WO2020134334A1 - 安检设备及其控制方法 - Google Patents

安检设备及其控制方法 Download PDF

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Publication number
WO2020134334A1
WO2020134334A1 PCT/CN2019/110380 CN2019110380W WO2020134334A1 WO 2020134334 A1 WO2020134334 A1 WO 2020134334A1 CN 2019110380 W CN2019110380 W CN 2019110380W WO 2020134334 A1 WO2020134334 A1 WO 2020134334A1
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WO
WIPO (PCT)
Prior art keywords
array
transmission
security inspection
panel
reception
Prior art date
Application number
PCT/CN2019/110380
Other languages
English (en)
French (fr)
Inventor
陈志强
游�燕
赵自然
马旭明
王凯
Original Assignee
清华大学
同方威视技术股份有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 清华大学, 同方威视技术股份有限公司 filed Critical 清华大学
Priority to JP2021538342A priority Critical patent/JP7420813B2/ja
Priority to AU2019414849A priority patent/AU2019414849B2/en
Priority to EP19902194.0A priority patent/EP3904915A4/en
Priority to KR1020217022883A priority patent/KR102635123B1/ko
Publication of WO2020134334A1 publication Critical patent/WO2020134334A1/zh
Priority to US17/304,927 priority patent/US20210325528A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/88—Radar or analogous systems specially adapted for specific applications
    • G01S13/887—Radar or analogous systems specially adapted for specific applications for detection of concealed objects, e.g. contraband or weapons
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/88—Radar or analogous systems specially adapted for specific applications
    • G01S13/89—Radar or analogous systems specially adapted for specific applications for mapping or imaging
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V3/00—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation
    • G01V3/12—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with electromagnetic waves
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V8/00—Prospecting or detecting by optical means
    • G01V8/005—Prospecting or detecting by optical means operating with millimetre waves, e.g. measuring the black losey radiation
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V8/00—Prospecting or detecting by optical means
    • G01V8/10—Detecting, e.g. by using light barriers
    • G01V8/20—Detecting, e.g. by using light barriers using multiple transmitters or receivers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/12—Supports; Mounting means
    • H01Q1/22—Supports; Mounting means by structural association with other equipment or articles
    • H01Q1/2258—Supports; Mounting means by structural association with other equipment or articles used with computer equipment

Definitions

  • the present disclosure relates to the technical field of safety inspection, in particular to a security inspection device and a control method thereof.
  • a security inspection device including:
  • the bottom plate is configured to carry the inspected object
  • a two-dimensional multi-transmission and multi-reception transceiver array panel is provided on the bottom plate and parallel to the bottom panel.
  • the two-dimensional multi-transmission and multi-reception transceiver array panel includes:
  • each two-dimensional multi-transmission and multi-reception transceiver array includes multiple transmit antennas and multiple receive antennas, each of the multiple transmit antennas and the multiple receive The midpoint of the connection line of the corresponding one of the receiving antennas serves as an equivalent phase center, and the plurality of transmitting antennas and the plurality of receiving antennas are arranged such that the equivalent phase centers are arranged in a two-dimensional array; and
  • a control circuit configured to control the plurality of transmitting antennas to transmit detection signals in the form of electromagnetic waves to the object to be inspected in a predetermined order, and control the plurality of receiving antennas to receive echo signals from the object to be inspected;
  • a signal processing device connected to the two-dimensional multi-transmission and multi-reception transceiver array panel, and configured to reconstruct the image of the object under inspection based on the received echo signal;
  • the display device is connected to the signal processing device and is configured to display the reconstructed image of the subject.
  • the security inspection device further includes at least one side panel, the at least one side panel is perpendicular to the bottom panel, and each side panel is provided with at least one of the two-dimensional multi-transmission, multi-reception, transceiver array panel.
  • the at least one side panel includes a first side panel, a second side panel, and a third side panel, a first detection space is formed between the first side panel and the second side panel, and the second side panel A second detection space is formed between the third side plate.
  • the two-dimensional multi-transmission, multi-reception transceiver array panel is installed inside or below the bottom plate.
  • the distance between adjacent transmitting antennas and/or adjacent receiving antennas in each two-dimensional multi-transmission and multi-reception sub-array is an integer multiple of the wavelength corresponding to one of the multiple frequencies of the detection signal, adjacent The distance between the equivalent phase centers is half the wavelength of the detection signal.
  • the two-dimensional multi-transmission and multi-reception sub-array includes two rows of transmitting antennas arranged in a first direction and two columns of receiving antennas arranged in a second direction perpendicular to the first direction, the two rows of transmitting antennas Forming a rectangular pattern with two columns of receiving antennas; or
  • the two-dimensional multi-transmission and multi-reception sub-array includes a row of transmitting antennas arranged along a first direction and a column of receiving antennas arranged along a second direction perpendicular to the first direction, and the rows and columns cross to form a cross shape.
  • control circuit is configured to control a plurality of transmitting antennas in each two-dimensional multi-transmission and multi-reception transceiver array to sequentially transmit detection signals, and control a plurality of receiving antennas in the two-dimensional multi-transmission and multi-reception transceiver array to receive Echo signals; or the control circuit is configured to control all the transmitting antennas in the two-dimensional multi-transmitting multi-receiving array panel to sequentially emit detection signals, and control all the receiving antennas in the two-dimensional multi-transmitting multi-receiving array panel Receive echo signals.
  • the security inspection device further comprises: a translation device configured to translate the two-dimensional multi-transmission multi-reception transceiver array panel in a plane where the two-dimensional multi-transmission multi-reception transceiver array panel is located.
  • a translation device configured to translate the two-dimensional multi-transmission multi-reception transceiver array panel in a plane where the two-dimensional multi-transmission multi-reception transceiver array panel is located.
  • the security inspection device further includes an alarm device connected to the signal processing device, the signal processing device is further configured to determine whether the detected object is based on a preset standard based on the reconstructed image of the detected object May contain dangerous goods, if so, control the alarm device to alarm.
  • the detection signal is a microwave millimeter wave with a frequency in the range of 10-300 GHz.
  • the length and width of the two-dimensional multi-transmission and multi-reception transceiver array panel are in the range of 10 cm to 50 cm.
  • control method of the foregoing security inspection device including:
  • the reconstructing the image of the inspected object includes reconstructing the image of the inspected object based on a holographic reconstruction algorithm or a backward projection algorithm.
  • the embodiments of the present disclosure use a 2D MIMO array panel to perform automatic security inspection on a part of the object to be inspected (such as a human foot) carried on the bottom plate by electromagnetic wave scanning.
  • the detection accuracy is high, and on the other hand, the object is not required. Taking off shoes improves the user experience while increasing the speed of security checks.
  • FIG. 1a shows a schematic structural diagram of a security inspection device according to an embodiment of the present disclosure.
  • FIG. 1b shows a schematic circuit diagram of the security inspection device of FIG. 1a.
  • FIG. 2a shows a schematic structural diagram of a security inspection device according to another embodiment of the present disclosure.
  • Fig. 2b shows a schematic circuit diagram of the security inspection device of Fig. 2a.
  • FIG. 3a shows a schematic structural diagram of a 2D MIMO antenna array according to an embodiment of the present disclosure.
  • FIG. 3b shows a schematic diagram of the equivalent phase center of the 2D MIMO antenna array of FIG. 3a.
  • FIG. 4 shows a schematic structural diagram of a 2D MIMO antenna array according to another embodiment of the present disclosure.
  • FIG. 5 shows a schematic structural diagram of a 2D MIMO antenna array according to another embodiment of the present disclosure.
  • FIG. 6 shows a schematic structural diagram of a 2D MIMO antenna array according to another embodiment of the present disclosure.
  • FIG. 7 shows a schematic structural diagram of a 2D MIMO antenna array according to another embodiment of the present disclosure.
  • FIG. 8a shows a schematic structural diagram of a 2D MIMO antenna array according to another embodiment of the present disclosure.
  • FIG. 8b shows a schematic diagram of the equivalent phase center of the 2D MIMO antenna array of FIG. 8a.
  • FIG. 9a shows a schematic structural diagram of a 2D MIMO antenna array according to another embodiment of the present disclosure.
  • FIG. 9b shows a schematic diagram of the equivalent phase center of the 2D MIMO antenna array of FIG. 9a.
  • FIG. 10 shows a schematic diagram of the working principle of a 2D MIMO antenna array according to an embodiment of the present disclosure.
  • FIG. 11 shows a schematic flowchart of a control method of a security inspection device according to an embodiment of the present disclosure.
  • FIG. 12 shows a schematic flowchart of a control method of a security inspection device according to another embodiment of the present disclosure.
  • FIG. 1a shows a schematic structural diagram of a security inspection device according to an embodiment of the present disclosure
  • FIG. 1b shows a schematic circuit diagram of the security inspection device of FIG. 1a.
  • the security inspection device 100 includes: a bottom plate 10, a two-dimensional multi-transmission and multi-reception array panel 20 and a signal processing device 30.
  • the bottom plate 10 is used to carry the object to be inspected 40.
  • the subject 40 is a human foot.
  • the bottom plate 10 may be made of various materials suitable for electromagnetic wave penetration, including but not limited to wood, rubber, glass, and the like.
  • a two-dimensional multi-transmission and multiple-receive (2D MIMO, 2-Demensional Multiple-Input Multiple-Output) array panel 20 is disposed on the base plate 10 and is parallel to the base plate 10.
  • the 2D MIMO array panel 20 is installed inside the bottom plate 10, and the size is set to match the size of the object to be inspected, for example, to match the size of human feet.
  • the 2D MIMO array panel 20 includes a 2D MIMO antenna array 21 and a control circuit 22.
  • the 2D MIMO antenna array 21 may include at least one 2D MIMO sub-array, and each 2D MIMO sub-array includes multiple transmit antennas and multiple receive antennas.
  • the midpoint of the connection line between each of the transmitting antennas and the corresponding one of the multiple receiving antennas serves as an equivalent phase center, the multiple transmitting antennas and the multiple The receiving antennas are arranged so that the equivalent phase centers are arranged in a two-dimensional array.
  • the control circuit 22 can control a plurality of transmitting antennas in the 2D MIMO antenna array 21 to transmit detection signals in the form of electromagnetic waves to the object to be inspected in a preset order, and control a plurality of receiving antennas to receive echo signals from the object to be inspected.
  • the 2D MIMO array panel 20 may be implemented by a 10-40 GHz chip, which has the advantages of high array integration and low cost.
  • the signal processing device 30 is connected to the 2D MIMO array panel 20, and can reconstruct the image of the subject 40 according to the received echo signal.
  • the signal processing device 30 may include an analog signal processor, a digital-to-analog converter (D/A converter), and a digital signal processor.
  • the 2D MIMO array panel 20 sends a detection signal in the form of microwave and millimeter waves to the detected object.
  • the echo signal generated after the detection signal reaches the detected object is received by the 2D MIMO array panel 20, which carries the equivalent of the 2D MIMO array panel 20 Echo data corresponding to the phase center.
  • the 2D MIMO array panel 20 sends the echo signal to the analog signal processor 21.
  • the analog signal processor converts the received echo signal in the form of a power signal into an analog signal and sends it to a digital-to-analog converter.
  • the digital-to-analog converter converts the received analog signal into a digital signal and sends it to the digital signal processor.
  • the digital signal processor performs image reconstruction based on the received digital signal.
  • the security inspection device 100 may further include a display device 50, as shown in FIG. 1b.
  • the display device 50 is connected to the signal processing device 20 and can display the image of the subject 40 reconstructed by the signal processing device 20.
  • the display device 3 can be implemented as various devices having a display function, such as a display screen, a projector, and so on.
  • the signal processing device 30 may also determine whether the detected object may contain dangerous goods based on a preset criterion based on the reconstructed image of the detected object.
  • feature templates of dangerous goods such as prohibited seeds, drugs, and explosives can be stored in advance, and the reconstructed image can be compared with the template to determine whether the detected object may contain dangerous goods, and further determine the possible dangers.
  • the type and quantity of the goods and the probability of containing such dangerous goods, etc. After detecting that the detected object 12 contains dangerous goods, the signal processing device 30 can control the display device 50 to present prompt information, for example, the prompt information can indicate the type of dangerous goods, the probability of containing the dangerous goods, etc., to help the staff to do To make further judgments, open the inspection if necessary.
  • the security inspection device 100 may further include an alarm device 60 connected to the signal processing device 2.
  • the signal processing device 30 can also determine whether the detected object 40 may contain dangerous goods based on a preset criterion based on the reconstructed image of the detected object 40, and if so, control the alarm device 60 to make an alarm.
  • the alarm device 60 can be implemented in various forms, including but not limited to devices such as speakers, vibrators, alarms, etc., that issue alarms through audio, vibration, and various other means. You can also set the alarm level.
  • the signal processing device 30 can control the alarm device 60 to sound with a lower volume of sound or weaker vibration when the probability of containing dangerous goods is low. When the probability of containing dangerous goods is high, The alarm device 60 is controlled to sound with a high volume sound or strong vibration.
  • the security inspection device may further include a translation device 70.
  • the translation device 70 may be installed on the security inspection device 100 for translating the 2D MIMO array panel 20 in the plane where the 2D MIMO array panel 20 is located.
  • the panning device 70 may pan the 2D MIMO array panel 20 according to a preset path and speed, so that whenever the 2D MIMO array panel 20 completes the scanning task (ie, whenever all the transmit antennas in the 2D MIMO array panel 20 complete detection The signal is transmitted, and the receiving antenna completes the reception of the echo signal), the 2D MIMO array panel 20 is translated to the next position, so that the 2D MIMO array panel 20 restarts the next round of scanning, and so on, so that a 2D can be used
  • the MIMO array panel 20 achieves the scanning effect of multiple 2D MIMO array panels 20, which saves costs and simplifies the system structure.
  • the translation device 70 may include a track, a motor, a connector, a slider, a control circuit, and the like, and the 2D MIMO array panel 20 may be installed on the slider through the connector to allow the motor to move along the track mobile.
  • FIG. 2a and 2b respectively show a structural schematic diagram and a schematic circuit diagram of a security inspection device according to another embodiment of the present disclosure.
  • the security inspection device 200 of FIG. 2 is similar to the security inspection device 100 of FIG. 1, except that the security inspection device 200 of FIG. 2 further includes three side panels 11, 12 and 13, each of the side panels 11, 12 and 13 (eg, internal or (Surface) are provided with the above 2D MIMO array panel. For the sake of brevity, the differences are mainly described in detail below.
  • FIG. 2 is similar to the security inspection device 100 of FIG. 1, except that the security inspection device 200 of FIG. 2 further includes three side panels 11, 12 and 13, each of the side panels 11, 12 and 13 (eg, internal or (Surface) are provided with the above 2D MIMO array panel.
  • the differences are mainly described in detail below.
  • the 2D MIMO array panel mounted on the bottom plate 10 is denoted as 20a
  • the 2D MIMO array panels mounted on the side plates 11, 12, and 13 are denoted as 20b, 20c, and 20d, respectively
  • the 2D MIMO array panel 20a , 20b, 20c, 20d are collectively referred to as 2D MIMO array panel 20.
  • a first detection space is formed between the side plates 11 and 12, and a second detection space is formed between the side plates 12 and 13.
  • the first detection space and the second detection space may respectively accommodate two parts of the subject 40, such as the left and right feet of a person.
  • the 2D MIMO array panel 20a mounted on the bottom plate 10 can be used to scan the bottom (eg, shoe sole) of the subject 40 (eg, human feet), and install the inside or surface of the side plates 11, 12, and 13
  • the upper 2D MIMO array panels 20b, 20c, and 20d can be used to scan the sides of the object 40 (eg, human feet).
  • the signal processing device 30 is connected to the 2D MIMO array panels 20a, 20b, 20c, and 20d.
  • the signal processing device 30 may have the structure described above, of course, other suitable structures may also be used.
  • 2D MIMO array panels 20a, 20b, 20c, and 20d transmit detection signals to different parts of the object 40 from different positions and receive echo signals from the parts of the object 40, for example, 2D MIMO array panel 20a
  • the bottom of the foot transmits the detection signal and receives the echo signal from the bottom of the person's feet.
  • the 2D MIMO array panels 20b and 20c respectively transmit detection signals to the left side of the person's left foot and receive the corresponding echo signals.
  • the 2D MIMO array panels 20c and 20d Transmit detection signals to both sides of the person's right foot and receive corresponding echo signals.
  • the signal processing device 30 can reconstruct the image of the detected object part corresponding to the 2D MIMO array panel according to the echo signals of each of the 2D MIMO array panels 20a, 20b, 20c, and 20d, for example, according to the 2D MIMO array panel 20a received
  • the echo signal is used to reconstruct the image of the bottom of the person's feet, and the images on both sides of the left foot are reconstructed according to the echo signals received by the 2D MIMO array panels 20b and 20c, and reconstructed based on the echo signals received by the 2D MIMO array panels 20c and 20d. Images on both sides of the right foot.
  • the signal processing device 30 may also reconstruct a part or the entire image of the subject based on the combination of the echo signals of the 2D MIMO array panels 20a, 20b, 20c, and 20d.
  • a side panel may be provided, the side panel being perpendicular to the bottom panel and located above the 2D MIMO array panel in the bottom panel, the space on both sides of the side panel is used to place the left and right feet of a person, respectively, the left and right sides of the side panel
  • At least one 2D MIMO array panel is provided on the surface or inside to scan the right side of the left foot and the left side of the right foot, respectively.
  • the shapes and sizes of the bottom plate and the side plates can also be set according to needs to adapt to the shapes and sizes of different detection objects.
  • the side plate can be designed into an arc shape, an irregular shape, etc.
  • the bottom plate can be designed into a circular shape, an irregular shape, etc.
  • a 2D MIMO array panel extending in other directions may be provided, for example, a top panel may be provided above the side panel, and a 2D MIMO array panel is provided in the top panel, for example, to scan the human foot surface, etc., which will not be repeated here. .
  • the aforementioned security inspection device may be used in combination with other security inspection devices, for example, it may be installed under a security inspection door based on millimeter wave detection, for example, and the inspected object stands on the security inspection device, waiting for the scanning detection of the millimeter wave security inspection door At the same time, complete the imaging of their feet.
  • the detection and imaging process of the security inspection device and the millimeter wave security gate can be performed simultaneously, and the display device and/or the alarm device can be shared.
  • the 2D MIMO array panel 20 may be implemented using a 10-40 GHz chip, and the 2D MIMO antenna array 21 in the 2D MIMO array panel 20 may include multiple transmit antennas and multiple receive antennas arranged in an array, transmitting The antenna and the receiving antenna can be installed on the substrate and arranged in various forms as required.
  • the 2D MIMO antenna array 21 may include at least one 2D MIMO sub-array, and the size of each sub-array is determined according to a tolerable error using an equivalent phase center, and is related to the imaging distance (detection distance).
  • the distance between adjacent transmit antennas and/or adjacent receive antennas in each 2D MIMO sub-array may be a wavelength corresponding to one of multiple frequencies of the detection signal (eg, center operating frequency) Integer multiple (for example, 1 times, 2 times, 3 times, 4 times, 5 times, etc.).
  • the distance between adjacent equivalent phase centers may be half of the wavelength corresponding to one of the multiple frequencies of the detection signal.
  • the size of the 2D MIMO antenna array 21 can be designed to be the same as the imaging area, or slightly smaller or slightly larger than the imaging area, so as to ensure that the image of the subject can be reconstructed correctly, for example, the length and width of the 2D MIMO antenna array can be in the range of 30cm-50cm Inside.
  • the imaging distance of the 2D MIMO antenna array 21, that is, the distance between the 2D MIMO antenna array 21 and the detected object may be in the range of 2cm-30cm.
  • FIG. 3a and 3b respectively show a schematic structural diagram and an equivalent phase center schematic diagram of a 2D MIMO antenna array according to an embodiment of the present disclosure.
  • the 2D MIMO antenna array includes a sub-array including two rows of transmitting antennas Tx arranged in the horizontal direction and two columns of receiving antennas Rx arranged in the vertical direction, two rows of transmitting antennas Tx and two columns of receiving
  • the antenna Rx forms a rectangular pattern.
  • the size of the 2D MIMO antenna array may be 30cm ⁇ 30cm, and the number of the transmitting antenna Tx and the receiving antenna Rx are 46 and 46, respectively.
  • the number of the transmitting antenna Tx and the receiving antenna Rx are only for illustration. Not the actual number.
  • the equivalent position of the transmitted and received signals can be represented by the phase center of the antenna, and the equivalent position is the physical center of two independent antennas or apertures.
  • the midpoint of the connection line between the transmitting antenna and the corresponding receiving antenna is taken as the equivalent phase center of the two.
  • one transmitting antenna Tx corresponds to multiple receiving antennas Rx.
  • the receiving antenna Rx and the transmitting antenna Tx are set not to be in the same position, such a system where the transmitting and receiving antennas are spatially separated can Using a virtual system simulation, in the virtual system, a virtual position is added between each group of transmitting antenna Tx and receiving antenna Rx, and this position is called the equivalent phase center.
  • the echo data collected by the transceiver antenna combination can be equivalent to the echo collected by the spontaneous and self-receiving antenna at the position of the equivalent phase center.
  • the distance between the adjacent transmitting antenna and the adjacent receiving antenna is the wavelength ⁇ of the detection signal, and the distance between adjacent equivalent phase centers is ⁇ /2, imaging
  • the sampling interval ie the interval of the equivalent phase center
  • ⁇ /2 which makes the reconstruction of the image without artifacts superimposed.
  • FIG. 4 shows a schematic structural diagram of a 2D MIMO antenna array according to another embodiment of the present disclosure.
  • the 2D MIMO antenna array includes 2 ⁇ 2 sub-arrays, and the size of each sub-array is set to 10cm ⁇ 10cm.
  • the overall size of the 2D MIMO antenna array is 20cm ⁇ 20cm.
  • the number of the transmit antenna Tx and the receive antenna Rx are respectively For 141, 141.
  • FIG. 5 shows a schematic structural diagram of a 2D MIMO antenna array according to another embodiment of the present disclosure.
  • the 2D MIMO antenna array includes 3 ⁇ 3 sub-arrays, each of which has a size of 8cm ⁇ 8cm, and the overall size of the 2D MIMO antenna array is 24cm ⁇ 24cm.
  • the number of transmit antenna Tx and receive antenna Rx are respectively 224, 224.
  • FIG. 6 shows a schematic structural diagram of a 2D MIMO antenna array according to another embodiment of the present disclosure.
  • the 2D MIMO antenna array may include 2 ⁇ 3 sub-arrays, and the size of each sub-array is 10cm ⁇ 10cm.
  • the overall size of the 2D MIMO antenna array is 20cm ⁇ 30cm.
  • the number of the transmit antenna Tx and the receive antenna Rx are respectively For 188, 213.
  • FIG. 7 shows a schematic structural diagram of a 2D MIMO antenna array according to another embodiment of the present disclosure.
  • the 2D MIMO antenna array includes 2 ⁇ 4 sub-arrays, and the size of each sub-array is 10cm ⁇ 10cm.
  • the overall size of the 2D MIMO antenna array is 20cm ⁇ 40cm.
  • the number of transmit antenna Tx and receive antenna Rx are 285, respectively. , 235.
  • the 2D MIMO array panel 20 can also be implemented as MIMO chips with other frequencies in the range of 2-100 GHz.
  • the length and width of the 2D MIMO antenna array 21 in the 2D MIMO array panel 20 can be in the range of 30cm-50cm, and the imaging distance (that is, the distance between the 2D MIMO antenna array and the object to be inspected) can be in the range of 2cm-30cm.
  • Table 1 shows the number of transmit antennas Tx and receive antennas Rx in different frequency bands for two different sub-array sizes in the case where the total size of the 2D MIMO antenna array is 30 cm ⁇ 30 cm, where * represents the center frequency.
  • the number of transmitting antennas is 18 and the number of receiving antennas is 18 ; If the sub-array size is 15cm ⁇ 15cm, then for the detection signal in the 2GHz-20GHz band, the number of transmitting antennas is 24, the number of receiving antennas is 24, and so on.
  • FIG. 8a shows a schematic structural diagram of a 2D MIMO antenna array according to another embodiment of the present disclosure.
  • FIG. 8b shows a schematic diagram of the equivalent phase center of the 2D MIMO antenna array of FIG. 8a.
  • the 2D MIMO antenna array includes a sub-array including a row of transmitting antennas Tx arranged in the horizontal direction and a row of receiving antennas Rx arranged in the vertical direction, and the row of transmitting antennas Tx and the row of receiving antennas Rx cross Form a cross-shaped pattern.
  • the equivalent phase center of the 2D MIMO antenna array of FIG. 9a is distributed in the form of an array at the center of the cross-shaped pattern.
  • FIG. 9a shows a schematic structural diagram of a 2D MIMO antenna array according to another embodiment of the present disclosure.
  • 9b shows a schematic diagram of the equivalent phase center of the 2D MIMO antenna array of FIG. 8a.
  • the 2D MIMO antenna array includes a sub-array including a row of transmitting antennas Tx arranged along the first diagonal direction of the array and a row of receiving antennas arranged along the second diagonal direction of the array
  • the antenna Rx, the row of transmitting antennas Tx and the row of receiving antennas Rx intersect to form a diagonal cross pattern on the panel.
  • the equivalent phase center of FIG. 9b is rotated 45 degrees relative to the equivalent phase center of FIG. 8b (clockwise or counterclockwise), because the 2D MIMO antenna array of FIG. 9a is relative to the 2D of FIG. 8a
  • the MIMO antenna array is rotated 45 degrees.
  • the structure of the 2D MIMO antenna array 11 of the present disclosure is not limited to this, the size of the sub-array, the size of the array, the arrangement of the antennas in the sub-array, and the number of antennas can be as needed Adjustment.
  • a 2D MIMO antenna array including 4 ⁇ 4 sub-arrays is used as an example for description.
  • Each sub-array 101 has the structure shown in FIG. 2 and the equivalent phase centers formed are arranged in the form of an array 102 ( (Also called the equivalent phase center network), (n x , n y ) represents the coordinate of the equivalent phase center in the array (equivalent phase center network).
  • the center reference point of the imaging area 103 of the 2D MIMO antenna array is determined by Indicates that the detected object contains a reference point located at the center Point scatterer.
  • the above 2D MIMO antenna array can be controlled by electronic scanning.
  • control circuit may control the transmitting antenna in each sub-array of the 2D MIMO antenna array to sequentially transmit detection signals, the receiving antenna to receive the echo signal, and then switch to the next sub-array, repeating this operation until the entire antenna array scan is completed, Obtain all scattering data from the object under different viewing angles.
  • control circuit may control all transmit antennas in the 2D MIMO antenna array to sequentially transmit detection signals, and control all receive antennas in the 2D MIMO antenna array to receive the echo signals.
  • the holographic reconstruction algorithm described below can be used for image reconstruction; for the case where the 2D MIMO antenna array includes multiple sub-arrays, the backward projection algorithm described below can be used Rebuild.
  • microwave millimeter waves with a frequency in the range of 10-300 GHz are used as detection signals, and the waves in this band have no ionization damage to the human body, and can be used for human security.
  • the 2D MIMO antenna array includes a plurality of transmitting antennas and a plurality of receiving antennas arranged in a two-dimensional array, and works by electronic scanning.
  • the electronic scanning has the advantages of fast detection speed, combined with fast Fourier Leaf transform (FFT) three-dimensional holographic algorithm algorithm can achieve real-time imaging.
  • FFT fast Fourier Leaf transform
  • the echo data collected by a pair of transceiver antennas can be equivalent to the spontaneous self-reception at the position of the equivalent phase center.
  • the echo collected by the antenna The equivalent phase centers are arranged in an array, and the interval between adjacent equivalent phase centers is basically half of the wavelength ⁇ of the detection signal, which makes the entire equivalent behavior center array basically a full array, and the applied imaging system uses
  • the sampling interval (that is, the interval of the equivalent phase center) is on the order of ⁇ /2, so that there is no artifact superposition in the resulting image and a clearer image can be formed, which increases the speed of image processing.
  • FIG. 11 shows a schematic flowchart of a control method of a security inspection device according to an embodiment of the present disclosure.
  • step S101 the 2D MIMO array panel 20 is controlled to transmit a detection signal to the subject and receive an echo signal from the subject.
  • the control circuit 22 can be used to control the 2D MIMO antenna array 21 to transmit a detection signal to the subject and receive an echo signal in the manner described above.
  • the detection signal may be an electromagnetic wave, such as a millimeter wave, specifically a millimeter wave terahertz wave.
  • step S102 the image of the subject is reconstructed according to the received echo signal.
  • a whole-system reconstruction algorithm or a backward projection algorithm can be used to reconstruct the image of the detected object.
  • Holographic re-algorithm can realize the real-time reconstruction of the object image.
  • the echo data collected by a pair of transceiver antennas can be equivalent to the echo collected by the spontaneous self-receiving antenna at the position of the equivalent phase center.
  • the signal processing device collects the echo data at the center of the equivalent phase. Assuming that the collected reflection data of the detected object is s(n x , n y ), the reflection data is corrected using the following formula to obtain the corrected reflection data matrix:
  • s(n x , n y ) is the uncorrected scattering data matrix
  • n x and n y are the positions of the equivalent phase centers in the network of equivalent phase centers (ie, the indices of the rows and columns).
  • a reference point representing the center of the imaging area 103, j represents an imaginary number, and k represents a spatial constant.
  • R u (n x , n y ) represents the calculated reflection set.
  • the following objects are sampled as shown in Figure 10. Point scatterer.
  • R o (n x , n y ) represents the calculated reflection set, where the calculated reflection set is obtained in the case of sampling the equivalent phase center network of the multi-reception and multi-transmission aperture (as shown in FIG. 10 ).
  • I(x, y) represents the scattering coefficient of the detected object
  • z 0 represents the distance between the 2D MIMO array panel and the detected object
  • j represents the imaginary number
  • k is the propagation constant
  • k x , k y are the spatial propagation Constant
  • FFT 2D is a two-dimensional Fourier transform
  • IFFT 2D is a two-dimensional inverse Fourier transform.
  • the collected echo data can be expressed as s(n x , n y ).
  • fast reconstruction can be achieved and imaging can be completed.
  • the purpose of the imaging algorithm is to invert the image of the detected object from the echo expression, that is, the scattering coefficient I(x, y) of the detected object.
  • the synthetic aperture holographic algorithm based on Fourier transform does not need to compare the entire imaging area. Point reconstruction, but use the advantages of fast Fourier transform to complete the reconstruction of the correct imaging area at one time. Therefore, the algorithm can realize fast scanning and fast image reconstruction, thus real-time imaging.
  • the reconstructed image is displayed on the display device, and the suspicious object alarm algorithm is combined to alarm the suspicious object.
  • Backward projection originated from computer tomography technology is an accurate imaging algorithm based on time-domain signal processing.
  • the basic idea is that for each imaging point in the imaging area, by calculating the delay between the point and the receiving and transmitting antennas, the contributions of all echoes to it are coherently superimposed to obtain the corresponding pixel value of the point in the image. In this way, the entire imaging area is coherently superimposed point by point to obtain an image of the imaging area.
  • the back projection algorithm is naturally easy to implement parallel computing, so it is suitable for the case where the receiving antennas in multiple sub-arrays receive the reflected electromagnetic waves simultaneously. Although it is necessary to reconstruct every point of the entire imaging interval, if the hardware in the processing system adopts GPU or FPGA technology, the reconstruction time can be greatly reduced, and even real-time reconstruction can be achieved.
  • the reconstruction formula can be expressed as,
  • z a is the imaging distance
  • j is the imaginary unit
  • k is the propagation constant
  • s(x t , y t , x r , y r , k) is a pair of transmitting antenna-receiving antenna combination receiving
  • the echo signal to the inspected object (x t , y t ) is the coordinate of the transmitting antenna, (x r , y r ) is the coordinate of the receiving antenna, and
  • z represents the distance between the 2D MIMO array panel and a certain fault of the inspected object distance.
  • step S102 other steps may also be performed, such as analyzing the reconstructed image of the inspected object to determine whether the inspected object may carry dangerous goods, and if so, control the alarm device to alarm.
  • the reconstructed image of the detected object can be compared with a pre-stored template. If the degree of matching with the characteristic template of a certain dangerous product is greater than a preset threshold, it is determined that the dangerous product may be contained, otherwise it is determined not to contain Dangerous goods.
  • the probability of containing dangerous goods may also be determined according to the degree of matching. For example, a higher matching degree indicates a higher probability of containing dangerous goods, and a lower matching degree indicates a lower probability of containing dangerous goods.
  • Alarm methods include but are not limited to screen display, audio alarm, vibration alarm and so on. You can also set the alarm level. For example, when the probability of containing dangerous goods is low, you can use low-volume sound or weak vibration to alarm. When the probability of containing dangerous goods is high, you can use high-volume sound or Strong vibration to alarm.
  • the image of the reconstructed object and/or the above judgment result can be presented to the user through the display device, for example, the reconstructed image can be displayed on the display screen after the image is reconstructed, and then the analysis result is presented on the display It can also be displayed on the display screen after the image reconstruction and analysis comparison are completed and the reconstructed image and judgment result are displayed again.
  • the presentation method of the determination result (such as which dangerous goods may be contained and the probability of containing the dangerous goods) can be selected according to the needs.
  • other methods such as audio and vibration can also be used
  • the judgment result can be played in the form of voice, or the alarm volume of the alarm can be used to indicate the judgment result.
  • a high-volume alarm represents a high probability of containing dangerous goods
  • a low-volume alarm The probability of containing dangerous goods is low.
  • FIG. 12 shows a schematic flowchart of a control method of a security inspection device according to another embodiment of the present disclosure.
  • step S201 the 2D MIMO array panel is controlled to send a detection signal to the subject and receive an echo signal from the subject.
  • a scanning method combining electronic scanning and mechanical scanning is adopted.
  • the 2D MIMO array panel performs electronic scanning at the current position.
  • step S202 it is determined whether the 2D MIMO array panel has completed the electronic scanning (that is, all the transmitting antennas have completed transmitting and the receiving antennas have completed receiving). If so, it indicates that the scanning of the current position is completed and proceeds to step S203 to pan to the next position, otherwise Return to step S201 to continue scanning at the current position.
  • FIG. 10 shows a schematic diagram of a scanning route combining mechanical scanning and electronic scanning of a security inspection device according to an embodiment of the present disclosure. As shown in FIG. 10, for a case where a 5cm ⁇ 5cm 2D MIMO array panel is used to mechanically scan a 30cm ⁇ 30cm area array, the path indicated by the arrow in FIG. 10 can be shifted one step at a time (for example, 5cm) , Until the scanning of all positions on the path is completed, so as to realize the scanning of a 30 cm ⁇ 30 cm area array.
  • a time for example, 5cm
  • step S203 it is judged whether the mechanical scanning is completed, that is, whether the electronic scanning of the last position on the translation path is completed. If it is, it means that the 2D MIMO array panel has completed the scanning of all positions on the path, so the scanning of the currently inspected object End, and proceed to step S204 for image reconstruction, otherwise perform step S205 to pan to the next position for scanning.
  • step S204 the obtained echo signal is used to reconstruct the image of the subject.
  • the reconstruction algorithm includes, but is not limited to, the above-mentioned whole-system reconstruction algorithm and backward projection algorithm.
  • step S205 the 2D MIMO array panel is translated, and the process returns to step S201 to perform scanning detection again at a new position.
  • the translation can be performed according to a preset path, for example, as shown in FIG. 10, each time a translation step is performed until the translation reaches the last position on the path.
  • steps S206 to 207 can also be performed after step S204.
  • step S206 the reconstructed image of the inspected object is analyzed to determine whether the inspected object may contain dangerous goods. If so, step S207 is executed, otherwise the safety inspection of the current inspected object is ended.
  • the reconstructed object image can be compared with a pre-stored template. If the degree of matching with the characteristic template of a certain dangerous product is greater than a preset threshold, it is determined that it may contain the dangerous product, otherwise it is determined that it does not contain a dangerous product Goods.
  • the probability of containing dangerous goods may also be determined according to the degree of matching. For example, a higher matching degree indicates a higher probability of containing dangerous goods, and a lower matching degree indicates a lower probability of containing dangerous goods.
  • step S207 the alarm device is controlled to make an alarm.
  • Alarm methods include but are not limited to screen display, audio alarm, vibration alarm and so on. You can also set the alarm level. For example, when the probability of containing dangerous goods is low, you can use low-volume sound or weak vibration to alarm. When the probability of containing dangerous goods is high, you can use high-volume sound or Strong vibration to alarm.
  • the security inspection device includes one 2D MIMO array panel.
  • the security inspection including four 2D MIMO array panels as shown in FIG. 2 Equipment and control methods are similar.
  • a combination of echo signals received by multiple 2D MIMO array panels may also be used to reconstruct the image of the subject.
  • an analysis may be performed based on a combination of multiple reconstructed images corresponding to multiple 2D MIMO array panels (for example, images of different angles of the human foot) to determine whether they may contain dangerous goods or types of dangerous goods , Quantity, etc.
  • Embodiments of the present disclosure also provide a computer-readable medium that stores instructions stored in the computer-readable medium, which when executed by the processor, causes the processor to perform the control method of the security inspection device described above.
  • the embodiments of the present disclosure can perform automatic security inspection on the part of the object to be inspected carried on the base plate (such as the feet of the human body) based on electromagnetic waves (for example, based on ultra-wideband radar technology).
  • the testee takes off his shoes, improving the speed of security and improving the user experience.
  • the embodiments of the present disclosure support a full electronic scanning method and a scanning method combining electronic scanning and mechanical scanning.
  • the full electronic scanning method has fast scanning speed, and combined with the three-dimensional holographic algorithm algorithm based on fast Fourier transform (FFT), real-time imaging can be realized.
  • FFT fast Fourier transform
  • the scanning method combining the electronic scanning and the mechanical scanning can realize the scanning of a larger imaging area with a smaller antenna array, which saves cost and has a simple structure.
  • the embodiments of the present disclosure can flexibly select 2D MIMO antenna arrays of various structures according to needs, and have high flexibility in use.
  • millimeter wave as the detection signal, it can penetrate the object to be imaged, thereby replacing the X-ray machine to achieve the purpose of safety detection, while providing higher detection quality and higher safety.
  • the embodiments of the present disclosure can provide automated threat detection by automatically analyzing the reconstructed image of the object to be tested, which greatly improves the detection efficiency and reduces the missed detection rate compared to the traditional method.

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Abstract

一种安检设备（100）及其控制方法，安检设备（100）包括：底板（10），被配置为承载被检对象（40）；二维多发多收收发阵列面板（20），设置在底板（10）上并且与底板（10）平行，二维多发多收收发阵列面板（20）包括：至少一个二维多发多收收发子阵列，每个二维多发多收收发子阵列包括多个发射天线（Tx）和多个接收天线（Rx），多个发射天线（Tx）和多个接收天线（Rx）被布置为使得等效相位中心排列成二维阵列；以及控制电路（22），被配置为控制多个发射天线（Tx）按照预设顺序向被检对象（40）发射电磁波形式的检测信号，以及控制多个接收天线（Rx）接收来自被检对象（40）的回波信号；信号处理装置（30），被配置为根据接收到的回波信号来重建被检对象（40）的图像；以及显示装置（50），被配置为显示所重建的被检对象（40）的图像。

Description

安检设备及其控制方法
本申请要求于2018年12月29日提交的、申请号为201811653597.4的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本公开涉及安全检测技术领域，具体涉及一种安检设备及其控制方法。
背景技术
机场、火车站、酒店、校园、银行等特殊场所的安全措施尚不能满足日益增长的安全需求。鞋底藏诸如毒品、爆炸物之类的危险品目前是常用的作案方式。对此通常采用的安检方式包括用金属探测器安检、人工安检和X射线安检。然而金属探测器只能探测金属、不能探测毒品、爆炸物等非金属物质。人工安检通常情况下要求被检对象配合，例如脱鞋或保持特定姿势，一方面给被检测对象和安检人员均造成不便，另一方面安检的速度和准确性较差。X射线安检存在电离辐射，影响人体健康。
发明内容
根据本公开的一方面，提供了一种安检设备，包括：
底板，被配置为承载被检对象；
二维多发多收收发阵列面板，设置在所述底板上并且与所述底板平行，所述二维多发多收收发阵列面板包括：
至少一个二维多发多收收发子阵列，每个二维多发多收收发子阵列包括多个发射天线和多个接收天线，所述多个发射天线中的每个发射天线和所述多个接收天线中的相应一个接收天线的连线的中点作为一个等效相位中心，所述多个发射天线和所述多个接收天线被布置为使得等效相位中心排列成二维阵列；以及
控制电路，被配置为控制所述多个发射天线按照预设顺序向被检对象发射电磁波形式的检测信号，以及控制所述多个接收天线接收来自被检对象的回波信号；
信号处理装置，与所述二维多发多收收发阵列面板相连，并且被配置为根据接收到的回波信号来重建被检对象的图像；以及
显示装置，与信号处理装置相连，并且被配置为显示所重建的被检对象的图像。
优选地，所述安检设备还包括至少一个侧板，所述至少一个侧板垂直于所述底板，每个侧板上设置有至少一个所述二维多发多收收发阵列面板。
优选地，所述至少一个侧板包括第一侧板、第二侧板和第三侧板，所述第一侧板与第二侧板之间形成第一检测空间，所述第二侧板和第三侧板之间形成第二检测空间。
优选地，所述二维多发多收收发阵列面板安装在所述底板内部或下方。
优选地，每个二维多发多收收发子阵列中相邻发射天线和/或相邻接收天线之间的距离是所述检测信号的多个频率之一对应的波长的整数倍，相邻的等效相位中心之间的距离为所述检测信号的波长的一半。
优选地，所述二维多发多收收发子阵列包括沿着第一方向排列的两行发射天线和沿着垂直于第一方向的第二方向排列的两列接收天线，所述两行发射天线与两列接收天线形成矩形图案；或者
所述二维多发多收收发子阵列包括沿着第一方向排列的一行发射天线和沿着垂直于第一方向的第二方向排列的一列接收天线，所述行和列交叉形成十字形状。
优选地，所述控制电路被配置成控制每个二维多发多收收发子阵列中的多个发射天线依次发射检测信号，并控制该二维多发多收收发子阵列中的多个接收天线接收回波信号；或者所述控制电路被配置成控制所述二维多发多收收发阵列面板中的所有发射天线依次发射检测信号，并控制所述二维多发多收收发阵列面板中的所有接收天线接收回波信号。
优选地，所述安检设备还包括：平移装置，被配置为在所述二维多发多收收发阵列面板所在的平面内平移所述二维多发多收收发阵列面板。
优选地，所述安检设备还包括：报警装置，与所述信号处理装置相连，所述信号处理装置还被配置为根据所重建的被检对象的图像基于预设的标准来判断被检对象是否可能含有危险品，如果是，则控制所述报警装置进行报警。
优选地，所述检测信号为频率在10-300GHz范围内的微波毫米波。
优选地，所述二维多发多收收发阵列面板的长度和宽度均在10cm至50cm的范围内。
根据本公开的另一方面，提供了一种上述安检设备的控制方法，包括：
利用所述二维多发多收收发阵列面板向被检对象发送检测信号，并接收来自被检对象的回波信号；以及
根据接收到的回波信号来重建被检对象的图像。
优选地，所述重建被检对象的图像包括基于全息重建算法或后向投影算法来重建被检对象的图像。
本公开的实施例利用2D MIMO阵列面板通过电磁波扫描对承载于底板上的被检对象的局部(例如人体的脚部)进行自动安检，一方面检测准确率高，另一方面不需要被检对象脱鞋，在提高安检速度的同时改善了用户使用体验。
附图说明
图1a示出了根据本公开一实施例的安检设备的结构示意图。
图1b示出了图1a的安检设备的示意电路图。
图2a示出了根据本公开另一实施例的安检设备的结构示意图。
图2b示出了图2a的安检设备的示意电路图。
图3a示出了根据本公开一实施例的2D MIMO天线阵列的结构示意图。
图3b示出了图3a的2D MIMO天线阵列的等效相位中心的示意图。
图4示出了根据本公开另一实施例的2D MIMO天线阵列的结构示意图。
图5示出了根据本公开另一实施例的2D MIMO天线阵列的结构示意图。
图6示出了根据本公开另一实施例的2D MIMO天线阵列的结构示意图。
图7示出了根据本公开另一实施例的2D MIMO天线阵列的结构示意图。
图8a示出了根据本公开另一实施例的2D MIMO天线阵列的结构示意图。
图8b示出了图8a的2D MIMO天线阵列的等效相位中心的示意图。
图9a示出了根据本公开另一实施例的2D MIMO天线阵列的结构示意图。
图9b示出了图9a的2D MIMO天线阵列的等效相位中心的示意图。
图10示出了根据本公开的实施例的2D MIMO天线阵列的工作原理的示意图。
图11示出了根据本公开一实施例的安检设备的控制方法的示意流程图。
图12示出了根据本公开另一实施例的安检设备的控制方法的示意流程图。
具体实施方式
尽管本公开的容许各种修改和可替换的形式，但是它的具体的实施例通过例子的方式在附图中示出，并且将详细地在本文中描述。然而，应该理解，随附的附图和详细的描述不是为了将本公开的限制到公开的具体形式，而是相反，是为了覆盖落入由随附的权利要求限定的本公开的精神和范围中的所有的修改、等同形式和替换形式。附图是为 了示意，因而不是按比例地绘制的。
在本说明书中使用了“上”、“下”、“左”、“右”等术语，并不是为了限定元件的绝对方位，而是为了描述元件在视图中的相对位置帮助理解；本说明书中“顶侧”和“底侧”是相对于一般情况下，物体正立的上侧和下侧的方位；“第一”、“第二”等也不是为了排序，而是为了区别不同部件。
下面参照附图描述根据本公开的多个实施例。
图1a示出了根据本公开一实施例的安检设备的结构示意图，图1b示出了图1a的安检设备的示意电路图。如图1a和1b(统称图1)所示，安检设备100包括：底板10、二维多发多收收发阵列面板20和信号处理装置30。
底板10用于承载被检对象40。在图1a的示例中，被检对象40是人脚。底板10可以由各种适合电磁波穿透的材料制成，包括但不限于木、橡胶、玻璃等等。
二维多发多收收发(2D MIMO，2-Demensional Multiple-Input Multiple-Output)阵列面板20设置在底板10上并且与底板10平行。在图1a中，2D MIMO阵列面板20安装在底板10内部，尺寸设置成与被检对象的尺寸相匹配，例如与人类双脚的尺寸相匹配。
2D MIMO阵列面板20包括2D MIMO天线阵列21和控制电路22。2D MIMO天线阵列21可以包括至少一个2D MIMO子阵列，每个2D MIMO子阵列包括多个发射天线和多个接收天线，所述多个发射天线中的每个发射天线和所述多个接收天线中的相应一个接收天线的连线的中点作为一个等效相位中心(phase center)，所述多个发射天线和所述多个接收天线被布置为使得等效相位中心排列成二维阵列。控制电路22可以控制2D MIMO天线阵列21中的多个发射天线按照预设顺序向被检对象发射电磁波形式的检测信号，以及控制多个接收天线接收来自被检对象的回波信号。在一些实施例中，2D MIMO阵列面板20可以由10-40GHz芯片来实现，具有阵列集成程度高、成本低等优点。
信号处理装置30与2D MIMO阵列面板20相连，可以根据接收到的回波信号来重建被检对象40的图像。例如，信号处理装置30可以包括模拟信号处理器，数模转换器(D/A转换器)和数字信号处理器。2D MIMO阵列面板20向被检对象发送微波毫米波形式的检测信号，检测信号达到被检测对象后产生的回波信号被2D MIMO阵列面板20接收，其承载了与2D MIMO阵列面板20的等效相位中心相对应的回波数据。2D MIMO阵列面板20将回波信号发送至模拟信号处理器21。模拟信号处理器将接收到的功率信号形式的回波信号转换成模拟信号并发送至数模转换器。数模转换器将接收到的模拟信号转换成数字信号并发送至数字信号处理器。数字信号处理器基于接收到的数字信号进 行图像重建。
在一些实施例中，安检设备100还可以包括显示装置50，如图1b所示。显示装置50与信号处理装置20相连，可以显示由信号处理装置20所重建的被检对象40的图像。显示装置3可以实现为各种具有显示功能的设备，例如显示屏、投影仪等等。在一些实施例中，信号处理装置30还可以在重建图像之后，根据所重建的被检对象的图像基于预设的标准来判断被检对象是否可能含有危险品。例如可以预先存储诸如违禁种子、毒品、爆炸物之类的危险品的特征模板，通过将重建的图像与模板比对来判断被检对象中是否可能含有危险品，还可以进一步判断可能含有的危险品的类型、数量以及可能含有该类危险品的概率等等。信号处理装置30在检测到被检对象12中含有危险品之后，可以控制显示装置50呈现提示信息，例如提示信息可以指示危险品的种类、含有该危险品的概率等等，以帮助工作人员做出进一步判断，必要时开包检验。
在一些实施例中，安检设备100还可以包括与信号处理装置2相连的报警装置60。在这种情况下，信号处理装置30还可以根据所重建的被检对象40的图像基于预设的标准来判断被检对象40是否可能含有危险品，如果是，则控制报警装置60进行报警。报警装置60可以采用各种形式来实现，包括但不限于诸如扬声器、振动器、警报器等通过音频、振动以及各种其他方式发出警报的装置。还可以设置报警级别，例如信号处理装置30可以在含有危险品的概率较低时，控制报警装置60以较低音量的声音或者较弱的振动来报警，当含有危险品的概率较高时，控制报警装置60以较高音量的声音或者较强的振动来报警。
在一些实施例中，安检设备还可以包括平移装置70。平移装置70可以安装在安检设备100上，用于在2D MIMO阵列面板20所在的平面内平移2D MIMO阵列面板20。例如，平移装置70可以按照预设的路径和速度来平移2D MIMO阵列面板20，使得每当2D MIMO阵列面板20完成扫描任务时(即，每当2D MIMO阵列面板20内的全部发射天线完成检测信号的发射，并且接收天线完成回波信号的接收)，将2D MIMO阵列面板20平移到下一个位置，使得2D MIMO阵列面板20重新开始下一轮扫描，以此类推，从而使得可以利用一个2D MIMO阵列面板20的达到多个2D MIMO阵列面板20的扫描效果，起到节省成本和简化系统结构的作用。下文将进一步对此进行详细说明。在一些实施例中，平移装置70可以包括轨道、电机、连接件、滑动件、控制电路等等，2D MIMO阵列面板20可以通过连接件安装在滑动件上，以在电机的作用下沿轨道可移动。
图2a和图2b(统称图2)分别示出了根据本公开另一实施例的安检设备的结构示意图和示意电路图。图2的安检设备200与图1的安检设备100类似，区别至少在于图2的安检设备200还包括三个侧板11、12和13，每个侧板11、12和13上(例如内部或表面)均设置有上述2D MIMO阵列面板。为了简明起见，下面主要对区别部分进行详细描述。在图2中，将安装在底板10上的2D MIMO阵列面板表示为20a，将安装在侧板11、12和13上的2D MIMO阵列面板分别表示为20b、20c和20d，2D MIMO阵列面板20a，20b，20c，20d统称2D MIMO阵列面板20。侧板11与侧板12之间形成第一检测空间，侧板12和侧板13之间形成第二检测空间。在图2a中，第一检测空间和第二检测空间可以分别容纳被检对象40的两个部分，例如人的左脚和右脚。安装在底板10上(例如内部或下方)的2D MIMO阵列面板20a可以用来扫描被检对象40(例如人的双脚)的底部(例如鞋底)，安装侧板11、12和13内部或表面上的2D MIMO阵列面板20b、20c和20d可以用来扫描被检对象40(例如人的双脚)的侧面。
信号处理装置30与2D MIMO阵列面板20a，20b，20c，20d相连。信号处理装置30可以具有以上描述的结构，当然也可以采用其他合适的结构。2D MIMO阵列面板20a，20b，20c，20d分别从不同位置向被检对象40的不同部分发射检测信号并接收来自被检对象40的各部分的回波信号，例如2D MIMO阵列面板20a向人双脚的底部发射检测信号和接收来自人双脚底部的回波信号，2D MIMO阵列面板20b和20c分别向人左脚两侧发射检测信号并接收相应的回波信号，2D MIMO阵列面板20c和20d分别向人右脚两侧发射检测信号并接收相应的回波信号。信号处理装置30可以根据2D MIMO阵列面板20a，20b，20c，20d中每一个的回波信号重建该2D MIMO阵列面板所对应的被检对象部分的图像，例如根据2D MIMO阵列面板20a接收到的回波信号重建人双脚底部的图像，根据2D MIMO阵列面板20b和20c接收到的回波信号分别重建左脚两侧的图像，根据2D MIMO阵列面板20c和20d接收到的回波信号分别重建右脚两侧的图像。信号处理装置30也可以根据2D MIMO阵列面板20a，20b，20c，20d的回波信号的组合来重建被检对象的部分或整体的图像。
以上虽然以三个侧板11、12和13并且每个侧板中设有一个2D MIMO阵列面板为例进行了描述，然而本领域技术人员应清楚，本公开的实施例不限于此，侧板的数量和排列方式以及侧板中2D MIMO阵列面板的数量和排列方式可以根据需要来设计。例如，可以设置一个侧板，该侧板垂直于底板并且位于底板中的2D MIMO阵列面板的上方，该侧板两侧空间分别用于放置人的左脚和右脚，该侧板左右两侧表面或内部分别设置有 至少一个2D MIMO阵列面板以分别扫描左脚的右侧和右脚的左侧。在一些实施例中，底板以及侧板的形状和尺寸也可以根据需要来进行设置，以适应不同检测对象的外形和尺寸。例如侧板可以设计成弧形、不规则形状等等，底板可以设计成圆形、不规则形状等等。在一些实施例中，可以提供其他方向延伸的2D MIMO阵列面板，例如可以提供位于侧板上方的顶板，顶板中设置有2D MIMO阵列面板，例如以扫描人体脚面，等等，在此不再赘述。
在一些实施例中，上述安检设备可以与其他安检设备相结合使用，例如可以安装在例如基于毫米波检测的安检门下方，被检对象站立在该安检设备上，在等待毫米波安检门扫描探测的同时，完成对其脚部的成像。该安检设备的检测与成像过程与毫米波安检门可以同时进行，并且可以共用显示装置和/或报警装置。
下面将参考图3至图10来描述根据本公开实施例的2D MIMO阵列面板20中的2D MIMO天线阵列21的结构。根据本公开的实施例，2D MIMO阵列面板20可以采用10-40GHz芯片来实现，2D MIMO阵列面板20中的2D MIMO天线阵列21可以包括布置成阵列的多个发射天线和多个接收天线，发射天线和接收天线可以安装在基板上，根据需要以多种形式来布置。2D MIMO天线阵列21可以包括至少一个2D MIMO子阵列，每个子阵列大小根据采用等效相位中心的能容忍的误差决定，与成像距离(检测距离)有关。在本公开的实施例中，每个2D MIMO子阵列中相邻发射天线和/或相邻接收天线之间的距离可以是检测信号的多个频率之一(例如中心工作频率)对应的波长的整数倍(例如1倍、2倍、3倍、4倍、5倍等等)。相邻的等效相位中心之间的距离可以为检测信号的多个频率之一对应的波长的一半。2D MIMO天线阵列21的尺寸可以设计成与成像区域相同，或者略小于或者略大于成像区域，以便确保能够正确重建被检对象的图像，例如2D MIMO天线阵列的长度和宽度可以在30cm-50cm范围内。2D MIMO天线阵列21的成像距离，即2D MIMO天线阵列21与被检对象之间的距离可以在2cm-30cm范围内。
图3a和3b(统称图3)分别示出了根据本公开一实施例的2D MIMO天线阵列的结构示意图和等效相位中心示意图。
如图3a所示，2D MIMO天线阵列包括一个子阵列，该子阵列包括沿水平方向排列的两行发射天线Tx和沿垂直方向排列的两列接收天线Rx，两行发射天线Tx和两列接收天线Rx形成矩形图案。图3a中，2D MIMO天线阵列的尺寸可以为30cm×30cm，发射天线Tx和接收天线Rx的数目分别为46、46，图中为了简明起见发射天线Tx和接收 天线Rx的数目仅仅是作为示意，而非实际数目。
如图3b所示，发射和接收信号的等效位置可以由天线的相位中心来表示，该等效位置为两个独立天线或孔径的物理中心。在本公开的实施例中，以发射天线与对应的接收天线的连线的中点作为二者的等效相位中心。在MIMO架构下，一个发射天线Tx对应着多个接收天线Rx，本公开的实施例中，接收天线Rx和发射天线Tx被设置为不处于同一位置，这种发射和接收天线空间分离的系统可以使用一个虚拟的系统模拟，在虚拟系统中，在每一组发射天线Tx与接收天线Rx之间添加一个虚拟位置，这个位置被称为等效相位中心。收发天线组合所采集的回波数据，可以等效为其等效相位中心所在位置自发自收天线所采集的回波。
图3中的2D MIMO天线阵列中，相邻的发射天线和相邻的接收天线之间的距离均为检测信号的波长λ，相邻的等效相位中心之间的距离为λ/2，成像的取样间隔(即等效相位中心的间隔)在λ/2的量级，这使得重建的图像中不存在伪影叠加。
图4示出了根据本公开另一实施例的2D MIMO天线阵列的结构示意图。如图4所示，2D MIMO天线阵列包括2×2个子阵列，每个子阵列的尺寸设置成10cm×10cm，2D MIMO天线阵列的总体尺寸为20cm×20cm，发射天线Tx和接收天线Rx的数目分别为141、141。
图5示出了根据本公开另一实施例的2D MIMO天线阵列的结构示意图。如图5所示，2D MIMO天线阵列包括3×3个子阵列，每个子阵列的尺寸为8cm×8cm，2D MIMO天线阵列的总体尺寸为24cm×24cm，发射天线Tx和接收天线Rx的数目分别为224、224。
图6示出了根据本公开另一实施例的2D MIMO天线阵列的结构示意图。如图6所示，2D MIMO天线阵列可以包括2×3个子阵列，每个子阵列的尺寸为10cm×10cm，2D MIMO天线阵列的总体尺寸为20cm×30cm，发射天线Tx和接收天线Rx的数目分别为188、213。
图7示出了根据本公开另一实施例的2D MIMO天线阵列的结构示意图。如图7所示，2D MIMO天线阵列包括2×4个子阵列，每个子阵列的尺寸为10cm×10cm，2D MIMO天线阵列的总体尺寸为20cm×40cm，发射天线Tx和接收天线Rx数目分别为285、235。
除了采用上述的10-40GHz芯片，2D MIMO阵列面板20也可以实现为2-100GHz范围内的其他频率的MIMO芯片。2D MIMO阵列面板20中2D MIMO天线阵列21的长度和宽度可以在30cm-50cm范围内，成像距离(即2D MIMO天线阵列与被检对象的距离)可以在2cm-30cm范围内。表1示出了在2D MIMO天线阵列的总尺寸为30cm×30cm 的情况下对于两种不同的子阵列尺寸在不同频段下的发射天线Tx和接收天线Rx的数目，其中*表示中心频率。例如，如表1所示，对于30cm×30cm的2D MIMO天线阵列，如果子阵列尺寸为30cm×30cm，那么对于2GHz-20GHz频段的检测信号，发射天线数目为18个，接收天线数目为18个；如果子阵列尺寸为15cm×15cm，那么对于2GHz-20GHz频段的检测信号，发射天线数目为24个，接收天线数目为24个，以此类推。
表1
Figure PCTCN2019110380-appb-000001
图8a示出了根据本公开另一实施例的2D MIMO天线阵列的结构示意图。图8b示出了图8a的2D MIMO天线阵列的等效相位中心的示意图。如图8a所示，2D MIMO天线阵列包括一个子阵列，该子阵列包括沿水平方向排列的一行发射天线Tx和沿垂直方向排列的一列接收天线Rx，该一行发射天线Tx和一行接收天线Rx交叉形成十字形图案。如图9b所示，图9a的2D MIMO天线阵列的等效相位中心以阵列的形式分布在十字形图案的中心位置。
图9a示出了根据本公开另一实施例的2D MIMO天线阵列的结构示意图。图9b示出了图8a的2D MIMO天线阵列的等效相位中心的示意图。如图9a所示，2D MIMO天线阵列包括一个子阵列，该子阵列包括沿阵列的第一对角线方向排列的一排发射天线Tx和沿阵列的第二对角线方向排列的一排接收天线Rx，该一排发射天线Tx和一排接收天线Rx交叉，从而在面板上形成对角线形式的十字形图案。如图9b所示，图9b的等 效相位中心相对于图8b的等效相位中心旋转了45度(顺时针或者逆时针)，这是因为图9a的2D MIMO天线阵列相对于是图8a的2D MIMO天线阵列旋转45度。
本领域技术人员应清楚，以上仅仅是示例，本公开的2D MIMO天线阵列11的结构不限于此，子阵的尺寸、阵列的尺寸、子阵中天线的排列方式以及天线的数目可以根据需要来调整。
下面参考图10来描述根据本公开实施例的2D MIMO天线阵列的工作原理。如图10所示，以包括4×4个子阵列的2D MIMO天线阵列为例进行描述，其中每个子阵列101具有如图2所示的结构，形成的等效相位中心排列成阵列102的形式(也称作等效相位中心网)，(n x，n y)表示等效相位中心在阵列(等效相位中心网)中的坐标。该2D MIMO天线阵列的成像区域103的中心参考点由
Figure PCTCN2019110380-appb-000002
表示，被检对象包含定位在中心参考点
Figure PCTCN2019110380-appb-000003
处的点散射体。在进行安全检测时，可以采用电子扫描的方式控制上述2D MIMO天线阵列。
作为示例，控制电路可以控制2D MIMO天线阵列的每一个子阵列中的发射天线依次发射检测信号，接收天线接收回波信号，然后切换下一个子阵列，重复该操作，直到完成整个天线阵列扫描，获得被检对象不同视角的所有散射数据。作为另一示例，控制电路可以控制2D MIMO天线阵列中的所有发射天线依次发射检测信号，并控制2D MIMO天线阵列中的所有接收天线接收回波信号。对于2D MIMO天线阵列包括仅一个子阵列的情况，可以采用下文将描述的全息重建算法来进行图像重建；对于2D MIMO天线阵列包括多个子阵列的情况下，可以采用下文将要描述的后向投影算法进行重建。
在本公开的实施例中，采用频率在10-300GHz范围内的微波毫米波作为检测信号，该波段的波对人体没有电离损伤，可用于人体安检。在本公开的实施例中，2D MIMO天线阵列包括布置成二维阵列的多个发射天线和多个接收天线，采用电子扫描的方式工作，电子扫描具备检测速度快的优点，结合基于快速傅里叶变换(FFT)的三维全息算法算法，可以实现实时成像。2D MIMO天线阵列中的一个发射天线和一个相应的接收天线能够产生一个等效相位中心，一对收发天线组合所采集的回波数据可以等效为其等效相位中心所在位置处的自发自收天线所采集的回波。等效相位中心排列成阵列，相邻的等效相位中心的间隔基本上是检测信号的波长λ的一半，这使得整个等效行为中心阵列基本上为一满阵，且应用的成像系统采用的取样间隔(即等效相位中心的间隔)在λ/2的量级，从而产生的图像中不存在伪影叠加且能够形成较清晰的图像，提高了图像处理的速度。
图11示出了根据本公开实施例的安检设备的控制方法的示意流程图。
在步骤S101，控制2D MIMO阵列面板20向被检对象发送检测信号，并接收来自被检对象的回波信号。例如可以利用控制电路22控制2D MIMO天线阵列21按照如上所述的方式向被检对象发射检测信号并接收回波信号。检测信号可以是电磁波，例如毫米波，具体地毫米波太赫兹波。
在步骤S102，根据接收到的回波信号来重建被检对象的图像。例如可以采用全系重建算法或后向投影算法来重建被检对象的图像。
全息重新算法可以实现对被检物图像的实时重建。一对收发天线组合所采集的回波数据可以等效为其等效相位中心所在位置处的自发自收天线所采集的回波。信号处理装置对等效相位中心处的回波数据进行采集，假设所采集的被检对象的反射数据为s(n x，n y)，利用如下公式校正反射数据，得到校正后反射数据矩阵：
Figure PCTCN2019110380-appb-000004
其中s(n x，n y)为未校正的散射数据矩阵，n x和n y是等效相位中心在等效相位中心网中的位置(即，行和列的指数)。
R u(n x，n y)与R o(n x，n y)计算公式如下，
Figure PCTCN2019110380-appb-000005
且
Figure PCTCN2019110380-appb-000006
其中，如图10所示，
Figure PCTCN2019110380-appb-000007
表示成像区域103的中心的参考点，j表示虚数，k表示空间常数。
R u(n x，n y)表示计算的反射集，在此情况下，如图10所示对如下的被检对象进行采样，被检对象包含一个定位在
Figure PCTCN2019110380-appb-000008
处的点散射体。
R o(n x，n y)表示计算的反射集，其中在对多收多发孔径的等效相位中心网进行采样(如图10所示)的情况下，得到该计算的反射集。
然后利用二维傅里叶变换算法重建，获得被检对象的散射系数：
Figure PCTCN2019110380-appb-000009
其中，I(x，y)表示被检对象的散射系数，z 0表示2D MIMO阵列面板和被检对象之间的距离，j表示虚数，k为传播常数、k x、k y分别是空间传播常数；FFT 2D为二维傅里叶变换，IFFT 2D为二维傅里叶逆变换。
完成二维孔径扫描后，采集到的回波数据可以表示为s(n x，n y)。最后，结合基于快速傅里叶变化的合成孔径全息算法，可以实现快速重建，完成成像。成像算法的目的就是从回波表达式中反演出被检对象的像，即被检对象的散射系数I(x，y)，基于傅里叶变换的合成孔径全息算法，无需对整个成像区域逐点重建，而是利用快速傅里叶变换的优势，一次对正确成像区域重建完成。因此，该算法能够实现快速扫描和快速图像重建，因此实现实时成像。重建的图像显示在显示装置上，结合可疑物报警算法，对可疑物进行报警。
后向投影起源于计算机断层扫描技术是一种基于时域信号处理的精确的成像算法。其基本思想是对成像区域内每一成像点，通过计算该点到收、发天线之间的延时，将所有回波对它的贡献相干叠加从而得到该点在图像中对应的像素值，这样对整个成像区域逐点地进行相干叠加处理，即可获得成像区域的图像。后向投影算法天然的易于实现并行计算，因此，适用于多个子阵列中的接收天线同时接收反射的电磁波的情况。虽然需要对整个成像区间每一个点重建，但是如果处理系统中的硬件采用GPU或者FPGA技术的话，重建时间可以大大降低，甚至实现实时重建。
重建公式可以表示为，
Figure PCTCN2019110380-appb-000010
其中，
Figure PCTCN2019110380-appb-000011
是被检对象的散射系数，z a是成像距离，j为虚数单位，k为传播常数，s(x t，y t，x r，y r，k)为一对发射天线-接收天线组合接收到被检对象的回波信号，(x t，y t)为发射天线坐标，(x r，y r)为接收天线的坐标，z表示2D MIMO阵列面板和被检对象某一断层之间的距离。
在步骤S102之后，还可以执行其他步骤，例如分析重建的被检对象的图像，以判断被检对象是否可能携带危险品，如果是，则控制报警装置进行报警。例如可以将重建的被检对象的图像与预先存储的模板相比较，如果与某种危险品的特征模板匹配程度大于预设的阈值，则判定为可能含有该种危险品，否则判定为不含有危险品。在一些实施 例中，还可以根据匹配程度的高低来确定含有危险品的概率的高低，例如匹配程度较高指示含有危险品的概率较高，匹配程度较低指示含有危险品的概率较低。报警的方式包括但不限于画面显示、音频报警、振动报警等等。还可以设置报警级别，例如当含有危险品的概率较低时，可以通过较低音量的声音或者较弱的振动来报警，当含有危险品的概率较高时，可以通过较高音量的声音或者较强的振动来报警。
此外，还可以通过显示装置将重建的被检对象的图像和/或上述判断结果呈现给用户，例如，可以在重建图像之后利用显示屏来显示所重建的图像，然后再将分析结果呈现在显示屏上；也可以在完成图像重建和分析比对之后再一并将重建的图像和判定结果呈现在显示屏上。判定结果(例如可能含有哪种危险品、含有该危险品的概率)的呈现方式可以根据需要来选择，除了上述在显示屏上以画面的形式呈现之外，还可以利用音频、振动等其他方式来呈现，例如可以判断结果以语音的形式播放，也可以利用报警器的报警音量高低或振动强弱来指示判断结果，比如高音量的报警代表含有危险品的可能性较高，低音量的报警代表含有危险品的可能性较低。
图12示出了根据本公开另一实施例的安检设备的控制方法的示意流程图。
在步骤S201，控制2D MIMO阵列面板向被检对象发送检测信号并接收来自被检对象的回波信号。在本实施例中采用的是电子扫描与机械扫描相结合的扫描方式，在本步骤中2D MIMO阵列面板在当前位置进行电子扫描。
在步骤S202，判断2D MIMO阵列面板是否完成电子扫描(即全部发射天线均完成发射并且接收天线完成接收)，如果是，则表示当前位置的扫描完成，进行到步骤S203平移到下一位置，否则返回步骤S201继续当前位置的扫描。图10示出了根据本公开实施例的安检设备的机械扫描与电子扫描相结合的扫描路线示意图。如图10所示，对于用一个5cm×5cm的2D MIMO阵列面板来机械扫描30cm×30cm的面阵的情况，可以沿着图10中箭头所指示的路径每次平移一个步长(例如5cm)，直到完成路径上所有位置的扫描，从而实现对30cm×30cm的面阵的扫描。
在步骤S203，判断机械扫描是否完成，即是否完成了平移路径上最后一个位置的电子扫描，如果是，则表示2D MIMO阵列面板已完成路径上所有位置的扫描，因此针对当前被检对象的扫描结束，并进行到步骤S204进行图像重建，否则执行步骤S205平移到下一个位置进行扫描。
在步骤S204，利用获得的回波信号来重建被检对象的图像。重建算法包括但不限于上述的全系重建算法和后向投影算法。
在步骤S205，平移2D MIMO阵列面板，并返回步骤S201，以在新的位置再次进行扫描检测。平移可以按照预设的路径进行，例如图10所示，每次平移一个步长，直到平移到路径上最后一个位置。
在一些实施例中，还可以在步骤S204之后执行步骤S206至207。
在步骤S206中，分析重建的被检对象的图像，以判断被检对象中是否可能含有危险品，如果是，则执行步骤S207，否则结束当前被检对象的安全检测。例如可以将重建的被检对象图像与预先存储的模板相比较，如果与某种危险品的特征模板匹配程度大于预设的阈值，则判定为可能含有该种危险品，否则判定为不含有危险品。在一些实施例中，还可以根据匹配程度的高低来确定含有危险品的概率的高低，例如匹配程度较高指示含有危险品的概率较高，匹配程度较低指示含有危险品的概率较低。
在步骤S207，控制报警装置进行报警。报警的方式包括但不限于画面显示、音频报警、振动报警等等。还可以设置报警级别，例如当含有危险品的概率较低时，可以通过较低音量的声音或者较弱的振动来报警，当含有危险品的概率较高时，可以通过较高音量的声音或者较强的振动来报警。
以上描述了对于安检设备包括一个2D MIMO阵列面板的情况，然而本领域技术人员应清楚，对于包括多个2D MIMO阵列面板的安检设备，如图2所示的包括四个2D MIMO阵列面板的安检设备，控制方法是类似的。在一些实施例中，还可以利用多个2D MIMO阵列面板接收到的回波信号的组合来重建被检对象的图像。在一些实施例中，还可以基于分别对应多个2D MIMO阵列面板的多个重建图像的组合(例如人脚的不同视角的图像)来进行分析，从而判断是否可能含有危险品、危险品的类型、数量等等。
本公开的实施例还提供了一种计算机可读介质，所述计算机可读介质中存储有指令，所述指令在由处理器执行时使处理器执行上述安检设备的控制方法。
本公开的实施例能够基于电磁波(例如基于超宽带雷达技术)对承载于底板上的被检对象的局部(例如人体的脚部)进行自动安检，一方面检测准确率高，另一方面不需要被检对象脱鞋，在提高安检速度的同时改善了用户使用体验。
本公开的实施例支持全电子扫描方式以及电子扫描与机械扫描相结合的扫描方式。全电子扫描方式扫描速度快，结合基于快速傅里叶变换(FFT)的三维全息算法算法，可以实现实时成像。电子扫描与机械扫描相结合的扫描方式可以利用较小的天线阵列实现较大成像区域的扫描，节省成本并且结构简单。
本公开的实施例可以根据需要灵活选用各种不同结构的2D MIMO天线阵列，具有 较高的使用灵活性。通过采用毫米波作为检测信号，能够穿透待测物品成像，从而取代X光机达到安全检测的目的的同时，提供了更高的检测质量和更高的安全性。
本公开的实施例通过自动分析重建的待测物品的图像，能够能提供自动化的威胁检测，相比于传统方式大大提高了检测效率，降低漏检率。
本领域的技术人员可以理解，上面所描述的实施例都是示例性的，并且本领域的技术人员可以对其进行改进，各种实施例中所描述的结构在不发生结构或者原理方面的冲突的情况下可以进行自由组合。
在详细说明本公开的较佳实施例之后，熟悉本领域的技术人员可清楚的了解，在不脱离随附权利要求的保护范围与精神下可进行各种变化与改变，且本公开亦不受限于说明书中所举示例性实施例的实施方式。

Claims (13)

  1. 一种安检设备，包括：
    底板，被配置为承载被检对象；
    二维多发多收收发阵列面板，设置在所述底板上并且与所述底板平行，所述二维多发多收收发阵列面板包括：
    至少一个二维多发多收收发子阵列，每个二维多发多收收发子阵列包括多个发射天线和多个接收天线，所述多个发射天线中的每个发射天线和所述多个接收天线中的相应一个接收天线的连线的中点作为一个等效相位中心，所述多个发射天线和所述多个接收天线被布置为使得等效相位中心排列成二维阵列；以及
    控制电路，被配置为控制所述多个发射天线按照预设顺序向被检对象发射电磁波形式的检测信号，以及控制所述多个接收天线接收来自被检对象的回波信号；
    信号处理装置，与所述二维多发多收收发阵列面板相连，并且被配置为根据接收到的回波信号来重建被检对象的图像；以及
    显示装置，与信号处理装置相连，并且被配置为显示所重建的被检对象的图像。
  2. 根据权利要求1所述的安检设备，还包括至少一个侧板，所述至少一个侧板垂直于所述底板，每个侧板上设置有至少一个所述二维多发多收收发阵列面板。
  3. 根据权利要求2所述的安检设备，其中，所述至少一个侧板包括第一侧板、第二侧板和第三侧板，所述第一侧板与第二侧板之间形成第一检测空间，所述第二侧板和第三侧板之间形成第二检测空间。
  4. 根据权利要求1所述的安检设备，其中，所述二维多发多收收发阵列面板安装在所述底板内部或下方。
  5. 根据权利要求1所述的安检设备，其中，每个二维多发多收收发子阵列中相邻发射天线和/或相邻接收天线之间的距离是所述检测信号的多个频率之一对应的波长的整数倍，相邻的等效相位中心之间的距离为所述检测信号的波长的一半。
  6. 根据权利要求1所述的安检设备，其中，
    所述二维多发多收收发子阵列包括沿着第一方向排列的两行发射天线和沿着垂直于第一方向的第二方向排列的两列接收天线，所述两行发射天线与两列接收天线形成矩形图案；或者
    所述二维多发多收收发子阵列包括沿着第一方向排列的一行发射天线和沿着垂直于第一方向的第二方向排列的一列接收天线，所述行和列交叉形成十字形状。
  7. 根据权利要求1所述的安检设备，其中，所述控制电路被配置成控制每个二维多发多收收发子阵列中的多个发射天线依次发射检测信号，并控制该二维多发多收收发子阵列中的多个接收天线接收回波信号；或者
    所述控制电路被配置成控制所述二维多发多收收发阵列面板中的所有发射天线依次发射检测信号，并控制所述二维多发多收收发阵列面板中的所有接收天线接收回波信号。
  8. 根据权利要求1至7中任一项所述的安检设备，还包括：平移装置，被配置为在所述二维多发多收收发阵列面板所在的平面内平移所述二维多发多收收发阵列面板。
  9. 根据权利要求1至7中任一项所述的安检设备，还包括：报警装置，与所述信号处理装置相连，所述信号处理装置还被配置为根据所重建的被检对象的图像基于预设的标准来判断被检对象是否可能含有危险品，如果是，则控制所述报警装置进行报警。
  10. 根据权利要求1至7中任一项所述的安检设备，其中，所述检测信号为频率在10-300GHz范围内的微波毫米波。
  11. 根据权利要求1至7中任一项所述的安检设备，其中，所述二维多发多收收发阵列面板的长度和宽度均在10cm至50cm的范围内。
  12. 一种根据权利要求1至11中任一项权利要求所述的安检设备的控制方法，包括：
    利用所述二维多发多收收发阵列面板向被检对象发送检测信号，并接收来自被检对象的回波信号；以及
    根据接收到的回波信号来重建被检对象的图像。
  13. 根据权利要求12所述的控制方法，其中，所述重建被检对象的图像包括基于全息重建算法或后向投影算法来重建被检对象的图像。
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