阅读说明：本技术 一种主动式毫米波三维成像安检装置 (Active millimeter wave three-dimensional imaging security inspection device ) 是由 温鑫 王威 费鹏 于 2019-10-29 设计创作，主要内容包括：本发明公开了一种主动式毫米波三维成像安检装置,解决大客流人员安检过程中已有技术存在的安检效率和安检精度相矛盾的问题。所述装置,包含：距离传感器、第一探测模块、第二探测模块、GPU；所述距离传感器,用于实时测量人员位置；所述第一探测模块和第二探测模块,用于接收侧面、正面或背面工作信号,在侧面、正面或背面预设区域发射和或接收多路毫米波线性调频信号进行二维电扫、并输出下变频后的回波信号；所述GPU,用于接收人员位置,输出侧面、正面或背面工作信号；还用于根据所述人员位置,实时修正成像区域中心,对所述回波信号进行三维成像。本发明实时性强、工程实用性强。(The invention discloses an active millimeter wave three-dimensional imaging security inspection device, which solves the problem that the security inspection efficiency and the security inspection precision are contradictory in the prior art in the security inspection process of large passenger flow personnel. The apparatus, comprising: the device comprises a distance sensor, a first detection module, a second detection module and a GPU; the distance sensor is used for measuring the position of a person in real time; the first detection module and the second detection module are used for receiving side, front or back working signals, transmitting and/or receiving multi-path millimeter wave chirp signals in a preset area on the side, front or back for two-dimensional electric scanning, and outputting echo signals after down-conversion; the GPU is used for receiving the position of a person and outputting a side face working signal, a front face working signal or a back face working signal; and the device is also used for correcting the center of an imaging area in real time according to the position of the person and carrying out three-dimensional imaging on the echo signal. The method has strong real-time performance and strong engineering practicability.)

1. An active millimeter wave three-dimensional imaging security inspection device is characterized by comprising: the device comprises a distance sensor, a first detection module, a second detection module and a GPU;

the distance sensor is placed near the first detection module or the second detection module and used for measuring the position of a person in real time;

the first detection module and the second detection module are used for

Receiving a side working signal sent by the GPU, transmitting and receiving a plurality of millimeter wave linear frequency modulation signals in a side preset area to perform two-dimensional electrical scanning, and outputting a down-converted echo signal;

the first detection module is also used for

Receiving a front side or back side working signal sent by the GPU, and transmitting a plurality of millimeter wave linear frequency modulation signals in a preset area on the front side or the back side for two-dimensional electric scanning;

the second detection module is also used for

Receiving the front side or back side working signal, receiving multiple paths of millimeter wave chirp signal echoes in a front side or back side preset area, and outputting an echo signal after down-conversion;

the GPU is used for processing the received data,

the front side working signal or the back side working signal is correspondingly output when the personnel position is greater than a distance threshold for the first time or not, and the side working signal is output when the personnel position is less than or equal to the distance threshold;

and the device is also used for correcting the center of an imaging area in real time according to the position of the person and carrying out three-dimensional imaging on the echo signal.

2. The active millimeter wave three-dimensional imaging security inspection device of claim 1, wherein the first detection module comprises a plurality of first antenna feeder modules and a first transceiver module, and the second detection module comprises a plurality of second antenna feeder modules and a second transceiver module;

the first or second antenna feeder modules are used for transmitting and/or receiving one or more millimeter wave linear frequency modulation signals in respective scanning areas to perform two-dimensional electrical scanning, and the scanning area formed by each first or second antenna feeder module covers the front surface, the back surface or the side surface preset area;

the first or second transceiver module is used for receiving the side face, front face or back face working signal, generating an intermediate frequency linear frequency modulation signal, up-converting to millimeter wave output, receiving a millimeter wave band echo signal, and down-converting to baseband output.

3. The active millimeter wave three-dimensional imaging security inspection device of claim 1, wherein the frequency of the millimeter wave chirp signal is 24.07GHz-32.07 GHz.

4. The active millimeter wave three-dimensional imaging security inspection device of claim 1, wherein the distance sensor is a Kinect somatosensory camera.

5. The active millimeter wave three-dimensional imaging security inspection device of claim 1, wherein the GPU is further configured to perform detection and identification of dangerous and suspicious objects based on three-dimensional imaging.

6. The active millimeter wave three-dimensional imaging security inspection device of claim 1, wherein the device adopts a design method of a fully coherent radar system.

7. The active millimeter wave three-dimensional imaging security inspection device of claim 2, wherein the first and second antenna feed modules each comprise 4 antenna array units, and a 2 x 2 arrangement is adopted, each antenna array unit comprises 2 transmitting antenna modules and 2 receiving antenna modules which are placed in parallel, and adjacent antenna array units share one transmitting antenna module or one receiving antenna module.

8. The active millimeter wave three-dimensional imaging security inspection device of claim 2, wherein the number of the first antenna feeder module and the second antenna feeder module is 9, and a 3 x 3 arrangement mode is adopted.

9. The active millimeter wave three-dimensional imaging security inspection device of claim 5, further comprising: a display module;

and the display module is used for receiving the three-dimensional imaging result and/or the detection result of the dangerous and suspicious article sent by the GPU.

10. The active millimeter wave three-dimensional imaging security inspection device of claim 7, wherein the lengths of the transmitting antenna module and the receiving antenna module are both 250mm, and each antenna module is composed of 24 antenna bellmouths with a distance of 10 mm.

Technical Field

The invention relates to the technical field of millimeter wave radars, in particular to an active millimeter wave three-dimensional imaging security inspection device.

Background

The millimeter wave security inspection imaging system comprises a passive millimeter wave human body security inspection system and an active millimeter wave human body security inspection system, the passive millimeter wave human body security inspection imaging system has the defects of poor imaging quality and low security inspection precision, the active millimeter wave security inspection imaging system has the defects of needing the stay and the cooperation of the inspected personnel, and low security inspection efficiency, and cannot meet the requirement of real-time passing under the large passenger flow scene. The existing active millimeter wave human body security inspection system adopts electric scanning and mechanical scanning, and has the defects that the person to be inspected needs to keep 1-2s in a specified posture and stay for a long time; two-dimensional plane electric scanning is adopted, and the defects are that the calculation amount of an imaging algorithm is large, and real-time imaging cannot be realized; and the electric scanning human body imaging security inspection system adopting the planar programmable lens has the defect that the resolution ratio of the system is poor due to the adoption of a single-point frequency imaging working mode.

Disclosure of Invention

The invention provides an active millimeter wave three-dimensional imaging security inspection device, which solves the problem that the security inspection efficiency and the security inspection precision are contradictory in the prior art in the security inspection process of large passenger flow personnel.

The embodiment of the invention provides an active millimeter wave three-dimensional imaging security inspection device, which comprises: the device comprises a distance sensor, a first detection module, a second detection module and a GPU; the distance sensor is placed near the first detection module or the second detection module and used for measuring the position of a person in real time; the first detection module and the second detection module are used for receiving a side working signal sent by the GPU, transmitting and receiving multiple paths of millimeter wave linear frequency modulation signals in a side preset area to perform two-dimensional electric scanning, and outputting echo signals after down-conversion; the first detection module is further configured to receive a front side or back side working signal sent by the GPU, and transmit a plurality of millimeter wave chirp signals to perform two-dimensional electrical scanning in a front side or back side preset region; the second detection module is further configured to receive the front or back working signal, receive multiple millimeter wave chirp echoes in a preset region on the front or back, and output an echo signal after down-conversion; the GPU is used for receiving the personnel position, correspondingly outputting the front side working signal or the back side working signal when the personnel position is greater than a distance threshold value for the first time or not, and outputting the side working signal when the personnel position is less than or equal to the distance threshold value; and the device is also used for correcting the center of an imaging area in real time according to the position of the person and carrying out three-dimensional imaging on the echo signal.

Furthermore, the first detection module comprises a plurality of first antenna feeder modules and a first transceiver module, and the second detection module comprises a plurality of second antenna feeder modules and a second transceiver module; the first or second antenna feeder modules are used for transmitting and/or receiving one or more millimeter wave linear frequency modulation signals in respective scanning areas to perform two-dimensional electrical scanning, and the scanning area formed by each first or second antenna feeder module covers the front surface, the back surface or the side surface preset area; the first or second transceiver module is used for receiving the side face, front face or back face working signal, generating an intermediate frequency linear frequency modulation signal, up-converting to millimeter wave output, receiving a millimeter wave band echo signal, and down-converting to baseband output.

Preferably, the frequency of the millimeter wave chirp signal is 24.07GHz-32.07 GHz.

Preferably, the distance sensor adopts a Kinect somatosensory camera.

Preferably, the GPU is further configured to perform detection and identification of dangerous and suspicious items according to three-dimensional imaging.

Preferably, the device adopts a design method of a full-coherent radar system.

Furthermore, the first and second antenna feeder modules each include 4 antenna array units, each antenna array unit includes 2 transmitting antenna modules and 2 receiving antenna modules disposed in parallel, and adjacent antenna array units share a transmitting antenna module or a receiving antenna module.

Furthermore, the number of the first antenna feeder module and the second antenna feeder module is 9, and a 3 × 3 arrangement mode is adopted.

Further, the method also comprises the following steps: a display module; and the display module is used for receiving the three-dimensional imaging result and/or the detection result of the dangerous and suspicious article sent by the GPU.

Furthermore, the lengths of the transmitting antenna module and the receiving antenna module are both 250mm, and each antenna module is composed of 24 antenna horn mouths with the distance of 10 mm.

The beneficial effects of the invention include: the invention greatly improves the security inspection efficiency under the condition of ensuring the security inspection precision, meets the automatic detection of dangerous and suspicious articles in the moving process of the inspected personnel, and realizes the security inspection requirements of the large passenger flow personnel of 'no contact, no perception and no stay'. By utilizing the characteristics of the full-coherent radar system, based on the position information of the detected personnel in the advancing process, the 360-degree all-directional imaging and detection in the straight-through advancing process of the detected personnel are realized by setting the working mode of the detection system.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention and not to limit the invention. In the drawings:

FIG. 1 is an embodiment of an active millimeter wave three-dimensional imaging security inspection apparatus;

FIG. 2 is an embodiment of an omnidirectional imaging principle of an active millimeter wave three-dimensional imaging security inspection device;

fig. 3(a) is an antenna array element arrangement of a first antenna feed module embodiment;

FIG. 3(b) is an equivalent phase center of a first antenna feed module embodiment;

FIG. 4 is a schematic diagram of an embodiment of an active millimeter wave three-dimensional imaging security inspection device including a display module;

fig. 5 is a schematic diagram of an embodiment of a three-dimensional imaging method in a single-station mode.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the specific embodiments of the present invention and the accompanying drawings. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The earliest product of the active millimeter wave human body imaging technology is a mixed scanning (electrical scanning and mechanical scanning) millimeter wave human body imaging security inspection system developed by national laboratories in the northwest of the pacific united states. The system needs the detected person to keep 1-2s according to the designated posture, and the safety inspection requirement of no stop and quick passing cannot be realized. 2011 Germany Rohde&Schwarz corporation develops a two-dimensional plane electric scanning human body imaging security inspection system, which has the real-time acquisition capability of target data in an imaging area, but because the calculated amount of an imaging algorithm is large, real-time imaging is not realized. Agilent corporation of America develops an electric scanning human body imaging security inspection system based on a plane programmable lens, and the scanning speed reaches 10⁷The security inspection of non-contact and no-stay is realized by spatial points/second, and the system has poor resolution due to the adoption of a working mode of single-point frequency imaging. The research on the active millimeter wave human body imaging technology in China starts late, but the development is fast in recent years, and a series of achievements are obtained. The Beijing radio measurement test institute originally completed the development of the first active millimeter wave cylindrical scanning human body three-dimensional imaging security inspection instrument in China, and has been used for demonstration in a plurality of airports in China.

The innovation points of the invention are as follows: the invention realizes the high-speed scanning of the three-dimensional imaging area based on the millimeter wave antenna array sparse arrangement technology and the MIMO radar working system; designing a full-coherent radar system, and setting a working mode of a detection system according to the position information of the detected person on the basis of the full-coherent radar system to realize 360-degree all-directional scanning and imaging of the detected person in traveling; optimizing the calculated amount of a three-dimensional imaging algorithm according to the position information of the detected person; and finishing the real-time reconstruction of the three-dimensional space of the detected person and the automatic detection of dangerous suspicious articles based on a GPU parallel computing platform.

The technical solutions provided by the embodiments of the present invention are described in detail below with reference to the accompanying drawings.

Fig. 1 is an embodiment of an active millimeter wave three-dimensional imaging security inspection apparatus, which is used for dynamically realizing three-dimensional imaging in real time during the personnel traveling process, and the active millimeter wave three-dimensional imaging security inspection apparatus includes: a first detection module 1, a second detection module 2, a distance sensor 3, a GPU (graphics processor) 4.

The distance sensor is placed near the first detection module or the second detection module and used for measuring the position of a person in real time; the first detection module and the second detection module are used for receiving a side working signal sent by the GPU, transmitting and receiving multiple paths of millimeter wave linear frequency modulation signals in a side preset area to perform two-dimensional electric scanning, and outputting echo signals after down-conversion; the first detection module is further configured to receive a front side or back side working signal sent by the GPU, and transmit a plurality of millimeter wave chirp signals to perform two-dimensional electrical scanning in a front side or back side preset region; the second detection module is further configured to receive the front or back working signal, receive multiple millimeter wave chirp echoes in a preset region on the front or back, and output an echo signal after down-conversion; the GPU is used for receiving the personnel position, correspondingly outputting the front side working signal or the back side working signal when the personnel position is greater than a distance threshold value for the first time or not, and outputting the side working signal when the personnel position is less than or equal to the distance threshold value; and the device is also used for correcting the center of an imaging area in real time according to the position of the person and carrying out three-dimensional imaging on the echo signal.

It should be noted that the present invention starts to work by the distance information triggering device, and therefore the short-distance active millimeter wave real-time three-dimensional imaging security inspection system presented in the text is the active millimeter wave three-dimensional imaging security inspection device of the present invention.

Preferably, the frequency of the millimeter wave chirp signal is 24.07GHz-32.07GHz, and it should be noted that broadband chirp signals in other millimeter wave frequency ranges may also be selected, which is not particularly limited herein.

As an embodiment of the present invention, the first detection module and the second detection module adopt an antenna array sparse arrangement technology and a radar detection technology of an MIMO system to realize real-time detection of a three-dimensional imaging area, and it should be noted that the antenna arrangement modes in the first detection module and the second detection module may be the same or different.

It should be noted that the front, back, or side preset areas may be the same or different, and may be a preset fixed area, or may be a preset area range adjusted according to the position information of the person, and when the adjustment is possible, the scanning range of the antenna beam may be reduced, and the calculation amount may be reduced, and in addition, the sequence of two-dimensional electrical scanning on the preset areas is not particularly limited herein.

As an embodiment of the present invention, the distance sensor employs a Kinect motion sensing camera, provides position information of a detected person during traveling, and feeds back the position information to the GPU for real-time calculation processing.

It should be noted that the distance threshold may be set in advance or in real time.

As an embodiment of the present invention, the method for performing three-dimensional imaging by the GPU is a beam domain convolution three-dimensional imaging algorithm, and it should be noted that the GPU may also adopt other three-dimensional imaging methods, which is not particularly limited herein.

As the embodiment of the invention, in order to realize 360-degree omnibearing imaging in the advancing process of a detected person, a close-range active millimeter wave real-time three-dimensional imaging security inspection system adopts a design method of a full-coherent radar system, namely the whole system shares one clock, broadband linear frequency modulation signals transmitted by each detection subsystem are synchronous, the system adopts 24-32GHz broadband linear frequency modulation signals for detection, the scanning time of an imaging area is less than 50ms, the parallel calculation time of a three-dimensional imaging algorithm and a dangerous suspected object detection algorithm is less than 50ms, and the output detection result video is ensured to be more than 20 frames/s through the working mode of a production line.

The embodiment of the invention provides a design method of a close-range active millimeter wave real-time three-dimensional imaging security inspection system.

Fig. 2 is an embodiment of an omnidirectional imaging principle of an active millimeter wave three-dimensional imaging security inspection device, which is used for realizing real-time omnidirectional three-dimensional imaging of pedestrians in the advancing process.

An active millimeter wave three-dimensional imaging security inspection device comprises: the first detection module 1, the second detection module 2, the distance sensor 3, the first detection module contains a plurality of first day and feeds module 5, the second detection module contains a plurality of second day and feeds the module.

The distance sensor is placed near the first detection module or the second detection module and used for measuring the position of a person in real time; the first detection module and the second detection module are used for receiving a side working signal sent by the GPU, transmitting and receiving multiple paths of millimeter wave linear frequency modulation signals in a side preset area to perform two-dimensional electric scanning, and outputting echo signals after down-conversion; the first detection module is further configured to receive a front side or back side working signal sent by the GPU, and transmit a plurality of millimeter wave chirp signals to perform two-dimensional electrical scanning in a front side or back side preset region; the second detection module is further configured to receive the front side or the back side working signal, receive multiple millimeter wave chirp echoes in the front side or the back side preset region, and output an echo signal after down-conversion.

The first or second antenna feeder modules are used for transmitting and/or receiving one or more millimeter wave chirp signals in respective scanning areas to perform two-dimensional electrical scanning, and the scanning area formed by each first or second antenna feeder module covers the front surface, the back surface or the side surface preset area.

In order to realize 360-degree all-directional imaging in the advancing process of a detected person, the short-distance active millimeter wave real-time three-dimensional imaging security inspection system adopts a design method of a full-coherent radar system, namely the whole system shares one clock, and broadband linear frequency modulation signals transmitted by each detection subsystem are synchronous. Under the condition, the working mode of the radar detection system is switched according to the position of the detected person in the process of moving, and 360-degree omnibearing imaging is realized.

The value of the person position which is fed back by the distance sensor in real time is defined as R, and the value of the distance threshold value is defined as R0. When the detected person does not enter the millimeter wave security inspection channel, that is, when R is greater than R0, as shown in fig. 2, at the leftmost position, the first detection module transmits a broadband millimeter wave detection signal, and at this time, the second detection module receives the broadband millimeter wave detection signal, thereby completing information acquisition on the front side of the detected person; when the detected person is located in the millimeter wave security inspection channel, namely R is not more than R0, as shown in the middle position of FIG. 2, the first detection module and the second detection module work in a self-sending and self-receiving working mode to complete the body side information acquisition of the detected person; when the detected person leaves the millimeter wave security inspection channel, that is, R > R0, as shown in the rightmost position in fig. 2, the first detection module transmits a broadband millimeter wave detection signal, and at this time, the second detection module receives the broadband millimeter wave detection signal, thereby completing information acquisition on the back of the detected person.

It should be noted that the distance threshold R0 may be determined according to actual operating parameters of the system.

In the embodiment of the present invention, the number of the first antenna feeder module and the number of the second antenna feeder module are both 9, and a 3 × 3 arrangement manner is adopted, it should be noted that the number of the first antenna feeder module and the number of the second antenna feeder module may also be other values, may also be the same or different, and is not particularly limited herein.

Further, in the embodiment of the present invention, independent scanning areas and scanning orders are preset for the 9 first or second antenna feeder modules, and each scanning area is combined together to at least cover a preset area, for example, when the system operates in a front scanning mode, each scanning area is combined together to at least cover the front preset area … ….

It should be noted that each of the first antenna feeder modules may transmit or receive a signal, the first antenna feeder modules may work simultaneously to form an MIMO operating mode, or each of the first antenna feeder modules may work simultaneously to form an MIMO operating mode, and the first antenna feeder modules may work simultaneously to form an MIMO operating mode.

The scanning order may be from top to bottom, from left to right, or may be in other orders, and is not particularly limited herein.

The embodiment of the invention provides a principle of omnibearing 360-degree three-dimensional imaging of the device, realizes 360-degree omnibearing imaging and detection in a straight-through advancing process of a detected person, does not need the detected person to wait, and improves the security inspection speed and efficiency.

Fig. 3(a) is an antenna array unit arrangement mode of the first embodiment of the antenna feed module, which illustrates a sparse antenna array arrangement mode.

The first antenna feed module comprises four antenna array units 7, a 2 × 2 arrangement mode is adopted, each antenna array unit comprises two transmitting antenna modules 8 and two receiving antenna modules 9 which are arranged in parallel, and adjacent antenna array units share the transmitting antenna modules or the receiving antenna modules.

In the embodiment of the invention, the antenna array unit on the upper left and the antenna array unit on the upper right share the receiving antenna module; the antenna array unit on the upper left and the antenna array unit under the seat share the transmitting antenna module; the antenna array unit on the upper right and the antenna array unit on the lower right share the transmitting antenna module; the antenna array unit at the lower left and the antenna array unit at the lower right share the receiving antenna module.

In the embodiment of the invention, the lengths of the transmitting antenna module and the receiving antenna module are both 250mm, and the transmitting antenna module and the receiving antenna module are both composed of 24 antenna horn mouths with the distance of 10 mm.

It should be noted that the arrangement of the transmitting antenna module and the receiving antenna module may be that the horizontal direction in the embodiment of the present invention is the transmitting antenna module, or that the opposite horizontal direction is the arrangement of the receiving antenna module.

Further, the antenna array elements of the second antenna feeder module and the first antenna feeder module are arranged in the same manner, and the description is not repeated here.

Fig. 3(b) is an equivalent phase center of a first antenna feed module embodiment.

When the system works, each transmitting antenna bell mouth in the antenna array unit corresponds to all receiving bell mouths and receives and transmits in series in sequence to form an equivalent sampling interval of 5mm multiplied by 5 mm.

The equivalent phase centers of any pair of transmitting/receiving antennas are shown in FIG. 3(b), and the distance between the target and the transmitting antenna aperture is

Target distance receiving antenna aperture face spacing of

Target-to-equivalent phase center distance of

The phase of the sampled echo data that needs to be compensated is

Wherein k is the wave number. With following

At larger, the point spread function of the system deteriorates to a greater extent, thus limiting the size of the antenna array element, which is defined as 25cm in design.

The embodiment of the invention provides a sparse arrangement mode of antenna arrays, and the horn mouth spacing of the antennas is reasonably designed, so that the working power of a system is reduced, and the energy expenditure is saved.

Fig. 4 is an embodiment of an active millimeter wave three-dimensional imaging security inspection device including a display module, which realizes all-dimensional three-dimensional imaging of pedestrians and automatic identification of dangerous goods in the traveling process.

An active millimeter wave three-dimensional imaging security inspection device comprises: a first detection module 1, a second detection module 2, a distance sensor 3, a GPU (graphic processing unit) 4 and a display module 14; the first detection module comprises: the first antenna feeder module 5 and the first transceiver module 9; the second detection module comprises: a second antenna feeder module 5 and a second transceiver module 10; the GPU includes: the system comprises a control unit 11, a three-dimensional imaging algorithm parallel computing unit 12 and a dangerous and suspicious article automatic detection unit 13; the first transceiver module includes: an intermediate frequency signal generating unit 15, a reference signal generating unit 16, a frequency doubling unit 17, a first mixer 18, second to fifth mixers 19 to 22, a first A/D sampling unit 23, a second A/D sampling unit 24, and an FPGA unit 25.

The intermediate frequency signal generating unit is used for outputting an intermediate frequency broadband linear frequency modulation signal of 3GHz-4GHz, the signal period is less than 5us, the conversion from the intermediate frequency signal to a millimeter wave signal is completed through the frequency doubling unit, and a millimeter wave linear frequency modulation signal of 24GHz-32GHz is output; the intermediate frequency reference signal generated by the reference signal generating unit is a dot frequency signal with the frequency of 70MHz, a millimeter wave linear frequency modulation detection signal with the frequency of 24.07GHz-32.07GHz is output through the up-conversion of the first frequency mixer, and the signal is fed into the first antenna feeding module to complete the detection of an imaging area.

In order to improve the real-time performance of the system, the first transceiver module adopts a one-transmission two-reception working mode, and can be configured into different one-transmission multi-reception modes according to actual conditions.

The received two paths of millimeter wave echo signals are down-converted to a baseband through a second mixer, a fifth mixer and an output I/Q signal, the echo signals are processed in the A/D sampling unit in a digital mode, and the echo signals are sent to the GPU for real-time calculation processing after the FPGA unit finishes preprocessing.

The control unit in the GPU receives the personnel position of the detected personnel fed back by the distance sensor in real time, the information is used as the center of an imaging area to be adjusted in real time, the range of the imaging area is reduced, the calculated amount is reduced, after the echo data arrangement fed back by the FPGA is completed, the three-dimensional space reconstruction and projection calculation of the detected personnel are carried out by the high-speed parallel imaging algorithm calculation unit, and the dangerous and suspicious article automatic detection unit completes the real-time detection and marking of the dangerous and suspicious article in the two-dimensional projection result output by the high-speed parallel imaging algorithm calculation unit.

The display module is used for receiving the three-dimensional imaging result and/or the detection result of the dangerous and suspicious articles sent by the GPU, and the display module is a terminal display workstation and is used for displaying and alarming the detection result of the detected personnel.

The first or second antenna feeder modules are used for transmitting and/or receiving one path of millimeter wave linear frequency modulation signals in respective scanning areas to perform two-dimensional electric scanning, and the scanning area formed by each first or second antenna feeder module covers the front surface, the back surface or the side surface preset area.

The first or second transceiver module is used for receiving the side face, front face or back face working signal, generating an intermediate frequency linear frequency modulation signal, up-converting to millimeter wave output, receiving a millimeter wave band echo signal, and down-converting to baseband output.

Further, the second transceiver module and the first transceiver module have the same components and are not repeatedly discussed here.

The active millimeter wave three-dimensional imaging security inspection device provided by the embodiment of the invention comprises a display module, can display the security inspection result in real time, and is clearer and convenient to use; the first transceiver module comprises an internal component unit, and is easy to realize in engineering.

Fig. 5 is a schematic diagram of an embodiment of a three-dimensional imaging method in a single-station mode according to the prior art, and provides a conventional three-dimensional imaging algorithm.

In the embodiment of the present invention, the target position, the scanning aperture position, and the position of the first or second transceiver module, which is the transceiver position in the figure, present the geometric structure as shown in the figure, and the acquisition of the echo signal of the target position is completed by sequentially moving and detecting within the scanning aperture range.

The three-dimensional imaging algorithm of the GPU adopts a beam domain convolution three-dimensional imaging algorithm which is small in calculation amount and easy to realize in parallel, and firstly, three-dimensional imaging is carried out after sampled echo data needs to be compensated into sampled data in a single-station mode.

Defining three-dimensional imaging measurement System in Single-station mode As shown in FIG. 5, the scanning aperture of the radar transceiver is defined in the XYZ plane, and the position of the transceiver is defined as (x ', y', Z)₁) The coordinate of any point on the target located in the imaging area is defined as (x, y, Z), the reflection characteristic of the target is defined as f (x, y, Z), and the measurement plane is defined as Z ═ Z₁Then the target to radar transceiver phase is:

the transceiver measures the signal as:

where k ═ ω/c is defined as the wavenumber, the attenuation of the amplitude is negligible. The exponential term in the equation, expressed as a spherical wave, can be decomposed into the summation of infinite plane waves:

wherein k is_x'And k_y'The range of variation is represented by (-2k,2 k). As a result of this, the number of the,

2-dimensional fourier transforms are performed on both sides of the equation and the difference between the transceiver and the target coordinates is ignored:

by using

Thus, the

Wherein the content of the first and second substances,

in the practical application processThe data S (x, y, ω) is sampled uniformly in each direction. Because of the uniform sampling along the (x, y) direction, the 2-dimensional Fourier transform can obtain S (k)_x,k_yω) because the angular frequency ω is (k)_x,k_y,k_Z) Result in F (k)_x,k_y,k_Z) At k_ZThe directions are non-uniformly distributed. To perform a 3-dimensional Fourier transform, the data needs to be along k_ZAnd (5) direction interpolation processing.

For the 2D plane, the echo data of each frequency point is defined as s (n)_x,n_yω), wherein n is_x,n_yCorresponding to the phase center in the x, y plane. Zero filling is carried out on the phase center point which is missed in the plane, then multi-station-single-station phase calibration is carried out on the echo data, the reference point is defined as the center of the imaging area, and the calibrated data are as follows:

wherein R is_u(n_x,n_yω) echo signal defined as reference point

Wherein the content of the first and second substances,

in order to be able to transmit the unit position,

for receiving unit location, define R₀(n_x,n_yω) echo data for a sample position under single station conditions:

calibration data

After zero padding, constructTo 2^NThe data structure of (a), then, the imaging equation in the multi-station mode:

the three-dimensional imaging algorithm under the system comprises the following calculation processes: first, along the rectangular aperture direction, the radar transceiver acquires sampled data s (n)_x,n_yω); secondly, using formula 8, multi-station sampling to single-station sampling correction; thirdly, zero filling is carried out on the sampling missing position; fourth, the sampled data is Fourier transformed S (k) along the (x, y) direction_x,k_yω); fifth, multiplying by the phase factor, shifts the data to the correct depth position:

from uniformly sampled S (k)_x,k_yω) to a uniform sampling position (k)_x,k_y,k_z) (ii) a Sixth, three-dimensional inverse Fourier transform

The present invention may be imaged by using the three-dimensional imaging method according to the embodiment of the present invention, and may also be imaged by using other methods, which are not particularly limited herein.

The embodiment of the invention provides an existing three-dimensional imaging method, which adopts a beam domain convolution three-dimensional imaging algorithm, is small in calculation amount and easy to realize in parallel.

It is to be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

The above description is only an example of the present invention, and is not intended to limit the present invention. Various modifications and alterations to this invention will become apparent to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.