阅读说明：本技术 一种基于弧形阵列的毫米波成像系统 (Millimeter wave imaging system based on arc array ) 是由 李世超 于 2020-10-30 设计创作，主要内容包括：本发明公开了一种基于弧形阵列的毫米波成像系统,涉及毫米波成像技术领域。该方法的一具体实施方式包括毫米波收发机、主控器、弧线形收发天线阵列和运动平台。该实施方式弧线阵列在通道数较少、成本较低的情况下,通过一维运动,对目标物进行多个不同角度的三维立体成像；通过阵列形式创新实现腿部、肋部、胳膊等弧形部位的高质量成像,大大降低产品成本。(The invention discloses a millimeter wave imaging system based on an arc array, and relates to the technical field of millimeter wave imaging. One specific implementation mode of the method comprises a millimeter wave transceiver, a main controller, an arc-shaped transceiving antenna array and a motion platform. In the embodiment, under the conditions of less channels and lower cost, the arc array performs three-dimensional imaging of a plurality of different angles on the target object through one-dimensional motion; high-quality imaging of arc-shaped parts such as legs, ribs and arms is innovatively realized through an array form, and the product cost is greatly reduced.)

1. A millimeter wave imaging system based on an arc array comprises a millimeter wave transceiver, a main controller, an arc-shaped transceiving antenna array and a motion platform,

the millimeter wave transceiver is used for generating a millimeter wave signal based on the trigger signal sent by the main controller, transmitting the millimeter wave signal to the arc-shaped transceiving antenna array for processing, receiving and processing a millimeter wave echo signal transmitted by the arc-shaped transceiving antenna array, obtaining a digital intermediate frequency signal and transmitting the digital intermediate frequency signal to the main controller for processing;

the arc-shaped receiving and transmitting antenna array is used for processing the millimeter wave signals transmitted by the millimeter wave transceiver to obtain the millimeter wave echo signals; the antenna array comprises a transmitting antenna array and a receiving antenna array, wherein the transmitting antenna array comprises a transmitting antenna and an electronic switch, the receiving antenna array comprises a receiving antenna and an electronic switch, the number of the receiving antenna and the electronic switch is equal, and the arc length between the adjacent transmitting antenna/adjacent receiving antenna is less than one time of the wavelength of electromagnetic waves;

the main controller is used for controlling gating sequential logic of the electronic switch, controlling motion logic of the motion platform, issuing a trigger signal to the millimeter wave transceiver, and performing synthetic aperture radar signal processing on a digital intermediate frequency signal received from the millimeter wave transceiver to obtain a three-dimensional image;

the moving platform is used for bearing the millimeter wave transceiver, the main controller and the arc-shaped transceiving antenna array so as to enable the millimeter wave transceiver, the main controller and the arc-shaped transceiving antenna array to move up and down together to perform array sampling on a target object once based on a control instruction issued by the main controller.

2. The system of claim 1, wherein the arc length between adjacent transmitting antennas/adjacent receiving antennas is 0.5 to 1 times the wavelength of the electromagnetic wave.

3. The system of claim 2, wherein the arc length between adjacent transmitting antennas/adjacent receiving antennas is 0.9 times the wavelength of the electromagnetic wave.

4. The system of any one of claims 1-3, wherein the arc shape is one of a circular arc, an elliptical arc, or a hyperbolic arc.

5. The system of claim 4, wherein when an arc or an elliptical arc is used, the transmit antenna array and the receive antenna array are offset by half the arc length along an arc in a horizontal direction and less than 5 times the wavelength of the electromagnetic wave in a vertical direction.

6. The system of any of claims 1-3, wherein the transmitting antenna and the receiving antenna are one of a pyramidal horn antenna, a conical horn antenna, a dual mode horn antenna, a patch antenna, a microstrip array antenna.

7. The system of claim 1, wherein the millimeter wave transceiver comprises a millimeter wave transmitter and a millimeter wave receiver;

the generating millimeter wave signal and transmitting to the arc-shaped receiving and transmitting antenna array for processing, receiving and processing the millimeter wave echo signal transmitted by the arc-shaped receiving and transmitting antenna array, obtaining a digital intermediate frequency signal and transmitting to the main controller for processing, comprises:

the millimeter wave transmitter is used for generating millimeter wave signals and transmitting the millimeter wave signals to the transmitting antenna array, the millimeter wave signals are transmitted to a transmitting antenna through an electronic switch of the transmitting antenna array so as to be transmitted to a space, the millimeter wave signals are scattered and then received by the receiving antenna, and the millimeter wave signals are subjected to signal amplification processing through the receiving antenna array to obtain millimeter wave echo signals;

the millimeter wave receiver is used for receiving the millimeter wave echo signals transmitted by the receiving antenna array, converting the millimeter wave echo signals into intermediate frequency signals through down-conversion, sampling, filtering and digital IQ processing, obtaining the digital intermediate frequency signals and sending the digital intermediate frequency signals to the main controller for processing.

8. The system of claim 1, wherein the logic for controlling the motion of the motion platform and issuing a trigger signal to the millimeter wave transceiver comprises:

the main controller issues a control instruction to the motion platform to control the motion platform to start to move;

receiving a pulse signal transmitted by the motion platform in the motion process of the motion platform; wherein the pulse signal reflects the motion position of the arc-shaped transceiving antenna array;

and converting the pulse signals into position information, and performing array sampling once according to a preset distance.

9. The system of claim 8, further comprising:

the main controller sets an array sampling frequency threshold according to the preset distance and the imaging height; and

and when the sampling times reach the threshold value of the sampling times, issuing a control instruction to the motion platform to stop the motion platform.

10. The system of claim 1, wherein the gating timing logic that controls the electronic switch comprises:

in a gated timing logic, a transmit antenna corresponds to two adjacent receive antennas in two timing cycles, respectively.

Technical Field

The invention relates to the technical field of millimeter wave imaging, in particular to a millimeter wave imaging system based on an arc array.

Background

At present, millimeter wave imaging security inspection is provided for security inspection requirements under various scenes and complex environments. In the process of implementing the invention, the inventor finds that at least the following problems exist in the prior art: all the active millimeter wave security inspection systems adopt linear antenna arrays, and if the good imaging of arc-shaped parts such as legs, ribs, arms and the like of a human body is to be realized, the motion tracks of the linear antenna arrays need to be specially designed, such as circular scanning motion, but great difficulty is brought to the system structure, and the system volume cannot be miniaturized.

Disclosure of Invention

In view of this, embodiments of the present invention provide a millimeter wave imaging system based on an arc array, which can at least solve the problem that the conventional antenna array cannot be specially designed.

In order to achieve the above object, according to an aspect of the embodiments of the present invention, there is provided a millimeter wave imaging system based on an arc array, comprising a millimeter wave transceiver, a main controller, an arc transceiving antenna array and a motion platform, wherein,

the millimeter wave transceiver is used for generating a millimeter wave signal based on the trigger signal sent by the main controller, transmitting the millimeter wave signal to the arc-shaped transceiving antenna array for processing, receiving and processing a millimeter wave echo signal transmitted by the arc-shaped transceiving antenna array, obtaining a digital intermediate frequency signal and transmitting the digital intermediate frequency signal to the main controller for processing;

the arc-shaped receiving and transmitting antenna array is used for processing millimeter wave signals transmitted by the millimeter wave transceiver to obtain millimeter wave echo signals; the antenna array comprises a transmitting antenna array and a receiving antenna array, wherein the transmitting antenna array comprises transmitting antennas and electronic switches, the receiving antenna array comprises receiving antennas and electronic switches, the number of the receiving antennas is equal to that of the receiving antennas, and the arc length between the adjacent transmitting antennas/adjacent receiving antennas is less than one time of the wavelength of electromagnetic waves;

the main controller is used for controlling gating sequential logic of the electronic switch, controlling motion logic of the motion platform, issuing a trigger signal to the millimeter wave transceiver, and performing synthetic aperture radar signal processing on a digital intermediate frequency signal received from the millimeter wave transceiver to obtain a three-dimensional image;

the motion platform is used for bearing the millimeter wave transceiver, the main controller and the arc-shaped transceiving antenna array so as to enable the millimeter wave transceiver, the main controller and the arc-shaped transceiving antenna array to move up and down together to perform array sampling on a target object for one time based on a control instruction issued by the main controller.

Optionally, the arc length between the adjacent transmitting antennas/adjacent receiving antennas is 0.5-1 times of the wavelength of the electromagnetic wave.

Optionally, the arc length between adjacent transmitting antennas/adjacent receiving antennas is 0.9 times the wavelength of the electromagnetic wave.

Optionally, the arc line is one of an arc, an elliptic arc or a hyperbolic arc.

Optionally, when an arc or an elliptical arc is adopted, the transmitting antenna array and the receiving antenna array are staggered by half of the arc length along an arc in the horizontal direction, and the distance in the vertical direction is less than 5 times of the wavelength of the electromagnetic wave.

Optionally, the transmitting antenna and the receiving antenna are one of a pyramidal horn antenna, a conical horn antenna, a dual-mode horn antenna, a patch antenna, and a microstrip array antenna.

Optionally, the millimeter wave transceiver includes a millimeter wave transmitter and a millimeter wave receiver;

the generating millimeter wave signals and transmitting to the arc-shaped receiving and transmitting antenna array for processing, receiving and processing millimeter wave echo signals transmitted by the arc-shaped receiving and transmitting antenna array, obtaining digital intermediate frequency signals and transmitting to the main controller for processing, comprises:

the millimeter wave transmitter is used for generating millimeter wave signals and transmitting the millimeter wave signals to the transmitting antenna array, the millimeter wave signals are transmitted to a transmitting antenna through the electronic switch of the transmitting antenna array so as to be transmitted to a space, the millimeter wave signals are scattered and then received by the receiving antenna, and the millimeter wave signals are amplified through the electronic switch of the receiving antenna array to obtain millimeter wave echo signals;

the millimeter wave receiver is used for receiving the millimeter wave echo signals transmitted by the receiving antenna array, converting the millimeter wave echo signals into intermediate frequency signals through down-conversion, sampling, filtering and digital IQ processing, obtaining the digital intermediate frequency signals and sending the digital intermediate frequency signals to the main controller for processing.

Optionally, the controlling the motion logic of the motion platform and issuing a trigger signal to the millimeter wave transceiver includes:

the main controller issues a control instruction to the motion platform to control the motion platform to start to move;

receiving a pulse signal transmitted by the motion platform in the motion process of the motion platform; wherein the pulse signal reflects the motion position of the arc-shaped transceiving antenna array;

and converting the pulse signals into position information, and performing array sampling once according to a preset distance.

Optionally, the method further includes: the main controller sets an array sampling frequency threshold according to the preset distance and the imaging height; and when the sampling times reach the sampling times threshold value, issuing a control instruction to the motion platform to stop the motion of the motion platform.

Optionally, the gating timing logic for controlling the electronic switch includes: in a gated timing logic, a transmit antenna corresponds to two adjacent receive antennas in two timing cycles, respectively.

According to the scheme provided by the invention, one embodiment of the invention has the following advantages or beneficial effects: the working time sequences of different transmitting and receiving antenna units are controlled, and arc-shaped receiving and transmitting antenna arrays are matched to perform linear scanning movement in the vertical direction to form arc-shaped equivalent sampling points, so that two-dimensional scanning of a detection target is completed.

Further effects of the above-mentioned non-conventional alternatives will be described below in connection with specific embodiments.

Drawings

The drawings are included to provide a better understanding of the invention and are not to be construed as unduly limiting the invention. Wherein:

FIG. 1 is a schematic diagram of a main structure of a millimeter wave imaging system based on an arc array according to an embodiment of the present invention;

fig. 2 is a schematic diagram of a main structure of an arc-shaped transmit-receive antenna array according to an embodiment of the present invention;

fig. 3 is a schematic diagram of the main structure of another arc-shaped transceiver antenna array according to the embodiment of the present invention;

fig. 4 is a schematic circuit diagram of an arc-shaped transmit-receive antenna array according to an embodiment of the present invention.

Detailed Description

Exemplary embodiments of the present invention are described below with reference to the accompanying drawings, in which various details of embodiments of the invention are included to assist understanding, and which are to be considered exemplary only. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the invention. Also, descriptions of well-known functions and constructions are omitted in the following description for clarity and conciseness.

The terms "comprises" and "comprising," as well as any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, or system, article, or apparatus that comprises a list of steps or elements is not limited to the listed steps or modules, but may alternatively include additional steps or modules not listed or inherent to such process, method, article, or apparatus.

Referring to fig. 1, a schematic diagram of a main structure of a millimeter wave imaging system 100 based on an arc array according to an embodiment of the present invention is shown, and an operating frequency range of the millimeter wave imaging system is 20GHz to 40 GHz. By controlling the working time sequences of different transmitting and receiving antenna units and matching with the array to perform linear scanning motion in the vertical direction, an arc equivalent sampling point is formed, so that two-dimensional scanning of a detection target is completed, and the method can be applied to the fields of security inspection imaging, nondestructive testing, medical imaging and the like.

The millimeter wave imaging system 100 includes: the millimeter wave transceiver (including the millimeter wave transmitter 200 and the millimeter wave receiver 300), the master controller 400, the arc-shaped transceiver antenna array (including the transmitting antenna array 500 and the receiving antenna array 600), and the motion platform 700.

1. Millimeter wave transceiver

1) The millimeter wave transmitter 200 is used for generating millimeter wave signals and transmitting the millimeter wave signals to the transmitting antenna array through the electronic switch; scattered by the transmit antenna array 500 and transmitted to the receive antenna array 600 for processing; the receiving antenna array 600 processes the millimeter wave signal to obtain a millimeter wave echo signal, and transmits the millimeter wave echo signal to the millimeter wave receiver 300 through the electronic switch.

2) The millimeter wave receiver 300 down-converts the received millimeter wave signal into an intermediate frequency signal having a frequency range of DC to 300 MHz. The millimeter wave receiver 300 samples the intermediate frequency signal to obtain a digital intermediate frequency signal and transmits the digital intermediate frequency signal to the master controller 400.

2. And the main controller 400 issues trigger signals to the millimeter wave transmitter 200 and the millimeter wave receiver 300, controls gating sequential logic of the electronic switches, and controls the motion platform to move at a constant speed.

The main controller 400 sets the array sampling time to 500 times according to the preset distance (such as 4mm) and the imaging height 2m (such as the height of the assumed target object), and the control system performs the array sampling until all 500 times of sampling are completed. The main controller 400 performs synthetic aperture radar signal processing on the digital intermediate frequency signal received from the millimeter wave receiver 300 to obtain a three-dimensional image.

3. The transmitting antenna array 500 and the receiving antenna array 600 are vertically arranged, and the arc shape preferably adopts an arc shape, an elliptic arc shape or a hyperbolic arc shape;

1) the transmitting antenna array 500 includes N transmitting antennas and N electronic switches, and the transmitting antennas are uniformly arranged along an arc line, and the arc length between adjacent transmitting antennas is less than one time of the wavelength of the electromagnetic wave, and the value range is 0.5-1, and preferably 0.9 times of the wavelength of the electromagnetic wave is adopted.

2) The receiving antenna array 600 corresponds to the transmitting antenna array 500 and includes N receiving antennas and N electronic switches, and the receiving antennas are uniformly arranged along an arc, the arc length between adjacent receiving antennas is less than one time of the wavelength of the electromagnetic wave, the value range is 0.5-1, and preferably 0.9 times of the wavelength of the electromagnetic wave is adopted.

Referring to fig. 2, the transmitting antenna array 500 and the receiving antenna array 600 are circular arc shaped with a radius of 60cm and a center angle of 90 ° corresponding to an arc length of 98 cm. The arc-shaped transmitting antenna array 500 comprises 96 transmitting antennas T0, T1 and T2 … … T95, and the arc-shaped receiving antenna array 600 comprises 96 receiving antennas R0, R1 and R2 … … R95. The electronic switches 501 and 601 are respectively connected with 96 transmitting antennas and 96 receiving antennas, and control the working state of each transmitting antenna and each receiving antenna.

The distance between the transmitting antenna array 500 and the receiving antenna array 600 in the vertical direction is less than 5 times of the wavelength of the electromagnetic wave, and the distance in the horizontal direction is staggered by D/2 along an arc line (D is the arc length between the adjacent transmitting antenna/receiving antenna). As shown in fig. 2, 96 transmitting antennas/receiving antennas are uniformly arranged along an arc, the arc length between adjacent transmitting antennas/receiving antennas is 10mm, and the transmitting antenna array 500 and the receiving antenna array 600 are staggered by 4mm along the arc in the horizontal direction and are spaced by 10mm in the vertical direction. The transmitting antenna and the receiving antenna both adopt pyramid horn antennas, and in actual operation, one of the pyramid horn antennas, dual-mode horn antennas, patch antennas and microstrip array antennas can be adopted.

Referring to fig. 3, the transmit antenna array 500 and the receive antenna array 600 are circular ellipses. The major axis of the elliptical arc is 200mm, the minor axis is 90mm, 96 transmitting antennas are uniformly arranged along the elliptical arc, the arc length between adjacent transmitting antennas is 10mm, the elliptical arc of 96 receiving antennas is uniformly arranged, and the arc length between adjacent transmitting antennas is 10 mm. The transmit antenna array 500 and the receive antenna array 600 are horizontally offset by 4mm along the elliptical arc and vertically spaced by 10 mm.

4. The moving platform 700 is used for carrying the millimeter wave transceiver, the main controller 400, the transmitting antenna array 500 and the receiving antenna array 600, so that the millimeter wave transceiver, the main controller 400, the transmitting antenna array 500 and the receiving antenna array 600 move up and down together.

The motion platform 700 controls the motion platform to move at a constant speed of 1m/s through a peripheral circuit, the motion platform 700 sends pulse signals to the main controller 400, the main controller 400 reversely deduces the motion distance according to the number of the pulse signals, and array sampling is performed once at intervals of 4 mm. Referring to fig. 3, the main controller 400 sets the number of array sampling times to 500 times according to a preset distance (e.g. 4mm) and an imaging height 2m (assuming the height of the target object), and the control system performs array sampling until all 500 times of sampling are completed, and then sends the array sampling times to the main controller 400 for data processing imaging.

In actual operation, the master controller 400 sends a control command to the motion platform 700 to control the motion platform 700 to start moving; in the process of moving the motion platform 700, receiving a pulse signal transmitted by the motion platform 700, converting the pulse signal into position information, and performing array sampling once according to a preset distance (such as 4 mm); wherein, the pulse signal corresponds to the motion position of the arc-shaped receiving and transmitting antenna array;

the flow operation performed by the system in one array sampling is specifically described here (one trigger of 4mm, each time including 2N-1 timing cycles), and one array sampling includes the following 4 small steps (the number of transmitting antennas and receiving antennas is set to be N):

a: after each time sequence period Pm (m is less than or equal to 2N-1) is started, the main controller 400 controls the electronic switches 501 and 601 to turn on the specific transmitting antenna Ti (i is less than or equal to 95) and the specific receiving antenna Rj (j is less than or equal to 95) according to the preset switch switching logic 1;

b: the master 400 transmits a trigger signal to the millimeter wave transmitter 200 and the millimeter wave receiver 300. The millimeter wave transmitter 200 generates a millimeter wave signal, transmits the millimeter wave signal to the transmitting antenna Ti turned on in the step A, and the millimeter wave signal is radiated by the ith transmitting antenna Ti (i is less than or equal to 95);

c: processing the signal scattered by the transmitting antenna Ti by the jth receiving antenna Rj (j is less than or equal to 95), processing to obtain a millimeter wave echo signal and transmitting the millimeter wave echo signal to the millimeter wave receiver 300; the millimeter wave receiver 300 down-converts the received millimeter wave echo signal into an intermediate frequency signal with a carrier frequency of 100MHz, and performs sampling, filtering and digital IQ processing on the intermediate frequency signal to obtain a digital intermediate frequency signal and store the digital intermediate frequency signal (see fig. 4 for the whole, which is only an example);

d: and repeating the steps A to C according to the switch switching logic table 1 in the next time sequence period until all the switch switching logics are completed, namely completing one-time array sampling.

TABLE 1 switch switching logic table

As shown in table 1, the electronic switches 501 and 601 control the operation of the transmitting antenna T0 and the receiving antenna R0 respectively in the first timing cycle. Therefore, in the gating timing logic, one transmitting antenna corresponds to two adjacent receiving antennas in two timing periods, so that the number of the timing periods is 2 × 96-1 ═ 191.

According to the system provided by the embodiment of the invention, under the conditions of less channels and lower cost, the arc array performs three-dimensional imaging of a plurality of different angles on the target object through one-dimensional motion; high-quality imaging of arc-shaped parts such as legs, ribs and arms is innovatively realized through an array form, and the product cost is greatly reduced.

The above-described embodiments should not be construed as limiting the scope of the invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations, and substitutions may occur depending on design requirements and other factors. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.