Security device, control method and data processing method

Abstract

This invention discloses a security inspection device, a control method, and a data processing method. The security inspection device includes a power unit, a base, and a body. A frame is mounted on one side of the base's bearing surface, capable of rotating around a central axis perpendicular to the bearing surface under the drive of the power unit. The frame divides the bearing surface into a bearing area near the rotation center and a detection area away from the rotation center. An array scanning module is also mounted on the frame, configured to emit millimeter-wave detection signals to the detection area and receive echo signals during rotation with the frame. The body includes a signal processing module, an image processing module, and a system controller. The signal processing module is configured to process the echo signals and generate digital signals under the control of the system controller. The image processing module is configured to generate three-dimensional image signals based on the digital signals and display a three-dimensional image corresponding to the three-dimensional image signals. This security inspection device operates in open environments and has high detection efficiency.

Description

Technical Field

[0001] This invention relates to the field of security inspection technology, and in particular to a security inspection device, a control method for the security inspection device, and a data processing method for the data. Background Technology

[0002] To ensure public safety and combat terrorism, security checks on people entering and exiting public places are becoming increasingly stringent. Traditional security methods mainly include the following: 1. Handheld metal detectors: These are limited in that they can only detect metal objects carried by the body, but cannot detect non-metallic prohibited items such as drugs, CDs, dangerous liquids, and ceramics. These require manual screening by security personnel, which is not only inefficient and inaccurate, but also causes resistance from those being checked; 2. X-ray body detection: Theoretically, a single dose of radiation on the order of μSv is sufficient to detect a person. This radiation dose is far less than that of X-ray machines used in medical diagnosis and will not cause harm. However, the World Health Organization (WHO) recommends avoiding any unnecessary ionizing radiation. There is no safe dose, therefore, the public still has concerns about the safety of X-ray body detection.

[0003] Compared to traditional security checks, millimeter waves, with frequencies between radio waves and infrared radiation, are gradually gaining attention as a novel detection method and are being promoted in the security field. Millimeter waves can penetrate clothing to achieve high-precision, harmless detection of the human body, accurately detecting both metal and non-metal contraband on the surface. Millimeter wave detection mainly takes two forms: active and passive. Passive detection works by using a focal plane array microwave radiation meter to measure and display the millimeter wave radiation signals scattered or reflected by the human body. However, passive detection has lower accuracy and slower imaging speed; to meet higher accuracy requirements, a sufficient number of radiation units are needed, resulting in higher costs. Active detection, compared to passive detection, offers higher resolution and imaging accuracy, better human body imaging, and is less susceptible to interference from surrounding radiation sources. For example, L3 Communications in the United States developed the ProVision security imaging system, which uses a one-dimensional electrically scanned antenna array cylindrical scanning. This system employs active holographic imaging technology, including two array antennas, to scan the human body, achieving a resolution of approximately ten millimeters. Smiths Detection in the United Kingdom developed the Eqo millimeter wave imaging security gate. The system employs a planar antenna array and performs imaging via electronic scanning, enabling real-time imaging. The Eqo millimeter-wave imaging system uses a single-source illumination, with a planar receiving array receiving the scattered echo signal, achieving an azimuth resolution of 4 millimeters.

[0004] Although the existing millimeter-wave human body security monitoring system has solved the problem of high-precision harmless detection, it still has certain shortcomings and defects, such as: 1. People to be inspected need to enter a relatively closed detection area to undergo security checks. The closed detection environment brings a sense of oppression to the people being inspected, which is inconvenient for some special groups to undergo security checks; 2. The rotating device can easily affect the accuracy of imaging during rotation; 3. The structure is complex and the cost is high. Summary of the Invention

[0005] In view of the above-mentioned problems existing in the prior art, the present invention provides a security inspection device with high detection efficiency and an open detection environment, a control method for the button device, and a data processing method.

[0006] To address the above problems, the technical solution provided by the embodiments of the present invention is as follows:

[0007] A security inspection device, comprising:

[0008] Power unit;

[0009] The base has a frame on one side of its bearing surface that can rotate around a central axis perpendicular to the bearing surface under the drive of the power device. The frame divides the bearing surface into a bearing area near the center of rotation and a detection area away from the center of rotation. The frame is also equipped with an array scanning module, which is configured to transmit millimeter-wave detection signals to the detection area and receive echo signals during the rotation process with the frame.

[0010] The body includes a signal processing module, an image processing module, and a system controller. The signal processing module is configured to process the echo signal and generate a digital signal under the control of the system controller. The image processing module is configured to generate a three-dimensional image signal based on the digital signal and display a three-dimensional image corresponding to the three-dimensional image signal.

[0011] In some embodiments, the signal processing module includes a transceiver module, a millimeter-wave switch module, and a data processing module; wherein, the millimeter-wave switch module is used to acquire the echo signal received by the array scanning module; the transceiver module is used to process the echo signal acquired by the millimeter-wave switch module and generate an intermediate frequency signal; and the data processing module is used to process the intermediate frequency signal and generate a digital signal.

[0012] In some embodiments, the array scanning module includes a transmitting array antenna and a receiving array antenna. The transmitting array antenna is used to transmit the millimeter-wave detection signal to perform millimeter-wave detection on the object under test in the detection area, and the receiving array antenna is used to receive the echo signal reflected back from the object under test.

[0013] In some embodiments, the image processing module includes an imaging processor and an image display, the imaging processor being configured to generate the three-dimensional image signal based on the digital signal, and the image display being used to display a three-dimensional image corresponding to the three-dimensional image signal.

[0014] In some embodiments, the rack includes a first cantilever and a second cantilever disposed opposite to each other, and the array scanning module includes a first array scanning module and a second array scanning module, wherein the first array scanning module and the second array scanning module are respectively disposed on the first cantilever and the second cantilever.

[0015] In some embodiments, the rotation angles of the first cantilever and the second cantilever are both 0° to 180°.

[0016] In some embodiments, the detection area includes a plurality of sub-detection areas evenly distributed around the rotation center.

[0017] A control method applied to the security inspection device described above includes:

[0018] The system detects whether an object to be inspected exists in the detection area. If so, it starts the power unit to drive the frame to rotate around the central axis in the first direction, and at the same time starts the array scanning module to transmit millimeter-wave detection signals to the detection area and receive echo signals to perform millimeter-wave detection on the object to be inspected.

[0019] Determine whether the rotation angle of the frame along the first direction meets the preset condition. If so, control the power device to drive the frame to rotate around the central axis along the second direction.

[0020] In some embodiments, prior to controlling the power unit to drive the frame to rotate about the central axis in the second direction, the following is also included:

[0021] The detection area is checked again to see if the object to be inspected exists. If so, the power device is controlled to drive the frame to rotate around the central axis in the second direction. At the same time, the array scanning module is activated to transmit millimeter-wave detection signals to the detection area and receive echo signals to perform millimeter-wave detection on the object to be inspected.

[0022] A data processing method is applied to a security inspection device, the security inspection device including an array scanning module rotatable about a central axis and a detection area located on the side of the array scanning module away from the central axis, the array scanning module being configured to continuously emit millimeter-wave detection signals to the detection area and receive echo signals from multiple detection angles during rotation, the method comprising:

[0023] Obtain the digital signal generated based on the echo signal;

[0024] Perform a Fourier transform on the digital signal along the height direction to obtain a height-oriented frequency domain signal;

[0025] The altitude-oriented frequency domain signal is subjected to Stolt transform processing along the plane formed by the range and altitude directions;

[0026] The height-frequency domain signals after Stolt transform processing at multiple detection angles are acquired, and phase compensation is performed on the height-frequency domain signals after Stolt transform processing at each detection angle to obtain compensated height-frequency domain signals.

[0027] The compensated height frequency domain signal at each detection angle is subjected to Fourier transform along the azimuth direction to obtain the azimuth frequency domain signal. The azimuth frequency domain signal at the zero azimuth Doppler position is selected as the azimuth compression signal at each detection angle, and the azimuth compression signal set composed of all the azimuth compression signals at the detection angles is obtained.

[0028] The azimuth compressed signal set is subjected to inverse Fourier transform along the plane formed by the range and height directions to obtain a three-dimensional image signal.

[0029] Compared with the prior art, the beneficial effects of the embodiments of the present invention are as follows:

[0030] The security inspection device of this invention can accurately detect metal and non-metal contraband concealed under clothing, achieving the goal of harmless security checks. It also boasts high detection efficiency, an open inspection environment that enhances the comfort of those being inspected, and facilitates security checks for special groups. The control method allows for automatic detection, improving efficiency and saving labor costs. The data processing method is simple and efficient, contributing to faster imaging. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the security inspection device according to an embodiment of the present invention;

[0032] Figure 2 This is a top view of the inspection area of ​​the security inspection device according to an embodiment of the present invention;

[0033] Figure 3 This is a structural block diagram of the security inspection device according to an embodiment of the present invention;

[0034] Figure 4 This is a flowchart of the control method for the security inspection device according to an embodiment of the present invention;

[0035] Figure 5 This is a flowchart of a data processing method according to an embodiment of the present invention.

[0036] Figure label:

[0037] 1-Base; 2-Frame; 3-Transparent protective cover; 4-Bearing area; 5-Detection area; 6-First cantilever; 7-Second cantilever; 8-First crossbeam; 9-Second crossbeam; 10-Array scanning module. Detailed Implementation

[0038] To enable those skilled in the art to better understand the technical solutions of the embodiments of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0039] See Figure 1 , Figure 2 As shown, this embodiment of the invention provides a security inspection device, which includes a power unit, a base 1, and a body. A frame 2 is provided on one side of the bearing surface of the base 1, which can rotate around a central axis perpendicular to the bearing surface under the drive of the power unit. The frame 2 divides the bearing surface into a bearing area 4 near the center of rotation and a detection area 5 away from the center of rotation. An array scanning module 10 is also provided on the frame 2. The array scanning module 10 is configured to emit millimeter-wave detection signals to the detection area 5 and receive echo signals during the rotation process of the frame 2. The body includes a signal processing module, an image processing module, and a system controller. The signal processing module is connected to the array scanning module and is configured to process the echo signals and generate digital signals under the control of the system controller. The image processing module is configured to generate three-dimensional image signals based on the digital signals and display a three-dimensional image corresponding to the three-dimensional image signals.

[0040] In the security inspection device with the above structure, the frame 2 is positioned on the base 1 near the center of rotation, and the detection area 5 is positioned on the base 1 away from the center of rotation, i.e., on the outside of the frame 2. During security inspection, the person being inspected stands in the detection area 5. The array scanning module 10, while rotating with the frame 2, emits millimeter-wave detection signals into the detection area 5 and receives the echo signals reflected by the person being inspected, thereby achieving the purpose of millimeter-wave detection of the person being inspected. The array scanning module 10 can sequentially inspect multiple persons standing in the detection area 5, resulting in high detection efficiency. Furthermore, because the detection area 5 is located on the outside of the frame 2, the inspection environment is open and less likely to create a sense of oppression, making the person being inspected more willing to undergo security inspection. In addition, for people with disabilities or other special needs, such as wheelchairs, they can be easily pushed into the detection area 5, overcoming the problem in existing technologies where assistive devices such as wheelchairs are not easy to pass through security inspection devices.

[0041] Specifically, in this embodiment, the base 1 is a circular base, which includes a bearing area 4 near its central axis and a detection area 5 away from its central axis, that is, the detection area 5 is located outside the bearing area 4, and the frame 2 is mounted on the bearing area 4. The base 1 is not limited to a circle, and can also be other shapes.

[0042] Furthermore, cooperation Figure 2 As shown, the detection area 5 may include multiple sub-detection areas evenly distributed around the rotation center. During detection, one object can be placed in each sub-detection area to facilitate the simultaneous detection of multiple objects, thereby improving security inspection efficiency. For example, in this embodiment, six sub-detection areas are evenly divided around the circumference of the circular base and labeled as A1, A2, B1, B2, C1, and C2, respectively. This allows six objects to stand in the detection area 5 simultaneously, resulting in high security inspection efficiency.

[0043] Furthermore, the power unit is located in the middle of the base 1. The power unit includes a servo motor and a transmission mechanism connected to the servo motor. The transmission mechanism is also connected to the frame 2. The servo motor can drive the frame 2 to rotate around the central axis of the circular base via the transmission mechanism. Alternatively, the power unit can employ a structure combining a hydraulic rod and a transmission mechanism, as long as it can drive the frame 2 to rotate around the central axis of the circular base.

[0044] Furthermore, a transparent protective cover 3 can be provided on the outside of the frame 2 to prevent the inspected object from accidentally touching the array scanning module 10 on the frame 2, thus protecting the personal safety of the inspected object and preventing damage to the security inspection device. Optionally, the outer edge of the transparent protective cover 3 is curved, and of course, the transparent protective cover 3 can also be set in, for example, a triangular prism, a quadrangular prism, or other shapes.

[0045] Furthermore, the frame 2 includes a first cantilever 6 and a second cantilever 7 arranged opposite to each other, and a first crossbeam 8 and a second crossbeam 9 connecting the first cantilever 6 and the second cantilever 7. The first cantilever 6 and the second cantilever 7 are located near the outer edge of the bearing area 4, i.e., near the inner edge of the detection area 5. The first crossbeam 8 is connected to a transmission mechanism, and a servo motor can drive the first cantilever 6 and the second cantilever 7 to rotate around the central axis of the base 1 via the transmission mechanism and the first crossbeam 8. The frame 2 can also adopt other structures, such as including multiple cantilever arms that are equidistantly distributed around the central axis of the circular base.

[0046] Furthermore, the array scanning module 10 includes a first sub-array scanning module and a second sub-array scanning module, which are respectively mounted on the first cantilever 6 and the second cantilever 7. As the first and second cantilever arms 6 and 7 rotate, the first and second sub-array scanning modules can simultaneously perform millimeter-wave detection on the object under test within the detection area 5. In this embodiment, for every 180° rotation of the first and second cantilever arms 6 and 7, the first and second sub-array scanning modules can jointly complete the millimeter-wave detection of the entire detection area 5. The array scanning module 10 may also include, for example, three, four, or more sub-array scanning modules. Correspondingly, the more sub-array scanning modules the array scanning module 10 includes, the smaller the angle that each sub-array scanning module needs to detect.

[0047] Furthermore, both the first subarray scanning module and the second subarray scanning module include a transmitting array antenna and a receiving array antenna. The transmitting array antenna is used to transmit millimeter-wave detection signals to the detection area 5, and the receiving array antenna is used to receive the echo signals reflected back by the object under test. By cooperating with the transmitting array antenna and the receiving array antenna, the purpose of millimeter-wave detection of the object under test in the detection area 5 can be achieved.

[0048] Furthermore, the first and second subarray scanning modules can transmit millimeter-wave detection signals towards the detection area 5 along the normal direction of the arc surface formed during rotation. In other words, the transmitting array antenna transmits millimeter-wave detection signals towards the detection area 5 along the normal direction of the transparent protective cover 3. By transmitting millimeter-wave detection signals along the normal direction of the transparent protective cover 3, the millimeter-wave detection signals are directed towards the object being inspected in a direction substantially perpendicular to the object, which improves the detection effect and avoids detection blind spots.

[0049] Cooperate Figure 3 As shown, the signal processing module includes a transceiver module, a millimeter-wave switch module, and a data processing module. The millimeter-wave switch module includes a transmit array switch module, a receive array switch module, a driver, and a switch controller. The switch controller controls the transmit and receive array switch modules via the driver. The transceiver module generates a millimeter-wave detection signal and transmits it to the transmit array switch module. The transmit array switch module transmits the generated millimeter-wave detection signal to the transmit array antenna. The receive array switch module receives the echo signal from the receive array antenna and transmits it to the transceiver module. The transceiver module also processes the echo signal and generates an intermediate frequency (IF) signal. The data processing module processes the IF signal and generates a digital signal. The data processing module may include components such as an analog-to-digital converter.

[0050] Furthermore, the image processing module includes an imaging processor and an image display. The imaging processor is configured to generate a three-dimensional image signal based on a digital signal. Specifically, the imaging processor can process the digital signal into a three-dimensional image signal based on a specific data processing method. The image display is used to display a three-dimensional image corresponding to the three-dimensional image signal, that is, the three-dimensional image corresponding to the object being inspected, so that security personnel can intuitively observe whether the object being inspected is carrying dangerous items through the image display.

[0051] See Figure 4 As shown, the present invention also provides a control method for the above-mentioned security inspection device, comprising:

[0052] If the detection area 5 is found to be inspected, the power unit is started to drive the frame 2 to rotate around the central axis in the first direction. At the same time, the array scanning module 10 is started to transmit millimeter wave detection signals to the detection area 5 and receive echo signals to perform millimeter wave detection on the inspected object.

[0053] Determine whether the rotation angle of the frame 2 along the first direction meets the preset condition. If so, control the power device to drive the frame 2 to rotate around the central axis along the second direction.

[0054] By adopting the above control method, the security inspection device can achieve automatic detection, which can improve security inspection efficiency, save labor costs, and also improve user experience.

[0055] Furthermore, when the angle of rotation of the frame 2 in the first direction reaches the preset condition, the presence of an object to be inspected in the detection area 5 can be detected again. If an object to be inspected exists, the power device is controlled to drive the frame 2 to rotate around the central axis in the second direction, while the array scanning module 10 is activated to transmit a millimeter-wave detection signal to the detection area 5 and receive the echo signal reflected back by the object to be inspected, so as to achieve the purpose of millimeter-wave detection of the object to be inspected. In this way, the array scanning module 10 can also perform millimeter-wave detection on the object to be inspected in the detection area 5 during the rotation of the frame 2 around the central axis in the second direction, further improving the button efficiency.

[0056] Specifically, the following steps may be included when controlling the security inspection device to perform security inspections using this control method:

[0057] S11: The presence of an object in detection zone 5 is detected by a sensor, such as a photoelectric sensor or an infrared sensor. When the sensor detects an object in any sub-detection zone 5, it sends a signal indicating the presence of an object to the system controller. After entering detection zone 5, the object should first stand facing the frame 2, i.e., facing the central axis of the base 1, as instructed by the security personnel.

[0058] S12: After receiving a signal indicating the presence of an object under inspection, the system controller starts the power unit to drive the frame 2 to rotate around the central axis in a first direction, which can be clockwise. At the same time, the system controller also starts the signal processing module, the array scanning module 10, and the image processing module to perform millimeter-wave detection on the object under inspection in the detection area 5. The system controller can control the power unit, the signal processing module, the array scanning module 10, and the image processing module via, for example, a local area network or RS232.

[0059] The specific principle of millimeter-wave detection of the object under inspection in detection area 5 is as follows: After the signal processing module is started, its transceiver module generates two millimeter-wave detection signals I1 and I2. Millimeter-wave signal I1 is amplified and transmitted to the transmitting array switch module. The transmitting array switch module transmits millimeter-wave detection signal I1 to the transmitting array antenna by selecting the on / off state of the millimeter-wave switch. The transmitting array antenna transmits the millimeter-wave detection signal. The millimeter-wave detection signal is reflected by the body of the person being inspected to form an echo signal. Each of the two receiving array antennas receives one reflected echo signal, which is then transmitted to the transceiver module through the receiving array switch module. The millimeter-wave detection signal I2 generated by the transceiver module is amplified and divided by power to output two millimeter-wave detection signals I1 and I2. 21 and I 22 Two millimeter-wave detection signals I 21 and I 22 The signals are mixed with the two received echo signals to form intermediate frequency (IF) signals IT1 and IT2, respectively. The data processing module performs analog-to-digital conversion on the IF signals IT1 and IT2 to generate corresponding digital signals MI1 and MI2, and finally transmits the digital signals MI1 and MI2 to the image processing module.

[0060] S13: The image processing module is configured to generate a three-dimensional image signal based on the digital signal and display a three-dimensional image corresponding to the three-dimensional image signal, that is, a three-dimensional image of the front of the object being inspected.

[0061] S131: The imaging processor receives the digital signal sent by the data processing module and processes the digital signal into a three-dimensional image signal through a specific data processing method;

[0062] S132: The image display shows a three-dimensional image of the front of the object under inspection, corresponding to the three-dimensional image signal, for the user to view.

[0063] S14: Determine whether the angle of rotation of the rack 2 along the first direction reaches the preset condition. The preset condition can be, for example, a preset angle. In this embodiment, the preset angle can be 180°. That is, when the rack 2 rotates clockwise to 180°, the preset condition is triggered. At this time, the system controller can pause the power unit, signal processing module, array scanning module 10 and image processing module. The security personnel can instruct the inspected object to adjust to stand with its back to the rack 2. When the sensor detects that the inspected object has re-entered the detection area 5, the sensor sends a signal to the system controller that the inspected object is present.

[0064] S15: The system controller restarts the power unit to drive the frame 2 to rotate in the second direction, which can be counterclockwise. Of course, the first and second directions can be adjusted according to actual needs. At the same time, the system controller restarts the signal processing module, array scanning module 10 and image processing module to perform millimeter wave detection on the object under test in the detection area 5. For the specific detection principle, please refer to step S2.

[0065] S16: The image processing module is configured to generate a three-dimensional digital signal based on the digital signal and display a three-dimensional image of the back of the object under inspection corresponding to the three-dimensional digital signal;

[0066] S161: The imaging processor receives digital signals sent by the data processing module and processes the digital signals into three-dimensional image signals through a specific data processing method;

[0067] S162: Display a three-dimensional image of the back of the object under inspection corresponding to the three-dimensional image signal on an image display for the user to view.

[0068] See Figure 5 As shown, this embodiment of the invention also provides a data processing method applied to the security inspection device described above. However, this data processing method is not limited to the button device described above, but can also be applied to other security inspection devices. The imaging processing module of the security inspection device in the above embodiment is not limited to processing digital signals using the data processing method of this embodiment, but can also use other data processing methods in the prior art to process digital signals. The security inspection device includes an array scanning module 10 capable of rotating around a central axis and a detection area 5 located on the side of the array scanning module 10 away from the central axis. The array scanning module 10 is configured to continuously emit millimeter-wave detection signals to the detection area 5 during rotation and receive echo signals from multiple detection angles to perform millimeter-wave detection on the object to be inspected located in the detection area 5. The processing method of this embodiment specifically includes the following steps:

[0069] S21. Obtain the digital signal generated based on the echo signal.

[0070] The path formed by the array scanning module 10 rotating around its central axis is cylindrical. Therefore, a cylindrical coordinate system can be constructed with the central axis as the height direction, the direction of the millimeter-wave detection signal transmission as the range direction, and the direction of the counterclockwise rotation around the central axis as the azimuth direction. For a point target at (r, θ, z) in the cylindrical coordinate system, its distance history can be expressed as follows:

[0071]

[0072] Where, θ n Let z be the azimuth angle of the element of the transmitting array antenna. m L represents the height of the transmit array antenna element, and L represents the rotation radius of the array scanning module.

[0073] Therefore, the digital signal generated based on the acquired step-frequency continuous wave echo signal can be expressed as:

[0074]

[0075] Where f is the operating frequency of the transmitting array antenna, c is the electromagnetic wave propagation speed, σ(r,θ,z) is the target scattering coefficient, and j is the imaginary unit.

[0076] S22. Perform a Fourier transform on the digital signal along the height direction to obtain the height-direction frequency domain signal.

[0077] Performing a Fourier transform on the digital signal along the height direction yields the height-oriented frequency domain signal, which can be represented as follows:

[0078]

[0079] in, Denotes the spatial wavenumber, k z This indicates the wave number in the altitude direction.

[0080] For a three-dimensional spatial target, the height-frequency domain signal can be represented as:

[0081]

[0082] S23. Perform Stolt transform processing on the altitude frequency domain signal along the plane formed by the range and altitude directions.

[0083] The mapping relationship for Stolt transformation along the plane formed by the range and height directions is as follows:

[0084]

[0085] Where, k r This indicates the range wavenumber.

[0086] The height-frequency domain signal, after Stolt transform processing, can be represented as follows:

[0087]

[0088] S24. Obtain the height-frequency domain signal after Stolt transform processing at multiple detection angles, and perform phase compensation on the height-frequency domain signal after Stolt transform processing at each detection angle to obtain a compensated height-frequency domain signal.

[0089] The slant range of the plane formed by the range and azimuth directions in the altitude-frequency domain signal after Stolt transform processing. Performing a Taylor expansion, we get:

[0090]

[0091] Omitting the higher-order terms in equation (7), and rewriting equation (6), the high-order frequency domain signal can be expressed as:

[0092]

[0093] The azimuth angle range of detection area 5 can be expressed as [θ min ,θ max ], θ min θ represents the minimum azimuth angle of detection area 5. max This represents the maximum azimuth angle of detection area 5, where θ = θ_max. η The target at that location has the following phase compensation function:

[0094]

[0095] The observation angle is θ = θ η The compensated altitude-frequency domain signal of the target at that location can be expressed as:

[0096]

[0097] During the calculation process, the height-frequency domain signal after Stolt transformation at each detection angle can be phase-compensated according to the sorting of the detection angles in the azimuth angle to obtain the compensated height-frequency domain signal.

[0098] S25. Perform a Fourier transform on the compensated height frequency domain signal at each detection angle along the azimuth direction to obtain an azimuth frequency domain signal. Select the azimuth frequency domain signal at the zero azimuth Doppler position as the azimuth compressed signal at each detection angle, and obtain an azimuth compressed signal set composed of all the azimuth compressed signals at the detection angles.

[0099] Among them, the azimuth frequency domain signal at the zero azimuth Doppler position is also the median value of the azimuth frequency domain signal, and the selected azimuth frequency domain signal is the detection angle θ. η The azimuth compression result of the target is obtained. During the calculation, the compensated altitude frequency domain signal at each detection angle is sequentially Fourier transformed along the azimuth direction according to the sorting of the detection angles in the azimuth angle, and the azimuth compression signal at each detection angle is obtained. S24 and S25 are repeated during the processing until the azimuth compression signals corresponding to all detection angles in the entire detection area 5 are obtained, and the azimuth compression signals corresponding to all detection angles are combined into an azimuth compression signal set. For example, when the azimuth angle corresponding to the detection area 5 is 0° to 60°, a detection angle can be set every 1°, and the azimuth compression signal at each detection angle can be obtained, finally forming an azimuth compression signal set consisting of 60 azimuth compression signals.

[0100] S26. Perform a two-dimensional inverse Fourier transform on the azimuth compressed signal set along the plane formed by the range and height directions to obtain a three-dimensional image signal.

[0101] A three-dimensional image signal can be represented as:

[0102] S 3D =σ(r,θ,z)·exp{-jk c r} (11)

[0103] Where, k c For k r The median value represents the center wavenumber.

[0104] Subsequently, the image display can show the corresponding three-dimensional image based on the three-dimensional image signal. This data processing method, which converts digital signals into three-dimensional image signals, is simple, computationally intensive, and reduces the burden on the imaging processor, thus improving data processing efficiency and ultimately increasing imaging speed.

[0105] The security inspection device of this invention can accurately detect metal and non-metal contraband concealed under clothing, achieving the goal of harmless security checks. It also boasts high detection efficiency, an open inspection environment that enhances the comfort of those being inspected, and facilitates security checks for special groups. The control method allows for automatic detection, improving efficiency and saving labor costs. The data processing method is simple and efficient, contributing to faster imaging.

[0106] The above embodiments are merely exemplary embodiments of the present invention and are not intended to limit the present invention. The scope of protection of the present invention is defined by the claims. Those skilled in the art can make various modifications or equivalent substitutions to the present invention within its spirit and scope of protection, and such modifications or equivalent substitutions should also be considered to fall within the scope of protection of the present invention.

Claims

1. A security inspection device, comprising: Power unit; The base has a frame on one side of its bearing surface that can rotate around a central axis perpendicular to the bearing surface under the drive of the power device. The frame divides the bearing surface into a bearing area near the center of rotation and a detection area away from the center of rotation. The frame is also equipped with an array scanning module, which is configured to transmit millimeter-wave detection signals to the detection area and receive echo signals during the rotation process with the frame. The body includes a signal processing module, an image processing module, and a system controller. The signal processing module is configured to process the echo signal and generate a digital signal under the control of the system controller. The image processing module is configured to generate a three-dimensional image signal based on the digital signal and display a three-dimensional image corresponding to the three-dimensional image signal. The signal processing module includes a transceiver module, a millimeter-wave switch module, and a data processing module; wherein, the millimeter-wave switch module is used to acquire the echo signal received by the array scanning module; the transceiver module is used to process the echo signal acquired by the millimeter-wave switch module and generate an intermediate frequency signal; and the data processing module is used to process the intermediate frequency signal and generate a digital signal. The array scanning module includes a transmitting array antenna and a receiving array antenna. The transmitting array antenna is used to transmit the millimeter-wave detection signal to perform millimeter-wave detection on the object under test in the detection area. The receiving array antenna is used to receive the echo signal reflected back by the object under test. The image processing module includes an imaging processor and an image display. The imaging processor is configured to generate the three-dimensional image signal based on the digital signal, and the image display is used to display a three-dimensional image corresponding to the three-dimensional image signal. The rack includes a first cantilever and a second cantilever arranged opposite to each other, and the array scanning module includes a first array scanning module and a second array scanning module, which are respectively mounted on the first cantilever and the second cantilever.

2. The security inspection device according to claim 1, characterized in that, The rotation angles of the first cantilever and the second cantilever are both 0° to 180°.

3. The security inspection device according to claim 1, characterized in that, The detection area includes multiple sub-detection areas evenly distributed around the rotation center.

4. The control method for the security inspection device according to any one of claims 1-3, comprising: The system detects whether an object to be inspected exists in the detection area. If so, it starts the power unit to drive the frame to rotate around the central axis in the first direction, and at the same time starts the array scanning module to transmit millimeter-wave detection signals to the detection area and receive echo signals to perform millimeter-wave detection on the object to be inspected. Determine whether the rotation angle of the frame along the first direction meets the preset condition. If so, control the power device to drive the frame to rotate around the central axis along the second direction.

5. The control method for the security inspection device according to claim 4, wherein, Before controlling the power unit to drive the frame to rotate about the central axis in the second direction, the following is also included: The detection area is checked again to see if the object to be inspected exists. If so, the power device is controlled to drive the frame to rotate around the central axis in the second direction. At the same time, the array scanning module is activated to transmit millimeter-wave detection signals to the detection area and receive echo signals to perform millimeter-wave detection on the object to be inspected.

6. A data processing method applied to the security inspection device as described in any one of claims 1-3, characterized in that, The security inspection device includes an array scanning module capable of rotating around a central axis and a detection area located on the side of the array scanning module away from the central axis. The array scanning module is configured to continuously emit millimeter-wave detection signals to the detection area and receive echo signals from multiple detection angles during rotation. The method includes: Obtain the digital signal generated based on the echo signal; Perform a Fourier transform on the digital signal along the height direction to obtain a height-oriented frequency domain signal; The altitude-oriented frequency domain signal is subjected to Stolt transform processing along the plane formed by the range and altitude directions; The height-frequency domain signals after Stolt transform processing at multiple detection angles are acquired, and phase compensation is performed on the height-frequency domain signals after Stolt transform processing at each detection angle to obtain compensated height-frequency domain signals. The compensated height frequency domain signal at each detection angle is subjected to Fourier transform along the azimuth direction to obtain the azimuth frequency domain signal. The azimuth frequency domain signal at the zero azimuth Doppler position is selected as the azimuth compression signal at each detection angle, and the azimuth compression signal set composed of all the azimuth compression signals at the detection angles is obtained. The azimuth compressed signal set is subjected to inverse Fourier transform along the plane formed by the range and height directions to obtain a three-dimensional image signal.

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