Millimeter wave imaging equipment and security inspection equipment

Abstract

The utility model provides millimeter wave imaging equipment and security inspection equipment. The millimeter wave imaging device includes a millimeter wave transmit-receive array and a reflecting plate, and the reflecting plate is configured to be opposite to the millimeter wave transmit-receive array. The millimeter wave imaging equipment can construct a holographic image of a main body of the inspected object based on the received millimeter waves reflected back from the surface of the inspected object, and reproduce a three-dimensional image of the main body of the inspected object based on the constructed holographic image of the main body; and the millimeter wave imaging device is also capable of constructing a holographic image of a side portion of the object to be inspected based on the millimeter waves reflected back from the reflecting plate, and reproducing a three-dimensional image of the side portion of the object to be inspected based on the constructed holographic image of the side portion, thereby determining whether the object to be inspected contains other articles.

Description

Technical Field

[0001] The present disclosure relates to the field of security inspection technology, and in particular to a millimeter wave imaging device, a security inspection device, and a security inspection method. Background Art

[0002] In my country, the application of millimeter wave body imaging security inspection equipment is constantly expanding, playing an active role in places involving personnel security inspection and inspection, including civil aviation airports, customs and ports, important places and major events. The wide inspection range, fast speed, good experience and non-contact, digital working mode of millimeter wave body security inspection equipment make it the preferred choice for various types of smart security.

[0003] However, existing millimeter-wave human body imaging devices all have areas with poor imaging effects due to poor coverage of millimeter-wave receiving and transmitting signals, such as the waist, shoulders, and sides of the legs of the human body. These areas even produce imaging blind spots in millimeter-wave images. If there are objects in these areas that absorb millimeter waves or have weak millimeter-wave reflectivity, or if the direction range of the millimeter waves reflected by the objects is limited and they are not received by the receiving antenna, it is easy to cause missed detection.

[0004] There is a need to further improve millimeter wave security inspection equipment, increase inspection accuracy, and reduce missed detections. Utility Model Content

[0005] The purpose of the present disclosure is to provide a millimeter wave imaging device, comprising:

[0006] A millimeter wave transceiver array for transmitting millimeter waves and receiving reflected millimeter waves; and

[0007] a reflector, configured to be opposite to the millimeter wave transceiver array and to move synchronously with the millimeter wave transceiver array, so as to be able to reflect part of the millimeter wave emitted by the millimeter wave transceiver array to the side of the inspected object, and the reflected signal can be reflected back to the reflector through the side of the inspected object, and the reflector can reflect the millimeter wave reflected back by the side of the inspected object to the millimeter wave transceiver array;

[0008] The millimeter wave transceiver array and the reflector define an inspection channel, and the surface of the inspected object located on the inspection channel reflects the millimeter waves emitted by the millimeter wave transceiver array back to the millimeter wave transceiver array;

[0009] The millimeter wave imaging device is capable of constructing a holographic image of the main body of the inspected object based on the received millimeter waves reflected from the surface of the inspected object, and reproducing a three-dimensional image of the main body of the inspected object based on the constructed holographic image of the main body; and the millimeter wave imaging device is capable of constructing a holographic image of the side of the inspected object based on the millimeter waves reflected from the reflecting plate, and reproducing a three-dimensional image of the side of the inspected object based on the constructed holographic image of the side, so as to determine whether the inspected object contains other items.

[0010] In an exemplary embodiment of the present disclosure, the reflection plate and the millimeter wave transceiver array form an angle of 0 to 90 degrees.

[0011] In an exemplary embodiment of the present disclosure, the millimeter wave transceiver array includes a first millimeter wave transceiver array located on a first side of the inspection channel and a second millimeter wave transceiver array located on a second side of the inspection channel opposite to the first side, and the reflective plate includes at least one first reflective plate arranged corresponding to the second millimeter wave transceiver array and at least one second reflective plate arranged corresponding to the first millimeter wave transceiver array; the at least one first reflective plate is capable of reflecting part of the millimeter waves emitted by the second millimeter wave transceiver array to the side of the inspected object, and is capable of reflecting the millimeter waves reflected by the side of the inspected object back to the second millimeter wave transceiver array; the at least one second reflective plate is capable of reflecting part of the millimeter waves emitted by the first millimeter wave transceiver array to the side of the inspected object, and is capable of reflecting the millimeter waves reflected by the side of the inspected object back to the first millimeter wave transceiver array.

[0012] In an exemplary embodiment of the present disclosure, the first millimeter wave transceiver array and the second millimeter wave transceiver array are arranged in the same direction, and are both arranged along one of a straight line, an arc line and a fold line.

[0013] In an exemplary embodiment of the present disclosure, the at least one first reflection plate is fixed above and / or below the first millimeter wave transceiver array; and / or the at least one second reflection plate is fixed below and / or above the second millimeter wave transceiver array.

[0014] In an exemplary embodiment of the present disclosure, the number of the first reflective plates is two, and the two first reflective plates are respectively fixed at the two ends of the first millimeter-wave transceiver array along the arrangement direction; and / or the number of the second reflective plates is two, and the two second reflective plates are respectively fixed at the two ends of the second millimeter-wave transceiver array along the arrangement direction.

[0015] In an exemplary embodiment of the present disclosure, the number of the first reflective plates is four, and the four first reflective plates are respectively fixed at the two ends of the first millimeter-wave transceiver array along the arrangement direction, wherein two first reflective plates are fixed above the first millimeter-wave transceiver array, and the other two first reflective plates are fixed below the first millimeter-wave transceiver array; and / or the number of the second reflective plates is four, and the four second reflective plates are respectively fixed at the two ends of the second millimeter-wave transceiver array along the arrangement direction, wherein two second reflective plates are fixed above the second millimeter-wave transceiver array, and the other two second reflective plates are fixed below the second millimeter-wave transceiver array.

[0016] In an exemplary embodiment of the present disclosure, the dimension of the first reflective plate along a first direction perpendicular to the arrangement direction is approximately equal to the dimension of the second millimeter-wave transceiver array along the first direction perpendicular to the arrangement direction; and / or the dimension of the second reflective plate along the first direction perpendicular to the arrangement direction is approximately equal to the dimension of the first millimeter-wave transceiver array along the first direction perpendicular to the arrangement direction.

[0017] In an exemplary embodiment of the present disclosure, the dimension of the first reflective plate along a second direction perpendicular to the first direction is smaller than half of the dimension of the second millimeter-wave transceiver array along the arrangement direction; and / or the dimension of the second reflective plate along the second direction perpendicular to the first direction is smaller than half of the dimension of the first millimeter-wave transceiver array along the arrangement direction.

[0018] In an exemplary embodiment of the present disclosure, the first millimeter wave transceiver array and the second millimeter wave transceiver array move synchronously in a vertical direction.

[0019] In an exemplary embodiment of the present disclosure, the first millimeter wave transceiver array and the second millimeter wave transceiver array move synchronously in a horizontal direction.

[0020] In an exemplary embodiment of the present disclosure, the first millimeter wave transceiver array and the second millimeter wave transceiver array move synchronously along an arc trajectory.

[0021] In an exemplary embodiment of the present disclosure, the at least one first reflective plate is arranged on a side of the first millimeter wave transceiver array away from the inspection channel, and extends in a direction perpendicular to the arrangement direction of the first millimeter wave transceiver array and extends beyond the first millimeter wave transceiver array; and / or, the at least one second reflective plate is arranged on a side of the second millimeter wave transceiver array away from the inspection channel, and extends in a direction perpendicular to the arrangement direction of the second millimeter wave transceiver array and extends beyond the second millimeter wave transceiver array.

[0022] In an exemplary embodiment of the present disclosure, the dimension of the at least one first reflective plate along a first direction perpendicular to the arrangement direction is approximately equal to the dimension of the millimeter wave imaging device along the first direction perpendicular to the arrangement direction; and / or the dimension of the at least one second reflective plate along the first direction perpendicular to the arrangement direction is approximately equal to the dimension of the millimeter wave imaging device along the first direction perpendicular to the arrangement direction.

[0023] In an exemplary embodiment of the present disclosure, the dimension of the at least one first reflection plate along a second direction perpendicular to the first direction is smaller than half of the dimension of the second millimeter wave transceiver array along the arrangement direction; and / or the dimension of the at least one second reflection plate along the second direction perpendicular to the first direction is smaller than half of the dimension of the first millimeter wave transceiver array along the arrangement direction.

[0024] In an exemplary embodiment of the present disclosure, the other objects have the property of absorbing millimeter waves or weakly reflecting millimeter waves, or the directional range of the millimeter waves reflected by the other objects is limited, resulting in the millimeter waves reflected back being not received by the millimeter wave transceiver array, and at least part of the other objects is located outside the inspected object in the three-dimensional image of the inspected object.

[0025] According to one aspect of the present disclosure, there is provided a security inspection device, comprising:

[0026] A millimeter wave imaging device as described above.

[0027] According to another aspect of the present disclosure, there is provided a security inspection method, comprising:

[0028] Use the millimeter wave imaging device as described above to emit millimeter waves to illuminate the inspected object in the inspection channel, and receive the millimeter waves reflected by the main body of the inspected object, and based on the constructed holographic image of the main body, reproduce the three-dimensional image of the main body of the inspected object; and construct a holographic image of the side of the inspected object by receiving the millimeter waves reflected from the reflecting plate through the millimeter wave imaging device, and based on the constructed holographic image of the side, reproduce the three-dimensional image of the side of the inspected object, so as to determine whether the inspected object contains other items.

[0029] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present disclosure, nor is it intended to limit the scope of the present disclosure. Other features of the present disclosure will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings are used to better understand the present solution and do not constitute a limitation of the present disclosure, wherein:

[0031] Figure 1 A device is shown to explain the principle of millimeter wave holographic measurement;

[0032] Figure 2 A schematic diagram of plane scanning millimeter wave holographic imaging is shown;

[0033] Figure 3 A schematic diagram of distinguishing suspicious objects according to the present disclosure is shown;

[0034] Figure 4 A schematic diagram of a millimeter wave imaging device according to an embodiment of the present disclosure is shown;

[0035] Figure 5 A working principle diagram of a millimeter wave transceiver array and a reflector of a millimeter wave imaging device according to an embodiment of the present disclosure is shown;

[0036] FIG. 6( a ) to FIG. 6 ( e ) are schematic diagrams showing the relative positions of a millimeter wave transceiver array and a reflective plate of a millimeter wave imaging device according to an embodiment of the present disclosure.

[0037] 7( a ) to 7 ( d ) illustrate operating modes of a millimeter wave imaging device according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0038] In order to more clearly explain the purpose, technical solutions and advantages of the present disclosure, the embodiments of the present disclosure will be described in detail below in conjunction with the accompanying drawings. It should be understood that the following description of the embodiments is intended to explain and illustrate the overall concept of the present disclosure and should not be understood as a limitation of the present disclosure. In the specification and the drawings, the same or similar reference numerals refer to the same or similar parts or components. For the sake of clarity, the drawings are not necessarily drawn to scale, and some well-known parts and structures may be omitted in the drawings.

[0039] Unless otherwise defined, the technical terms or scientific terms used in the present disclosure should be understood by people with ordinary skills in the field to which the present disclosure belongs. The "first", "second" and similar words used in the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. The wording "one" or "an" does not exclude multiple. "Including" or "comprising" and similar words mean that the elements or objects appearing in front of the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up", "down", "left", "right", "top" or "bottom" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly. When an element such as a layer, a film, a region or a substrate substrate is referred to as being "on" or "under" another element, the element may be "directly" located "on" or "under" another element, or there may be an intermediate element.

[0040] Millimeter-wave electromagnetic radiation has a wavelength range of 1 to 10 mm, corresponding to a frequency range of 30 to 300 GHz, and is widely used in radar, remote sensing, communications, perception, and nondestructive testing. Many materials that are impenetrable in the optical frequency band are nearly transparent to millimeter waves, so millimeter-wave imaging has a natural advantage in many cases and is suitable for contactless, non-invasive security inspections.

[0041] The wavelength of millimeter waves is in the millimeter range. Compared with X-rays, they do not have ionizing properties and are difficult to penetrate the surface of human skin, so low-power millimeter wave signals are harmless to the human body. At the same time, millimeter waves can achieve half-wavelength high-resolution imaging. For millimeter waves with a wavelength between 1 and 10 mm, objects of 0.5 to 5 mm can be distinguished, thus meeting the inspection of prohibited items such as guns, knives, explosives, and even lighters and small bags of drugs in human security inspections.

[0042] Millimeter waves have a strong ability to penetrate common clothing. When the frequency is less than 300GHz, the penetration rate of millimeter waves through clothing is greater than -3dB, and decreases with increasing frequency. When the frequency approaches mid-infrared, the penetration rate drops to a level close to -30dB.

[0043] The reflectivity of human skin to millimeter waves is close to that of metal, so the signal-to-noise ratio of the millimeter-wave signal reflected from the human body surface is relatively high. At the same time, against the bright human background, the outlines of low-brightness powdery suspicious objects and various other suspicious objects will stand out.

[0044] Millimeter-wave imaging can be divided into active millimeter-wave imaging and passive millimeter-wave imaging. Passive millimeter-wave imaging does not transmit millimeter waves, but only uses a receiving antenna to receive millimeter waves emitted by the inspected object, such as the human body. Therefore, it has the advantages of not irradiating the human body with millimeter waves at all and having a fast imaging speed, but is relatively greatly affected by the environment. Active millimeter-wave imaging uses a transmitting antenna to transmit millimeter waves to illuminate objects such as the human body, and uses a receiving antenna to receive the returned millimeter waves. Therefore, the cost is relatively high and the acquisition time is relatively long, but it is less affected by the environment and has good image quality.

[0045] Active millimeter wave imaging can achieve holographic imaging. "Holography" refers to all the information required to reconstruct the image of an object, including amplitude and phase information. The millimeter wave holographic imaging system is usually in the form of an array, without a lens focusing device, and focusing imaging is achieved through signal processing algorithms. The commonality between active millimeter wave holographic imaging and optical holographic imaging is that both obtain three-dimensional images by recording the amplitude and phase information of the wave. The difference is that millimeter wave holography directly demodulates and records the amplitude and phase information. Due to the high optical frequency band, it is difficult to directly demodulate and record the phase information of optical holography, and the phase information is usually recorded indirectly. Optical holographic imaging generally includes a recording process and a reproduction process: in the recording process, a reference light is introduced to interfere with the object light wave on the holographic interference plate to form interference fringes and record the object light wavefront information: in the reproduction process, the reference light is used to illuminate the holographic interference plate to reproduce the object light wave, so that a three-dimensional image of the object can be seen.

[0046] Unlike optical holographic imaging, millimeter-wave holographic imaging relies on heterodyne mixing technology. What is measured is no longer the millimeter-wave intensity, but a complex signal containing amplitude and phase information. Figure 1 As shown in the figure, the millimeter wave signal emitted by the millimeter wave source is divided into two paths through the coupler. One signal is irradiated on the imaging object through the transmitting antenna, and the other signal is input into the I / Q demodulator as a reference signal. The millimeter wave signal reflected by the object is received by the receiving antenna, and after passing through the power amplifier, it is input into the I / Q demodulator as a measurement signal. The I / Q demodulator uses the reference signal to extract the phase of the measurement signal.

[0047] Without considering the signal amplitude, assume that the millimeter wave signal emitted by the millimeter wave source is cosωt, where ω is the angular frequency of the millimeter wave signal and t is time. The millimeter wave signal received by the receiving antenna has experienced the process of being incident on the surface of the object and reflected back, which introduces the phase to be measured. , so the signal can be expressed as cos(ωt+ ). The mixer mainly includes a multiplier and a bandpass filter. The product of the two signals input to mixer 1 is:

[0048]

[0049] Mixer 1 performs low-pass filtering on the above signal to obtain the real part I of the complex signal to be measured. The reference signal input to mixer 2 is first phase-shifted by 90 degrees and then passes through the multiplier to obtain:

[0050]

[0051] Similarly, the imaginary part Q of the complex signal to be measured can be obtained by low-pass filtering the above signal. In actual measurement, the output signal of the I / Q demodulator also contains amplitude information:

[0052]

[0053] In the above formula, A is the amplitude of the complex signal to be measured, is the phase of the complex signal to be measured.

[0054] Millimeter-wave holographic imaging can directly extract phase information using the above-mentioned measurement circuit, so no reference wave irradiation is required, which greatly simplifies the imaging device and facilitates imaging of any field of view.

[0055] In one embodiment of the present disclosure, reference Figure 2 The transmitting and receiving antennas RX and TX of the millimeter-wave direct holographic imaging system are arranged adjacent to each other and are approximately considered to be in the same position. The transmitting antenna TX emits a spherical wave exp(-jkr) / r (r is the distance) to illuminate the imaging object. Each point on the object scatters the millimeter-wave signal, and the scattered signal received by the receiving antenna will be the superposition of the scattered signals at various positions on the surface of the object. Under the assumption of Born's single scattering approximation and isotropic scattering, the millimeter-wave signal received by the receiving antenna can be expressed as:

[0056]

[0057] Where (x0, y0) is the position of the transmitting and receiving antennas, f(x, y) is the complex reflectivity image of the object at the position (x, y), is the distance between a point on the object and the transmitting and receiving antennas (assuming that the imaging object is two-dimensional, and the distance between the object and the scanning aperture is Z0). In the above formula, s(x0,y0) is the complex signal measured by heterodyne mixing technology. The hologram to be measured can be obtained by scanning the entire plane aperture, and then the complex reflectivity image f(x,y) of the object is inverted by the image reconstruction algorithm.

[0058] According to the present disclosure, in the actual security inspection process, there may be situations where missed inspections occur, such as Figure 3 As shown in the figure, the human body carries a foreign object (located on the side of the human body). When irradiated with visible light, the foreign object may produce a shadow like the human body, and the result is as follows Figure 3However, in the case of holographic imaging, the transmitting antenna transmits millimeter waves toward the human body, and the human body reflects millimeter waves strongly, so the human body appears bright in the image, and the space (background) outside the human body appears black in the image. If the foreign matter carried by the human body has a strong absorption of millimeter waves, the millimeter waves are absorbed and reflected in the image as black, the same color as the image of the (space) background, so the contrast of the foreign matter part in the obtained image is weak (or the image with foreign matter cannot be seen). If such foreign matter is in the imaging area of ​​the human body, it can be distinguished, but if the foreign matter is outside or near the human body, for example, the foreign matter is in Figure 3 In the position shown, the foreign matter and the background appear black in the image, which makes them difficult to distinguish and may result in missed detection.

[0059] According to an embodiment of the present disclosure, a millimeter wave holographic imaging device is provided, including millimeter wave transceiver arrays 1, 2 for transmitting millimeter waves and receiving reflected millimeter waves; and reflecting plates 11, 12, 21, 22, which are arranged opposite to the millimeter wave transceiver arrays 1, 2 so as to be able to reflect part of the millimeter waves transmitted by the millimeter wave transceiver arrays 1, 2 to the side of the inspected object, and the reflected signal can be reflected back to the reflecting plates 11, 12, 21, 22 via the side of the inspected object, and then the reflecting plates 11, 12, 21, 22 can reflect the millimeter waves reflected back by the side of the inspected object to the millimeter wave transceiver arrays 1, 2.

[0060] In an embodiment, the millimeter wave transceiver arrays 1 and 2 have at least one row of transmitting antennas TX and receiving antennas RX. For example, each transmitting antenna TX and one receiving antenna RX can be arranged adjacent to each other, and can form a pair of transmitting antennas TX-receiving antennas RX, and multiple pairs of transmitting antennas TX-receiving antennas RX are arranged in one dimension. The millimeter wave transceiver array may include a row of transmitting antennas TX-receiving antennas RX pairs, or may include two or more rows of transmitting antennas TX-receiving antennas RX pairs. In one embodiment, each pair of transmitting antennas TX-receiving antennas RX may be arranged along the millimeter wave transceiver array, for example, in the horizontal direction; in another embodiment, each pair of transmitting antennas TX-receiving antennas RX may be arranged horizontally along the millimeter wave transceiver array, for example, arranged up and down, in which case all transmitting antennas TX form a row, and all receiving antennas RX form a row; in other embodiments, each pair of transmitting antennas TX-receiving antennas RX may be arranged in other directions.

[0061] A pair of transceiver antennas is called a channel. For an array, the transceiver array includes a group of transceiver antenna pairs, for example, n pairs of transceiver antennas, that is, n channels. When implementing the inspection, the first pair of transceiver antennas starts to transmit and receive signals, for example, for a few milliseconds, and then the second pair of transceiver antennas starts to transmit and receive signals, which lasts for a few milliseconds. The n pairs of transceiver antennas work in sequence to complete a scan of the transceiver antenna array, in which the transmitted signal is a fixed frequency (so-called fixed frequency scanning). The transceiver antenna array can perform a second scan, which operates similarly to the first scan, but the transmitted signal is another fixed frequency. The transceiver antenna array can perform multiple scans of a set of frequencies.

[0062] In one embodiment, the millimeter wave transceiver array is arranged opposite to the reflector plate and defines an inspection channel. The inspected object (e.g., human body, other inspected objects, etc.) stays on the inspection channel to complete the inspection. Specifically, the main body of the inspected object located on the inspection channel (e.g., the front and back areas of the human body) reflects the millimeter waves emitted by the millimeter wave transceiver array back to the millimeter wave transceiver array; at the same time, the reflector plate reflects part of the millimeter waves emitted by the millimeter wave transceiver array to the side of the inspected object (e.g., the waist, leg sides, neck sides, etc. of the human body), and the signal reflected by the reflector plate can be reflected back to the reflector plate through the side of the inspected object, and then the reflector plate can reflect the millimeter waves reflected back from the side of the inspected object to the millimeter wave transceiver array. The millimeter wave imaging device can construct a holographic image of the main body of the inspected object (e.g., the front and back of the human body) based on the received millimeter waves reflected back from the surface of the inspected object, and reproduce a three-dimensional image of the main body of the inspected object based on the constructed holographic image of the main body. The millimeter wave imaging device can also obtain mirror images at the mirror areas 41 and 42 based on the millimeter waves reflected from the reflective plates 21 and 22, so as to construct a holographic image of the side of the inspected object, and reproduce a three-dimensional image of the side of the inspected object based on the constructed holographic image of the side, such as Figure 5 By providing the first millimeter wave transceiver array 1 and the second millimeter wave transceiver array 2, the surface image of the main body of the inspected object can be reproduced through the holographic image, and the first reflector plates 11, 12 and the second reflector plates 21, 22 can be combined at their respective symmetrical positions to reconstruct the image of the original weak area that was not visible, thereby effectively solving the poor imaging effect or imaging blind area problem caused by the poor coverage of the millimeter wave signal, thereby improving the detection accuracy, avoiding missed detection, and greatly reducing the imaging complexity.

[0063] For example, there is a suspicious object on the side of the human body, such as Figure 3As shown, the millimeter waves emitted by the millimeter wave transceiver array irradiate the human body, and the millimeter waves are reflected by the human body back to the millimeter wave transceiver array. However, since the suspected object absorbs the millimeter waves, the millimeter waves are not directly reflected back to the millimeter wave transceiver array. The millimeter wave imaging device constructs a holographic image of the main body of the human body (e.g., the front and back of the human body) based on the received millimeter waves reflected back from the human body, and reproduces the three-dimensional image of the main body of the human body based on the constructed holographic image of the main body. Since the suspected object is reflected in the image as black, which is the same color as the (spatial) background image, the suspected object is not obvious in the three-dimensional image of the main body of the human body. According to this embodiment, the reflector reflects the millimeter waves emitted by the millimeter wave transceiver array to the side of the human body, and the side of the human body reflects the millimeter waves. The reflected millimeter waves are then reflected back to the millimeter wave transceiver array through the reflector. The millimeter wave imaging device constructs a holographic image of the side of the human body based on the millimeter waves reflected from the reflective plate, and reproduces a three-dimensional image of the side of the human body based on the constructed holographic image of the side of the human body. Since the human body appears bright in the image, while the suspicious object is reflected in black in the image, and the suspicious object is located in the middle of the side of the human body in the three-dimensional image of the side of the human body, the suspicious object is more obvious.

[0064] In one embodiment, the reflector and the millimeter wave transceiver array form an angle of 0 to 90 degrees, so that the side of the inspected object can receive the millimeter wave signal emitted by the millimeter wave transceiver array and reflected by the reflector, and at the same time, the reflected signal in the above area can be reflected back to the receiving antenna of the millimeter wave transceiver array through the reflector for reception and collection.

[0065] In one embodiment, Figure 4As shown, the millimeter wave transceiver array includes a first millimeter wave transceiver array 1 located at a first side of the inspection channel and a second millimeter wave transceiver array 2 located at a second side of the inspection channel opposite to the first side. The reflector includes at least one first reflector 11, 12 arranged corresponding to the second millimeter wave transceiver array 2 and at least one second reflector 21, 22 arranged corresponding to the first millimeter wave transceiver array 1. The first reflectors 11, 12 are at an angle of 0 to 90 degrees with the second millimeter wave transceiver array 2, so that the first reflectors 11, 12 can reflect part of the millimeter waves emitted by the second millimeter wave transceiver array 2 to the side of the inspected object, and can reflect the millimeter waves reflected by the side of the inspected object back to the second millimeter wave transceiver array 2, and the second millimeter wave transceiver array 2 can receive the millimeter waves reflected back by the first reflectors 11, 12. The second reflective plates 21, 22 form an angle of 0 to 90 degrees with the first millimeter wave transceiver array 1, so that the second reflective plates 21, 22 can reflect part of the millimeter waves emitted by the first millimeter wave transceiver array 1 to the side of the inspected object, and can reflect the millimeter waves reflected from the side of the inspected object back to the first millimeter wave transceiver array 1, and the first millimeter wave transceiver array 1 can receive the millimeter waves reflected back by the second reflective plates 21, 22.

[0066] In the embodiments of the present disclosure, Figure 4 As shown, the arrangement direction X of the first millimeter wave transceiver array 1 and the second millimeter wave transceiver array 2 is the same, and both are arranged in the horizontal direction, that is, the multiple transmitting antennas TX and receiving antennas RX of the first millimeter wave transceiver array 1 are arranged in the horizontal direction, and the multiple transmitting antennas TX and receiving antennas RX of the second millimeter wave transceiver array 2 are also arranged in the horizontal direction. In this embodiment, as shown in FIG. 7 (a), the first millimeter wave transceiver array 1 and the second millimeter wave transceiver array 2 arranged in the horizontal direction move synchronously in the vertical direction, that is, move from top to bottom or from bottom to top in the same direction at the same speed at the same time. A first vertical rail assembly 31 and a second vertical rail assembly 32 may be provided, and the first millimeter wave transceiver array 1 and the second millimeter wave transceiver array 2 are supported by the first vertical rail assembly 31 and the second vertical rail assembly 32, respectively, and move synchronously in the vertical direction through the first vertical rail assembly 31 and the second vertical rail assembly 32, respectively, so as to realize vertical scanning of the inspected object.

[0067] In the embodiments of the present disclosure, Figure 4As shown, the at least one first reflector 11, 12 is fixed above the first millimeter wave transceiver array 1, and the at least one second reflector 21, 22 is fixed below the second millimeter wave transceiver array 2. It should be noted that in some other embodiments of the present disclosure, as shown in FIG6 (b), the at least one second reflector 21, 22 may also be fixed above the second millimeter wave transceiver array 2; or, as shown in FIG6 (c), the two first reflectors 11, 12 may also be fixed below the first millimeter wave transceiver array 1; or, as shown in FIG6 (d), first reflectors 11a, 11b, 12a, 12b are arranged above and below the first millimeter wave transceiver array 1, and second reflectors 21a, 21b, 22a, 22b are arranged above and below the second millimeter wave transceiver array 2. By arranging the reflectors above and / or below the millimeter wave transceiver array, the equipment footprint can be greatly reduced.

[0068] In the embodiments of the present disclosure, Figure 4 As shown, there are two first reflectors 11 and 12, which are respectively fixed at two ends of the first millimeter wave transceiver array 1 along the arrangement direction X, so as to respectively scan the opposite sides of the inspected object. There are also two second reflectors 21 and 22, which are respectively fixed at two ends of the second millimeter wave transceiver array 2 along the arrangement direction X, so as to respectively scan the opposite sides of the inspected object.

[0069] FIG6( d ) shows an embodiment of a millimeter wave imaging device according to the present disclosure, Figure 4 The embodiment shown is different in that the number of first reflectors is four, and the four first reflectors are respectively fixed at the two ends of the first millimeter wave transceiver array 1 along the arrangement direction X, wherein two first reflectors 11a and 12a are fixed above the first millimeter wave transceiver array 1, and the other two first reflectors 11b and 12b are fixed below the first millimeter wave transceiver array 1. The number of the second reflectors may also be four, and the four second reflectors are respectively fixed at the two ends of the second millimeter wave transceiver array 2 along the arrangement direction X, wherein two second reflectors 21a and 22a are fixed above the second millimeter wave transceiver array 2, and the other two second reflectors 21b and 22b are fixed below the second millimeter wave transceiver array 2.

[0070] In the embodiments shown in FIG. 6 (a) to FIG. 6 (d), in order to ensure that the first reflective plates 11 and 12 can cover the inspected object in the first direction Y (i.e., the vertical direction in the figure) and the size is as small as possible to reduce the cost, the size of the first reflective plates 11 and 12 along the first direction Y perpendicular to the arrangement direction X is substantially equal to the size of the second millimeter wave transceiver array 2 along the first direction Y perpendicular to the arrangement direction X. Similarly, the size of the second reflective plates 21 and 22 along the first direction Y perpendicular to the arrangement direction X is substantially equal to the size of the first millimeter wave transceiver array 1 along the first direction Y perpendicular to the arrangement direction X. In order to ensure that the first reflective plates 11, 12 can cover the inspected object in the second direction perpendicular to the first direction Y (i.e., the horizontal direction in the figure) and the size is as small as possible to reduce costs, the size of the first reflective plates 11, 12 along the second direction perpendicular to the first direction Y is smaller than half of the size of the second millimeter wave transceiver array 2 along the arrangement direction X; and / or the size of the second reflective plates 21, 22 along the second direction perpendicular to the first direction Y is smaller than half of the size of the first millimeter wave transceiver array 1 along the arrangement direction X.

[0071] FIG6(e) shows an embodiment of a millimeter wave imaging device according to the present disclosure. Different from the embodiment shown in FIG6(a), the at least one first reflector 11, 12 is arranged on a side of the first millimeter wave transceiver array 1 away from the inspection channel, and extends in a direction perpendicular to the arrangement direction X of the first millimeter wave transceiver array 1 and extends beyond the first millimeter wave transceiver array 1. The at least one second reflector 21, 22 can be arranged on a side of the second millimeter wave transceiver array 2 away from the inspection channel, and extends in a direction perpendicular to the arrangement direction X of the second millimeter wave transceiver array 2 and extends beyond the second millimeter wave transceiver array 2. In the embodiment shown in FIG6(e), the first reflectors 11, 12 and the second reflectors 21, 22 do not move with the array, so the sizes of the first reflectors 11, 12 and the second reflectors 21, 22 are relatively large to ensure that the inspected object can be covered in the first direction Y perpendicular to the arrangement direction X. Preferably, the size of the at least one first reflector 11, 12 along the first direction Y perpendicular to the arrangement direction X is substantially equal to the size of the millimeter wave imaging device along the first direction Y perpendicular to the arrangement direction X, so as to ensure that the inspected object is covered in the first direction Y perpendicular to the arrangement direction X (i.e., the vertical direction in the figure). The size of the at least one second reflector 21, 22 along the first direction Y perpendicular to the arrangement direction X is substantially equal to the size of the millimeter wave imaging device along the first direction Y perpendicular to the arrangement direction X, so as to ensure that the inspected object is covered in the first direction Y perpendicular to the arrangement direction X (i.e., the vertical direction in the figure). The size of the at least one first reflector 11, 12 along the second direction perpendicular to the first direction Y is less than half of the size of the second millimeter wave transceiver array along the arrangement direction X, so as to ensure that the inspected object is covered in the second direction perpendicular to the first direction Y (i.e., the horizontal direction in the figure). The dimension of the at least one second reflective plate 21, 22 along the second direction perpendicular to the first direction Y is smaller than half of the dimension of the first millimeter wave transceiver array along the arrangement direction X, so as to ensure that the inspected object is covered in the second direction perpendicular to the first direction Y (i.e., the horizontal direction in the figure).

[0072] In one embodiment of the present disclosure, the millimeter wave imaging device may include a driving device for driving a slider of the first vertical slide rail assembly 31 to move up and down relative to the slide rail of the first vertical slide rail assembly 31, so as to drive the first millimeter wave transceiver array 1 connected to the slider to move up and down. The driving device may also drive a slider of the second vertical slide rail assembly 32 to move up and down relative to the slide rail of the second vertical slide rail assembly 32, so as to drive the second millimeter wave transceiver array 2 connected to the slider to move up and down. The driving device may be, for example, a servo driving device.

[0073] like Figure 4As shown, the millimeter wave imaging device may further include a platform 4, and the first vertical slide rail assembly 31 and the second vertical slide rail assembly 32 may be supported on the platform 4. During the inspection, a person may stand on the platform 4 to be inspected.

[0074] According to an embodiment of the present disclosure, the first reflective plates 11 , 12 and the second reflective plates 21 , 22 may be similar reflective plates, but they do not need to be completely the same.

[0075] The surface material of the first reflective plates 11 , 12 and the second reflective plates 21 , 22 is metal, such as aluminum, iron, copper and alloys thereof, or a non-metal substrate covered with a metal film.

[0076] FIG7(b) shows an embodiment of a millimeter wave imaging device according to the present disclosure. Unlike the embodiment shown in FIG7(a), the first millimeter wave transceiver array 1 and the second millimeter wave transceiver array 2 are arranged in the vertical direction. In this embodiment, the first millimeter wave transceiver array 1 and the second millimeter wave transceiver array 2 arranged in the vertical direction move synchronously in the horizontal direction (as shown by the arrows in the figure), for example, they move in the same direction at the same speed at the same time. FIG7 does not show a slide rail assembly for supporting and moving the first millimeter wave transceiver array 1 and the second millimeter wave transceiver array 2, respectively. However, it should be understood that similar to FIG7(a), the first millimeter wave transceiver array 1 and the second millimeter wave transceiver array 2 are arranged in the vertical direction. Figure 4 In the embodiment, a first horizontal slide rail assembly and a second horizontal slide rail assembly may be provided, thereby allowing the first millimeter wave transceiver array 1 and the second millimeter wave transceiver array 2 to move in the horizontal direction to achieve horizontal scanning of the inspected object. Figure 4 The millimeter wave imaging device shown is the same and will not be described again here.

[0077] FIG7 (c) shows an embodiment of a millimeter wave imaging device according to the present disclosure, which is different from the embodiment shown in FIG7 (b) in that the first millimeter wave transceiver array 1 and the second millimeter wave transceiver array 2 arranged in the vertical direction move along an arc-shaped track or line (as shown by the arrows in the figure). For example, a first horizontal slide rail assembly and a second horizontal slide rail assembly having an arc-shaped track are provided, thereby allowing the first millimeter wave transceiver array 1 and the second millimeter wave transceiver array 2 to move along the arc-shaped track to achieve cylindrical scanning of the inspected object. In this embodiment, the first millimeter wave transceiver array 1 and the second millimeter wave transceiver array 2 move synchronously along the arc-shaped track, for example, scanning in the same direction at the same speed at the same time.

[0078] FIG7(d) shows an embodiment of a millimeter wave imaging device according to the present disclosure. Different from the embodiment shown in FIG7(a), the first millimeter wave transceiver array 1 and the second millimeter wave transceiver array 2 have an arc shape. In other words, the multiple transmitting antennas TX and receiving antennas RX pairs of the first millimeter wave transceiver array 1 are arranged along an arc, for example, arranged along an arc in a horizontal plane. The arc-shaped first millimeter wave transceiver array 1 and the arc-shaped second millimeter wave transceiver array 2 define an inspection channel, and the arc-shaped first millimeter wave transceiver array 1 and the arc-shaped second millimeter wave transceiver array 2 surround a human body or other detected object. Figure 4 Similar to the millimeter wave imaging device shown, the first millimeter wave transceiver array 1 arranged in an arc shape in the horizontal plane and the second millimeter wave transceiver array 2 arranged in an arc shape can be synchronously moved up and down on the first vertical slide rail assembly and the second vertical slide rail assembly respectively, for example, scanning at the same speed in the same direction at the same time to achieve cylindrical scanning of the inspected object. The embodiment of FIG7 (d) realizes the surrounding of the human body or the inspected object with the millimeter wave transceiver array, so compared with FIG7 (a), the human body or the inspected object can be illuminated from more angles, thereby achieving more reliable inspection. For example, when a person carries a suspected object, if the array and the reflector are in the form of Figure 7 (a), and the millimeter waves reflected from the front, back, and reflector cannot illuminate the suspected object, then the suspected object cannot be distinguished from the main image on the front and back of the array and the image of the side mirror image corresponding to the reflector; however, since the millimeter wave transceiver array in Figure 7 (d) can illuminate the human body from more angles, the millimeter waves emitted from the transceiver array or reflected from the reflector can illuminate the suspected object at these angles, so the suspected object can be distinguished from the main image or the image of the side mirror image corresponding to the reflector. Through appropriate algorithms, the identification of suspected objects can be achieved, greatly improving the accuracy and reliability of the equipment.

[0079] It should be noted that in some other embodiments of the present disclosure, the first millimeter wave transceiver array 1 and the second millimeter wave transceiver array 2 may also have a fold line shape. In other words, multiple transmitting antennas TX and receiving antennas RX pairs of the first millimeter wave transceiver array 1 and the second millimeter wave transceiver array 2 are arranged along the fold line. Here, the fold line refers to a plurality of line segments, wherein the plurality of line segments are connected to each other at an angle. The first millimeter wave transceiver array 1 and the second millimeter wave transceiver array 2 arranged in a fold line surround the human body or other detected objects. In addition, the scanning method of the millimeter wave imaging device is not limited to the plane scanning and cylindrical scanning disclosed in this article, and a scanning method of linear array plus mechanical scanning or full electronic scanning can also be adopted.

[0080] One aspect of the present disclosure further provides a security inspection device, comprising the above-mentioned millimeter wave imaging device.

[0081] The millimeter wave imaging device may also include other auxiliary devices.

[0082] One aspect of the present disclosure also provides a security inspection method, comprising: using the above-mentioned millimeter wave imaging device to emit millimeter waves to illuminate the inspected object in the inspection channel, and receiving the millimeter waves reflected back by the main body of the inspected object, and reproducing a three-dimensional image of the main body of the inspected object based on the constructed holographic image of the main body; and constructing a holographic image of the side of the inspected object by receiving the millimeter waves reflected back from the reflecting plate through the millimeter wave imaging device, and reproducing the three-dimensional image of the side of the inspected object based on the constructed holographic image of the side, so as to determine whether the inspected object contains other items.

[0083] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps recorded in this disclosure can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of this disclosure can be achieved, and this document is not limited here.

[0084] The above specific implementations do not constitute a limitation on the protection scope of the present disclosure. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions may be made to the disclosed embodiments or examples according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present disclosure shall be included in the protection scope of the present disclosure.

Claims

1. A millimeter wave imaging device, characterized in that: The millimeter wave imaging device comprises: A millimeter wave transceiver array for transmitting millimeter waves and receiving reflected millimeter waves; and a reflector, arranged to be opposite to the millimeter wave transceiver array, so as to be able to reflect part of the millimeter wave emitted by the millimeter wave transceiver array to the side of the inspected object, and the reflected signal can be reflected back to the reflector through the side of the inspected object, and the reflector can reflect the millimeter wave reflected back by the side of the inspected object to the millimeter wave transceiver array; The millimeter wave transceiver array and the reflector define an inspection channel, and the surface of the inspected object located on the inspection channel reflects the millimeter waves emitted by the millimeter wave transceiver array back to the millimeter wave transceiver array; Among them, the millimeter wave imaging device is capable of constructing a holographic image of the main body of the inspected object based on the received millimeter waves reflected from the surface of the inspected object, and reproducing a three-dimensional image of the main body of the inspected object based on the constructed holographic image of the main body; and the millimeter wave imaging device is also capable of constructing a holographic image of the side of the inspected object based on the millimeter waves reflected from the reflecting plate, and reproducing a three-dimensional image of the side of the inspected object based on the constructed holographic image of the side, so as to determine whether the inspected object contains other items.

2. The millimeter wave imaging device according to claim 1, wherein: The reflection plate and the millimeter wave transceiver array form an angle of 0 to 90 degrees.

3. The millimeter wave imaging device according to claim 2, wherein: The millimeter wave transceiver array comprises a first millimeter wave transceiver array located at a first side of the inspection channel and a second millimeter wave transceiver array located at a second side of the inspection channel opposite to the first side, and the reflector comprises at least one first reflector arranged corresponding to the second millimeter wave transceiver array and at least one second reflector arranged corresponding to the first millimeter wave transceiver array; the at least one first reflector can reflect part of the millimeter wave emitted by the second millimeter wave transceiver array to the side of the inspected object, and can reflect the millimeter wave reflected by the side of the inspected object back to the second millimeter wave transceiver array; The at least one second reflector can reflect part of the millimeter waves emitted by the first millimeter wave transceiver array to the side of the inspected object, and can reflect the millimeter waves reflected by the side of the inspected object back to the first millimeter wave transceiver array.

4. The millimeter wave imaging device according to claim 3, wherein: The first millimeter wave transceiver array and the second millimeter wave transceiver array are arranged in the same direction, and are both arranged along one of a straight line, an arc line and a fold line.

5. The millimeter wave imaging device according to claim 4, wherein: The at least one first reflection plate is fixedly disposed above and / or below the first millimeter wave transceiver array; and / or the at least one second reflection plate is fixedly disposed below and / or above the second millimeter wave transceiver array.

6. The millimeter wave imaging device according to claim 5, wherein: The number of the first reflective plates is two, and the two first reflective plates are respectively fixed at the two ends of the first millimeter-wave transceiver array along the arrangement direction; and / or the number of the second reflective plates is two, and the two second reflective plates are respectively fixed at the two ends of the second millimeter-wave transceiver array along the arrangement direction.

7. The millimeter wave imaging device according to claim 5, wherein: The number of the first reflective plates is four, and the four first reflective plates are respectively fixed at the two ends of the first millimeter-wave transceiver array along the arrangement direction, wherein two first reflective plates are fixed above the first millimeter-wave transceiver array, and the other two first reflective plates are fixed below the first millimeter-wave transceiver array; and / or the number of the second reflective plates is four, and the four second reflective plates are respectively fixed at the two ends of the second millimeter-wave transceiver array along the arrangement direction, wherein two second reflective plates are fixed above the second millimeter-wave transceiver array, and the other two second reflective plates are fixed below the second millimeter-wave transceiver array.

8. The millimeter wave imaging device according to claim 4, wherein: The dimension of the first reflector along a first direction perpendicular to the arrangement direction is approximately equal to the dimension of the second millimeter-wave transceiver array along the first direction perpendicular to the arrangement direction; and / or the dimension of the second reflector along the first direction perpendicular to the arrangement direction is approximately equal to the dimension of the first millimeter-wave transceiver array along the first direction perpendicular to the arrangement direction.

9. The millimeter wave imaging device according to claim 8, wherein: The dimension of the first reflector along a second direction perpendicular to the first direction is smaller than half of the dimension of the second millimeter-wave transceiver array along the arrangement direction; and / or the dimension of the second reflector along a second direction perpendicular to the first direction is smaller than half of the dimension of the first millimeter-wave transceiver array along the arrangement direction.

10. The millimeter wave imaging device according to claim 5, wherein: The first millimeter wave transceiver array and the second millimeter wave transceiver array move synchronously in a vertical direction.

11. The millimeter wave imaging device according to claim 5, wherein: The first millimeter wave transceiver array and the second millimeter wave transceiver array move synchronously in a horizontal direction.

12. The millimeter wave imaging device according to claim 5, wherein: The first millimeter wave transceiver array and the second millimeter wave transceiver array move synchronously along an arc trajectory.

13. The millimeter wave imaging device according to claim 4, wherein: The at least one first reflective plate is arranged on a side of the first millimeter wave transceiver array away from the inspection channel, and extends in a direction perpendicular to the arrangement direction of the first millimeter wave transceiver array and extends beyond the first millimeter wave transceiver array; And / or, the at least one second reflective plate is arranged on a side of the second millimeter wave transceiver array away from the inspection channel, and extends in a direction perpendicular to the arrangement direction of the second millimeter wave transceiver array and extends beyond the second millimeter wave transceiver array.

14. The millimeter wave imaging device according to claim 13, wherein: The dimension of the at least one first reflective plate along the first direction perpendicular to the arrangement direction is approximately equal to the dimension of the millimeter wave imaging device along the first direction perpendicular to the arrangement direction; and / or, the dimension of the at least one second reflective plate along the first direction perpendicular to the arrangement direction is approximately equal to the dimension of the millimeter wave imaging device along the first direction perpendicular to the arrangement direction.

15. The millimeter wave imaging device according to claim 14, wherein: The dimension of at least one first reflective plate along a second direction perpendicular to the first direction is smaller than half of the dimension of the second millimeter-wave transceiver array along the arrangement direction; and / or the dimension of at least one second reflective plate along a second direction perpendicular to the first direction is smaller than half of the dimension of the first millimeter-wave transceiver array along the arrangement direction.

16. The millimeter wave imaging device according to any one of claims 1 to 15, wherein: The other objects have the property of absorbing millimeter waves or weakly reflecting millimeter waves, or the directional range of the millimeter waves reflected by the other objects is limited, resulting in the millimeter waves reflected back not being received by the millimeter wave transceiver array, and at least part of the other objects is located outside the inspected object in the three-dimensional image of the inspected object.

17. A security inspection device, characterized in that: The security inspection equipment includes: Millimetre wave imaging apparatus as claimed in any preceding claim.

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