CN106772367B - Long distance staring imaging device and method in the coding high-resolution of Terahertz frequency range aperture - Google Patents
Long distance staring imaging device and method in the coding high-resolution of Terahertz frequency range aperture Download PDFInfo
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Abstract
The invention belongs to radar imaging technology field, long distance staring imaging device and method in espespecially a kind of Terahertz frequency range aperture coding high-resolution.The imaging device includes terahertz sources module 1, transmitting antenna 2, automatically controlled secondary reflector array 3, paraboloid principal reflection mirror 4, reception antenna 5, Terahertz receiving module 6, memory 7 and system control host 8.The terahertz sources module is connect with transmitting antenna, and the automatically controlled secondary reflector array is connect with system control host；The paraboloid principal reflection mirror is reflected and is collimated to Terahertz coding wave beam；Reception antenna acquires the scatter echo signal of target surface；Terahertz receiving module carries out low noise amplification, mixing and quadrature demodulation to scatter echo signal and handles；System controls host to be associated imaging to echo-signal and reference signal, obtains object reconstruction image.The present invention, which obtains, to be exceeded with high resolution in the wave beam of bore conventional radar diffraction limit, and pattern switching speed is fast.
Description
Technical field
The invention belongs to radar imaging technology fields, and in particular to high resolution radar staring imaging technology, it is espespecially a kind of too
Long distance staring imaging device and method in the coding high-resolution of hertz frequency range aperture.
Background technology
High resolution radar imaging be realize battle reconnaissance, target detection and identification important means, ensuring national strategy
Safety, contention battlefield masters face have the function of very important.Conventional microwave radar system can active probe, penetration capacity
By force, can round-the-clock, all weather operations, but since microwave frequency is low, wavelength is long, and angular resolution is low, and due to image-forming principle
Limitation, need be imaged integration time, can not realize high frame frequency, high-resolution forword-looking imaging.Synthetic aperture radar (SAR) and inverse conjunction
Into aperture radar (ISAR) although imaging can obtain the high-resolution in transverse direction by synthetic aperture, the two all relies on
The relative motion of radar and target, under the conditions of forward sight, corner very little, even zero, can not staring imaging, limit SAR with
ISAR is in the application of certain occasions.And optical sensor can forword-looking imaging, wavelength is short, high resolution, and image taking speed is fast, but according to
Rely in target emanation, it is poor to penetration capacitys such as cloud, cigarette, mist and barriers, easily by such environmental effects.And in true battlefield surroundings
In, it generally requires the targets such as vehicle, strong point, personnel in penetrating outside the logarithms such as the smoke of gunpowder, haze km in remote operating distance and carries out
Quick accurately detecting and identification, for guiding, our weapon system realizes that precision strike is provided with targeted elimination to enemy's military target
Information support.And existing radar imaging system is difficult to fully meet the above-mentioned application to high-resolution, high frame frequency, forward sight staring imaging
Demand.
Terahertz aperture coding high-resolution imaging Radar Technology refers to change imaging plane by automatically controlled secondary reflector array
Terahertz emission field space width distributed mutually come obtain target scattering coefficient distribution imaging mode.Relative to microwave and light wave, too
The frequency and wavelength of hertz fall between so that Terahertz radar has relatively large absolute bandwidth and higher imaging
Resolution ratio and penetration capacity is preferably imaged, aperture coding techniques is combined under same apertures antenna conditions, is more also easy to produce more
The irradiation mode of sample and faster pattern switching speed, the potentiality that target high-resolution imaging is carried out using echo are also bigger.
Meanwhile aperture coded imaging technology can be by realizing forward sight staring imaging to target single snap.Therefore, it is expected to using limited
Aperture obtains the resolution ratio exceeded with bore conventional radar diffraction limit within the extremely short time.Although Terahertz aperture encodes
High-resolution imaging Radar Technology has many advantages relative to conventional radar imaging technique, but it is urgently to be resolved hurrily to still remain some
Problem, such as the image-forming range of system are limited, and terahertz wave beam is difficult to realize the on-mechanical uniform scanning of imaging plane, imaging
The quasi-optical design difficulty of system is larger etc..In consideration of it, there is an urgent need to carry out Terahertz frequency range aperture coding high-resolution in long distance into
As technical research, develop in high frame frequency, high-resolution, forward sight staring imaging ability and thousands of meters of system imaging distance covering
Long distance imaging device provides one for application of the Terahertz radar in the fields such as battle reconnaissance and warning, target detection and identification
New technological approaches.
Invention content
For above-mentioned technical problem, the present invention proposes a kind of device, can take into account imaging resolution and imaging speed simultaneously
Degree, and is avoided that mechanical scanning of the imaging device to imaging plane, wherein, imaging plane refer to plane where being located at target and
Comprising the geometrical plane with specific dimensions including object cross section, as shown in Figure 1, its size is joined by the structure of imaging device
Number determines.Specific technical solution is as follows：
Long distance staring imaging device in a kind of Terahertz frequency range aperture coding high-resolution, including terahertz sources module 1, hair
Penetrate antenna 2, automatically controlled secondary reflector array 3, paraboloid principal reflection mirror 4, reception antenna 5, Terahertz receiving module 6, memory 7 with
And system control host 8.
The terahertz sources module is connect with transmitting antenna, the terahertz sources letter that the terahertz sources module generates
Number, automatically controlled secondary reflector array is radiated to after emitted antenna in the form of terahertz wave beam；The automatically controlled secondary reflector array
It is connect with system control host, loading hole diameter encodes the automatically controlled secondary reflector array simultaneously under the control of system control host
Random phase shift factor and lens phase modulation factor, and aperture coding and phase are carried out to the terahertz wave beam that transmitting antenna gives off
Position modulation obtains Terahertz coding wave beam, and Terahertz further is encoded beams reflected to paraboloid principal reflection mirror；The throwing
Object plane principal reflection mirror is reflected and is collimated to Terahertz coding wave beam；Reception antenna acquires the scatter echo signal of target surface
And be transmitted to Terahertz receiving module, the Terahertz receiving module to scatter echo signal carry out low noise amplification, mixing and
Quadrature demodulation is handled, and scatter echo signal is exported to memory storage by treated；Terahertz sources will be based on to believe
Number deducing obtained reference signal is input to the memory storage；Scattering that treated in system control host calling memory
Echo-signal is associated imaging with reference signal, obtains the reconstructed image of target.
Further, the height on the automatically controlled secondary reflector array vertical direction is l, and N number of battle array is included on vertical direction
Member, each array element refer to single independent reflection phase-shifting unit, and the ratio of l and N represent the pitch of single array element.As shown in Figure 1,
Establish rectangular coordinate system, coordinate origin is overlapped with the vertex of paraboloid principal reflection mirror, horizontal axis x positive directions to the right, longitudinal axis y positive directions
Straight up, the level interval of automatically controlled secondary reflector array and transmitting antenna is e, and the level interval of focal plane is a together, with imaging
The level interval of plane is b, and b also represents the detection range of described device simultaneously.Automatically controlled secondary reflector array lower extreme point and transmitting
The vertical spacing of antenna is g, and the vertical spacing of upper extreme point and x-axis is d, coordinate origin together focal plane level interval (i.e.：Parabolic
The focal length of face principal reflection mirror) it is p.
Further, there is the work of digital lens after the automatically controlled secondary reflector array loaded lenses phase modulation factor
With the number lens focal plane coincides with confocal face with paraboloid principal reflection mirror focal plane, and confocal face where transmitting antenna with putting down
Face is conjugated about digital lens, and the automatically controlled secondary reflector array is full between focal plane and the level interval a and e of transmitting antenna together
Foot states relationship：
Wherein, f is the focal length of digital lens.
Further, the meridian plane equation of paraboloid principal reflection mirror is：
y2=4px, (2)
The present invention also provides a kind of Terahertz frequency range apertures to encode long distance staring imaging method in high-resolution, and use is above-mentioned
Terahertz frequency range aperture coding high-resolution in long distance staring imaging device, specifically include following steps：
(S1) terahertz sources module generates terahertz sources signal, after emitted antenna in the form of terahertz wave beam spoke
It is incident upon automatically controlled secondary reflector array；
(S2) the automatically controlled secondary reflector array loading aperture of system control host computer control encodes random phase shift factor and lens phase
Position modulation factor, and aperture coding is carried out to the terahertz wave beam that transmitting antenna gives off and obtains Terahertz coding with phase-modulation
Wave beam, and Terahertz is further encoded into beams reflected to paraboloid principal reflection mirror；
(S3) paraboloid principal reflection mirror is reflected and is collimated to Terahertz coding wave beam；
(S4) reception antenna acquires the scatter echo signal of target surface and is transmitted to Terahertz receiving module, the terahertz
Hereby receiving module carries out scatter echo signal low noise amplification, mixing and quadrature demodulation are handled, and will treated is scattered back
Wave signal is exported to the memory and is stored；
(S5) it deduces to obtain reference signal, and reference signal is input to the memory and is deposited based on terahertz sources signal
Storage；
(S6) treated in system control host calling memory, and echo-signal is associated with reference signal at imaging
Reason, obtains the reconstructed image of target.
Further, the step (S2) and the detailed process of (S3) are：
Aperture during system controls host according to the following formula encodes random phase shift factor generation corresponding phase distribution map, is input to
Phase loading is completed on automatically controlled secondary reflector array：
PC=random (pl,ph, m), (3)
Wherein, PCRepresent that aperture encodes random phase shift factor, plAnd phThe upper limit in random phase shift section is represented respectively under
Limit, random represent to apply m-th of array element on automatically controlled secondary reflector array vertical direction uniform in phase shift section
It is distributed random phase, the natural number that m arrives N for 1, i.e. m=1,2 ..., N；
Lens phase modulation factor during system controls host according to the following formula generates corresponding phase distribution map, is input to automatically controlled
Phase loading is completed on secondary reflector array：
Wherein, PLRepresent lens phase modulation factor, k=2 π fc/ c, fcThe centre frequency of wave beam is encoded for Terahertz, c is
The light velocity, π values be pi, ymFor the ordinate of m-th of array element central point on automatically controlled secondary reflector array vertical direction, m 1
To the natural number of N, i.e. m=1,2 ..., N；y0Phase center for lens phase modulation factor on automatically controlled secondary reflector array (makes
Obtain PL=1) ordinate of array element central point where.Lens phase modulation factor is about phase center ym=y0Central symmetry, in phase
At the center of position, PL=1, it is equivalent to and does not apply phase-modulation.
If the phase center y of lens phase modulation factor on automatically controlled secondary reflector array0Initial position be A1, and from A1
Point moves to A2Point, A1Point and A2Spacing is s, and A between point1A2The central point of line and automatically controlled secondary reflector array center point weight
It closes, basis is incident to A respectively1Point and A2The incidence angle combination mirror-reflection theorem of light determines Terahertz coding wave beam warp at point
It crosses after digital lens focus in the focus point B in confocal face1Point and B2Point, B1Point and B2Point is simultaneously again positioned at paraboloid principal reflection mirror
Focal plane on, and B1Point and B2Spacing is q between point.
A1Point and A2Distance s and B between point1Point and B2Spacing q is calculated respectively by formula (5) and (6) between point：
When phase center is located at A2During point, focus point is located at B at this time2Point, two reflection light A1B2And A2B2It hands over and throws respectively
Object plane principal reflection mirror is in C1And C2, C is calculated respectively with reference to the meridian plane equation of paraboloid principal reflection mirror at 2 points1And C22 points
Coordinate (s1,t1) and (s2,t2), in conjunction with the fundamental property of paraboloid principal reflection mirror, then by paraboloid principal reflection mirror in C1And C2
Two point reflections Terahertz coding wave beam two rim ray slopes be respectively：
Two rim rays are calculated in the terahertz light spot size that imaging plane is formed by following formula：
D1=k2(p+a+b-t2)+s2-k1(p+a+b-t1)-s1。 (9)
When phase center is located at A1During point, focus point is located at B at this time1Point, two reflection light A1B1And A2B1It hands over and throws respectively
Object plane principal reflection mirror is in C3And C4, C is calculated respectively with reference to the meridian plane equation of paraboloid principal reflection mirror at 2 points3And C42 points of seats
Mark (s3,t3) and (s4,t4), then by paraboloid principal reflection mirror in C3And C4Two edges of the Terahertz coding wave beam of two point reflections
Light slope k3With k4And the dimension D of imaging plane Terahertz hot spot at this time2It is calculated respectively by formula (10) and formula (11)：
k3=k4=0, (10)
D2=s4-s3。 (11)
The longitudinal size h of the imaging plane and caliber size w of paraboloid principal reflection mirror is counted respectively by formula (12) and formula (13)
It calculates：
H=s4-k1(p+a+b-t1)-s1, (12)
According to above-mentioned conclusion, all standing scanning, lens phase tune are carried out to imaging plane to ensure that Terahertz encodes wave beam
The phase center y of the factor processed0To fix moving step length from A on automatically controlled secondary reflector1It puts to A2Point movement, moving step length take
Value section is calculated by following formula：
Wherein, symbol Ceil (X) represents the smallest positive integral more than or equal to X.
The advantageous effects obtained using the present invention：1st, the present invention encodes random phase shift factor at automatically controlled time using aperture
Random phase shift is carried out at each array element of reflecting surface array to incident terahertz wave beam, and then changes imaging plane terahertz emission
Field space width distributed mutually, finally enables imaging device obtain and exceeds with high-resolution in the wave beam of bore conventional radar diffraction limit
Power, and pattern switching speed is fast, without being imaged integration time.2nd, the present invention makes automatically controlled time instead using the phase modulation factor of lens
The face array of penetrating plays the role of digital lens, and incident terahertz wave beam is focused and is controlled with being directed toward, while utilizes paraboloid
Principal reflection mirror is reflected and is collimated to wave beam, improves the transmission power in specific objective direction, clutter reduction/interference radiating way work(
Rate, improve signal-to-noise ratio, so as to increase the EFFECTIVE RANGE of imaging system so that Terahertz encode wave beam middle long distance be imaged away from
From above remaining that preferable collimation carries out on-mechanical all standing scanning to imaging plane, improve the imaging frame rate of device with it is steady
It is qualitative.3rd, apparatus of the present invention and method are, it can be achieved that the Terahertz frequency range aperture encodes long distance staring imaging device in high-resolution
Target during logarithm km is outer in remote operating distance carries out high frame frequency, high-resolution, forward sight and stares all standing scanning imagery.
Description of the drawings
Fig. 1 is the structure diagram of apparatus of the present invention；
Fig. 2 is the method for the present invention flow diagram；
Figure label is：
1st, terahertz sources module, 2, transmitting antenna, 3, automatically controlled secondary reflector array, 4, paraboloid principal reflection mirror, 5, connect
Receive antenna, 6, Terahertz receiving module, 7, memory, 8, system control host.
Specific embodiment
The invention will be further described in the following with reference to the drawings and specific embodiments.
In the present invention, it is contemplated that the operating mode of the device in the horizontal and vertical directions has symmetry, with vertical side
The present invention will be described for.Establish rectangular coordinate system as shown in Figure 1, coordinate origin and paraboloid principal reflection mirror
Vertex overlaps, and to the right, longitudinal axis y positive directions are straight up for horizontal axis x positive directions.The present invention proposes a kind of Terahertz frequency range aperture and compiles
Code high-resolution in long distance staring imaging device, as shown in Figure 1, described device include terahertz sources module 1, transmitting antenna 2,
Automatically controlled secondary reflector array 3, paraboloid principal reflection mirror 4, reception antenna 5, Terahertz receiving module 6, memory 7 and system control
Host 8 processed.Wherein, system control host mainly includes three functions, respectively：For being controlled to automatically controlled secondary reflector array
System deduces reference signal on the basis of terahertz sources signal and is carried out scatter echo signal and reference signal
Relevance imaging processing.
The method of the present invention flow chart is as shown in Fig. 2, terahertz sources module is connect with transmitting antenna, terahertz sources module
The terahertz sources signal of generation is radiated to automatically controlled secondary reflector array after emitted antenna in the form of terahertz wave beam；Electricity
Control secondary reflector array is connect with system control host, and loading hole diameter coding is random simultaneously under the control of system control host moves
Phase factor and lens phase modulation factor, and aperture coding and phase-modulation are carried out to the terahertz wave beam that transmitting antenna gives off
Terahertz coding wave beam is obtained, and Terahertz is further encoded into beams reflected to paraboloid principal reflection mirror；It is loaded with lens phase
The automatically controlled secondary reflector array of position modulation factor has the function of digital lens, the number lens focal plane and paraboloid principal reflection
Mirror focal plane coincides with confocal face, and paraboloid principal reflection mirror is reflected and collimated to Terahertz coding wave beam；Reception antenna is adopted
Collect target surface scatter echo signal simultaneously be transmitted to Terahertz receiving module, Terahertz receiving module to scatter echo signal into
Row low noise amplification, mixing and quadrature demodulation processing, and scatter echo signal is exported to memory storage by treated；
The reference signal deduced based on terahertz sources signal is input to memory storage；System control host calls memory
In treated echo-signal and reference signal and combine existing parametric method, orthogonal matching pursuit, matched filtering or sparse
The data processing techniques such as reconstruct are associated imaging, obtain the reconstructed image of target.
In embodiment, the height on the automatically controlled secondary reflector array vertical direction is l, and N number of battle array is included on vertical direction
Member, each array element refer to single independent reflection phase-shifting unit, and the level interval of automatically controlled secondary reflector array and transmitting antenna is e,
The level interval of focal plane is a together, and the level interval with imaging plane is b, automatically controlled secondary reflector array lower extreme point and transmitting day
The vertical spacing of line is g, and the vertical spacing of upper extreme point and x-axis is d, coordinate origin together focal plane level interval (i.e.：Paraboloid
The focal length of principal reflection mirror) for p, A on automatically controlled secondary reflector array1Point and A2Spacing is s, and A between point1A2The central point of line
It is overlapped with automatically controlled secondary reflector array center point, therefore A1Point coordinates be (a+p ,-d- (l+s)/2), A2Point coordinates is (a+p ,-d-
(l-s)/2).The ratio of l and N represents the pitch of single array element, and pitch is smaller, then can be on smaller unit scale to emitting day
The terahertz wave beam of beta radiation carries out aperture coding and phase-modulation, to obtain better encoding efficiency and Wave beam forming ability,
Its specific value is determined by the processing technology of automatically controlled secondary reflector array, with the reflective phased array plane day based on crystal liquid substrate
For line, array element pitch is usually hundreds of microns.B represents the detection range of device of the present invention, and usually 2000.00m is extremely
Middle long distance areas imaging in the range of 10000.00m.Transmitting antenna will not be right with automatically controlled secondary reflector array in device is ensured
Under the premise of Terahertz coding wave beam generation is blocked, the geometric dimension of system can be reduced by reducing the value of g and d, usually
It can be set in the section of 0.01m to 0.05m.A, the value of p and e can be set in the section of 1.00m to 5.00m.
In the present invention, automatically controlled secondary reflector array meets following together between focal plane and the level interval a and e of transmitting antenna
Relationship：
Wherein, f is the focal length of digital lens.
In the present invention, the meridian plane equation of paraboloid principal reflection mirror is：
y2=4px.
As shown in Figure 1, phase center (the ordinate of array element center where phase center of lens phase modulation factor
As y in formula (4)0Value) from A1Point moves to A2Point, at this time according to the incidence angle combination minute surface for being incident to light at the point
Reflection theorem can determine that focus point of the Terahertz coding wave beam in confocal face after digital lens focus is respectively B1Point and B2
Point.B1Point and B2Point is simultaneously again on the focal plane of paraboloid principal reflection mirror, and B1Point and B2Spacing is q, B between point1Point is sat
It is designated as (p, 0), B2Point coordinates is (p, q).
When the phase center of lens phase modulation factor is located at A1During point, closed according to mirror-reflection theorem and light path geometry
System, derives：
When the phase center of lens phase modulation factor is located at A2During point, can similarly it obtain：
When phase center is located at A2During point, focus point is located at B at this time2Point, two reflection light A1B2And A2B2It hands over and throws respectively
Object plane principal reflection mirror is in C1And C2, C is calculated respectively with reference to the meridian plane equation of paraboloid principal reflection mirror at 2 points1And C22 points
Coordinate (s1,t1) and (s2,t2), in conjunction with the fundamental property of paraboloid principal reflection mirror, then by paraboloid principal reflection mirror in C1And C2
Point reflection Terahertz coding wave beam two rim ray slopes be respectively：
Two rim rays are calculated in the terahertz light spot size that imaging plane is formed by following formula：
D1=k2(p+a+b-t2)+s2-k1(p+a+b-t1)-s1。
When phase center is located at A1During point, focus point is located at B at this time1Point, two reflection light A1B1And A2B1It hands over and throws respectively
Object plane principal reflection mirror is in C3And C4, C is calculated respectively with reference to the meridian plane equation of paraboloid principal reflection mirror at 2 points3And C42 points of seats
Mark (s3,t3) and (s4,t4), then by paraboloid principal reflection mirror in C3And C4Two edges of the Terahertz coding wave beam of two point reflections
Light slope k3With k4And the dimension D of imaging plane Terahertz hot spot at this time2It is calculated respectively by following formula：
k3=k4=0,
D2=s4-s3。
The longitudinal size h of imaging plane is calculated with the caliber size w of paraboloid principal reflection mirror by following formula respectively：
H=s4-k1(p+a+b-t1)-s1,
According to above-mentioned conclusion, all standing scanning, lens phase tune are carried out to imaging plane to ensure that Terahertz encodes wave beam
The phase center y of the factor processed0It must be with particular step size from A on automatically controlled secondary reflector1It puts to A2Point movement, moving step length take
Value section is calculated by following formula：
Wherein, symbol Ceil (X) represents the smallest positive integral more than or equal to X.
In the present invention, the method that the relevance imaging processing uses includes existing parametric method, orthogonal matching pursuit, matching
Filtering or sparse reconstruct etc..The method that relevance imaging processing uses can only with a kind of above-mentioned method or wherein
Several method is used in combination.
In the present invention, the automatically controlled secondary reflector array of described device can be used the reflective phased array based on crystal liquid substrate and put down
The reflective phased array flat plane antenna based on Meta Materials technology can also be used in surface antenna.
Below by taking the reflective phased array flat plane antenna based on crystal liquid substrate as an example, determine that automatically controlled secondary reflector array is vertical
Height l=0.10m on direction includes 200 array elements, i.e. N=200, automatically controlled secondary reflector array and transmitting on vertical direction
The level interval of antenna is e=1.00m, is b=2500.00m with the level interval of imaging plane, under automatically controlled secondary reflector array
The vertical spacing of endpoint and transmitting antenna is g=0.02m, and the vertical spacing of upper extreme point and x-axis is d=0.01m, coordinate origin with
The level interval in confocal face is (i.e.：The focal length of paraboloid principal reflection mirror) it is p=5.00m, the focal length f=0.50m of digital lens.
With reference to above-mentioned parameter, the level interval a=of automatically controlled secondary reflector array focal plane together is calculated by formula (1)
1.00m。
System controls host to encode random phase shift factor P according to apertureC=random (- 0.5 π, 0.5 π, m) generations correspond to
Phase distribution figure, be input on automatically controlled secondary reflector array complete phase loading, wherein m be 1 to 200 natural number, i.e. m=1,
2 ..., 200.Meanwhile system controls host according to lens phase modulation factorGenerate corresponding phase distribution
Figure is input on automatically controlled secondary reflector array and completes phase loading.Wherein, k=2 π fc/ c, the center frequency of Terahertz coding wave beam
Rate fc=300.00GHz, light velocity c=3 × 108m/s。ymFor m-th of array element central point on automatically controlled secondary reflector array vertical direction
Ordinate, m be 1 to 200 natural number, i.e. m=1,2 ..., 200.y0To be located at A on automatically controlled secondary reflector array1Point and A2
The ordinate of array element central point where lens phase modulation factor phase center between point.In embodiment, each array element center
Point ordinate can according to automatically controlled secondary reflector array sizes with comprising array number calculated.
A on automatically controlled secondary reflector array is calculated according to formula (5)1Point and A2Spacing is s=0.01m, and A between point1A2
Central point is overlapped with automatically controlled secondary reflector array center point, then A1Point coordinates be (6, -0.065), A2Point coordinates for (6 ,-
0.055).B is calculated according to formula (6)1Point and B2Spacing is q=0.02m between point, then B1Point coordinates be (5,0), B2Point is sat
It is designated as (5,0.02).
When phase center is located at A2During point, C can be obtained1Point and C2Point coordinate be respectively (0.17,0.0014) and (0.67,
0.02) two rim ray slope ks of Terahertz coding wave beam after collimation are calculated, and by formula (7) and formula (8) respectively1=-
0.0040 and k2=-0.0039 then calculates the dimension D of the outer imaging plane Terahertz hot spots of 2500.00m at this time according to formula (9)1=
0.63m。
When phase center is located at A1During point, C can be obtained3Point and C4Point coordinate be respectively (0.050,0.00013) and
(0.55,0.015) understands two rim ray slope ks by formula (10)3=k4=0 and by formula (11) understand at this time
The dimension D of imaging plane Terahertz hot spot at 2500.00m2=0.50m.
Respectively according to formula (12) and formula (13) calculate imaging plane longitudinal size h=10.39m and paraboloid master it is anti-
Penetrate the caliber size w=0.62m of mirror.
The phase center y of lens phase modulation factor is finally obtained according to formula (14)0In automatically controlled secondary reflector from A1Point to
A2The interval of the mobile step-length of point is 0.00048m≤Δ≤0.00053m, therefore, step-length may be selected in implementation process
Δ=0.0005m.
According to above structure index obtain in the present embodiment imaging plane of the imaging device at the 2500.00m that adjusts the distance into
During row blocked scan, scanning light spot change in size ranging from 0.50m~0.63m, almost maintain it is constant, illustrate be at this
Terahertz coding wave beam has good collimation property under system framework, and the imaging performances such as resolution ratio for promoting imaging system have
It is significant.
The explanation of the preferred embodiment of the present invention contained above, this be for the technical characteristic that the present invention will be described in detail, and
It is not that invention content is limited in the described concrete form of embodiment, other modifications that content purport carries out according to the present invention
It is also protected with modification by this patent.The purport of the content of present invention is defined by the claims rather than by the specific of embodiment
Description is defined.
Claims (6)
1. a kind of long distance staring imaging device in Terahertz frequency range aperture coding high-resolution, it is characterised in that：It is sent out including Terahertz
Penetrate module (1), transmitting antenna (2), automatically controlled secondary reflector array (3), paraboloid principal reflection mirror (4), reception antenna (5), terahertz
Hereby receiving module (6), memory (7) and system control host (8)；
The terahertz sources module is connect with transmitting antenna, the terahertz sources signal that the terahertz sources module generates,
Automatically controlled secondary reflector array is radiated to after emitted antenna in the form of terahertz wave beam；Automatically controlled secondary reflector array vertical direction
On height for l, refer to the ratio of single independent reflection phase-shifting unit, l and N comprising N number of array element, each array element on vertical direction
The pitch of single array element is represented, establishes rectangular coordinate system, coordinate origin is overlapped with the vertex of paraboloid principal reflection mirror, and horizontal axis x is just
To the right, straight up, the level interval of automatically controlled secondary reflector array and transmitting antenna is e to longitudinal axis y positive directions, together focal plane in direction
Level interval for a, the level interval with imaging plane is b, automatically controlled secondary reflector array lower extreme point and transmitting antenna it is vertical
Spacing is g, and the vertical spacing of upper extreme point and x-axis is d；The automatically controlled secondary reflector array is connect with system control host, described
Loading hole diameter encodes random phase shift factor and lens phase to automatically controlled secondary reflector array simultaneously under the control of system control host
Modulation factor, and aperture coding is carried out to the terahertz wave beam that transmitting antenna gives off and obtains Terahertz coding wave with phase-modulation
Beam, and Terahertz is further encoded into beams reflected to paraboloid principal reflection mirror；The focal length of the paraboloid principal reflection mirror is p,
Focal plane and the focal plane of digital lens coincide with confocal face, and the paraboloid principal reflection mirror carries out Terahertz coding wave beam anti-
It penetrates and collimates；The scatter echo signal of reception antenna acquisition target surface is simultaneously transmitted to Terahertz receiving module, the Terahertz
Receiving module carries out scatter echo signal low noise amplification, mixing and quadrature demodulation are handled, and will treated scatter echo
Signal is exported to the memory and is stored；System control host call in memory treated scatter echo signal with based on too
The reference signal that hertz transmitting signal is deduced is associated imaging, obtains the reconstructed image of target.
2. long distance staring imaging device in a kind of Terahertz frequency range aperture coding high-resolution according to claim 1, special
Sign is：The level interval of the automatically controlled secondary reflector array and coordinate origin is a+p, and the automatically controlled secondary reflector array is together
Meet following relationships between focal plane and the level interval a and e of transmitting antenna：
Wherein, f is the focal length of digital lens.
3. long distance staring imaging device in a kind of Terahertz frequency range aperture coding high-resolution according to claim 1, special
Sign is：The phase center initial position of lens phase modulation factor is A on the automatically controlled secondary reflector1Point, A1Point is located at automatically controlled
Below secondary reflector array center point at s/2, Terahertz is corresponded at this time and encodes wave beam after digital lens focus in confocal face
Focus point be B1Point, B1Point is located exactly at the intersection point of confocal face and x-axis, and s is given by：
4. a kind of long distance staring imaging method in Terahertz frequency range aperture coding high-resolution, it is characterised in that：It will using such as right
The Terahertz frequency range aperture described in 1 or 2 is asked to encode long distance staring imaging device in high-resolution, specifically includes following steps：
(S1) terahertz sources module generates terahertz sources signal, is radiated in the form of terahertz wave beam after emitted antenna
Automatically controlled secondary reflector array；
(S2) the automatically controlled secondary reflector array loading aperture of system control host computer control encodes random phase shift factor and lens phase tune
The factor processed makes it have the effect of digital lens, and carries out aperture coding and phase to the terahertz wave beam that transmitting antenna gives off
Position modulation obtains Terahertz coding wave beam, and Terahertz further is encoded beams reflected to paraboloid principal reflection mirror；
(S3) focal length of paraboloid principal reflection mirror is p, and focal plane and the focal plane of digital lens coincide with confocal face, paraboloid
Principal reflection mirror is reflected and is collimated to Terahertz coding wave beam；
(S4) reception antenna acquires the scatter echo signal of target surface and is transmitted to Terahertz receiving module, and the Terahertz connects
It receives module and low noise amplification, mixing and quadrature demodulation processing is carried out to scatter echo signal, and scatter echo is believed by treated
Number output to the memory store；
(S5) it deduces to obtain reference signal, and reference signal is input to the memory and is stored based on terahertz sources signal；
(S6) treated in system control host calling memory, and scatter echo signal is associated with reference signal at imaging
Reason, obtains the reconstructed image of target.
5. long distance staring imaging method in a kind of Terahertz frequency range aperture coding high-resolution according to claim 4, special
Sign is：The specific design process of the step (S2) is：
The phase center initial position of lens phase modulation factor is A on automatically controlled secondary reflector array1, and from A1Point moves to A2Point,
A1Point and A2Spacing is s, and A between point1A2The central point of line is overlapped with automatically controlled secondary reflector array center point, is distinguished at this time
According to being incident to A1Point and A2The incidence angle combination mirror-reflection theorem of light determines Terahertz coding wave beam by number thoroughly at point
In the focus point B in confocal face after mirror focusing1Point and B2Point, B1Point and B2Point is simultaneously again positioned at the focal plane of paraboloid principal reflection mirror
On, and B1Point and B2Spacing is q between point；B1Point and B2Spacing q is calculated by formula (6) between point：
6. long distance staring imaging method in a kind of Terahertz frequency range aperture coding high-resolution according to claim 5, special
Sign is：The specific design process of the step (S3) is：
When phase center is located at A2During point, focus point is located at B at this time2Point, two reflection light A1B2And A2B2Paraboloid is handed over respectively
Principal reflection mirror is in C1And C2, C is calculated respectively with reference to the meridian plane equation of paraboloid principal reflection mirror at 2 points1And C22 points of coordinate
(s1,t1) and (s2,t2), in conjunction with the fundamental property of paraboloid principal reflection mirror, then by paraboloid principal reflection mirror in C1And C22 points
Reflection Terahertz coding wave beam two rim ray slopes be respectively：
Two rim rays are calculated in the terahertz light spot size that imaging plane is formed by following formula：
D1=k2(p+a+b-t2)+s2-k1(p+a+b-t1)-s1； (9)
When phase center is located at A1During point, focus point is located at B at this time1Point, two reflection light A1B1And A2B1Paraboloid is handed over respectively
Principal reflection mirror is in C3And C4, C is calculated respectively with reference to the meridian plane equation of paraboloid principal reflection mirror at 2 points3And C42 points of coordinate
(s3,t3) and (s4,t4), then by paraboloid principal reflection mirror in C3And C4Two edge-lights of the Terahertz coding wave beam of two point reflections
Line slope k3With k4And the dimension D of imaging plane Terahertz hot spot at this time2It is calculated respectively by formula (10) and formula (11)：
k3=k4=0, (10)
D2=s4-s3； (11)
The longitudinal size h of the imaging plane and caliber size w of paraboloid principal reflection mirror is calculated respectively by formula (12) and formula (13)：
H=s4-k1(p+a+b-t1)-s1, (12)
All standing scanning is carried out to imaging plane to ensure that Terahertz encodes wave beam, the phase center of lens phase modulation factor exists
To fix moving step length from A on automatically controlled secondary reflector1It puts to A2Point movement, the interval of moving step length are calculated by following formula：
Wherein, symbol Ceil (X) represents the smallest positive integral more than or equal to X.
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| CN107607944B (en) * | 2017-08-29 | 2020-01-17 | 中国人民解放军国防科技大学 | Forward-looking imaging device based on terahertz frequency band transmission type aperture coding |
| CN107918125B (en) * | 2017-11-15 | 2018-10-02 | 中国人民解放军国防科技大学 | Single-emitting multi-receiving terahertz aperture coding imaging device and method |
| CN107942328B (en) * | 2017-11-15 | 2018-11-13 | 中国人民解放军国防科技大学 | Terahertz aperture coding three-dimensional target scanning imaging method |
| CN108132465B (en) * | 2017-12-13 | 2021-06-29 | 西安电子科技大学 | Terahertz radar forward-looking imaging method based on reflecting antenna |
| CN108917929B (en) * | 2018-05-24 | 2024-04-19 | 中国科学院上海微系统与信息技术研究所 | Terahertz confocal microscopic imaging system and imaging method thereof |
| CN109633619A (en) * | 2019-01-08 | 2019-04-16 | 湖南赛博诺格电子科技有限公司 | A kind of radar system based on information Super-material antenna |
| CN110764107B (en) * | 2019-10-14 | 2021-10-26 | 中国人民解放军国防科技大学 | Terahertz aperture coding phase-free imaging device and method based on array incoherent detector |
| CN110780296A (en) * | 2019-10-25 | 2020-02-11 | 西安电子科技大学 | Real aperture radar imaging method based on digital coding metamaterial and compressed sensing |
| CN110988906A (en) * | 2019-11-22 | 2020-04-10 | 湖北三江航天险峰电子信息有限公司 | Terahertz intensity correlation detection device |
| CN113447906B (en) * | 2021-08-31 | 2022-01-04 | 江苏易珩空间技术有限公司 | Detection and identification method, device and system based on information superstructure surface |
| CN114859353B (en) * | 2022-07-11 | 2022-09-27 | 中国人民解放军国防科技大学 | Aperture coding imaging system modeling method and device based on radiation field equivalent measurement |
| CN116136496B (en) * | 2023-04-04 | 2023-07-21 | 中国科学院光电技术研究所 | BRDF measurement system based on parabolic reflector |
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