MIMO security check system for large passenger flow security check and working method thereof

Abstract

The invention relates to passenger security check, in particular to an MIMO security check system for large passenger flow security check and a working method of the MIMO security check system for large passenger flow security check, a correlation type infrared light curtain sensor provides an initial detection trigger signal for the system so as to judge whether passengers enter a security check area; the metal detector is used for detecting metal substances hidden in the foot sole of the passenger, sending a detection image to the upper computer and providing a second detection trigger signal for the system through a built-in pressure sensor so as to further judge the validity of the passenger remaining in the security check area and the real-time millimeter wave image; the signal processor is used for controlling the frequency controller to generate a millimeter wave signal of a step frequency continuous wave of a composite frequency band; the multi-channel transceiving array is used for transmitting millimeter wave signals to a security check area and transmitting received echo signals to the upper computer; according to the technical scheme, the defects that in the prior art, the 360-degree range of the whole body of a passenger cannot be covered, the overall occupied area of equipment is large, and the single-time detection time is long can be overcome.

Description

Technical Field

[0001] The present invention relates to passenger security inspection, and in particular to a MIMO security inspection system for large passenger flow security inspection and a working method thereof. Background Art

[0002] At present, the commonly used passenger security check method in high-speed railway stations, railway stations and other places is still the close-body scanning by security personnel using handheld metal detectors. This passenger security check method has the disadvantages of low security efficiency, high labor intensity, and easy to cause resistance from passengers, especially during periods of large passenger flow and dense passenger flow.

[0003] To address these issues, domestic and international companies have launched passive terahertz body imaging and active millimeter wave security systems. Passive terahertz body imaging systems typically utilize a rotating mirror or a three-mirror design with a folded optical path. These systems can achieve a maximum imaging frame rate of 12 frames per second, offering near-real-time performance. However, the overall footprint of the system is large, with a maximum length of 4.2 meters. Existing security inspection channels cannot meet these size requirements, and the missed detection rate is high. Active millimeter wave security inspection systems typically utilize a "one-dimensional line scan + one-dimensional mechanical scan" mode, requiring passengers to stand still and cooperate. One-dimensional line scans cannot cover a passenger's entire body 360 degrees, resulting in blind spots. Each inspection takes a long time and requires manual re-inspection, severely impacting the efficiency of security inspection channels and easily causing congestion. Summary of the Invention

[0004] (1) Technical problems solved

[0005] In response to the above-mentioned shortcomings of the existing technology, the present invention provides a MIMO security inspection system and its working method for large passenger flow security inspection, which can effectively overcome the defects of the existing technology such as the inability to cover the 360-degree range of the passenger's entire body, the large overall equipment footprint, and the long single detection time.

[0006] (2) Technical solution

[0007] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0008] A MIMO security inspection system for large passenger flow security inspection, including a folding MIMO security inspection array, a beam-type infrared light curtain sensor, a metal detector, a signal processor, a frequency controller, a multi-channel transceiver array, an optical camera, a host computer and a display and control terminal;

[0009] The through-beam infrared light curtain sensor provides the system with an initial detection trigger signal to determine whether a passenger has entered the security inspection area;

[0010] The metal detector detects metal objects hidden under the passenger's feet and sends the detection image to the host computer. At the same time, the built-in pressure sensor provides the system with a second detection trigger signal to further determine whether the passenger remains in the security inspection area and the validity of the real-time millimeter wave image;

[0011] The signal processor controls the frequency controller to generate a millimeter wave signal of a stepped frequency continuous wave in a composite frequency band based on the initial detection trigger signal and the second detection trigger signal;

[0012] A multi-channel transceiver array transmits millimeter wave signals to the security inspection area and sends the received echo signals to the host computer;

[0013] The optical camera collects multiple optical images of passengers, provides a third detection trigger signal to the system to determine the validity of the multiple optical images, and sends the multiple optical images to the host computer;

[0014] The host computer generates imaging instructions based on the initial detection trigger signal and the second detection trigger signal, creates a real-time millimeter-wave image of the passenger rotating 360 degrees in place, and superimposes the detection image captured by the metal detector on the real-time millimeter-wave image to obtain a superimposed image. Simultaneously, the host computer performs character feature judgment on the multi-channel optical images captured by the optical camera and binds the multi-channel optical images to the real-time millimeter-wave image based on the judgment results.

[0015] The display and control terminal displays the superimposed image in real time.

[0016] Preferably, the opposed infrared light curtain sensor is arranged on the surface of the folding MIMO security inspection array. The opposed infrared light curtain sensor adopts a dot matrix type, and the light curtain coverage height is 1m. When the trigger time of more than 2 / 3 of the infrared sensors reaches the time threshold, an initial detection trigger signal is generated and sent to the host computer through the switch to determine whether the passenger has entered the security inspection area.

[0017] Preferably, the metal detector uses the initial detection trigger signal generated by the opposed infrared light curtain sensor as the working starting signal, and the second detection trigger signal generated by the pressure sensor is sent to the host computer through the switch, and is mutually verified with the initial detection trigger signal generated by the opposed infrared light curtain sensor to further determine whether the passenger remains in the security inspection area and the validity of the real-time millimeter wave image.

[0018] Preferably, the metal detector is arranged 30 cm in front of the folding MIMO security inspection array, and the height of the metal detector is consistent with the existing high-speed railway station passenger inspection platform to retain the existing security inspection habits to the greatest extent.

[0019] Preferably, the signal processor is arranged inside the folded MIMO security inspection array. The signal processor provides the clock frequency and initial phase for the millimeter wave signal generated by the frequency controller, and collects the orthogonal demodulation signal fed back by the frequency controller to perform digital filtering, signal extraction and image reconstruction.

[0020] Preferably, the multi-channel transceiver array is arranged inside the folded MIMO security inspection array. The multi-channel transceiver array is composed of a plurality of sub-arrays to form a two-dimensional transceiver array, which is used to transmit millimeter wave signals to the security inspection area and pre-process the received echo signals and send them to the host computer through the switch to generate real-time millimeter wave images.

[0021] Among them, multiple opening arrays are deployed on the front and folding pages of the folding MIMO security inspection array.

[0022] Preferably, the optical cameras are arranged on the top and both sides of the folding MIMO security inspection array. The third detection trigger signal generated by the optical camera is sent to the host computer through the switch, and is mutually verified with the initial detection trigger signal generated by the opposing infrared light curtain sensor and the second detection trigger signal generated by the pressure sensor to determine the validity of the multi-channel optical image;

[0023] Among them, the optical camera adopts a fisheye micro optical camera, which has both wide-angle shooting and hidden shooting functions.

[0024] Preferably, the host computer performs character feature judgment on the multiple optical images collected by the optical camera, and if the character features corresponding to the multiple optical images are all the same character features, the multiple optical images are bound to the real-time millimeter wave image.

[0025] Preferably, the folding MIMO security inspection array adopts a folding design to effectively detect the blind spots on the side of the human body. The overall size is 1500*450*2000mm, which is in line with the existing security inspection channel design. The weight of a single machine meets the requirements of two people carrying it, and it can be quickly deployed to the security inspection channel.

[0026] A method for operating a MIMO security inspection system for large passenger flow security inspection includes the following steps:

[0027] S1. A passenger passes through the security inspection channel and enters the security inspection area in front of the folding MIMO security inspection array. The through-beam infrared light curtain sensor provides the system with an initial detection trigger signal to determine whether the passenger has entered the security inspection area.

[0028] S2: The metal detector uses the initial detection trigger signal generated by the infrared light curtain sensor as the starting point to detect metal objects hidden under the passenger's feet and send the detection image to the host computer. At the same time, the built-in pressure sensor provides the system with a second detection trigger signal to further determine whether the passenger remains in the security inspection area and the validity of the real-time millimeter wave image.

[0029] S3. The signal processor controls the frequency controller to generate a millimeter wave signal of a stepped frequency continuous wave in a composite frequency band based on the initial detection trigger signal and the second detection trigger signal;

[0030] S4. The multi-channel transceiver array transmits millimeter wave signals to the security inspection area. The passenger rotates 360 degrees on the spot under the guidance of the security personnel. The multi-channel transceiver array pre-processes the received echo signals and sends them to the host computer through the switch.

[0031] S5. The optical camera collects multiple optical images of the passenger, provides a third detection trigger signal to the system to determine the validity of the multiple optical images, and sends the multiple optical images to the host computer;

[0032] S6. The host computer generates an imaging instruction based on the initial detection trigger signal and the second detection trigger signal, generates a real-time millimeter-wave image of the passenger rotating 360 degrees in place, and superimposes the detection image collected by the metal detector on the real-time millimeter-wave image to obtain a superimposed image. Simultaneously, the host computer performs a person feature judgment on the multi-channel optical images collected by the optical camera, and binds the multi-channel optical images to the real-time millimeter-wave image based on the judgment results.

[0033] S7. The display and control terminal displays the superimposed image in real time, stores the superimposed image for a period of time as required, and destroys it periodically.

[0034] (3) Beneficial effects

[0035] Compared with the prior art, the MIMO security inspection system and its working method for large passenger flow security inspection provided by the present invention have the following beneficial effects:

[0036] 1) The MIMO security inspection system uses two-dimensional planar electronic scanning technology, which is easy to operate and can obtain real-time millimeter wave images of passengers. During the security inspection process, passengers can rotate 360 degrees on the spot, ensuring no blind spots. This meets the needs of rapid passenger inspection and clearance during periods of high passenger flow, while effectively reducing the labor intensity of security inspections.

[0037] 2) The MIMO security inspection system addresses the blind spot detection problem in existing security inspection systems, effectively resolving the issue of metal detection on the sides of the human body and on the soles of the feet, while simplifying the security inspection process.

[0038] 3) The MIMO security inspection system occupies a small area and can be deployed within existing security inspection channels, avoiding the cost waste caused by on-site modification;

[0039] 4) The MIMO security inspection system adopts a highly integrated design with small size, light weight, and is not restricted by the use environment. It has the ability to be quickly and flexibly deployed and can be manually transported to other security inspection channels;

[0040] 5) Compared with the existing security inspection system, the MIMO security inspection system is cheaper and reduces the consumption of social resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive effort.

[0042] Figure 1 A schematic diagram of the system of the present invention;

[0043] Figure 2 It is a structural schematic diagram of the present invention;

[0044] Figure 3 This is a schematic diagram of the internal structure of the folded MIMO security inspection array in the present invention;

[0045] Figure 4 This is a schematic diagram of the structure of the multi-channel transceiver array inside the folded MIMO security inspection array of the present invention;

[0046] Figure 5 A schematic diagram of a passenger standing on a metal detector facing security personnel in the present invention;

[0047] Figure 6 This is a schematic diagram of a passenger standing on a metal detector and rotating in place according to the present invention. DETAILED DESCRIPTION

[0048] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0049] A MIMO security inspection system for large passenger flow security inspection, such as Figures 1 to 3As shown, it includes a folding MIMO security inspection array 1, a beam-type infrared light curtain sensor 104, a metal detector 2, a signal processor 102, a frequency controller 103, a multi-channel transceiver array 101, an optical camera 105, a host computer 107 and a display and control terminal 3;

[0050] The infrared light curtain sensor 104 provides the system with an initial detection trigger signal to determine whether a passenger has entered the security inspection area;

[0051] Metal detector 2 detects metal objects hidden under the passenger's feet and sends the detection image to the host computer 107. At the same time, the built-in pressure sensor 201 provides the system with a second detection trigger signal to further determine whether the passenger remains in the security inspection area and the validity of the real-time millimeter wave image;

[0052] The signal processor 102 controls the frequency controller 103 to generate a millimeter wave signal of a stepped frequency continuous wave in a composite frequency band based on the initial detection trigger signal and the second detection trigger signal;

[0053] The multi-channel transceiver array 101 transmits millimeter wave signals to the security inspection area and sends the received echo signals to the host computer 107;

[0054] The optical camera 105 collects multiple optical images of the passenger, provides a third detection trigger signal to the system to determine the validity of the multiple optical images, and sends the multiple optical images to the host computer 107;

[0055] The host computer 107 generates an imaging instruction based on the initial detection trigger signal and the second detection trigger signal, and generates an image generating instruction for the passenger to rotate 360 degrees in place (such as Figure 5 and Figure 6 The real-time millimeter wave image is obtained by superimposing the detection image collected by the metal detector 2 on the real-time millimeter wave image to obtain a superimposed image, and at the same time, the multi-channel optical images collected by the optical camera 105 are subjected to character feature judgment, and the multi-channel optical images are bound to the real-time millimeter wave image according to the judgment result;

[0056] The display and control terminal 3 displays the superimposed image in real time.

[0057] like Figure 2 As shown, the opposed infrared light curtain sensor 104 is arranged on the surface of the folding MIMO security inspection array 1. The opposed infrared light curtain sensor 104 adopts a dot matrix type, and the light curtain coverage height is 1m. When the trigger time of more than 2 / 3 of the infrared sensors reaches the time threshold, an initial detection trigger signal is generated and sent to the host computer 107 through the switch 106 to determine whether the passenger has entered the security inspection area.

[0058] In the technical solution of the present application, the opposing infrared light curtain sensor 104 includes but is not limited to other infrared technical methods, such as the combined signals of multiple opposing infrared sensors.

[0059] The metal detector 2 uses the initial detection trigger signal generated by the opposed infrared light curtain sensor 104 as the working starting signal, and the second detection trigger signal generated by the pressure sensor 201 is sent to the host computer 107 through the switch 106, and is mutually verified with the initial detection trigger signal generated by the opposed infrared light curtain sensor 104 to further determine whether the passenger remains in the security inspection area and the validity of the real-time millimeter wave image.

[0060] like Figure 2 As shown, the metal detector 2 is set 30 cm in front of the folding MIMO security inspection array 1. The height of the metal detector 2 is consistent with the existing high-speed railway station passenger inspection platform to retain the existing security inspection habits to the greatest extent.

[0061] like Figure 3 As shown, the signal processor 102 is arranged inside the folded MIMO security inspection array 1. The signal processor 102 provides the clock frequency and initial phase for the millimeter wave signal generated by the frequency controller 103, and collects the orthogonal demodulation signal fed back by the frequency controller 103 to perform digital filtering, signal extraction and image reconstruction.

[0062] like Figure 4 As shown, the multi-channel transceiver array 101 is arranged inside the folded MIMO security inspection array 1. The multi-channel transceiver array 101 is a two-dimensional transceiver array composed of multiple sub-arrays, which is used to transmit millimeter wave signals to the security inspection area and pre-process the received echo signals before sending them to the host computer 107 through the switch 106 to generate real-time millimeter wave images.

[0063] Among them, multiple opening arrays are deployed on the front and folding pages of the folding MIMO security inspection array 1.

[0064] like Figure 2 As shown, the optical cameras 105 are installed on the top and both sides of the folding MIMO security inspection array 1. The third detection trigger signal generated by the optical camera 105 is sent to the host computer 107 through the switch 106. The third detection trigger signal is verified with the initial detection trigger signal generated by the opposing infrared light curtain sensor 104 and the second detection trigger signal generated by the pressure sensor 201 to determine the validity of the multi-channel optical image.

[0065] The optical camera 105 adopts a fisheye micro optical camera, which has both wide-angle shooting and hidden shooting functions.

[0066] like Figure 3As shown, the host computer 107 performs character feature judgment on the multiple optical images collected by the optical camera 105. If the character features corresponding to the multiple optical images are all the same character features, the multiple optical images are bound to the real-time millimeter wave image.

[0067] like Figure 2 and Figure 3 As shown, the folding MIMO security inspection array 1 adopts a folding design, which can effectively detect the blind spots on the side of the human body. The overall size is 1500*450*2000mm, which is in line with the design of existing security inspection channels. The weight of a single unit meets the requirements of two people carrying it, and it can be quickly deployed to the security inspection channel.

[0068] In the technical solution of this application, based on the above-mentioned MIMO security inspection system for large passenger flow security inspection, a working method of the MIMO security inspection system for large passenger flow security inspection is also disclosed, including the following steps:

[0069] S1: A passenger passes through the security inspection channel and enters the security inspection area in front of the folding MIMO security inspection array 1. The infrared light curtain sensor 104 provides the system with an initial detection trigger signal to determine whether the passenger has entered the security inspection area.

[0070] S2, the metal detector 2 uses the initial detection trigger signal generated by the infrared light curtain sensor 104 as the working starting signal to detect metal objects hidden under the passenger's feet and sends the detection image to the host computer 107. At the same time, the built-in pressure sensor 201 provides the system with a second detection trigger signal to further determine whether the passenger remains in the security inspection area and the validity of the real-time millimeter wave image;

[0071] S3. The signal processor 102 controls the frequency controller 103 to generate a stepped-frequency continuous-wave millimeter-wave signal in a composite frequency band based on the initial detection trigger signal and the second detection trigger signal.

[0072] S4, the multi-channel transceiver array 101 transmits millimeter wave signals to the security inspection area, and the passenger rotates 360 degrees on the spot under the guidance of the security personnel (such as Figure 5 and Figure 6 As shown), the multi-channel transceiver array 101 pre-processes the received echo signal and sends it to the host computer 107 through the switch 106;

[0073] S5. The optical camera 105 collects multiple optical images of the passenger, provides a third detection trigger signal to the system to determine the validity of the multiple optical images, and sends the multiple optical images to the host computer 107.

[0074] S6. The host computer 107 generates an imaging instruction based on the initial detection trigger signal and the second detection trigger signal, generates a real-time millimeter wave image of the passenger rotating 360 degrees in place, and superimposes the detection image collected by the metal detector 2 on the real-time millimeter wave image to obtain a superimposed image. At the same time, the host computer 107 performs character feature judgment on the multi-channel optical images collected by the optical camera 105, and binds the multi-channel optical images to the real-time millimeter wave image according to the judgment results.

[0075] S7. The display and control terminal 3 displays the superimposed image in real time, stores the superimposed image for a period of time as required, and destroys it periodically.

[0076] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A MIMO security inspection system for large passenger flow security inspection, characterized by: It includes a folding MIMO security inspection array (1), a beam-type infrared light curtain sensor (104), a metal detector (2), a signal processor (102), a frequency controller (103), a multi-channel transceiver array (101), an optical camera (105), a host computer (107) and a display and control terminal (3); A beam-type infrared light curtain sensor (104) provides the system with an initial detection trigger signal to determine whether a passenger has entered the security inspection area; A metal detector (2) detects metal objects hidden under the feet of passengers and sends the detection image to the host computer (107). At the same time, a second detection trigger signal is provided to the system through a built-in pressure sensor (201) to further determine whether the passenger remains in the security inspection area and the validity of the real-time millimeter wave image; The signal processor (102) controls the frequency controller (103) to generate a millimeter wave signal of a stepped frequency continuous wave in a composite frequency band based on the initial detection trigger signal and the second detection trigger signal; A multi-channel transceiver array (101) transmits millimeter wave signals to the security inspection area and sends the received echo signals to the host computer (107); The optical camera (105) collects multiple optical images of the passenger, provides a third detection trigger signal to the system to determine the validity of the multiple optical images, and sends the multiple optical images to the host computer (107); The host computer (107) generates an imaging instruction based on the initial detection trigger signal and the second detection trigger signal, generates a real-time millimeter wave image of the passenger rotating 360 degrees in situ, and superimposes the detection image collected by the metal detector (2) on the real-time millimeter wave image to obtain a superimposed image. At the same time, the host computer (107) performs character feature judgment on the multi-channel optical images collected by the optical camera (105), and binds the multi-channel optical images to the real-time millimeter wave image according to the judgment result. The display and control terminal (3) displays the superimposed image in real time.

2. The MIMO security inspection system for large passenger flow security inspection according to claim 1, characterized in that: The opposed-beam infrared light curtain sensor (104) is arranged on the surface of the folding MIMO security inspection array (1). The opposed-beam infrared light curtain sensor (104) adopts a dot matrix type, and the light curtain coverage height is 1m. When the trigger time of more than 2 / 3 of the infrared sensors reaches a time threshold, an initial detection trigger signal is generated and sent to a host computer (107) through a switch (106) to determine whether a passenger has entered the security inspection area.

3. The MIMO security inspection system for large passenger flow security inspection according to claim 2, characterized in that: The metal detector (2) uses the initial detection trigger signal generated by the opposing infrared light curtain sensor (104) as a working starting point signal, and the second detection trigger signal generated by the pressure sensor (201) is sent to the host computer (107) through the switch (106), and is mutually verified with the initial detection trigger signal generated by the opposing infrared light curtain sensor (104), so as to further judge whether the passenger remains in the security inspection area and the validity of the real-time millimeter wave image.

4. The MIMO security inspection system for large passenger flow security inspection according to claim 3 is characterized in that: The metal detector (2) is arranged 30 cm in front of the folding MIMO security inspection array (1). The height of the metal detector (2) is consistent with the existing high-speed railway station passenger inspection platform to retain the existing security inspection habits to the greatest extent.

5. The MIMO security inspection system for large passenger flow security inspection according to claim 3 is characterized in that: The signal processor (102) is arranged inside the folded MIMO security inspection array (1). The signal processor (102) provides a clock frequency and an initial phase for the millimeter wave signal generated by the frequency controller (103), collects the orthogonal demodulation signal fed back by the frequency controller (103), and performs digital filtering, signal extraction, and image reconstruction.

6. The MIMO security inspection system for large passenger flow security inspection according to claim 5, characterized in that: The multi-channel transceiver array (101) is arranged inside the folded MIMO security inspection array (1). The multi-channel transceiver array (101) is composed of a plurality of aperture arrays to form a two-dimensional transceiver array, and is used to transmit millimeter wave signals to the security inspection area, and pre-process the received echo signals and send them to the host computer (107) through the switch (106) to generate real-time millimeter wave images. Among them, multiple opening arrays are deployed on the front and folding pages of the folding MIMO security inspection array (1).

7. The MIMO security inspection system for large passenger flow security inspection according to claim 6, characterized in that: The optical camera (105) is arranged on the top and both sides of the folding MIMO security inspection array (1). The third detection trigger signal generated by the optical camera (105) is sent to the host computer (107) through the switch (106) and mutually verified with the initial detection trigger signal generated by the opposing infrared light curtain sensor (104) and the second detection trigger signal generated by the pressure sensor (201) to determine the validity of the multi-channel optical image; The optical camera (105) is a fisheye micro optical camera with both wide-angle shooting and hidden shooting functions.

8. The MIMO security inspection system for large passenger flow security inspection according to claim 7, characterized in that: The host computer (107) performs character feature judgment on the multi-channel optical images collected by the optical camera (105), and if the character features corresponding to the multi-channel optical images are all the same character features, the multi-channel optical images are bound to the real-time millimeter wave image.

9. The MIMO security inspection system for large passenger flow security inspection according to any one of claims 1 to 8, characterized in that: The folding MIMO security inspection array (1) adopts a folding design, which can effectively detect the side blind spots of the human body. The overall size is 1500*450*2000mm, which is in line with the design of the existing security inspection channel. The weight of a single unit meets the requirements of two people carrying it, and it can be quickly deployed to the security inspection channel.

10. A method for operating a MIMO security inspection system for large passenger flow security inspection, based on the MIMO security inspection system for large passenger flow security inspection according to claim 1, characterized in that: The following steps are involved: S1. A passenger enters the security inspection area in front of the folding MIMO security inspection array (1) through the security inspection channel, and the opposing infrared light curtain sensor (104) provides the system with an initial detection trigger signal to determine whether the passenger has entered the security inspection area; S2, the metal detector (2) uses the initial detection trigger signal generated by the infrared light curtain sensor (104) as a working starting signal to detect metal objects hidden under the passenger's feet, and sends the detection image to the host computer (107). At the same time, the built-in pressure sensor (201) provides the system with a second detection trigger signal to further determine whether the passenger remains in the security inspection area and the validity of the real-time millimeter wave image; S3, the signal processor (102) controls the frequency controller (103) to generate a millimeter wave signal of a stepped frequency continuous wave in a composite frequency band based on the initial detection trigger signal and the second detection trigger signal; S4, the multi-channel transceiver array (101) transmits millimeter wave signals to the security inspection area. The passenger rotates 360 degrees on the spot under the guidance of the security personnel. The multi-channel transceiver array (101) pre-processes the received echo signals and sends them to the host computer (107) through the switch (106); S5, the optical camera (105) collects multiple optical images of the passenger, provides a third detection trigger signal to the system to determine the validity of the multiple optical images, and sends the multiple optical images to the host computer (107); S6, the host computer (107) generates an imaging instruction based on the initial detection trigger signal and the second detection trigger signal, generates a real-time millimeter wave image of the passenger rotating 360 degrees in situ, and superimposes the detection image collected by the metal detector (2) on the real-time millimeter wave image to obtain a superimposed image, and simultaneously performs character feature judgment on the multi-channel optical images collected by the optical camera (105), and binds the multi-channel optical images to the real-time millimeter wave image according to the judgment result; S7. The display and control terminal (3) displays the superimposed image in real time, stores the superimposed image for a period of time as required, and destroys it periodically.

Images