CN109655931B - Millimeter wave/terahertz wave imaging device and method for detecting human body or article - Google Patents
Millimeter wave/terahertz wave imaging device and method for detecting human body or article Download PDFInfo
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- CN109655931B CN109655931B CN201811654162.1A CN201811654162A CN109655931B CN 109655931 B CN109655931 B CN 109655931B CN 201811654162 A CN201811654162 A CN 201811654162A CN 109655931 B CN109655931 B CN 109655931B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V8/00—Prospecting or detecting by optical means
- G01V8/005—Prospecting or detecting by optical means operating with millimetre waves, e.g. measuring the black losey radiation
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V8/00—Prospecting or detecting by optical means
- G01V8/10—Detecting, e.g. by using light barriers
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Abstract
The Y-shaped reflecting plate comprises a first reflecting plate, a second reflecting plate and a third reflecting plate, wherein the Y-shaped reflecting plate can rotate around a rotating axis of the Y-shaped reflecting plate so that a first reflecting surface of the first reflecting plate, a first reflecting surface of the second reflecting plate and a first reflecting surface wheel flow of the third reflecting plate serve as a first working surface to receive and reflect millimeter wave/terahertz wave spontaneously radiated or reflected by a part of a first detected object, which is positioned at different positions of a first visual field; and a millimeter wave/terahertz wave detector array adapted to receive the beam from the quasi-optical assembly. The millimeter wave/terahertz wave imaging device is simple to control and high in stability.
Description
Technical Field
The present disclosure relates to the field of imaging technologies, and in particular, to a millimeter wave/terahertz wave imaging apparatus and a method for detecting a human body or an article using the same.
Background
In the increasingly severe situation of the current domestic and foreign anti-terrorist situation, terrorists carry dangerous articles such as cutters, guns, explosives and the like with themselves in a hidden mode to form a serious threat to public safety. The human body security inspection technology based on passive millimeter wave/terahertz wave has the unique advantages that imaging is achieved through millimeter wave/terahertz wave radiation of a detection target, active radiation is not needed, security inspection is conducted on a human body, and detection of hidden dangerous objects is achieved through penetrating capacity of millimeter wave/terahertz wave. However, the existing millimeter wave/terahertz wave imaging apparatus has low working efficiency.
Disclosure of Invention
The present disclosure is directed to solving at least one of the above-mentioned problems and disadvantages of the prior art.
According to an embodiment of one aspect of the present disclosure, there is provided a millimeter wave/terahertz wave imaging apparatus including:
the quasi-optical assembly comprises a Y-shaped reflecting plate, wherein the Y-shaped reflecting plate comprises a first reflecting plate, a second reflecting plate and a third reflecting plate, and the Y-shaped reflecting plate can rotate around the rotation axis of the Y-shaped reflecting plate so that a first reflecting surface of the first reflecting plate, a first reflecting surface of the second reflecting plate and a first reflecting surface wheel flow of the third reflecting plate are used as a first working surface to receive and reflect millimeter wave/terahertz waves spontaneously radiated or reflected by parts of a first detected object, which are positioned at different positions of a first view field; and
A millimeter wave/terahertz wave detector array adapted to receive a beam from the quasi-optical assembly.
In some embodiments, the quasi-optical assembly further includes a fourth reflecting plate, and when the Y-shaped reflecting plate rotates, a second reflecting surface of the first reflecting plate opposite to the first reflecting surface, a second working surface of the second reflecting plate opposite to the first reflecting surface, and a second working surface wheel flow of the third reflecting plate opposite to the first reflecting surface serve as a first working surface for receiving and reflecting millimeter wave/terahertz wave spontaneously radiated or reflected from a portion of a second object to be inspected located at a different position of a second field of view to the fourth reflecting plate;
a chopper on the reflection wave path of the first working face and the reflection wave path of the fourth reflecting plate, the chopper being configured to reflect or transmit only millimeter wave/terahertz waves from the first working face or only millimeter wave/terahertz waves from the fourth reflecting plate to the millimeter wave/terahertz wave detector array at any one time, the chopper rotating about its central axis so that millimeter wave/terahertz waves from the first working face and the fourth reflecting plate of the Y-shaped reflecting plate are alternately received by the millimeter wave/terahertz wave detector array.
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 comprises a first focusing lens adapted to focus millimeter-wave/terahertz waves from the first working face of the Y-shaped reflective plate and a second focusing lens adapted to focus millimeter-wave/terahertz waves from the second working face of the Y-shaped reflective plate.
In some embodiments, the millimeter wave/terahertz wave imaging apparatus further includes a wave absorbing material adapted to absorb millimeter wave/terahertz waves from the first working face reflected via the chopper and millimeter wave/terahertz waves from the fourth reflecting plate transmitted via the chopper.
In some embodiments, the angles between the 3 reflective plates and the rotation axis are increased or decreased in the rotation direction of the Y-shaped reflective plate.
In some embodiments, the chopper includes at least one blade.
In some embodiments, a plurality of the vanes are equally spaced about the central axis.
In some embodiments, the millimeter wave/terahertz wave imaging apparatus further includes a housing, the quasi-optical assembly and the millimeter wave/terahertz wave detector array are located within the housing, and a first window through which a beam from the first object to be inspected passes and a second window through which a beam from the second object to be inspected passes are provided on opposite side walls of the housing, respectively.
In some embodiments, the millimeter wave/terahertz wave imaging apparatus further includes a first driving device adapted to drive the Y-shaped reflecting plate to rotate.
In some embodiments, the millimeter wave/terahertz wave imaging apparatus further includes a second driving device adapted to drive the chopper to rotate.
In some embodiments, the millimeter wave/terahertz wave imaging apparatus further includes:
a data processing device connected with the millimeter wave/terahertz wave detector array to respectively receive image data for the first inspected object and image data for the second inspected object from the millimeter wave/terahertz wave detector array and respectively generate millimeter wave/terahertz wave images; and
and the display device is connected with the data processing device and is used for receiving and displaying millimeter wave/terahertz wave images from the data processing device.
In some embodiments, the millimeter wave/terahertz wave imaging apparatus further includes an alarm device connected to the data processing device such that an alarm indicating the existence of a suspicious item in the millimeter wave/terahertz wave image is issued when the data processing device recognizes the suspicious item in the millimeter wave/terahertz wave image.
In some embodiments, the millimeter wave/terahertz wave imaging apparatus further includes a calibration source located on an object plane of the quasi-optical assembly, and the data processing device receives calibration data for the calibration source from the millimeter wave/terahertz wave detector array and updates 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 apparatus further includes an optical imaging device including a first optical imaging device adapted to acquire an optical image of the first object to be inspected and a second optical imaging device adapted to acquire an optical image of the second object to be inspected, the first and second optical imaging devices being connected to the display device, respectively.
In some embodiments, the display device includes a display screen including a first display area adapted to display the millimeter wave/terahertz wave image and a second display area adapted to display an optical image captured by the optical imaging device.
In some embodiments, the first and second reflecting plates, the second and third reflecting plates, and the third and first reflecting plates each have an included angle of 120 °.
In some embodiments, the millimeter wave/terahertz wave imaging apparatus further includes a fifth reflecting plate that swings reciprocally around its center axis to receive and reflect the millimeter wave/terahertz wave spontaneously radiated or reflected by the first object to be inspected onto the first working face to be received by the millimeter wave/terahertz wave detector array after reflection via the first working face, the swing period T1 of the fifth reflecting plate being 2m times the rotation period of the Y-shaped reflecting plate, where m is an integer of 1 or more.
In some embodiments, the millimeter wave/terahertz wave imaging apparatus further includes a third driving device adapted to drive the fifth reflecting plate to reciprocate.
According to another aspect of the present disclosure, there is also provided a method for detecting a human body or an article using the above millimeter wave/terahertz wave imaging apparatus, including the steps of:
s1: driving the Y-shaped reflecting plate to rotate, so that the first reflecting surface of the first reflecting plate, the first reflecting surface of the second reflecting plate and the first reflecting surface of the third reflecting plate are used as a first working surface to receive and reflect millimeter wave/terahertz wave spontaneously radiated or reflected back by the first detected object; the second reflection surface of the first reflection plate, the second reflection surface of the second reflection plate and the second reflection surface of the third reflection plate are used as a second working surface to receive and reflect millimeter wave/terahertz wave spontaneously radiated or reflected back by a second detected object; while the Y-shaped reflecting plate rotates, a chopper rotates around a central axis thereof to alternately enable the millimeter wave/terahertz wave from the first working face and the millimeter wave/terahertz wave from the second working face reflected by a fourth reflecting plate to be received by the millimeter wave/terahertz wave detector array;
s2: transmitting image data received by the millimeter wave/terahertz wave detector array with respect to the first object and with respect to the second object to a data processing apparatus; and
S3: reconstructing image data of the first object and image data of the second object with the data processing apparatus to generate millimeter wave/terahertz wave images of the first object and the second object, respectively.
According to the millimeter wave/terahertz wave imaging apparatus and the method of detecting a human body or an article of the above-described various embodiments of the present disclosure, by adopting the Y-shaped reflecting plate including the first reflecting plate, the second reflecting plate, and the third reflecting plate, the Y-shaped reflecting plate is driven to rotate around the junction of the first reflecting plate, the second reflecting plate, and the third reflecting plate so that the first reflecting surface of the first reflecting plate, the first reflecting surface of the second reflecting plate, and the first reflecting surface of the third reflecting plate are used as the first working surface to receive and reflect the millimeter wave/terahertz wave spontaneously radiated or reflected back from the portion of the first object to be detected located at the different positions of the first field of view, thereby realizing imaging of the object to be detected, and being simple in control and low in cost.
Drawings
Fig. 1 is a schematic structural view of a millimeter wave/terahertz wave imaging apparatus according to an embodiment of the present disclosure;
fig. 2 is a schematic structural view of a millimeter wave/terahertz wave imaging apparatus according to another embodiment of the present disclosure, after removing a housing;
Fig. 3 is an installation schematic view of a Y-shaped reflection plate of a millimeter wave/terahertz wave imaging apparatus according to an exemplary embodiment of the present disclosure;
fig. 4 is a side view of the Y-shaped reflecting plate shown in fig. 3;
FIG. 5 is a schematic view of angles produced by respective reflection plates and rotation axes of a polygon mirror according to another embodiment of the present disclosure;
fig. 6 is a schematic structural view of an exemplary embodiment of a chopper of a millimeter wave/terahertz wave imaging apparatus according to the present disclosure;
fig. 7 is a schematic structural view of another exemplary embodiment of a chopper of a millimeter wave/terahertz wave imaging apparatus according to the present disclosure;
fig. 8 is a schematic structural view of still another exemplary embodiment of a chopper of a millimeter wave/terahertz wave imaging apparatus according to the present disclosure;
fig. 9 is a schematic structural view of still another exemplary embodiment of a chopper of a millimeter wave/terahertz wave imaging apparatus according to the present disclosure;
FIG. 10 is a schematic diagram of lens imaging;
fig. 11 is a schematic structural view of a millimeter wave/terahertz wave imaging apparatus according to still another embodiment of the present disclosure;
fig. 12 is a schematic structural view of a millimeter wave/terahertz wave imaging apparatus according to still another embodiment of the present disclosure;
fig. 13 is a schematic diagram of a total pixel of a millimeter wave/terahertz wave imaging apparatus, scanning pixels of respective reflection plates, and a sparsely arranged millimeter wave/terahertz wave detector array according to one embodiment of the present disclosure;
Fig. 14 is a flowchart of a method of inspecting a human body or an article by a millimeter wave/terahertz wave imaging apparatus according to an embodiment of the present disclosure; and
fig. 15 is an application scenario diagram of a millimeter wave/terahertz wave imaging apparatus according to an embodiment of the present disclosure.
Detailed Description
While the present disclosure will be fully described with reference to the accompanying drawings, which contain preferred embodiments of the present disclosure, it is to be understood before this description that one of ordinary skill in the art can modify the disclosure described herein while achieving the technical effects of the present disclosure. Accordingly, it is to be understood that the foregoing description is a broad disclosure by those having ordinary skill in the art, and is not intended to limit the exemplary embodiments described in the present disclosure.
Furthermore, in the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough 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 the drawings in order to simplify the drawings.
Fig. 1 schematically illustrates a millimeter wave/terahertz wave imaging apparatus according to an exemplary embodiment of the present disclosure. As shown in the drawing, the millimeter wave/terahertz wave imaging apparatus 100 includes a quasi-optical assembly, a millimeter wave/terahertz wave detector array 2, and a chopper 8, wherein the quasi-optical assembly includes a Y-shaped reflecting plate 1, the Y-shaped reflecting plate 1 includes a first reflecting plate 1A, a second reflecting plate 1B, and a third reflecting plate 1C, the Y-shaped reflecting plate 1 is rotatable about a junction (i.e., a rotation axis o) of the first reflecting plate 1A, the second reflecting plate 1B, and the third reflecting plate 1C such that a first reflection surface of the first reflecting plate 1A, a first reflection surface of the second reflecting plate 1B, and a first reflection surface wheel of the third reflecting plate 1C serve as a first working surface to receive and reflect millimeter waves/terahertz waves spontaneously radiated or reflected by portions of the first inspected object 31A located at different positions of the first field of view 3A; the quasi-optical assembly further includes a fourth reflection plate 7, and when the Y-shaped reflection plate 1 rotates, a second reflection surface of the first reflection plate 1A opposite to the first reflection surface, a second working surface of the second reflection plate 1B opposite to the first reflection surface, and a second working surface wheel flow of the third reflection plate 1C opposite to the first reflection surface serve as the second working surface to receive and reflect the millimeter wave/terahertz wave spontaneously radiated or reflected back from a portion of the second object under test 31B located at a different position of the second field of view 3B to the fourth reflection plate 7. The quasi-optical element further comprises a first focusing lens 4A and a second focusing lens 4B, the first focusing lens 4A being adapted to converge the beam from the first working surface and the second focusing lens 4B being adapted to converge the beam from the second working surface. The chopper 8 is located on the reflection wave path of the first working surface and the reflection wave path of the fourth reflection plate 7, the chopper 8 being configured such that only millimeter wave/terahertz wave from the first working surface is transmitted to the millimeter wave/terahertz wave detector array 2 or only millimeter wave/terahertz wave from the fourth reflection plate 7 is reflected to the millimeter wave/terahertz wave detector array 2 at any one time, the chopper 8 being rotated about its central axis to alternately cause millimeter wave/terahertz wave from the first working surface of the Y-shaped reflection plate 1 and the fourth reflection plate 7 to be received by the millimeter wave/terahertz wave detector array 2. The millimeter wave/terahertz wave detector array 2 is suitable for receiving the beams reflected and converged by the quasi-optical component; the number of detectors in the millimeter wave/terahertz wave detector array 2 is determined according to the required size of the fields of view 3A, 3B and the required resolution, the arrangement direction is perpendicular to the normal line of the fields of view and parallel to the horizontal plane, and the size of the detectors is determined according to the wavelength, the processing technology and the required sampling density.
According to the millimeter wave/terahertz wave imaging apparatus 100 of the embodiment of the present disclosure, by driving the Y-shaped reflection plate 1 to rotate around the junction of the first reflection plate 1A, the second reflection plate 1B, and the third reflection plate 1C to complete data collection of the first field of view 3A and the second field of view 3B, respectively, in the course of rotation of the Y-shaped reflection plate 1, millimeter wave/terahertz waves from the first field of view 3A and the second field of view 3B are alternately switched to the same millimeter wave/terahertz wave detector array 2 through the chopper 8, thereby realizing imaging of two inspected objects 31A, 31B located in the two fields of view 3A, 3B, while the number of millimeter wave/terahertz wave detectors can be reduced to reduce the apparatus cost, and the stability is high and the occupied space is small.
In this embodiment, the focusing lens 4 includes a first focusing lens 4A and a second focusing lens 4B, the first focusing lens 4A being located between the Y-shaped reflecting plate 1 and the chopper 8 and adapted to focus millimeter wave/terahertz wave from the first working surface of the Y-shaped reflecting plate, and the second focusing lens 4B being located between the Y-shaped reflecting plate 1 and the fourth reflecting plate 7 and adapted to focus millimeter wave/terahertz wave from the second working surface of the Y-shaped reflecting plate 1. The focal lengths of the two focusing lenses 4A, 4B are f1, f2, respectively, wherein the sizes of f1 and f2 can be the same or different. Since the chopper 8 is placed in the wave path after being focused by the focusing lenses 4A, 4B, the size of the blade 82 of the chopper 8 can be small, in which case the specific size of the blade 82 of the chopper 8 is determined by the beam spot size at the place where the chopper 8 is placed in advance after being focused by the focusing lenses 4A, 4B. Assume that the beam spot radius after focusing by the focusing lenses 4A, 4B where the chopper 8 is pre-positioned is w cut Then the size (area) of the blade 82 of the chopper 8 is selected to be
It should be noted that in other embodiments of the present disclosure, as shown in fig. 2, a focusing lens 4 may also be employed, the focusing lens 4 being located between the chopper 8 and the millimeter wave/terahertz wave detector array 2. In this case, since the chopper 8 is placed in an unfocused wave path, the size of its blades 82 should be matched to the reflective surface of the Y-shaped reflective plate 1.
In the exemplary embodiment shown in fig. 1 and 2, the millimeter wave/terahertz wave imaging apparatus further includes a wave absorbing material 9, the wave absorbing material 9 being adapted to absorb millimeter wave/terahertz waves from the first working surface reflected via the chopper 8, and millimeter wave/terahertz waves from the fourth reflecting plate 7 transmitted via the chopper 8.
In the exemplary embodiment shown in fig. 1 and 2, the angle θ produced by the first reflection plate 1A, the second reflection plate 1B, and the second reflection plate 1C is 120 °. It should be noted that, in other embodiments of the present disclosure, the angle θ of two adjacent first reflection plates 1A, second reflection plates 1B, and second reflection plates 1C may be other values.
In the exemplary embodiment shown in fig. 1 and 2, the first, second and third reflection plates 1A, 1B and 1C are rectangular and have lengths and widths corresponding to those of the corresponding focusing lens 4, and in general, the widths of the first, second and third reflection plates 1A, 1B and 1C are greater than or equal to those of the corresponding focusing lens 4, and the lengths of the first, second and third reflection plates 1A, 1B and 1C are equal to those of the corresponding focusing lens 4The diameter of the focusing lens 4 may be, for example, 3cm to 50cm.
In the exemplary embodiment shown in fig. 1 to 4, the first reflection plate 1A, the second reflection plate 1B, and the third reflection plate 1C are all parallel to the rotation axis o. It should be noted that, in other embodiments of the present disclosure, the angles between the first reflection plate 1A, the second reflection plate 1B, and the third reflection plate 1C and the rotation axis o may be increased or decreased by an increment of α along the rotation direction of the Y-shaped reflection plate 1 to realize a pixel difference value, so that the detectors of the millimeter wave/terahertz wave detector array 2 may be sparsely distributed, thereby reducing the number of the detectors.
Wherein d is calculated from the following equation:
where lambda is the wavelength of millimeter wave/terahertz wave,
D is the diameter of the focusing lens 4.
It should be noted that the above formula is just an angular resolution estimation formula under ideal convergence of one lens. In practical systems the size of alpha should be fine-tuned according to the experimental results so that the final pixel arrangement is as uniform as possible and without overlap and gaps. That is, the angles between the reflection plates 1A, 1B, 1C and the rotation axis o on the Y-shaped reflection plate 1 are finely adjustable.
As shown in fig. 5, in one exemplary embodiment, the magnitudes of angles between the first, second, and third reflection plates 1A, 1B, 1C and the rotation axis o are increased in the rotation direction of the Y-shaped reflection plate 1. The angle θ between the first reflection plate 1A and the rotation axis o is 0 °, the angle θ between the second reflection plate 1B and the rotation axis o is +α, and the angle θ between the third reflection plate 1C and the rotation axis o is- α. It should be noted that, in other embodiments of the present disclosure, the magnitudes of the angles between the first, second, and third reflection plates 1A, 1B, 1C and the rotation axis o decrease along the rotation direction of the Y-shaped reflection plate 1.
Fig. 6 to 9 show schematic structural views of several choppers, respectively, the chopper 8 including at least one blade, for example, 1, 2, 3, 4, etc., a plurality of blades 82 being disposed at equal intervals around the central axis 81. During rotation of the chopper 8 about its central axis 81, when millimeter wave/terahertz wave from the first working surface is incident on the blade 82 of the chopper 8 at any one time, the blade 82 reflects the millimeter wave/terahertz wave from the first working surface to the wave-absorbing material 9 to be absorbed by the wave-absorbing material 9 while reflecting the millimeter wave/terahertz wave from the fourth reflecting plate 7 to the millimeter wave/terahertz wave detector array 2. As the chopper 8 rotates about its central axis 81, at the next moment, the millimeter wave/terahertz wave from the first working surface is incident on the portion of the chopper 8 where the blade 82 is not provided (i.e., the empty portion) to be transmitted to the millimeter wave/terahertz wave detector array 2, and the portion of the chopper 8 where the blade 82 is not provided simultaneously transmits the millimeter wave/terahertz wave from the fourth reflection plate 7 to the wave-absorbing material 9 to be absorbed by the wave-absorbing material 9, and sequentially circulates.
It should be noted that the chopper 8 may be replaced by other devices capable of switching to the highly reflective and highly transmissive states quickly.
In the exemplary embodiment shown in fig. 1 and 2, the chopper 8 is placed at an angle of 45 degrees to both the wave path from the first working surface and the wave path from the fourth reflecting plate 7. It should be noted that, in other embodiments of the present disclosure, the chopper 8 may be disposed at other angles to the wave path from the first working surface and the wave path from the fourth reflecting plate 7.
As shown in fig. 1, in an exemplary embodiment, the millimeter wave/terahertz wave imaging apparatus further includes a housing 6, the quasi-optical assembly and the millimeter wave/terahertz wave detector array 2 are located within the housing 6, and a first window 61A through which millimeter wave/terahertz waves spontaneously radiate or reflect from the first object under test 31A and a second window 61B through which millimeter wave/terahertz waves spontaneously radiate or reflect from the second object under test 31B pass are provided on opposite side walls of the housing 6, respectively.
As shown in fig. 3 and 4, in an exemplary embodiment, a joint of the first reflection plate 1A, the second reflection plate 1B, and the second reflection plate 1C is provided with a rotation shaft 11, and both ends of the rotation shaft 11 are rotatably connected with the housing 6 via bearings 10A, 10B so that the Y-shaped reflection plate can rotate, thereby causing the first reflection surface of the first reflection plate 1A, the first reflection surface of the second reflection plate 1B, and the first reflection surface of the second reflection plate 1C to reflect beams from portions of the subject 31A located at different vertical positions of the field of view 3A, respectively, while the second reflection surface of the first reflection plate 1A, the second reflection surface of the second reflection plate 1B, and the second reflection surface of the second reflection plate 1C reflect beams from portions of the subject 31B located at different vertical positions of the field of view 3B, respectively.
As shown in fig. 3 and 4, in an exemplary embodiment, the millimeter wave/terahertz wave imaging apparatus further includes a first driving device 13, such as a servo motor, adapted to drive the Y-shaped reflecting plate 1 to rotate.
As shown in fig. 3 and 4, in an exemplary embodiment, the millimeter wave/terahertz wave imaging apparatus further includes an angular displacement measuring mechanism 12, such as a photoelectric encoder, that detects the angular displacement of the Y-shaped reflecting plate in real time, so as to accurately calculate the posture of the Y-shaped reflecting plate, which can considerably reduce the difficulty in developing the control algorithm and the imaging algorithm.
As in an exemplary embodiment not shown, the millimeter wave/terahertz wave imaging apparatus further includes a second driving device, such as a servo motor, adapted to drive the chopper 8 to rotate at a high speed about its central axis 81, the rotation period of the chopper 8 should be matched with the scanning period of the Y-shaped reflecting plate 1 so that the millimeter wave/terahertz wave imaging apparatus can simultaneously image the two objects 31A, 31B of the two fields of view 3A, 3B, respectively, preferably the rotation period of the chopper 8 is 1/1000-1/2 of the scanning period of the Y-shaped reflecting plate.
In this embodiment, the static field of view of the detector is a horizontal field of view, and assuming that the number of detectors is N and the center-to-center distance d between two adjacent detectors, the maximum offset distance y of the detectors m Then
Thus, the static view field of the millimeter wave/terahertz wave detector array 2 can be calculated to be H 0 . As shown in fig. 10, the static field of view H of the millimeter wave/terahertz wave detector array 2 0 Distance from object L 1 Image distance L 2 It is required to satisfy the following relation
The Y-shaped reflecting plate 1 rotates around the rotation axis o, the angle of data acquisition is determined according to the field of view range of the height direction of the detected objects 31A and 31B to be scanned, and the angle orientation corresponding to the imaging field of view required by the height direction is assumed to be theta m Then the corresponding scan-field angle is θ rot ＝θ m /2。
Wherein the Y-shaped reflecting plate 1 performs the number of times N of swinging required for reflection of the vertical range of the field of view where the corresponding object 31A (31B) is located v Calculated by the following formula:
wherein [ (formula) represents an upward rounding);
l is the distance from the center of the field of view 3A (3B) to the center of the first working surface (second working surface 1B);
delta represents object resolution;
θ m the view field angle corresponding to the vertical view field range H.
The Y-shaped reflecting plate 1 rotates one cycle to complete the acquisition of 3 images for each field of view.
The height direction sampling density is determined by the beam residence time, and the Y-shaped reflecting plate 1 rotates for one period, and each view field outputs 3 images. Assuming an angular resolution of θ for the detector res The Y-shaped reflecting plate 1 rotates for one period to contain 3dB wave beam number as follows
n＝360°/θ res (5)
Assuming that the imaging rate requirement is mHz, the average dwell time τ in the height direction for each sampled beam d Is that
At an imaging distance of 3000mm from the system, the angular resolution θ res For example, when the object resolution is δ=30mm and the imaging rate is 10Hz, the number of steps acquired in the height direction can be found to be 67, and the residence time of each beam is τ d =100 ms/67=1.47 ms. The first driving means 13 controls the rotation of the Y-shaped reflecting plate 1 with a period of 0.05s.
In an exemplary embodiment, a millimeter wave/terahertz wave imaging apparatus operating at a center frequency of 94GHz has n=30 detectors arranged in a row with a center-to-center spacing d=7mm, and a detector array length of 2y m =21 cm. Object distance L 1 =3.5m, image distance L 2 =0.7m, the static field of view H can be calculated according to equation (3) 0 =105 cm. Assuming that the height direction size of the imaging region is 1.8m, the scanning angle in the height direction for reconstructing the image is θ m ＝34°。
In another exemplary embodiment, the millimeter wave/terahertz wave imaging device works at a center frequency of 220GHz, the number of detectors is N=48, the detectors are arranged in a row, d=3 mm between centers of the detectors, and the detector array length is 2y m =14.4 cm. Object distance L 1 =5m, image distance L 2 =0.7m, the static field of view H can be calculated according to equation (3) 0 =103 cm. Assuming that the height direction size of the imaging region is 1.8m, the scanning angle in the height direction for reconstructing the image is θ m ＝20°。
In an exemplary embodiment, the millimeter wave/terahertz wave imaging apparatus further includes a data processing device (not shown). The data processing apparatus is connected wirelessly or by wire to the millimeter wave/terahertz wave detector array 2 to receive image data about the first object under test 31A and about the second object under test 31B received by the millimeter wave/terahertz wave detector array 2, respectively.
In one exemplary embodiment, the imaging apparatus 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 apparatus further includes a calibration source 5, the calibration source 5 being located within the housing 6 and on the object plane of the quasi-optical assembly such that when the first working surface is rotated to the calibration area, calibration data about the calibration source 5 is received by 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 updates the image data of the first object under test 31A and the second object under test 31B in real time based on the calibration data. Since the calibration source 5 is enclosed inside the housing 1, the millimeter wave/terahertz wave imaging apparatus is made more stable and reliable than the calibration with remote air.
In this embodiment, the calibration source 5 is located obliquely above the Y-shaped reflecting plate 1, and it should be noted that, as long as the position of the calibration source 5 is such that the millimeter wave/terahertz wave detector array 2 receives calibration data about the calibration source 5 and image data of the inspected objects 31A, 31B without interfering with each other, the beam radiated by the calibration source 5 is reflected to the millimeter wave/terahertz wave detector array 2 via the first working surface and/or the second working surface, so that calibration of the complete receiving channel including the focusing lens 4 and the detector can be achieved, and uniformity of the channel is further ensured.
In the exemplary embodiment shown in fig. 1 and 2, the rotation shaft 11 of the Y-shaped reflection plate 1 is horizontally disposed so that the first working surface, the second working surface reflect beams from portions of the respective objects 31A, 31B to be inspected located at different vertical positions of the field of view. It should be noted that, in other embodiments of the present disclosure, the rotation axis 11 of the Y-shaped reflective plate 1 may be vertically disposed, so that the first working surface and the second working surface reflect beams from portions of the respective objects 31A and 31B located at different horizontal positions of the field of view. The calibration source 5 may be a wave-absorbing material having an emissivity close to 1, such as plastic or foam, or a black body or a semiconductor refrigerator.
By nyquist sampling law, an image can be completely restored with at least two sampling points within a half-power beamwidth. The arrangement direction of the millimeter wave/terahertz wave detector array 2 in this embodiment is perpendicular to the normal line of the field of view and parallel to the horizontal plane to sample the field of view in the height direction, and the arrangement density of the millimeter wave/terahertz wave detector array 2 determines the sampling density. The image formed by the millimeter wave imaging system is actually a gray image, and when the space sampling rate of the image does not reach the Nyquist sampling requirement (undersampling), the image of the target scene can still be imaged, but the imaging effect is relatively poor. In order to compensate for pixel loss caused by undersampling, an interpolation algorithm can be adopted to increase data density in the later signal processing.
As shown in fig. 1, in an exemplary embodiment, the length direction of the calibration source 5 is parallel to the rotation axis 11 of the Y-shaped reflecting plate, the length of the calibration source 5 is equal to or greater than the field size of the millimeter wave/terahertz wave detector array 2 in the direction parallel to the rotation axis 11, and the width of the calibration source 5 is 10 times the antenna beam width of the millimeter wave/terahertz wave detector 2. However, it should be noted that, as will be understood by those skilled in the art, the width of the calibration source 5 may be 1 or 2 times or other times the antenna beam width of the millimeter wave/terahertz wave detector.
In one embodiment, the millimeter wave/terahertz wave imaging apparatus further includes an optical imaging device including a first optical imaging device adapted to collect an optical image of the first object under test 31A and a second optical imaging device adapted to collect an optical image of the second object under test 31B, the optical imaging device being connected to a display device, the optical imaging device being capable of realizing real-time imaging of visible light, giving image information of the first object under test 31A and the second object under test 31B to be collated with the millimeter wave/terahertz wave image for reference by a user.
In an exemplary embodiment, not shown, the display device includes a display screen including a first display area adapted to display millimeter wave/terahertz wave images of the first object under test 31A and the second object under test 31B and a second display area adapted to display optical images of the first object under test 31A and the second object under test 31B acquired by the optical imaging device, so that a user can compare the optical images acquired by the optical imaging device with the millimeter wave/terahertz wave images.
In an exemplary embodiment, which is not shown, the millimeter wave/terahertz wave imaging apparatus further includes an alarm device connected to the data processing device so that when suspicious articles in the millimeter wave/terahertz wave images of the first object to be inspected 31A and/or the second object to be inspected 31B are identified, an alarm, such as an alarm lamp, is set up, for example, under the millimeter wave/terahertz wave image corresponding to the corresponding object to be inspected, it should be noted that an alarm manner of acoustic prompt may also be adopted.
In an exemplary embodiment, the data processing device may be used to generate and transmit control signals to the first driving device 13 and the second driving device to drive the Y-shaped reflecting plate 1 and the chopper 8 to rotate, respectively. In another exemplary embodiment, the image forming apparatus may also include a control device independent from the data processing device.
Fig. 11 is a schematic structural view of a millimeter wave/terahertz wave imaging apparatus according to still another embodiment of the disclosure. As shown in fig. 11, the millimeter wave/terahertz wave imaging apparatus includes a Y-shaped reflecting plate 1 and a focusing lens 4, and imaging of a monoscopic field is achieved by driving the Y-shaped reflecting plate 1 to rotate so that a first reflecting surface of a first reflecting plate 1A, a first reflecting surface of a second reflecting plate 1B, and a first reflecting surface of a second reflecting plate 1C reflect beams from portions of a subject 31A located at different positions of a field of view 3A, respectively, and the acquisition of 3 images can be completed by one rotation of the Y-shaped reflecting plate 1.
Fig. 12 is a schematic structural view of a millimeter wave/terahertz wave imaging apparatus according to still another embodiment of the disclosure. As shown in fig. 12, the optical system further includes a Y-shaped reflecting plate 1, a focusing lens 4, and a fifth reflecting plate 14, the fifth reflecting plate 14 swings reciprocally around its center axis to receive and reflect millimeter wave/terahertz wave spontaneously radiated or reflected by a first object under test 31A onto the first working surface to be received by the millimeter wave/terahertz wave detector array 2 after reflection by the first working surface, and a swing period T1 of the fifth reflecting plate 14 is 2m times a rotation period of the Y-shaped reflecting plate 1, where m is an integer of 1 or more. In this embodiment, the number of scanning columns in the horizontal direction of the object to be measured 31 is increased by driving the fifth reflecting plate 14 to reciprocate around its central axis, and since the range of oscillation of the fifth reflecting plate 14 just allows the range of movement of the image of the object to be measured on the image plane to be the distance between two adjacent detection units, when the fifth reflecting plate 14 reciprocates around its central axis, the pixel points adjacent to the detection units in the millimeter wave/terahertz wave detector array 2 can be sequentially fed into each detection unit.
Under the condition that the fifth reflecting plate 14 does not swing, millimeter wave/terahertz wave emitted or reflected by the detected object 31A is reflected to the Y-shaped reflecting plate 1 through the fifth reflecting plate 14, the Y-shaped reflecting plate 1 rotates stably at a high speed around the rotation axis o of the Y-shaped reflecting plate, when the first reflecting plate 1A, the second reflecting plate 1B and the third reflecting plate 1C in the Y-shaped reflecting plate 1 rotate to a wave path behind the fifth reflecting plate 14, one-dimensional multi-array rapid scanning is completed in the vertical column direction of the detected object 31A, then the millimeter wave/terahertz wave is converged by the focusing lens 4 to form an image of the detected object 31A, and finally the image is received by the millimeter wave/terahertz wave detector array 2 arranged on the image plane, and the number of detected columns on the detected object 31A is consistent with the number of detection units in the millimeter wave/terahertz wave detector array 2.
When the fifth reflecting plate 14 is deflected by an angle around its center, the image plane of the object under test 31A behind the focusing lens 4 is also correspondingly moved by a certain angle, and each detecting unit in the millimeter wave/terahertz wave detector array 2 detects a certain column of pixels originally left or right of the position where it is located, and if the angle of rotation of the fifth reflecting plate 14 is appropriate, each detecting unit can receive pixels not received by any detecting unit before the rotation of the fifth reflecting plate 14, i.e., pixels between the original two adjacent detecting units, as shown in fig. 13. Therefore, the fifth reflecting plate 14 deflects by a certain angle, so that the scanning column number of the measured object can be increased on the basis of not increasing the detecting units in the millimeter wave/terahertz wave detector array 2, namely, the pixel number of the measured object 31A in the horizontal line direction is increased, the scanning speed can be increased, and in addition, the system stability is higher because the swinging angle of the fifth reflecting plate 14 is smaller.
Before the image forming apparatus is started, the components in the system are arranged as required so that the fifth reflecting plate 14 is placed at the maximum angle on the left or right side of the center thereof, and the first reflecting plate 1A, the second reflecting plate 1B, and the third reflecting plate 1C in the Y-shaped reflecting plate 1 are parallel to the center axis of the fifth reflecting plate 14. After the imaging device is started, the fifth reflecting plate 14 and the Y-shaped reflecting plate 1 synchronously move, and the millimeter wave/terahertz wave detector array 2 starts to receive millimeter wave/terahertz waves transmitted by the focusing lens 4, and the millimeter wave/terahertz wave detector array 2 converts millimeter wave/terahertz wave signals into direct-current voltage signals.
As shown in fig. 14, the present disclosure further provides a method for detecting a human body or an article using a millimeter wave/terahertz wave imaging apparatus, including the steps of:
s1: the Y-shaped reflecting plate 1 is driven to rotate, so that the first reflecting surface of the first reflecting plate 1A, the first reflecting surface of the second reflecting plate 1B and the first reflecting surface of the third reflecting plate 1C receive and reflect the millimeter wave/terahertz wave spontaneously radiated or reflected back by the first object 31A in turn; millimeter wave/terahertz wave spontaneously radiated or reflected back by the second object under test 31B is received and reflected in turn by the second reflecting surface of the first reflecting plate 1A, the second reflecting surface of the second reflecting plate 1B, and the second reflecting surface of the third reflecting plate 1C; while the Y-shaped reflecting plate 1 is rotated, the chopper 8 is rotated about its central axis to alternately cause the millimeter wave/terahertz wave from the first working surface and the millimeter wave/terahertz wave from the second working surface reflected by the fourth reflecting plate 7 to be received by the millimeter wave/terahertz wave detector array 2;
S2: transmitting the image data for the first inspected object 31A and the image data about the second inspected object 31B obtained by the millimeter wave/terahertz wave detector array 2 to a data processing apparatus; and
s3: the image data of the first object 31A and the image data of the second object 31B are reconstructed by a data processing apparatus to generate millimeter wave/terahertz wave images of the first object 31A and the second object 31B, respectively.
The method can simultaneously carry out omnidirectional imaging and detection on two detected objects 31A and 31B, wherein the detected object 31 can be a human body or an article. When the objects 31A, 31B are human bodies, the millimeter wave/terahertz wave imaging apparatus 100 may be used in cooperation with the article imaging apparatus 200, as shown in fig. 15, the two objects 31A and 31B may be detected at the left-side position to be detected and the right-side position to be detected, respectively, or may walk to the right-side position to be detected along a path shown by an arrow after the front detection of one object 31A at the left-side position to be detected is completed, and the back detection is completed, so that the omnidirectional detection may be completed without turning the object 31A.
In an exemplary embodiment, the method further comprises the following step before step S3: when the Y-shaped reflecting plate 1 is rotated to the calibration area, calibration data about the calibration source 5 is received through the millimeter wave/terahertz wave detector array 2; and updates the received image data of the first object 31A and the second object 31B in real time based on the calibration data of the calibration source 5.
Detected output voltage V out The corresponding antenna temperature is T A Which should satisfy the following relationship,
T A ＝(V out -b)/a (7)
where a is the gain scaling factor,
b is the offset scaling factor.
Thus, updating the received image data of the subject 31 based on the calibration data of the calibration source 5 includes correction of the offset calibration coefficient b and correction of the gain calibration coefficient a.
The radiation brightness temperature of the calibration source 5 and its surroundings can be regarded as uniform in the calibration area, i.e. the antenna temperature T of all channels A Is consistent. When the channels are completely consistent, the focal plane array receives the output V of the channels out Should be completely consistent, if the outputs are inconsistent, the gain scaling coefficient a and offset scaling coefficient b of each channel need to be adjusted to make the outputs of all channels consistent, thereby realizing the consistency adjustment of the channels. The gain scaling parameter a reflects the total gain and equivalent bandwidth of the channel, and is debugged in the channelThis part is already carefully adjusted and the gain scaling factor a for each channel can be considered approximately equal, so that correction is accomplished by adjusting the offset scaling factor b during normal use.
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 correction of the offset calibration coefficient b, comprising the steps of:
A1: calculating the average value of the multiple measurement output voltages of all channels of the millimeter wave/terahertz wave detector array in the calibration area
A2: the data after the calibration of the detection area of each channel is the data V collected by the detection area of each channel i Subtracting the average valueThen divided by the gain scaling factor a for each channel i 。
The method can carry out integral calibration on the receiving channel array of the focal plane array system, and the calibration algorithm only needs simple operation, consumes little time and can realize real-time calibration; channel consistency calibration is performed for each image.
When the apparatus is operated for a long period of time or used in place of replacement, the gain scaling factor a of each channel is often changed due to deterioration of the system performance caused by drift of the system temperature. The gain scaling factor a and offset scaling factor b of the channel are required to be adjusted at this time, and the method specifically comprises the following steps of
B1: measuring the voltage value V of air by using the millimeter wave/terahertz wave detector array air (i) I epsilon 1, number of channels]And calculates the average voltage value of the air of all channels
B2: setting the temperature of the calibration source to have a difference from the temperature of the air, usingThe millimeter wave/terahertz wave detector array measures the voltage value V of the calibration source cal (i) I epsilon 1, number of channels]And calculates the average voltage value of the calibration sources of all channelsAnd the gain scaling factor a for each channel is calculated by the following equation i And offset scaling factor b i ：
B3: the data after calibration of the detection area of each channel is thatWhere V is the absolute value of i Data acquired for the detection zone of each channel.
The data processing device acquires data twice in each 3dB beam azimuth, so that in the embodiment shown in fig. 1, at least 10 acquired data are obtained per channel in the calibration area. The output voltage data in the calibration area and the output voltage data in the detection area are both stored in the same data table of the data processing device.
As an exemplary embodiment, the method may further include S4: after the millimeter wave/terahertz wave images of the first and second objects 31A and 31B are generated, whether or not the first and second objects 31A and 31B carry suspicious objects and the positions of the suspicious objects are identified and the results are output.
In the above steps, the identification of the suspicious object and the position thereof can be performed by a method of automatic identification by a computer or manual identification or a combination of the two methods. The outputting of the result may be achieved by, for example, displaying a conclusion marked with a direct display of whether or not there is a suspicious object on the display device, or the like, and the detection result may be printed or transmitted directly.
The security check personnel executing the detection can confirm whether the human body or the article has suspicious objects and the positions of the suspicious objects according to the detection result given in the step S4, and can check by manual detection.
Those skilled in the art will appreciate that the embodiments described above are exemplary and that modifications may be made by those skilled in the art, and that the structures described in the various embodiments may be freely combined without conflict in terms of structure or principle.
Having described the preferred embodiments of the present disclosure in detail, those skilled in the art will readily appreciate that various changes and modifications may be made without departing from the scope and spirit of the following claims, and that the present disclosure is not limited to the implementations of the exemplary embodiments set forth in the specification.
Claims (20)
1. A millimeter wave/terahertz wave imaging apparatus comprising:
the quasi-optical assembly comprises a Y-shaped reflecting plate, wherein the Y-shaped reflecting plate comprises a first reflecting plate, a second reflecting plate and a third reflecting plate, and the Y-shaped reflecting plate can rotate around the rotation axis of the Y-shaped reflecting plate so that a first reflecting surface of the first reflecting plate, a first reflecting surface of the second reflecting plate and a first reflecting surface wheel flow of the third reflecting plate are used as a first working surface to receive and reflect millimeter wave/terahertz waves spontaneously radiated or reflected by parts of a first detected object, which are positioned at different positions of a first view field; and
A millimeter wave/terahertz wave detector array adapted to receive a beam from the quasi-optical assembly.
2. The imaging apparatus according to claim 1, wherein the quasi-optical assembly further includes a fourth reflection plate to which a second reflection surface of the first reflection plate opposite to the first reflection surface, a second working surface of the second reflection plate opposite to the first reflection surface, and a second working surface wheel flow of the third reflection plate opposite to the first reflection surface serve as a portion of the second working surface that receives and reflects spontaneous radiation or reflected millimeter wave/terahertz wave of a second object to be inspected at a different position of a second field of view when the Y-shaped reflection plate rotates;
a chopper on the reflection wave path of the first working face and the reflection wave path of the fourth reflecting plate, the chopper being configured to reflect or transmit only millimeter wave/terahertz waves from the first working face or only millimeter wave/terahertz waves from the fourth reflecting plate to the millimeter wave/terahertz wave detector array at any one time, the chopper rotating about its central axis so that millimeter wave/terahertz waves from the first working face and the fourth reflecting plate of the Y-shaped reflecting plate are alternately received by the millimeter wave/terahertz wave detector array.
3. The millimeter wave/terahertz wave imaging device of claim 2, wherein the quasi-optical assembly further comprises a focusing lens located between the chopper and the millimeter wave/terahertz wave detector array.
4. The millimeter wave/terahertz wave imaging apparatus according to claim 2, wherein the quasi-optical assembly further comprises a first focusing lens adapted to focus millimeter wave/terahertz waves from the first working face of the Y-shaped reflecting plate and a second focusing lens adapted to focus millimeter wave/terahertz waves from the second working face of the Y-shaped reflecting plate.
5. The millimeter wave/terahertz wave imaging apparatus according to claim 2, further comprising a wave absorbing material adapted to absorb millimeter wave/terahertz waves from the first working face reflected via the chopper and millimeter wave/terahertz waves from the fourth reflecting plate transmitted via the chopper.
6. The millimeter wave/terahertz wave imaging apparatus according to claim 2, wherein angles between 3 of the reflection plates and the rotation axis are increased or decreased in an increasing or decreasing direction along the rotation direction of the Y-shaped reflection plate.
7. The millimeter wave/terahertz wave imaging apparatus according to claim 2, wherein the chopper includes at least one blade.
8. The millimeter wave/terahertz wave imaging apparatus as set forth in claim 7, wherein a plurality of the blades are disposed around the central axis at equal intervals.
9. The millimeter wave/terahertz wave imaging apparatus according to claim 2, further comprising a housing in which the quasi-optical assembly and the millimeter wave/terahertz wave detector array are located, a first window through which a beam from the first object to be inspected passes and a second window through which a beam from the second object to be inspected passes being provided on opposite side walls of the housing, respectively.
10. The millimeter wave/terahertz wave imaging apparatus as set forth in claim 9, further comprising a first driving device adapted to drive the Y-shaped reflecting plate to rotate.
11. The millimeter wave/terahertz wave imaging apparatus according to claim 2, further comprising a second driving device adapted to drive the chopper to rotate.
12. The millimeter wave/terahertz wave imaging device according to any one of claims 2 to 11, wherein further comprising:
A data processing device connected with the millimeter wave/terahertz wave detector array to respectively receive image data for the first inspected object and image data for the second inspected object from the millimeter wave/terahertz wave detector array and respectively generate millimeter wave/terahertz wave images; and
and the display device is connected with the data processing device and is used for receiving and displaying millimeter wave/terahertz wave images from the data processing device.
13. The millimeter wave/terahertz wave imaging apparatus according to claim 12, further comprising an alarm device connected to the data processing device so that an alarm indicating that a suspicious item is present in the millimeter wave/terahertz wave image is issued when the data processing device recognizes the suspicious item in the millimeter wave/terahertz wave image.
14. The millimeter wave/terahertz wave imaging apparatus according to claim 12, further comprising a calibration source located on an object plane of the quasi-optical assembly, the data processing device receiving calibration data for the calibration source from the millimeter wave/terahertz wave detector array and updating image data of the first subject and image data of the second subject based on the calibration data.
15. The millimeter wave/terahertz wave imaging apparatus according to claim 12, further comprising an optical imaging device including a first optical imaging device adapted to acquire an optical image of the first object to be inspected and a second optical imaging device adapted to acquire an optical image of the second object to be inspected, the first and second optical imaging devices being connected to the display device, respectively.
16. The millimeter wave/terahertz wave imaging apparatus according to claim 15, wherein the display device includes a display screen including a first display area adapted to display the millimeter wave/terahertz wave image and a second display area adapted to display an optical image acquired by the optical image pickup device.
17. The millimeter wave/terahertz wave imaging apparatus according to claim 1, wherein the first and second reflection plates, the second and third reflection plates, and the third and first reflection plates each have an included angle of 120 °.
18. The millimeter wave/terahertz wave imaging apparatus as set forth in claim 16, further comprising a fifth reflecting plate that swings reciprocally around its center axis to receive and reflect millimeter wave/terahertz wave spontaneously radiated or reflected back by a first object to be inspected onto the first working face to be received by a millimeter wave/terahertz wave detector array after reflection via the first working face, the swing period T1 of the fifth reflecting plate being 2m times the rotation period of the Y-shaped reflecting plate, where m is an integer of 1 or more.
19. The millimeter wave/terahertz wave imaging apparatus as set forth in claim 18, further comprising a third driving device adapted to drive the fifth reflecting plate to oscillate reciprocally.
20. A method of detecting a human body or an article using the millimeter wave/terahertz wave imaging apparatus according to any one of claims 2 to 15, comprising the steps of:
s1: driving the Y-shaped reflecting plate to rotate, so that the first reflecting surface of the first reflecting plate, the first reflecting surface of the second reflecting plate and the first reflecting surface of the third reflecting plate are used as a first working surface to receive and reflect millimeter wave/terahertz wave spontaneously radiated or reflected back by the first detected object; the millimeter wave/terahertz wave spontaneously radiated or reflected by the second detected object is alternately formed by the second reflecting surface of the first reflecting plate, the second reflecting surface of the second reflecting plate and the second reflecting surface of the third reflecting plate to be received and reflected by the second working surface; while the Y-shaped reflecting plate rotates, a chopper rotates around a central axis thereof to alternately enable the millimeter wave/terahertz wave from the first working face and the millimeter wave/terahertz wave from the second working face reflected by a fourth reflecting plate to be received by the millimeter wave/terahertz wave detector array;
S2: transmitting image data received by the millimeter wave/terahertz wave detector array with respect to the first object and with respect to the second object to a data processing apparatus; and
s3: reconstructing image data of the first object and image data of the second object with the data processing apparatus to generate millimeter wave/terahertz wave images of the first object and the second object, respectively.
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| JP7508208B2 (en) * | 2019-09-20 | 2024-07-01 | キヤノン株式会社 | Image capture device, image capture device control method, and program |
| CN113008907B (en) * | 2019-12-19 | 2024-04-12 | 华为技术有限公司 | Terahertz sensing system and terahertz sensing array |
| CN113131224B (en) * | 2020-01-16 | 2022-08-19 | 华为技术有限公司 | Antenna beam propagation direction adjustment system |
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