CN206832995U - The system of the full coherent Terahertz three-dimension high-resolution imaging of heterodyne system - Google Patents
The system of the full coherent Terahertz three-dimension high-resolution imaging of heterodyne system Download PDFInfo
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Abstract
The utility model discloses a kind of full coherent Terahertz three-dimension high-resolution imaging system of heterodyne system, system includes transmit-receive sharing lens antenna, Terahertz linear frequency modulation ripple transmitter module, Terahertz linear frequency modulation ripple receiving module, X Y two-dimensional scanning platforms, the full coherent module of signal, data acquisition and processing (DAP) module, image processing module and image-display units.The utility model has frequency in Terahertz frequency range, and the full coherent design of total system heterodyne, using single antenna, system architecture is simple, small volume, plane, Depth Imaging high resolution, is millimeter magnitude, the advantages such as system frequency, power stability are good.
Description
Technical field
The system that the utility model is related to a kind of full coherent Terahertz three-dimension high-resolution imaging of heterodyne system.
Background technology
U.S. jet propulsion laboratory (Jet Propulsion Laboratory), Pacific Northwest National Laboratory
(Pacific Northwest National Laboratory), German applied science research institute (FGAN-Research
Institute), China Engineering Physics Research Institute, Chinese Academy of Sciences's electromagnetic radiation and Detection Techniques laboratory, Capital Normal University
Terahertz wave spectrum and imaging experiment the room equal input research of department of physics Terahertz 3-D imaging system simultaneously has made great progress.
But the Terahertz three-dimensional imaging that they design uses double antenna (an antenna transmission signal, an antenna reception signal), except electricity
Outside sub- device, it is also necessary to optical element, such as spectroscope etc., light path system is built, therefore, system architecture is complicated, and cost is higher,
Integrated difficulty, is not suitable for practical implementation；It is additionally, since and the signal source such as a frequency source and linear frequency sweep source is only realized into heterodyne
Coherent is not implemented in formula coherent, other active devices (such as power amplifier, frequency multiplier), is protected enough so as to which the stability of a system lacks
Barrier.In addition, for the bandwidth center frequency of system than relatively low, depth resolution is poor, and is had a long way to go with flat resolution, such as
The centre frequency of China Engineering Physics Research Institute's design is 140GHz, the 3-D imaging system with a width of 5GHz, bandwidth center ratio
Frequency ratio only 3.57%, flat resolution 1.4mm, depth resolution 30mm.
Therefore, it is necessary to which a kind of system architecture is simple, using single antenna, and the not pure electronic device knot of Additional passes system
Structure, bandwidth center frequency than it is big, stability is good, the full coherent Terahertz 3-D imaging system of high resolution heterodyne system.
Utility model content
The utility model is in order to solve the above problems, it is proposed that a kind of full coherent Terahertz three-dimension high-resolution of heterodyne system into
The system of picture, the utility model are based on Terahertz science, linear frequency modulation ranglng principle and super-heterodyne technique, design hardware circuit production
Raw, reception Terahertz ultra wide band transmission signal simultaneously ensures integrated circuit element coherent, realizes to measurand high-resolution, clearly
Reliable three-dimensional imaging.
To achieve these goals, the utility model adopts the following technical scheme that：
A kind of system of the full coherent Terahertz three-dimension high-resolution imaging of heterodyne system, including X-Y two-dimensional scanning platforms, terahertz
Hereby linear frequency modulation ripple transmitter module, Terahertz linear frequency modulation ripple receiving module, transmit-receive sharing lens antenna, the full phase moduli of signal
Block, data acquisition and processing (DAP) module, image processing module and image-display units, wherein：
The X-Y two-dimensional scanning platforms fix measurand, and move measurand point by point along X-axis and Y-axis；
The Terahertz linear frequency modulation ripple transmitter module produces radiofrequency signal and is sent to measurand；
The echo-signal that the Terahertz linear frequency modulation ripple receiving module detection is reflected back from measurand, and produce local oscillator
Signal obtains test signal with echo-signal down-converted；
The transmit-receive sharing lens antenna is believed to the echo that the radiofrequency signal of measurand transmitting focusing and reception are reflected back
Number；
Radiofrequency signal and local oscillation signal down-converted are obtained reference signal by the full coherent module of signal, then will ginseng
Examine signal and the further down-converted of test signal obtains difference frequency signal；
The data acquisition and processing (DAP) module stops in any in X-Y two-dimensional scanning platforms and after stabilization, collection difference frequency letter
Number and store, be then uploaded to processor processes data；
Described image processing module builds 3-D view according to the data after all processing, and is made using image processing techniques
It is apparent；
Described image display unit shows measurand clearly reliable three-dimensional imaging figure.
Further, the Terahertz linear frequency modulation ripple transmitter module, Terahertz linear frequency modulation ripple receiving module and data
Collection and processing module are started working after the pulse signal synchronization hardware external trigger of signal generator output.
Further, the Terahertz linear frequency modulation ripple transmitter module include the first signal source, K-band linear frequency sweep source,
Power splitter, the first frequency mixer, the first power amplifier, varactor doubler, the first frequency tripler, the first directional coupler and second are fixed
To coupler, first signal source connects the local oscillator end of the first frequency mixer, and the K-band linear frequency sweep source connects by power splitter
Connect the intermediate frequency end of the first frequency mixer, the RF output end of the first frequency mixer be connected with turn the first power amplifier, varactor doubler,
First frequency tripler, the first directional coupler and the second directional coupler.
Further, the Terahertz linear frequency modulation ripple receiving module includes secondary signal source, the K-band linear frequency sweep
Source, power splitter, the second frequency mixer, the second power amplifier, the second frequency tripler, the 3rd directional coupler, the first subharmonic mix
Frequency device, the first bandpass filter and the first low-noise amplifier, the secondary signal source connect the local oscillator end of the second frequency mixer, institute
The intermediate frequency end that K-band linear frequency sweep source connects the second frequency mixer by power splitter is stated, the RF output end of the second frequency mixer is successively
It is connected with the second power amplifier, the second frequency tripler and the 3rd directional coupler, the first th harmonic mixer local oscillator end
Receive the output signal of the 3rd directional coupler and radio-frequency head receives the output signal of second directional coupler, intermediate frequency output
End is sequentially connected the first bandpass filter and the first low-noise amplifier.
Further, first signal source and secondary signal source are point-frequency signal source.
Further, the full coherent module of the signal causes Terahertz linear frequency modulation ripple transmitter module and Terahertz linearly to adjust
Frequency ripple receiving module is realized relevant.
Further, the full coherent module of the signal includes the second th harmonic mixer, the second bandpass filter, second low
Noise amplifier and three-mixer, the output signal of the 3rd directional coupler and the first directional coupler respectively enter
The local oscillator end of second harmonic mixer and radio-frequency head, the second th harmonic mixer medium frequency output end are sequentially connected the second bandpass filtering
Device, the second low-noise amplifier and three-mixer.Further, the three-mixer radio-frequency head and local oscillator end receive respectively
The output signal of the output signal of second low-noise amplifier and the first low-noise amplifier, and be mixed, down-converted
Intermediate frequency end output difference frequency signal afterwards.
Further, the data acquisition and processing (DAP) module includes usb data capture card and processor, usb data collection
Card collection difference frequency signal simultaneously stores, and processor carries out data two dimension according to X-Y two-dimensional scanning platforms move mode and reset, then carries out
The processing such as fast Fourier transform, wherein frequency characterize the positional information of measurand depth direction, and amplitude characterizes measurand
Reflected signal strength.
Further, image processing module builds measurand 3-D view according to the data after processing, then passes through figure
Picture fusion, enhancing, recovery, conversion and signature analysis scheduling algorithm become apparent from image, and visual display unit shows finally clear
Reliable three-dimensional imaging figure.
Method of work based on said system, comprises the following steps：
(1) measurand is placed in X-Y two-dimensional scanning platforms, is moved along X and Y-direction, is stopped after being often moved to a bit；
(2) stop and after stabilization after X-Y two-dimensional scanning platforms, signal generator produces pulse signal and triggers Terahertz simultaneously
Linear frequency modulation ripple transmitter module, Terahertz linear frequency modulation ripple receiving module and data acquisition and processing module are started working；
(3) Terahertz linear frequency modulation ripple transmitter module generation transmission signal, scanned by transmit-receive sharing lens antenna tested
Object, transmit-receive sharing lens antenna receive the echo-signal that measurand is reflected back, the production of Terahertz linear frequency modulation ripple receiving module
Raw local oscillation signal obtains test signal with echo-signal down-converted；
(4) transmission signal and local oscillation signal are mixed to obtain reference signal first by the full coherent module of signal, then will refer to letter
Number it is mixed to obtain difference frequency signal with test signal；
(5) data acquisition and processing (DAP) module is acquired and stored to difference frequency signal, and then X-Y two-dimensional scanning platforms move to
The next position, by that analogy, so as to realize the scanning of N number of point, the scanning in face is finally realized, the data of storage are carried out through processor
A variety of processing such as 2-D data rearrangement, Fast Fourier Transform (FFT), Windowed filtering；
(6) image processing module builds 3-D view according to data, and utilizes image enhaucament, recovery, segmentation and feature point
The image processing techniques such as analysis make apparent.
(7) image-display units show the measurand generated clearly reliable three-dimensional imaging figure.
Compared with prior art, the beneficial effects of the utility model are：
(1) it is simple in construction, it is easy of integration：Signal source, power amplifier, frequency multiplier and the directional couple that the utility model uses
The electronic device small volume such as device, and single antenna is received and dispatched, and makes circuit structure simple, easy of integration.
(2) cost is relatively low, and is adapted to engineer applied：The utility model is merely with electronic device, it is not necessary to expensive optics
Device (such as laser), the cost of system is greatly reduced, while be also more convenient to move and for actual engineering-environment.
(3) imaging resolution is high：The utility model obtains 171.6~219.6GHz frequency using many times frequency multiplication mode,
Bandwidth is up to 48GHz, and flat resolution can reach 3.12mm, and depth resolution can reach 3.125mm.
(4) stability is good：The utility model is using Terahertz linear frequency modulation ripple transmitter module and the full coherent of receiving module
The problems such as designing, making all active devices, the frequency displacement of passive device and temperature drift is obtained for effective suppression, and at present in the world
The system of other research units design is only by signal source coherent, therefore the stability of a system of the utility model design has uniqueness
Advantage.
(5) signal to noise ratio is high：System uses active terahertz imaging, and echo-signal signal to noise ratio is significantly larger than passive type terahertz
The hereby signal to noise ratio of imaging system reception signal, and then obtain higher image quality.
(6) it is widely used：There is high-resolution imaging and structure using the full coherent Terahertz 3-D imaging system of heterodyne system
The advantages that simple, it can be used for various types of materials (such as glass, ceramics, timber) nondestructive inspection, contraband detecting and remote sensing
Etc. multiple fields.
Brief description of the drawings
The Figure of description for forming the part of the application is used for providing further understanding of the present application, and the application's shows
Meaning property embodiment and its illustrate be used for explain the application, do not form the improper restriction to the application.
Fig. 1 is the block diagram of system of the present utility model；
Fig. 2 is hardware external trigger schematic diagram of the present utility model；
Fig. 3 is the circuit diagram of transmitter module of the present utility model, receiving module and the full coherent module of signal；
Fig. 4 is structural representation of the present utility model；
Fig. 5 is the flow chart of imaging process of the present utility model.
Wherein, 101, Terahertz linear frequency modulation ripple transmitter module, 102, transmit-receive sharing lens antenna, 103, Terahertz it is linear
Frequency-modulated wave receiving module, 104, the full coherent module of signal, 105, data acquisition and processing (DAP) module, 106, image processing module,
107th, image-display units, 108, measurand, 109, X-Y two-dimensional scanning platforms；
201st, processor, 202, signal generator, 203, usb data capture card；
301 first signal sources, the 302, first frequency mixer, the 303, first power amplifier, 304, varactor doubler, 305, first
Frequency tripler, the 306, first directional coupler, the 307, second directional coupler, 308, K-band linear frequency sweep source, 309, work(point
Device, 310, secondary signal source；
311st, the second frequency mixer, the 312, second power amplifier, the 313, second frequency tripler, the 314, the 3rd directional couple
Device, the 315, first th harmonic mixer, the 316, first bandpass filter, the 317, first low-noise amplifier, 318, second is humorous
Wave mixing device, the 319, second bandpass filter, the 320, second low-noise amplifier, 321, three-mixer；
401st, measurand defect, 402, circuit system.
Embodiment：
The utility model is described in further detail with embodiment below in conjunction with the accompanying drawings.
It is noted that described further below is all exemplary, it is intended to provides further instruction to the application.It is unless another
Indicate, all technologies used herein and scientific terminology are with usual with the application person of an ordinary skill in the technical field
The identical meanings of understanding.
It should be noted that term used herein above is merely to describe embodiment, and be not intended to restricted root
According to the illustrative embodiments of the application.As used herein, unless the context clearly indicates otherwise, otherwise singulative
It is also intended to include plural form, additionally, it should be understood that, when in this manual using term "comprising" and/or " bag
Include " when, it indicates existing characteristics, step, operation, device, component and/or combinations thereof.
As background technology is introduced, Terahertz three-dimensional imaging in the prior art be present and use a double antenna (antenna
Transmission signal, an antenna reception signal), in addition to electronic device, it is also necessary to optical element, system architecture is complicated, cost is higher,
In integrated difficult, unsuitable practical implementation and the unrealized coherent of active device (such as power amplifier, frequency multiplier), bandwidth
Frequency of heart is more poor than relatively low, depth resolution and the deficiency that is had a long way to go with flat resolution, in order to which the technology solved as above is asked
Topic, present applicant proposes a kind of linear frequency-modulated wave transmitter module of ether hertz, Terahertz linear frequency modulation ripple receiving module, signal are complete
Coherent module is that the structure of core is simple, stability is good, high resolution Terahertz 3-D imaging system.
In a kind of typical embodiment of the application, Terahertz 3-D imaging system is broadly divided into terahertz time-domain spectroscopy
Imaging and THz continuous wave imaging.Terahertz time-domain spectroscopy imaging general principle be：Gain freedom space and sample respectively
Terahertz pulse time domain waveform, contain intensity and phase information in time domain waveform, obtained by appropriate processing and analysis
The Terahertz 3-D view of sample.The general principle of THz continuous wave three-dimensional imaging is：Based on linear frequency modulation ranglng principle, obtain
Resolution ratio of the measurand in depth direction is obtained, the amplitude for gathering signal characterizes intensity.Terahertz time-domain spectroscopy is imaged and continuous
The maximum difference of ripple imaging is transmission power, and the transmission power of time-domain spectroscopy system is the nanowatt order of magnitude, and continuous wave imaging system
The transmission power of system is in milliwatt or wattage magnitude；In addition, time-domain spectroscopy system is all formed using optics, structure ten
Divide complicated and be not suitable for engineer applied, and continuous wave imaging system is built by electronic device, it is simple in construction easy of integration.
As shown in figure 1, the utility model includes：
X-Y two-dimensional scanning platforms 109, for fixing and in X, Y-direction movement measurand 108；
Terahertz linear frequency modulation ripple transmitter module 101, for produce be transmitted to by transmit-receive sharing lens antenna 102 it is tested
The radiofrequency signal of object 108；
Terahertz linear frequency modulation ripple receiving module 103, received for detecting by transmit-receive sharing lens antenna 102 from tested
The Terahertz LFM Echo signal that object 108 is reflected back, caused local oscillation signal and echo-signal are then subjected to lower change
Frequency processing obtains test signal；
Transmit-receive sharing lens antenna 102, for launching Terahertz linear frequency modulation transmission signal to measurand 108 and receiving
The Terahertz LFM Echo signal reflected from measurand 108, and by Terahertz linear frequency modulation ripple transmitter module 101
The Terahertz linear frequency modulation ripple of transmitting converges to measurand 108；
The full coherent module 104 of signal, for radiofrequency signal that Terahertz linear frequency modulation ripple transmitter module 101 is provided with too
The local oscillation signal down coversion that the linear frequency-modulated wave receiving module 103 of hertz provides obtains reference signal, then by reference signal and too
The test signal down coversion that the linear frequency-modulated wave receiving module 103 of hertz provides obtains difference frequency signal；
Data acquisition and processing (DAP) module 105, for being stopped in X-Y two-dimensional scanning platforms 109 in any and after stabilization, collection
The difference frequency signal exported from the full coherent module 104 of signal and storage, are then uploaded to the processing data of processor 201；
Image processing module 106, the data for gathering and handling according to data acquisition and processing (DAP) module 105 build three-dimensional
Image, and made using image processing techniques apparent；
Image-display units 107, for showing that the measurand 108 generated by image processing module 106 is clearly reliable
Three-dimensional imaging figure.
As shown in Fig. 2 Terahertz linear frequency modulation ripple transmitter module 101, the sum of Terahertz linear frequency modulation ripple receiving module 103
According to collection and processing module 105 by the way of hardware external trigger；X-Y two-dimensional scanning platforms 109 are by along X-axis and Y-axis side
Superincumbent measurand 108 is placed to mobile, so as to realize system point by point scanning measurand 108, X-Y two-dimensional scanning platforms
109 be moved to a little after at once give data acquisition and processing (DAP) module 105 in the backhaul signals of processor 201, then processor 201 send out
Sending instruction, its output pulse signal is linear to Terahertz linear frequency modulation ripple transmitter module 101, Terahertz to the life of signal generator 202
In frequency-modulated wave receiving module 103 in the triggering input port in K-band linear frequency sweep source 308 and data acquisition and processing (DAP) module 105
The external trigger input port of usb data capture card 203, the linear frequency modulation letter of the now output of K-band linear frequency sweep source 308 K-band
Number, usb data capture card 203 starts to gather the difference frequency signal that the full coherent module 104 of signal exports, then data acquisition and processing (DAP)
Module 105, which sends instructions to X-Y two-dimensional scanning platforms 109, allows it to continuously move to second point, by that analogy, so as to realize N
The scanning of individual point, finally realizes the scanning in face.
As shown in figure 3, Terahertz linear frequency modulation ripple transmitter module 101 includes the first signal source 301, K-band linear frequency sweep
Source 308, power splitter 309, the first frequency mixer 302, the first power amplifier 303, varactor doubler 304, the first frequency tripler 305,
First directional coupler 306 and the second directional coupler 307, Terahertz linear frequency modulation ripple transmitter module 101 pass through for generation
Transmit-receive sharing lens antenna 102 is transmitted to the Terahertz linear frequency modulation radiofrequency signal of measurand 108.
Specifically, the first signal source 301 is the point-frequency signal source that working frequency is 10.1GHz, can be expressed as：
Wherein, A1It is expressed as initial magnitude, f1For frequency 10.1GHz, t is the time,For the initial of the first signal source 301
Phase value, by signal output to the local oscillator end of the first frequency mixer 302；
K-band linear frequency sweep source 308 is the Sweep Source that working frequency is 18.5~26.5GHz, can be expressed as：
Wherein, A3It is expressed as initial magnitude, f3For 18.5~26.5GHz of frequency,For the first of K-band linear frequency sweep source 308
Beginning phase value, through power splitter 309 by signal output to the intermediate frequency end of the first frequency mixer 302；
First signal source 301 and the signal of K-band linear frequency sweep source 308 are mixed by the first frequency mixer 302, and up-conversion obtains
Exported to first power amplifier 303 to the signal that frequency is 28.6~36.6GHz and by radio-frequency head；
First power amplifier 303 is amplified to reach two frequencys multiplication to the signal power that frequency is 28.6~36.6GHz
The firm power input range of device 304；
Frequency is reached 57.2~73.2GHz by varactor doubler 304 for the frequency multiplication of frequency two of 28.6~36.6GHz signals, and
Export to the input of the first frequency tripler 305；
First frequency tripler 305 by the frequency frequency tripling that frequency is 57.2~73.2GHz signals be 171.6~
219.6GHz, and export to the input of the first directional coupler 306；
First directional coupler 306 determines the signal that frequency is 171.6~219.6GHz by straight-through end output to second
To the straight-through end of coupler 307, exported by coupled end to the radio-frequency head of the second th harmonic mixer 318；
The input of second directional coupler 307 is connected to transmit-receive sharing lens antenna 102, finally through transmit-receive sharing lens
Antenna 102 sends Terahertz linear frequency modulation ripple the radiofrequency signal launched to measurand 108, transmit-receive sharing lens antenna 102
For：
Wherein, A1' be radiofrequency signal amplitude,It is the phase of radiofrequency signal.
Further as shown in figure 3, Terahertz linear frequency modulation ripple receiving module 103 includes secondary signal source 310, K-band
Linear frequency sweep source 308, power splitter 309, the first frequency mixer 311, the second power amplifier 312, the second frequency tripler the 313, the 3rd
Directional coupler 314, the second directional coupler 307, the first th harmonic mixer 315, the first bandpass filter 316 and first are low
Noise amplifier 317, Terahertz linear frequency modulation ripple receiving module 103 are used to receive the Terahertz being reflected back from measurand 108
LFM Echo signal.
Specifically, secondary signal source 310 is the point-frequency signal source that working frequency is 10GHz, can be expressed as：
Wherein, A2It is expressed as initial magnitude, f2For frequency 10GHz,For the initial phase value in secondary signal source 310, will believe
Number output is to the local oscillator end of the second frequency mixer 311；
K-band linear frequency sweep source 308 is through power splitter 309 by signal output that working frequency is 18.5~26.5GHz to the
The intermediate frequency end of two frequency mixers 311；
Second frequency mixer 311 by frequency caused by secondary signal source 310 and K-band linear frequency sweep source 308 be 10GHz and
18.5~26.5GHz signals are mixed, and up-conversion obtains the signal that frequency is 28.5~36.5GHz and exported by radio-frequency head
To the second power amplifier 312；
Second power amplifier 312 is amplified to reach the two or three to frequency for the power of 28.5~36.5GHz signals
The firm power input range of the input of frequency multiplier 313；
Frequency reaches 85.5 for the frequency frequency tripling of 28.5~36.5GHz signals by the second frequency tripler 313~
109.5GHz, and output this to the input of the 3rd directional coupler 314；
The straight-through end of 3rd directional coupler 314 is by 85.5~109.5GHz signal output to the first th harmonic mixer
315 local oscillator end；
The Terahertz that second directional coupler 307 is obtained by input reception by transmit-receive sharing lens antenna 102 is linear
Frequency modulation echo-signal：
Wherein, A1" be the amplitude of echo-signal, Δ f be according to linear frequency modulation ranglng principle, because of measurand 108 or by
The relative transmit-receive sharing lens antenna 102 of object defect 401 is surveyed apart from caused difference frequency signal,It is the phase of echo-signal, so
Exported by coupled end to the radio-frequency head of the first th harmonic mixer 315；
85.5~109.5GHz the frequency multiplication of signal two is obtained frequency by the first th harmonic mixer 315 local oscillator end first
171~219GHz signal, then obtain testing intermediate-freuqncy signal with the echo-signal mixing of radio-frequency head, down coversion, and will test
Signal output is to the first bandpass filter 316；
The centre frequency of first bandpass filter 316 is 600MHz, with a width of 8MHz, by the first th harmonic mixer 315
Clutter in test intermediate-freuqncy signal beyond 596~604MHz filters out, and it is low that the output end of the first bandpass filter 316 is connected to first
Noise amplifier 317；
First low-noise amplifier 317 by the noise of the output signal of the first bandpass filter 316 reduce and power amplification with
The power output for improving test intermediate-freuqncy signal in 596~604MHz obtains test signal, and the output of the first low-noise amplifier 317 is surveyed
To the radio-frequency head of three-mixer 321, test signal is represented by trial signal：
Wherein, AmIt is the amplitude of test signal, f0It is the difference on the frequency between the first signal source 301 and secondary signal source 310
6 times,It is the phase of test signal.
Further as shown in figure 3, the full coherent module 104 of signal includes the 3rd directional coupler 314, the first directional couple
Device 306, the second th harmonic mixer 318, the second bandpass filter 319, the second low-noise amplifier 320 and three-mixer
321, for by local oscillation signal caused by Terahertz linear frequency modulation receiving module 103 respectively with becoming under radiofrequency signal and echo-signal
Frequency processing obtains reference signal and test signal, and reference signal and test signal down coversion then are obtained into difference frequency signal.
Specifically, the coupled end of the 3rd directional coupler 314 is defeated by the signal that working frequency is 85.5~109.5GHz
Go out to the local oscillator end of the second th harmonic mixer 318；
The coupled end of first directional coupler 306 is by signal output that working frequency is 171.6~219.6GHz to second
The radio-frequency head of th harmonic mixer 318；
85.5~109.5GHz the frequency multiplication of signal two is obtained frequency by the second th harmonic mixer 318 local oscillator end first
171~219GHz signal, then obtain frequency with 171.6~219.6GHz of radio-frequency head signal mixing, down coversion and be
600MHz reference intermediate-freuqncy signal, and export to the second bandpass filter 319；
The centre frequency of second bandpass filter 319 is 600MHz, with a width of 8MHz, by the second th harmonic mixer 318
Filtered out with reference to the clutter beyond 596~604MHz in intermediate-freuqncy signal, it is low that the output end of the second bandpass filter 319 is connected to second
Noise amplifier 320；
Second low-noise amplifier 320 by the noise of the output signal of the second bandpass filter 319 reduce and power amplification with
The power output of 596~604MHz internal reference intermediate-freuqncy signals is improved, the second low-noise amplifier 320 exports reference signal to the 3rd
The local oscillator end of frequency mixer 321, reference signal are represented by：
Wherein, ArIt is the amplitude of reference signal,It is the phase of reference signal.
The reference signal at local oscillator end and the test signal of radio-frequency head are mixed by three-mixer 321, obtain the difference of down coversion
Frequency signal, difference frequency signal are represented by：
Wherein, AΔIt is the amplitude of difference frequency signal,It is the phase of difference frequency signal, and outputs this to data acquisition and processing (DAP)
Module 105.
As shown in figure 4, Terahertz linear frequency modulation ripple transmitter module 101, Terahertz linear frequency modulation ripple receiving module 103 and letter
Number full coherent module 104 constitutes circuit system 402, and circuit system 402 is by transmit-receive sharing lens antenna 102 to being placed on X-
Chirped terahertz electromagnetic wave, measurand defect are launched and received to measurand 108 in Y two-dimensional scanning platforms 109
401 can cause the phase and amplitude of chirped THz wave to produce change.
As shown in figure 5, using the system of the full coherent Terahertz three-dimension high-resolution imaging of above-mentioned heterodyne system to measurand
Imaging process comprise the following steps：
X-Y two-dimensional scanning platforms 109 move the measurand 108 being fixed in the above along X-axis, Y direction, are often moved to one
Stop after point；
Terahertz linear frequency modulation ripple transmitter module 101 generates radio frequency letter after by the pulse signal triggering of signal generator 202
Number；
Emission of radio frequency signals to measurand 108, it is anti-then to be received measurand 108 by transmit-receive sharing lens antenna 102
The echo-signal that is emitted back towards simultaneously is transferred to Terahertz linear frequency modulation receiving module 103；Terahertz linear frequency modulation ripple receiving module 102 by
Receives echo-signal after the pulse signal triggering of signal generator 202, down-converted then is carried out to echo-signal and surveyed
Trial signal is simultaneously sent to the full coherent module 104 of signal；
The full coherent module 104 of signal is linear to the radiofrequency signal and Terahertz of Terahertz linear frequency modulation ripple transmitter module 101
The local oscillation signal of frequency-modulated wave receiving module 103 is mixed to obtain reference signal, is then mixed to obtain difference frequency signal with test signal；
Data acquisition and processing (DAP) module 105 is acquired and stored to the difference frequency signal from the full coherent module 104 of signal,
Then X-Y two-dimensional scanning platforms 109 move to the next position, by that analogy, so as to realize the scanning of N number of point, finally realize face
Scanning, the data of storage carry out a variety of processing such as 2-D data rearrangement, Fast Fourier Transform (FFT), Windowed filtering through processor 201；
Image processing module 106, the data for gathering and handling according to data acquisition and processing (DAP) module 105 build three-dimensional
Image, and made using image processing techniques such as image enhaucament, recovery, segmentation and signature analysises apparent；
Image-display units 107, for showing that the measurand 108 generated by image processing module 106 is clearly reliable
Three-dimensional imaging figure.
The preferred embodiment of the application is the foregoing is only, is not limited to the application, for the skill of this area
For art personnel, the application can have various modifications and variations.It is all within spirit herein and principle, made any repair
Change, equivalent substitution, improvement etc., should be included within the protection domain of the application.
It is not new to this practicality although above-mentioned specific embodiment of the present utility model is described with reference to accompanying drawing
The limitation of type protection domain, one of ordinary skill in the art should be understood that on the basis of the technical solution of the utility model, ability
Field technique personnel need not pay the various modifications that creative work can make or deformation still in protection model of the present utility model
Within enclosing.
Claims (9)
1. a kind of system of the full coherent Terahertz three-dimension high-resolution imaging of heterodyne system, it is characterized in that：Put down including X-Y two-dimensional scans
Platform, Terahertz linear frequency modulation ripple transmitter module, Terahertz linear frequency modulation ripple receiving module, transmit-receive sharing lens antenna, signal are complete
Coherent module, data acquisition and processing (DAP) module, image processing module and image-display units, wherein：
The X-Y two-dimensional scanning platforms fix measurand, and move measurand point by point along X-axis and Y-axis；
The Terahertz linear frequency modulation ripple transmitter module produces radiofrequency signal and is sent to measurand；
The echo-signal that the Terahertz linear frequency modulation ripple receiving module detection is reflected back from measurand, and produce local oscillation signal
Test signal is obtained with echo-signal down-converted；
The echo-signal that the transmit-receive sharing lens antenna is reflected back to the radiofrequency signal of measurand transmitting focusing and reception；
Radiofrequency signal and local oscillation signal down-converted are obtained reference signal by the full coherent module of signal, then will refer to letter
Number and the further down-converted of test signal obtain difference frequency signal；
The data acquisition and processing (DAP) module stops in any in X-Y two-dimensional scanning platforms and after stabilization, and collection difference frequency signal is simultaneously
Storage, is then uploaded to processor processes data；
Described image processing module builds 3-D view according to all data for gathering and handling, and is made using image processing techniques
It is apparent；
Described image display unit shows measurand clearly reliable three-dimensional imaging figure.
2. a kind of system of the full coherent Terahertz three-dimension high-resolution imaging of heterodyne system as claimed in claim 1, it is characterized in that：
The Terahertz linear frequency modulation ripple transmitter module, Terahertz linear frequency modulation ripple receiving module and data acquisition and processing (DAP) module pass through
Started working after the pulse signal synchronization hardware external trigger of signal generator output.
3. a kind of system of the full coherent Terahertz three-dimension high-resolution imaging of heterodyne system as claimed in claim 1, it is characterized in that：
The Terahertz linear frequency modulation ripple transmitter module include the first signal source, K-band linear frequency sweep source, power splitter, the first frequency mixer,
First power amplifier, varactor doubler, the first frequency tripler, the first directional coupler and the second directional coupler, described first
Signal source connects the local oscillator end of the first frequency mixer, and the K-band linear frequency sweep source is connected in the first frequency mixer by power splitter
Frequency end, the RF output end of the first frequency mixer are connected with the first power amplifier, varactor doubler, the first frequency tripler, in turn
One directional coupler and the second directional coupler.
4. a kind of system of the full coherent Terahertz three-dimension high-resolution imaging of heterodyne system as claimed in claim 3, it is characterized in that：
The Terahertz linear frequency modulation ripple receiving module mixes including secondary signal source, the K-band linear frequency sweep source, power splitter, second
Frequency device, the second power amplifier, the second frequency tripler, the 3rd directional coupler, the first th harmonic mixer, the first bandpass filtering
Device and the first low-noise amplifier, the secondary signal source connect the local oscillator end of the second frequency mixer, the K-band linear frequency sweep source
The intermediate frequency end of the second frequency mixer is connected by power splitter, the RF output end of the second frequency mixer is connected with the second power amplification in turn
Device, the second frequency tripler and the 3rd directional coupler, the first th harmonic mixer local oscillator end receive the 3rd directional coupler
Output signal and radio-frequency head receive the output signal of second directional coupler, medium frequency output end is sequentially connected the first band logical
Wave filter and the first low-noise amplifier.
5. a kind of system of the full coherent Terahertz three-dimension high-resolution imaging of heterodyne system as claimed in claim 4, it is characterized in that：
First signal source and secondary signal source are point-frequency signal source.
6. a kind of system of the full coherent Terahertz three-dimension high-resolution imaging of heterodyne system as claimed in claim 1, it is characterized in that：
The full coherent module of signal causes Terahertz linear frequency modulation ripple transmitter module and Terahertz linear frequency modulation ripple receiving module to realize
It is relevant.
7. a kind of system of the full coherent Terahertz three-dimension high-resolution imaging of heterodyne system as claimed in claim 4, it is characterized in that：
The full coherent module of signal includes the second th harmonic mixer, the second bandpass filter, the second low-noise amplifier and the 3rd
Frequency mixer, the output signal of the 3rd directional coupler and the first directional coupler respectively enter the second th harmonic mixer
Local oscillator end and radio-frequency head, the second th harmonic mixer medium frequency output end is sequentially connected the second bandpass filter, the second low noise is put
Big device and three-mixer；The three-mixer radio-frequency head and local oscillator end receive the output letter of the second low-noise amplifier respectively
Number and the first low-noise amplifier output signal, and be mixed, intermediate frequency end exports difference frequency signal after down-converted.
8. a kind of system of the full coherent Terahertz three-dimension high-resolution imaging of heterodyne system as claimed in claim 1, it is characterized in that：
The data acquisition and processing (DAP) module includes usb data capture card and processor, usb data capture card collection difference frequency signal, place
Manage device and data two dimension rearrangement is carried out according to X-Y two-dimensional scanning platforms move mode, then data are subjected to fast Fourier transform, its
Middle frequency characterizes the positional information of measurand depth direction, and amplitude characterizes the reflected signal strength of measurand.
9. a kind of system of the full coherent Terahertz three-dimension high-resolution imaging of heterodyne system as claimed in claim 1, it is characterized in that：
Described image processing module builds measurand 3-D view according to data after collection and processing, then passes through image co-registration, increasing
By force, conversion and filtering algorithm become apparent from image, and described image display unit shows final clear reliable three-dimensional imaging figure.
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106990413A (en) * | 2017-06-02 | 2017-07-28 | 吉林大学 | The system and method for the full coherent Terahertz three-dimension high-resolution imaging of heterodyne system |
| CN108398691A (en) * | 2018-05-25 | 2018-08-14 | 中国工程物理研究院流体物理研究所 | A kind of difference frequency signal generation device and method |
| CN111812412A (en) * | 2020-06-30 | 2020-10-23 | 西安西电光电缆有限责任公司 | Device and method for rapidly detecting resonant point frequency of leaky cable |
| CN111965440A (en) * | 2020-07-02 | 2020-11-20 | 云南大学 | Terahertz receiver noise test system |
-
2017
- 2017-06-02 CN CN201720634522.6U patent/CN206832995U/en active Active
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106990413A (en) * | 2017-06-02 | 2017-07-28 | 吉林大学 | The system and method for the full coherent Terahertz three-dimension high-resolution imaging of heterodyne system |
| CN108398691A (en) * | 2018-05-25 | 2018-08-14 | 中国工程物理研究院流体物理研究所 | A kind of difference frequency signal generation device and method |
| CN108398691B (en) * | 2018-05-25 | 2023-10-17 | 中国工程物理研究院流体物理研究所 | Difference frequency signal generating device and method |
| CN111812412A (en) * | 2020-06-30 | 2020-10-23 | 西安西电光电缆有限责任公司 | Device and method for rapidly detecting resonant point frequency of leaky cable |
| CN111965440A (en) * | 2020-07-02 | 2020-11-20 | 云南大学 | Terahertz receiver noise test system |
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