CN209296949U - Millimeter wave/terahertz wave imaging equipment - Google Patents

Abstract

Disclosed is a millimeter-wave/terahertz-wave imaging device, comprising a quasi-optical assembly, including a polygonal rotating mirror and a third reflecting plate, the polygonal rotating mirror can rotate around its rotation axis, so that multiple reflecting plates on the polyhedral rotating mirror take turns It is used as the first reflector to receive and reflect the millimeter wave/terahertz wave beam from the first object to be inspected; another reflector adjacent to the first reflector among the plurality of reflectors is used as the second reflector to receive and reflect Reflecting the millimeter wave/terahertz wave beam from the second object to be inspected; the chopper is configured so that only the beam from the second reflector reflected by the first reflector or the third reflector is incident on the detector at any moment array, the chopper is rotated about its central axis so that the beams from the first reflector and the third reflector are alternately received by the detector array. The device can simultaneously image two inspected objects, and has high detection efficiency and high detector utilization.

Description

Millimeter wave/terahertz wave imaging equipment

technical field

The present disclosure relates to the field of imaging technology, in particular to a millimeter wave/terahertz wave imaging device.

Background technique

Under the current increasingly severe anti-terrorism situation at home and abroad, terrorists use hidden methods to carry dangerous items such as knives, guns, and explosives with them, posing a serious threat to public safety. The human body security inspection technology based on passive millimeter wave/terahertz wave has unique advantages. It realizes imaging by detecting the millimeter wave/terahertz wave radiation of the target itself, without active radiation, and performs security inspection on the human body. Penetration capability enables detection of hidden dangers. However, existing millimeter-wave/terahertz-wave imaging devices work inefficiently.

Utility model content

The purpose of the present disclosure is to solve at least one aspect of the above-mentioned problems and disadvantages existing in the prior art.

According to an embodiment of the present disclosure, there is provided a millimeter-wave/terahertz-wave imaging device including a quasi-optical component, a millimeter-wave/terahertz-wave detector array, and a chopper,

The quasi-optical components include:

A polyhedron rotating mirror, each side of the polyhedron rotating mirror is provided with a reflection plate respectively, and the polyhedron rotating mirror can rotate around its rotation axis, so that a plurality of reflection plates are used as the first reflection plate in turn to receive and reflect the first Part of the spontaneously radiated or reflected millimeter-wave/terahertz wave beams of the object located at different positions in the first field of view; another reflector adjacent to the first reflector among the plurality of reflectors is used as The second reflecting plate is used to receive and reflect the part of the spontaneous radiation or the reflected millimeter wave/terahertz wave beam of the second object at different positions in the second field of view; and

a third reflector adapted to reflect millimeter//terahertz waves from said second reflector onto said chopper;

The chopper is located on the reflected wave path of the first reflector and the reflected wave path of the third reflector, and the chopper is configured to only transmit millimeter waves/waves from the first reflector at any time. The terahertz wave or only the millimeter wave/terahertz wave from the third reflection plate is reflected or transmitted to the millimeter wave/terahertz wave detector array, and the chopper rotates around its central axis to make the The millimeter wave/terahertz wave of the first reflector and the third reflector are alternately received by the millimeter wave/terahertz wave detector array; and

The millimeter-wave/terahertz-wave detector array is adapted to receive beams from the quasi-optical component.

In some embodiments, the quasi-optical assembly further includes a focusing lens located between the chopper and the millimeter-wave/terahertz-wave detector array.

In some embodiments, the quasi-optical assembly further includes a first focusing lens and a second focusing lens, the first focusing lens is located between the first reflecting plate and the chopper, and the second focusing lens A lens is located between the second reflective plate and the third reflective plate.

In some embodiments, the millimeter wave/terahertz wave imaging device further includes a wave-absorbing material adapted to absorb the millimeter wave/terahertz wave reflected from the first reflecting plate via the chopper wave, and the millimeter wave/terahertz wave from the third reflection plate transmitted through the chopper.

In some embodiments, the number of the reflecting plates of the polygonal rotating mirror is m, where 6≥m≥3.

In some embodiments, the m reflection plates are all parallel to the rotation axis.

In some embodiments, the angles between the m reflection plates and the rotation axis increase or decrease along the rotation direction of the polygon mirror.

In some embodiments, the chopper includes at least one blade.

In some embodiments, a plurality of said blades are equally spaced around said central axis.

In some embodiments, the millimeter wave/terahertz wave imaging device further includes a housing, the quasi-optical assembly and the millimeter wave/terahertz wave detector array are located in the housing, and the opposite sides of the housing are A first window through which the beam from the first inspected object passes and a second window through which the beam from the second inspected object passes are respectively arranged on the wall.

In some embodiments, the millimeter wave/terahertz wave imaging device further includes a first driving device adapted to drive the rotation of the polygon mirror.

In some embodiments, the millimeter wave/terahertz wave imaging device further includes a second driving device adapted to drive the chopper to rotate.

In some embodiments, the millimeter wave/terahertz wave imaging device also includes:

a data processing device, the data processing device is connected to the millimeter wave/terahertz wave detector array to respectively receive the image data and generating millimeter wave/terahertz wave images respectively for the image data of the second inspected object; and

A display device, the display device is connected to the data processing device, and is used to receive and display the millimeter wave/terahertz wave image from the data processing device.

In some embodiments, the millimeter wave/terahertz wave imaging device further includes an alarm device connected to the data processing device so that when the data processing device recognizes the millimeter wave/terahertz wave When there are suspicious items in the image, an alarm is issued indicating that there are suspicious items in the millimeter wave/terahertz wave image.

In some embodiments, the millimeter-wave/terahertz-wave imaging device further includes a calibration source, the calibration source is located on the object plane of the quasi-optical component, and the data processing device receives data from the millimeter-wave/terahertz-wave Calibration data of the detector array for the calibration source, and updating the image data of the first inspected object and the image data of the second inspected object based on the calibration data.

In some embodiments, the millimeter wave/terahertz wave imaging device further includes an optical imaging device, the optical imaging device includes a first optical imaging device adapted to acquire an optical image of the first object to be inspected and a first optical imaging device adapted to acquire The second optical camera device for the optical image of the second object under inspection, the first optical camera device and the second optical camera device are respectively connected to the display device.

In some embodiments, the display device includes a display screen, and the display screen includes a first display area suitable for displaying the millimeter wave/terahertz wave image and a first display area suitable for displaying the optical image collected by the optical camera device. of the second display area.

According to the millimeter-wave/terahertz-wave imaging device described in the above-mentioned various embodiments of the present disclosure, by driving the polygon mirror to rotate around the rotation axis, a plurality of reflectors are used as the first reflector in turn to receive and reflect the first Part of the spontaneously radiated or reflected millimeter-wave/terahertz wave beams of the object located at different positions in the first field of view; another reflector adjacent to the first reflector among the plurality of reflectors is used as the second reflector Two reflecting plates are used to receive and reflect part of the spontaneous radiation or reflected millimeter-wave/terahertz wave beams of the second object located at different positions in the second field of view, so as to realize imaging of the two objects to be inspected, thereby improving detection High efficiency, high detector utilization, simple control and low cost.

Description of drawings

FIG. 1 is a schematic structural diagram of a millimeter wave/terahertz wave imaging device according to an embodiment of the present disclosure;

FIG. 2 is a schematic structural diagram of a millimeter-wave/terahertz-wave imaging device according to another embodiment of the present disclosure after removing the casing;

3 is a front view of a polygon mirror of a millimeter wave/terahertz wave imaging device according to an exemplary embodiment of the present disclosure;

Fig. 4 is the side view of the polyhedron rotating mirror shown in Fig. 3;

5 is a schematic structural diagram of an exemplary embodiment of a chopper of a millimeter-wave/terahertz-wave imaging device according to the present disclosure;

6 is a schematic structural diagram of another exemplary embodiment of a chopper of a millimeter-wave/terahertz-wave imaging device according to the present disclosure;

FIG. 7 is a schematic structural diagram of yet another exemplary embodiment of a chopper of a millimeter-wave/terahertz-wave imaging device according to the present disclosure;

8 is a schematic structural diagram of another exemplary embodiment of a chopper of a millimeter wave/terahertz wave imaging device according to the present disclosure;

Fig. 9 is a schematic diagram of lens imaging; and

10 is a schematic diagram of the angle between each reflector and the rotation axis of a polyhedral rotating mirror according to another embodiment of the present disclosure;

11 is a schematic diagram of the total pixels of the millimeter wave/terahertz wave imaging device, the scanning pixels of each reflector and the sparsely arranged millimeter wave/terahertz wave detector array according to an embodiment of the present disclosure;

FIG. 12 is a flowchart of a method for inspecting a human body or an object by a millimeter-wave/terahertz-wave imaging device according to an embodiment of the present disclosure; and

Fig. 13 is an application scene diagram of a millimeter wave/terahertz wave imaging device according to an embodiment of the present disclosure.

Detailed ways

Although the present disclosure will be fully described with reference to the accompanying drawings containing preferred embodiments of the present disclosure, it should be understood before proceeding that those skilled in the art can modify the disclosure described herein while obtaining the technical effects of the present disclosure. Therefore, it should be understood that the above description is a broad disclosure for those of ordinary skill in the art, and its content is not intended to limit the exemplary embodiments described in the present disclosure.

In addition, in the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a comprehensive understanding of the embodiments of the present disclosure. It may be evident, however, that one or more embodiments may be practiced without these specific details. In other instances, well-known structures and devices are shown in diagrammatic form to simplify the drawings.

FIG. 1 schematically shows a millimeter-wave/terahertz-wave imaging device 100 according to an exemplary embodiment of the present disclosure. As shown in the figure, the millimeter-wave/terahertz-wave imaging device 100 includes a quasi-optical component, a chopper 8, and a millimeter-wave/terahertz-wave detector array 2. The quasi-optical component includes a polygonal rotating mirror 1. Reflecting plates 1A, 1B, 1C, and 1D are respectively provided on each side, and the polygon mirror 1 can rotate around its rotation axis o, so that multiple reflecting plates 1A, 1B, 1C, and 1D are used in turn as the first reflecting plate to receive And reflect the part of the spontaneous radiation or the reflected millimeter wave/terahertz wave of the first object 31A located at different positions in the first field of view 3A; at the same time, the first reflecting plate among the multiple reflecting plates 1A, 1B, 1C, and 1D Another adjacent reflecting plate is used as a second reflecting plate to receive and reflect part of the spontaneous radiation or reflected millimeter-wave/terahertz wave beams of the second object 31B located at different positions in the second field of view 3B; the quasi-optical The assembly also includes a third reflector 7 adapted to reflect the beam reflected by the second reflector onto the chopper 8 . The quasi-optical element also includes a first focusing lens 4A and a second focusing lens 4B, the first focusing lens 4A is suitable for converging the beam from the first reflecting plate 1A, and the second focusing lens 4B is suitable for converging the beam from the second reflecting plate 1B beam. The chopper 8 is located on the reflection wave path of the first reflection plate and the reflection wave path of the third reflection plate 7, and is configured so that only the millimeter wave/terahertz wave from the first reflection plate or only from the third reflection plate at any moment The millimeter wave/terahertz wave of 7 is reflected or transmitted to the millimeter wave/terahertz wave detector array 2, and the chopper 8 can rotate around its central axis 81 to make the millimeter wave from the first reflecting plate and the third reflecting plate 7 The /terahertz waves are alternately received by the millimeter wave/terahertz wave detector array 2 . The millimeter-wave/terahertz-wave detector array 2 is suitable for receiving reflected and converged beams from quasi-optical components; the number of detectors in the millimeter-wave/terahertz-wave detector array 2 depends on the required field of view 3A, 3B The size and the required resolution are determined, and its arrangement direction is perpendicular to the normal of the field of view and parallel to the horizontal plane. The size of the detector is determined according to the wavelength, processing technology and required sampling density.

According to the millimeter-wave/terahertz-wave imaging device according to the embodiment of the present disclosure, the polyhedral rotating mirror 1 is driven to rotate around its rotation axis o so that a plurality of reflecting plates 1A, 1B, 1C, and 1D are used as the first reflecting plate in turn. receiving and reflecting the part of the spontaneously radiated or reflected millimeter wave/terahertz wave beams of the first object 31A located at different positions in the first field of view 3A; Another reflector adjacent to the first reflector is used as a second reflector to receive and reflect part of the spontaneous radiation or reflected millimeter wave/terahertz wave of the second object 31B located at different positions in the second field of view 3B. The beam, during the rotation of the polygon mirror 1, switches the millimeter wave/terahertz wave from the first field of view 3A and the second field of view 3B alternately to the same millimeter wave/terahertz wave detection through the chopper 8 Detector array 2, so as to realize imaging of two objects 31A, 31B located in two fields of view 3A, 3B, while reducing the number of millimeter wave/terahertz wave detectors, so as to reduce equipment cost and occupy an area Small space.

In this embodiment, the focusing lens 4 includes a first focusing lens 4A and a second focusing lens 4B, the first focusing lens 4A is located between the first reflecting plate and the chopper 8, and the second focusing lens 4B is located between the second reflecting plate Between the third reflecting plate 7 and the focal lengths of the two focusing lenses 4A and 4B are f1 and f2 respectively, where the sizes of f1 and f2 may be the same or different. Since the chopper 8 is placed in the wave path focused by the focusing lenses 4A, 4B, the size of the blade 82 of the chopper 8 can be relatively small. In this case, the specific size of the blade 82 of the chopper 8 is given by After being focused by the focusing lenses 4A and 4B, the size of the beam spot at the place where the chopper 8 is pre-placed is determined. Assuming that the beam spot radius at the place where the chopper 8 is pre-placed after being focused by the focusing lenses 4A and 4B is W _cut , the size (area) of the blade 82 of the chopper 8 is selected as

It should be noted that those skilled in the art should understand that in some other embodiments of the present disclosure, as shown in FIG. Between 2 terahertz wave detector arrays. In this case, since the chopper 8 is placed in the unfocused wave path, the size of its blades 82 should match the reflective surface of the polygon mirror.

In the exemplary implementation shown in FIG. 1 and FIG. 2, the millimeter wave/terahertz wave imaging device further includes a wave-absorbing material 9, which is suitable for absorbing millimeter wave/terahertz wave, and the millimeter wave/terahertz wave from the third reflector 7 transmitted through the chopper 8.

In the exemplary embodiment shown in Fig. 1 and Fig. 2, each reflecting plate 1A, 1B, 1C, 1D is rectangular, and its length and width should match the corresponding focusing lens 4A, 4B, usually, each The width of each reflection plate 1A, 1B, 1C, 1D is greater than or equal to the diameter of the corresponding focusing lens 4A, 4B, and the length of each reflection plate 1A, 1B, 1C, 1D should be its width times, the diameter of the focusing lenses 4A, 4B can be, for example, 3cm-50cm.

As shown in FIG. 1 , in an exemplary embodiment, the millimeter wave/terahertz wave imaging device further includes a casing 6, and the quasi-optical components and the millimeter wave/terahertz wave detector array 2 are located in the casing 6, On the opposite side walls of the casing 6 are respectively provided with a first window 61A through which the millimeter wave/terahertz wave spontaneously radiated by the first subject 31A passes through and a millimeter wave/terahertz wave through which the second subject 31B spontaneously radiates. The wave passes through the second window 61B.

As shown in Fig. 3 and Fig. 4, in an exemplary embodiment, the polyhedron lens 1 further includes a rotating shaft 11, and the two ends of the rotating shaft 11 are rotatably connected with the housing 6 via bearings 10A, 10B, so that the polyhedron rotating mirror 1 can be rotated, so that the first reflecting plate and the second reflecting plate respectively reflect the beams from the parts of the inspected objects 31A, 31B located at different vertical positions in the field of view 3A, 3B.

As shown in FIG. 3 and FIG. 4 , in an exemplary embodiment, the millimeter wave/terahertz wave imaging device further includes a first driving device 13 suitable for driving the rotation shaft 11 , such as a servo motor.

As shown in Figures 3 and 4, in an exemplary embodiment, the millimeter wave/terahertz wave imaging device also includes an angular displacement measuring mechanism 12 for real-time detection of the angular displacement of the polygon mirror 1, such as a photoelectric code disc, In order to accurately calculate the attitude of the polyhedral rotating mirror 1, this can considerably reduce the difficulty of developing control algorithms and imaging algorithms.

Fig. 5 to Fig. 8 respectively show the structural diagrams of several kinds of choppers, chopper 8 comprises at least one blade, for example 1, 2, 3 and 4 etc., a plurality of blades 82 are equally spaced around the center Axis 81 is provided. During the rotation of the chopper 8 around its central axis 81, at any moment when the millimeter wave/terahertz wave from the first reflection plate is incident on the blade 82 of the chopper 8, the blade 82 will come from the first reflected The millimeter wave/terahertz wave of the plate is reflected to the wave absorbing material 9 to be absorbed by the wave absorbing material 9, and at the same time, the millimeter wave/terahertz wave from the third reflecting plate 7 is reflected to the millimeter wave/terahertz wave detector array 2 . As the chopper 8 rotates around its central axis 81, at the next moment, the millimeter wave/terahertz wave from the first reflecting plate is incident on the part of the chopper 8 that is not provided with the blade 82 (ie, the empty part), To transmit to the millimeter wave/terahertz wave detector array 2, the part of the chopper 8 that is not provided with the blade 82 transmits the millimeter wave/terahertz wave from the third reflector 7 to the wave-absorbing material 9, so that the The wave-absorbing material 9 absorbs and circulates successively.

It should be noted that the chopper 8 can also be replaced by other devices capable of quickly switching between high reflection and high transmission states.

In the exemplary embodiment shown in FIG. 1 and FIG. 2 , the chopper 8 is placed at an angle of 45 degrees to both the wave path from the first reflection plate and the wave path from the third reflection plate 7 . It should be noted that those skilled in the art should understand that in some other embodiments of the present disclosure, the chopper 8 and the wave path from the first reflector and the wave path from the third reflector 7 can also be placed at other angles .

In an exemplary embodiment not shown, the millimeter wave/terahertz wave imaging device 100 further includes a second driving device suitable for driving the chopper 8 to rotate, such as a servo motor, so as to drive the chopper 8 to rotate Its central axis 81 rotates at a high speed, and the rotation period of the chopper 8 should match the scanning period of the polygon mirror 1, so that the millimeter wave/terahertz wave imaging device 100 can simultaneously detect the two fields of view 3A, 3B. The two inspected objects are respectively imaged, and the rotation period of the chopper 8 is preferably 1/1000-1/2 of the scanning period of the polygon mirror.

In this embodiment, the static field of view of the detector is the horizontal field of view, assuming that the number of detectors is N, and when the distance between the centers of two adjacent detectors is d, the maximum offset distance of the detector is y _m , but

From this, the static field of view of the millimeter wave/terahertz wave detector array 2 can be calculated as H ₀ . As shown in Figure 9, the static field of view H ₀ , the object distance L ₁ , and the image distance L _{2 of the millimeter wave/terahertz wave detector array 2} need to satisfy the following relationship

The polyhedral rotating mirror 1 rotates around its rotation axis o, and the angle of data acquisition is determined according to the field of view range in the height direction of the object 31 to be scanned. It is assumed that the angle and orientation of the imaging field of view required in the height direction is θ _m , then the corresponding scanning field angle is θ _rot =θ _m /2.

The number of swings _Nv required for the first reflector 1A (second reflector 1B) to complete the reflection of the vertical range of the field of view where the corresponding object 31A (31B) is located is calculated by the following formula:

In the formula, [] represents rounding up;

L is the distance from the center of the field of view 3A (3B) to the center of the first reflector 1A (second reflector 1B);

δ represents the object space resolution;

θ _m is the field of view angle corresponding to the vertical field of view range.

The polygonal rotating mirror 1 rotates in one cycle to collect m images for each field of view, where m is the number of reflecting plates of the polygonal rotating mirror.

The sampling density in the height direction is determined by the dwell time of the beam. The polyhedral rotating mirror 1 rotates for one cycle and outputs m images in each of the two viewing field directions. Assuming that the angular resolution of the detector is θ _res , the number of 3dB beams contained in the rotation θ _rot of the polyhedral rotating mirror 1 is n=360°/θ _res (4)

Assuming that the imaging rate requirement is mHz, the average dwell time τ _d of each sampling beam in the height direction is

Taking the imaging distance from the system at 3000mm, the angular resolution θ _res = 0.57°, the object space resolution is δ = 30mm, and the imaging rate is 10Hz as an example, the number of acquisition steps in the height direction can be obtained to be about 67, and the average The dwell time is τd = 100ms/67 = _1.47ms .

In an exemplary embodiment, the millimeter-wave/terahertz-wave imaging device 100 operating at a center frequency of 94 GHz has N=30 detectors arranged in a row, and the distance between the centers of the detectors is d=7 mm. Array length 2y _m = 21 cm. The object distance L ₁ =3.5m, the image distance L ₂ =0.7m, and the static field of view H ₀ =105cm can be calculated according to formula (2). Assuming that the size of the imaging area in the height direction is 1.8 m, then the scanning angle in the height direction used to reconstruct the image is θ _m =34°.

In another exemplary embodiment, the millimeter-wave/terahertz-wave imaging device 100 working at a center frequency of 220 GHz has N=48 detectors arranged in a row, and the distance between the centers of the detectors is d=3 mm. Array length 2y _m = 14.4 cm. Object distance L ₁ =5m, image distance L ₂ =0.7m, according to formula (2), the static field of view H ₀ =103cm can be calculated. Assuming that the size of the imaging area in the height direction is 1.8 m, then the scanning angle in the height direction used to reconstruct the image is θ _m =20°.

In the exemplary embodiment shown in FIGS. 1 to 3 , the polygonal rotating mirror 1 includes four reflecting plates 1A, 1B, 1C, and 1D, and the four reflecting plates are all parallel to the rotation axis o. It should be noted that those skilled in the art should understand that in some other embodiments of the present disclosure, the polygonal rotating mirror 1 may also include other numbers of reflecting plates, preferably the number m of reflecting plates is 3 to 6. In addition, in some embodiments, the angles between the m reflecting plates and the rotation axis o can be increased or decreased in increments of α along the rotation direction of the polygonal mirror 1 to realize the pixel difference, so that mm The detectors of the wave/terahertz wave detector array 2 are sparsely distributed (as shown in FIG. 11 ), thereby reducing the number of detectors.

where α is calculated by the following equation:

In the formula, λ is the wavelength of millimeter wave/terahertz wave,

D is the diameter of the equivalent lens 9 of the ellipsoid reflector.

It should be noted that the above formula is only a formula for estimating angular resolution under ideal lens gathering. In the actual system, the size of α should be fine-tuned according to the experimental results, so that the final pixel arrangement is as uniform as possible without overlapping and gaps. That is to say, the angles between the reflection plates 1A, 1B, 1C, 1D on the polygonal rotating mirror 1 and the rotation axis o can be finely adjusted.

As shown in FIG. 10 , in an exemplary embodiment, the angles between the four reflecting plates 1A, 1B, 1C, 1D and the rotation axis o increase gradually along the rotation direction of the polygon mirror 1 . The angle θ between the first reflector 1A and the rotation axis o is The angle between the second reflector and the rotation axis o is The angle θ between the third reflecting plate 1C and the rotation axis o is The angle θ between the fourth reflector 1D and the rotation axis o is It should be noted that those skilled in the art should understand that in some other embodiments of the present disclosure, the angle θ between the four reflecting plates 1A, 1B, 1C, 1D and the rotation axis o can also be rotated along the polyhedron. The rotation direction of mirror 1 is decreasing.

In some embodiments, when m is an odd number, the angle θ between the first reflector and the rotation axis o of the m reflectors along the rotation direction of the polyhedral rotating mirror 1 is 0°, and the first The angle θ between a reflector and the rotation axis o is No. The angle θ between a reflector and the rotation axis o is For example, when m is 3, the angle θ between the first reflector 1A and the rotation axis o is 0°, the angle θ between the second reflector 1B and the rotation axis o is +α, and the third reflection The angle θ between the plate 1C and the axis of rotation o is -α.

In some embodiments, when m is an even number, the angle θ between the first reflector in the rotation direction and the rotation axis o among the m reflectors is No. The angle θ between a reflector and the rotation axis o is No. The angle θ between a reflector and the rotation axis o is

In an exemplary embodiment, the millimeter wave/terahertz wave imaging device 100 further includes a data processing device (not shown). The data processing device is wirelessly or wiredly connected to the millimeter-wave/terahertz-wave detector array 2 to receive data about the first object 31A and about the second object received by the millimeter-wave/terahertz-wave detector array 2 respectively. 31B of image data.

In an exemplary embodiment, the imaging device may further include a display device connected to the data processing device for receiving and displaying the millimeter wave/terahertz wave image from the data processing device.

As shown in FIG. 1, in an exemplary embodiment, the millimeter wave/terahertz wave imaging device 100 further includes a calibration source 5, the calibration source 5 is located in the housing 6 and on the object plane of the quasi-optical assembly, To receive the calibration data about the calibration source 5 through the millimeter wave/terahertz wave detector array 2, the data processing device receives the calibration data about the calibration source 5 received by the millimeter wave/terahertz wave detector array 2, and based on the calibration data The image data of the first inspected object 31A and the second inspected object 31B are updated in real time. Since the calibration source 5 is packaged inside the housing 1 , the millimeter wave/terahertz wave imaging device 100 is more stable and reliable than using remote air for calibration.

In this embodiment, the calibration source 5 is located obliquely above the polygonal rotating mirror 1. It should be noted that the position of the calibration source 5 only needs to make the millimeter wave/terahertz wave detector array 2 receive the calibration data about the calibration source 5 and be The image data of the inspection objects 31A and 31B need not interfere with each other, and the beam radiated by the calibration source 5 is reflected to the millimeter-wave/terahertz-wave detector array 2 through the reflector, so that complete reception of the focusing lens 4 and the detector can be realized. The calibration of the channel further ensures the consistency of the channel.

In the exemplary embodiment shown in FIG. 1 and FIG. 2 , the rotating shaft 11 of the polygonal rotating mirror 1 is arranged horizontally, so that the first reflector and the second reflector are located in different fields of view from the corresponding inspected objects 31A and 31B. The part of the beam in the vertical position is reflected. It should be noted that those skilled in the art should understand that in some other embodiments of the present disclosure, the rotating shaft 11 of the polygonal rotating mirror 1 can also be vertically arranged, so that the first reflector and the second reflector pair come from the corresponding The beams of the parts of the inspected objects 31A and 31B located at different horizontal positions in the field of view are reflected. In addition, the calibration source 5 can be a wave-absorbing material with an emissivity close to 1, such as plastic or foam, or a black body or a semiconductor refrigerator can be used.

According to the Nyquist sampling law, there are at least two sampling points within a half-power beamwidth to fully restore the image. The arrangement direction of the millimeter wave/terahertz wave detector array 2 in this embodiment is perpendicular to the field of view normal and parallel to the horizontal plane, so as to sample the field of view in the height direction, and the millimeter wave/terahertz wave detector array 2 The arrangement density of determines the sampling density. The image formed by the millimeter-wave imaging system is actually a grayscale image. When the spatial sampling rate does not meet the Nyquist sampling requirement (undersampling), the target scene can still be imaged, but the imaging effect is relatively poor. In order to compensate for the lack of pixels caused by undersampling, an interpolation algorithm can be used to increase the data density in the later signal processing.

As shown in Figure 1, in an exemplary embodiment, the length direction of the calibration source 5 is parallel to the rotation axis 11 of the polygon mirror 1, and the length of the calibration source 5 is greater than or equal to that of the millimeter wave/terahertz wave detector array 2 in parallel For the size of the field of view in the direction of the rotating axis 11 , the width of the calibration source 5 is 10 times the width of the antenna beam of the millimeter wave/terahertz wave detector 2 . However, it should be noted that those skilled in the art should understand that the width of the calibration source 5 may also be 1 or 2 times or other multiples of the antenna beam width of the millimeter wave/terahertz wave detector.

In one embodiment, the millimeter wave/terahertz wave imaging device 100 further includes an optical imaging device, the optical imaging device includes a first optical imaging device adapted to acquire an optical image of the first object 31A to be inspected and a first optical imaging device adapted to acquire The second optical imaging device of the optical image of the second inspected object 31B, the optical imaging device is connected with the display device, the optical imaging device can realize visible light real-time imaging, and presents the first inspected object 31A and the second inspected object 31B Image information for comparison with millimeter-wave/terahertz-wave images for user reference.

In an exemplary embodiment not shown, the display device includes a display screen including a first display suitable for displaying millimeter-wave/terahertz-wave images of the first inspected object 31A and the second inspected object 31B. area and a second display area suitable for displaying the optical images of the first inspected object 31A and the second inspected object 31B collected by the optical imaging device, so that the user can combine the optical images collected by the optical imaging device with the millimeter wave/ Terahertz wave images for comparison.

In an exemplary embodiment not shown, the millimeter wave/terahertz wave imaging device 100 further includes an alarm device connected to the data processing device so that when the first object 31A and/or or suspicious items in the millimeter-wave/terahertz-wave image of the second inspected object 31B, for example, an alarm is issued below the millimeter-wave/terahertz-wave image corresponding to the corresponding inspected object. Yes, the alarm method of sound prompt can also be adopted.

In an exemplary embodiment, the data processing device can be used to generate a control signal and send the control signal to the first driving device 13 and the second driving device, so as to respectively drive the rotation of the polygon mirror and the chopper 8 . In another exemplary embodiment, the imaging device may also include a control device independent of the data processing device.

As shown in FIG. 12 , the present disclosure also provides a method for detecting a human body or an object using a millimeter wave/terahertz wave imaging device 100, including the following steps:

S1: Drive the polygonal rotating mirror 1 to rotate, so that multiple reflectors 1A, 1B, 1C, and 1D are used in turn as the first reflector to receive and reflect the spontaneous parts of the first object 31A located at different positions in the first field of view 3A The millimeter wave/terahertz wave beam that is radiated or reflected back; another reflector adjacent to the first reflector among the plurality of reflectors 1A, 1B, 1C, and 1D is used as a second reflector to receive And reflect the second subject 31B located in different positions of the second field of view 3B part of the spontaneous radiation or reflected back millimeter wave/terahertz wave beam; during the rotation of the polygon mirror 1, the chopper 8 rotates around its central axis Rotate so that the millimeter wave/terahertz wave from the first reflecting plate and the millimeter wave/terahertz wave from the second reflecting plate reflected by the third reflecting plate 7 are alternately detected by the millimeter wave/terahertz wave Device array 2 receives;

S2: Send the image data of the first inspected object 31A and the image data of the second inspected object 31B obtained by the millimeter wave/terahertz wave detector array 2 to the data processing device;

S3: Using the data processing device to reconstruct the image data of the first inspected object 31A and the image data of the second inspected object 31B respectively to generate millimeter wave/terahertz images of the first inspected object 31A and the second inspected object 31B wave image.

This method can perform omni-directional imaging and detection on two inspected objects 31A and 31B at the same time, wherein the inspected object 31 can be a human body or an article. When the objects to be inspected 31A and 31B are human bodies, the millimeter wave/terahertz wave imaging device 100 can be used in conjunction with the object imaging device 200, as shown in FIG. 13, the two objects to be inspected 31A and 31B are respectively at the positions to be inspected on the left side and the position to be inspected on the right, or, after an object 31A to be inspected has completed the front detection at the position to be inspected on the left, it can walk along the path indicated by the arrow to the position to be inspected on the right, and complete the rear detection, so that all-round detection can be completed without turning around the subject 31A.

In an exemplary embodiment, the method further includes the following steps before step S3: when the polygon mirror 1 rotates to the calibration area, the calibration data about the calibration source 5 is received by the millimeter wave/terahertz wave detector array 2 and updating the received image data of the first inspected object 31A and the second inspected object 31B in real time based on the calibration data of the calibration source 5 .

The antenna temperature corresponding to the detection output voltage V _out is T _A , which should satisfy the following relationship,

T _A =(V _out -b)/a (7)

In the formula, a is the gain scaling coefficient,

b is the bias scaling coefficient.

Therefore, updating the received image data of the inspected object 31A, 31B based on the calibration data of the calibration source 5 includes correction of the bias scaling coefficient b and correction of the gain scaling coefficient a.

In the calibration area, the radiation brightness temperature of the calibration source 5 and its surrounding environment can be regarded as uniform, that is, the antenna temperatures T _A of all channels are consistent. When the channels are completely consistent, the output V _out of the receiving channel of the focal plane array should be completely consistent. If the output is inconsistent, it is necessary to adjust the gain scaling coefficient a and bias scaling coefficient b of each channel to make the output of all channels consistent, so as to realize Consistency regulation of channels. The gain scaling parameter a reflects the total gain and equivalent bandwidth of the channel. This part has been carefully adjusted during channel debugging. It can be considered that the gain scaling coefficient a of each channel is approximately equal. Offset scaling factor b to complete.

In an exemplary embodiment, updating the received image data of the inspected object 31 based on the calibration data of the calibration source 5 mainly includes correcting the bias calibration coefficient b, including the following steps:

A1: Calculate the average value of the multiple measured output voltages of all channels of the millimeter wave/terahertz wave detector array in the calibration area

A2: The calibrated data of the detection area of each channel is the data V _i collected in the detection area of each channel minus the average value It is then divided by the gain scaling factor a _i for each channel.

The method can perform overall calibration of the receiving channel array of the focal plane array system, and the calibration algorithm only needs simple calculations, consumes very little time, and can realize real-time calibration; channel consistency calibration is performed on each image.

When the equipment is in long-term operation or the place of use is changed, the system performance deteriorates due to system temperature drift, and the gain calibration coefficient a of each channel usually changes. At this time, it is necessary to adjust the gain scaling coefficient a and the bias scaling coefficient b of the channel, which specifically includes the following steps

B1: Use the millimeter wave/terahertz wave detector array to measure the air voltage value V _air (i), i∈[1, number of channels], and calculate the average air voltage value of all channels

B2: Set the temperature of the calibration source to have a difference with the temperature of the air, and use the millimeter wave/terahertz wave detector array to measure the voltage value V _cal (i) of the calibration source, i∈[1, the number of channels ], and calculate the average voltage value of the calibration source for all channels And calculate the gain scaling factor a _i and bias scaling factor b _i of each channel through the following equation:

B3: The data after calibration of the detection area of each channel is The absolute value of , where V _i is the data collected in the detection area of each channel.

The data processing device acquires twice in each 3dB beam azimuth, so in the embodiment shown in FIG. 1 , each channel obtains at least 10 acquisition data in the calibration area. Both the output voltage data in the calibration area and the output voltage data in the detection area are stored in the same data table of the data processing device.

As an exemplary embodiment, the method may further include S4: after generating the millimeter-wave/terahertz-wave images of the first inspected object 31A and the second inspected object 31B, the first inspected object 31A and the second inspected object 31A Identify whether the object 31B has a suspicious object and the location of the suspicious object, and output the result.

In the above steps, the identification of the suspicious object and its location can be carried out by computer automatic identification or manual identification or a combination of both. The output of the result can be realized by, for example, displaying a conclusion marked on the display device to directly show whether there is a suspicious object, or the detection result can be directly printed or sent.

The security inspector who performs the detection can confirm whether the human body or object contains suspicious objects and the location of the suspicious objects according to the detection results given in the above step S4, and can also conduct a review through manual detection.

Those skilled in the art can understand that the above-described embodiments are exemplary, and those skilled in the art can improve them, and the structures described in various embodiments do not conflict with each other in terms of structure or principle Can be combined freely.

After describing the preferred embodiments of the present disclosure in detail, those skilled in the art can clearly understand that various changes and changes can be made without departing from the scope and spirit of the appended claims, and the present disclosure is not limited by Implementation is limited to the exemplary embodiments set forth in the specification.

Claims (17)

1. a kind of millimeter wave/THz wave imaging device, which is characterized in that visited including quasi-optics component, millimeter wave/THz wave Device array and chopper are surveyed,

The quasi-optics component includes:

Polygonal-mirror, each side of the polygonal-mirror are respectively arranged with reflecting plate, and the polygonal-mirror can be around Its pivot axis is located at so that multiple reflecting plates are used as the first reflecting plate in turn to receive and reflect the first checked object The part spontaneous radiation of first visual field different location or reflected millimeter wave/THz wave wave beam；Multiple reflecting plates In another reflecting plate adjacent with first reflecting plate be used as the second reflecting plate and receive and reflect the second checked object position Part spontaneous radiation or reflected millimeter wave/THz wave wave beam in the second visual field different location；With

Third reflecting plate, the third reflecting plate is adapted to will the millimeter wave from second reflecting plate // THz wave reflection Onto the chopper；

The chopper is located at the reflection wave paths of first reflecting plate and the back wave road of the third reflecting plate, described to cut Wave device is configured to be only from millimeter wave/THz wave of first reflecting plate at any one time or to be only from the third anti- It penetrates millimeter wave/THz wave reflection of plate or is transmitted to the millimeter wave/terahertz wave detector array, the chopper is around it Center axis thereof so that millimeter wave/THz wave from first reflecting plate and the third reflecting plate alternately by institute State millimeter wave/terahertz wave detector array received；And

The millimeter wave/terahertz wave detector array is suitable for receiving the wave beam from the quasi-optics component.

2. millimeter wave according to claim 1/THz wave imaging device, which is characterized in that the quasi-optics component is also Including condenser lens, the condenser lens is between the chopper and the millimeter wave/terahertz wave detector array.

3. millimeter wave according to claim 1/THz wave imaging device, which is characterized in that the quasi-optics component is also Including the first condenser lens and the second condenser lens, first condenser lens is located at first reflecting plate and the chopper Between, second condenser lens is between second reflecting plate and the third reflecting plate.

4. millimeter wave according to claim 1/THz wave imaging device, which is characterized in that it further include absorbing material, institute Absorbing material is stated to be suitable for absorbing the millimeter wave/THz wave from first reflecting plate reflected via the chopper, And millimeter wave/the THz wave from the third reflecting plate transmitted via the chopper.

5. millimeter wave according to claim 1/THz wave imaging device, which is characterized in that the polygonal-mirror The quantity of the reflecting plate is m, wherein 6 >=m >=3.

6. millimeter wave according to claim 5/THz wave imaging device, which is characterized in that the m reflecting plates and institute It is parallel for stating pivot center.

7. millimeter wave according to claim 5/THz wave imaging device, which is characterized in that the m reflecting plates and institute The angle between pivot center is stated along the direction of rotation increasing or decreasing of the polygonal-mirror.

8. millimeter wave according to claim 1/THz wave imaging device, which is characterized in that the chopper includes extremely A few blade.

9. millimeter wave according to claim 8/THz wave imaging device, which is characterized in that between multiple described blades etc. It is arranged every ground around the central axis.

10. millimeter wave according to claim 1/THz wave imaging device, which is characterized in that it further include shell, it is described Quasi-optics component and the millimeter wave/terahertz wave detector array are located in the shell, in the opposing sidewalls of the shell It is respectively arranged with the first window for supplying the wave beam from first checked object to pass through and for from second checked object The second window for passing through of wave beam.

11. millimeter wave according to claim 1/THz wave imaging device, which is characterized in that further include being suitable for driving The first driving device of the polygonal-mirror rotation.

12. millimeter wave according to claim 1/THz wave imaging device, which is characterized in that further include being suitable for driving Second driving device of the chopper rotation.

13. millimeter wave described in any one of -12/THz wave imaging device according to claim 1, which is characterized in that also wrap It includes:

Data processing equipment, the data processing equipment are connect with the millimeter wave/terahertz wave detector array to connect respectively It receives from the millimeter wave/terahertz wave detector array for the image data of first checked object and for described The image data of second checked object simultaneously generates millimeter wave/THz wave image respectively；With

Display device, the display device are connected with the data processing equipment, for receiving and showing from the data The millimeter wave of processing unit/THz wave image.

14. millimeter wave according to claim 13/THz wave imaging device, which is characterized in that it further include warning device, The warning device is connect with the data processing equipment so that when the data processing equipment identify the millimeter wave/ The instruction millimeter wave/THz wave image is issued when suspicious object in THz wave image, and there are the alarms of suspicious object.

15. millimeter wave according to claim 13/THz wave imaging device, which is characterized in that it further include calibration source, institute It states calibration source to be located on the object plane of the quasi-optics component, the data processing equipment, which receives, comes from the millimeter wave/Terahertz The calibration data for the calibration source of wave detector array, and first checked object is updated based on the calibration data Image data and second checked object image data.

16. millimeter wave according to claim 13/THz wave imaging device, which is characterized in that further include optical camera Device, the optical pick-up apparatus include the first optical camera dress suitable for acquiring the optical imagery of first checked object It sets and the second optical pick-up apparatus of the optical imagery suitable for acquiring second checked object, first optical camera fills It sets and is connect respectively with the display device with second optical pick-up apparatus.

17. millimeter wave according to claim 16/THz wave imaging device, which is characterized in that the display device packet Display screen is included, the display screen includes being suitable for showing the first viewing area of the millimeter wave/THz wave image and being applicable in In the second viewing area for showing the optical pick-up apparatus optical imagery collected.