along the passing direction of the detection channel 101, and the thickness of the ramp blocks 113 gradually increases in the direction close to the non-metal pedal 111, so that the human body can enter or leave the detection channel 101 through the ramp, avoiding the need for the human body to step over steps when entering or leaving the detection channel 101.

[0063] In this embodiment, the door body 10 includes a top plate 14, a first side plate 12, and a second side plate 13. The two ends of the top plate 14 are respectively connected to the first side plate 12 and the second side plate 13. Shielding components 15 are arranged on both sides of the first side and the second side plate 13 along the passing direction of the detection channel 101. The shielding components 15 are used to shield external electromagnetic signals and prevent external signals from entering the detection channel 101 and interfering with the security detection.

[0064] In this embodiment, the detection logic of the millimeter-wave security door is as follows: When a person to be tested enters the security door, the shielding component 15 is activated to shield external signals. Subsequently, the millimeter-wave transceiver emits millimeter waves. The millimeter waves are reflected back to the millimeter-wave transceiver after contacting the human body and are imaged according to the signals of the millimeter waves in the backend control system (not shown in the figure). Subsequently, the backend control system analyzes the image. When there is metal on the human body, the backend controller issues an alarm. In addition, the detection logic of the foot metal detector 21 can be referred to in the appendix Figure 6As shown, after a person enters the millimeter-wave security checkpoint and stands on the identification area 1111, the foot metal detector 21 detects the foot area of the person. An electromotive force is generated on the receiving coil assembly 213 and received by the signal processor. Subsequently, the signal processor stops receiving electrical signals. The signal processor determines whether the received electromotive force exceeds the detection threshold. If the electromotive force exceeds the detection threshold, it indicates that there is metal on the person's foot. At this time, the signal processor further distinguishes whether the metal is on the left foot or the right foot of the person according to the positive and negative values of the signal, and finally outputs the result and issues an alarm to the security personnel.

[0065] In summary, the present application has at least the following beneficial effects: The foot metal detector 21 is provided at the bottom of the millimeter-wave security checkpoint. The foot metal detector 21 can detect whether there is metal at the bottom of the detection channel 101. According to experiments, the maximum detection distance of the foot metal detector 21 in the height direction is about 20 cm. On the other hand, the transmitting coil 212 is arranged at the center position of the support frame 112, effectively solving the interference of metal on the magnetic field generated by the transmitting coil 212 and improving the detection stability of the foot metal detector 21. In addition, the transmitting coil 212 has a polygonal structure similar to the fixed plate 211, so that the magnetic field generated by the transmitting coil 212 is a multi-dimensional magnetic field, avoiding the situation where metal does not cut the magnetic induction line in the magnetic field, and finally resulting in the receiving coil assembly 213 being unable to detect the presence of metal. Finally, in the present application, the foot metal detector 21 and the millimeter-wave transceiver are independent of each other and are both modular designs, and there is no interference between them. At the same time, the foot metal detector 21 can be used alone in the security checkpoint or in cooperation with the millimeter-wave transceiver to improve the applicability of the security checkpoint.

[0066] For the sake of convenience of description, spatial relative terms such as "above...", "over...", "on the upper surface of...", "above" etc. can be used here to describe the spatial position relationship between a device or feature shown in the figure and other devices or features. It should be understood that the spatial relative terms are intended to include different orientations in use or operation in addition to the orientation described in the figure for the device. For example, if the device in the drawing is inverted, the device described as "above other devices or structures" or "over other devices or structures" will be positioned as "below other devices or structures" or "under other devices or structures" afterwards. Thus, the exemplary term "above..." can include both orientations of "above..." and "below...". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and corresponding explanations are made for the spatial relative descriptions used here.

[0067] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Without additional declaration, the above terms have no special meaning, and therefore should not be construed as a limitation on the scope of protection of this application.

[0068] The above are only the preferred embodiments of this application and are not used to limit this application. For those skilled in the art, various changes and modifications can be made to this application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this application shall be included within the scope of protection of this application.

Claims

1. A foot metal detector, characterized in that: include: A fixing plate (211); A transmitting coil (212), wherein the transmitting coil (212) is arranged on the fixing plate (211), and the transmitting coil (212) is surrounded to form a polygonal structure; A receiving coil assembly (213), wherein the receiving coil assembly (213) is arranged on the fixing plate (211), and the receiving coil assembly (213) is located inside the polygonal structure, the receiving coil assembly (213) comprises a left foot receiving coil group (2131) and a right foot receiving coil group (2132) arranged at intervals, the left foot receiving coil group (2131) and the right foot receiving coil group (2132) are electrically connected via a connecting line (2135), and a detection area for a human foot to stand on is formed above the left foot receiving coil group (2131) and the right foot receiving coil group (2132); The signal processing component is electrically connected to the left foot receiving coil group (2131) and the right foot receiving coil group (2132) respectively.

2. The foot metal detector according to claim 1, characterized in that: The positive pole of one of the left foot receiving coil group (2131) and the right foot receiving coil group (2132) is connected to the negative pole of the other one through the connecting line (2135).

3. The foot metal detector according to claim 1, characterized in that: The fixing plate (211) is an octagonal plate, and the transmitting coil (212) extends along the edge of the fixing plate (211) and is arranged to form an octagonal structure similar to the fixing plate (211); or, The transmitting coil (212) is arranged on the surface of the fixing plate (211) to form an octagonal structure.

4. The foot metal detector according to claim 1, characterized in that: The minimum distance L between the receiving coil component (213) and the transmitting coil (212) satisfies the relationship: 3mm≤L≤7mm.

5. The foot metal detector according to claim 1, characterized in that: The foot metal detector further comprises a support assembly (11), wherein the support assembly (11) is located at the outer periphery of the foot metal detector, and a marking area (1111) corresponding to the detection area is arranged on the top of the support assembly (11).

6. The foot metal detector according to claim 5, characterized in that: The identification area (1111) comprises a heel accommodating portion (1114), the heel accommodating portion (1114) being used to accommodate a human heel, and along the height direction of the foot metal detector, a projection surface of at least the heel accommodating portion (1114) of the identification area (1111) is located within a projection surface of the detection area; and / or, The identification area (1111) includes a left foot identification (1112) and a right foot identification (1113); the left foot identification (1112) is arranged correspondingly to the left foot receiving coil group (2131); and the right foot identification (1113) is arranged correspondingly to the right foot receiving coil group (2132).

7. The foot metal detector according to claim 6, characterized in that: The angle A between the midline of the left foot mark (1112) and the midline of the right foot mark (1113) satisfies the relationship: 45°≤A≤65°.

8. The foot metal detector according to any one of claims 5 to 7, characterized in that: The support assembly (11) comprises a support frame (112) and a non-metal pedal (111), wherein the non-metal pedal (111) is fixed on the top of the support frame (112), and the identification area (1111) is arranged on the non-metal pedal (111). The fixing plate (211) is arranged on the supporting frame (112), and the transmitting coil (212) is located at a central position of the supporting frame (112).

9. The foot metal detector according to any one of claims 1 to 7, characterized in that: The receiving coil assembly (213) further comprises a positive connection (2133) and a negative connection (2134); one of the left foot receiving coil assembly (2131) and the right foot receiving coil assembly (2132) is electrically connected to the signal processing assembly via the positive connection (2133), and the other of the two is electrically connected to the signal processing assembly via the negative connection (2134).

10. A millimeter wave security door, characterized in that: The millimeter wave security gate comprises the foot metal detector according to any one of claims 1 to 9.

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