CN106108899A - A kind of holographic microwave imaging system and formation method thereof - Google Patents

Abstract

The present invention relates to a kind of holographic microwave imaging system and formation method thereof, imaging system includes signal generating unit, signal transmitter unit, signal receiving unit, signaling control unit, signal and image conversion unit and image-display units；Microwave signal is launched to determinand by signal generating unit by signal transmitter unit, forms scattering electric field around determinand；Signal receiving unit measures scattering electric field, and the change of determinand inside and around electric field information, and transmits measurement result to signaling control unit；Signaling control unit obtains the scattering electric field visibility distribution of determinand, and transmits to signal and image conversion unit；Signal and image conversion unit build the four-dimensional image obtaining determinand, and transmit to image-display units and show.Formation method includes launching single-frequency territory microwave signal to determinand；Receive scattered field；Obtain amplitude and Phase delay information；Realize four-dimensional image reconstruction.

Description

A kind of holographic microwave imaging system and formation method thereof

Technical field

The invention belongs to microwave Imaging Technique field, be specifically related to a kind of holographic microwave imaging system and formation method thereof.

Background technology

At present, the cerebral edema utilizing the imaging means such as X-CT, MRI can cause cerebral hemorrhage, ischemia carries out imaging, but X-CT is difficult to be used for multiple times owing to there is radioactivity, and X-CT and MRI broadly falls into main equipment, it is impossible to make continuously by sick bed With, cannot continuously, monitor in real time to organism pathophysiologic features evolution.Noncontact microwave biological body imaging is for brain The monitoring method of the dielectric constant changes in distribution of the organism parts such as portion, it can be applicable to the detection of brain diseases.Existing 3D hologram microwave Imaging Technique has that image sensitivity is low, resolution is low and high in cost of production limitation, and the most domestic Outer the most not report to the method and apparatus of multidimensional holographic microwave imaging.

Summary of the invention

In order to solve the problems referred to above that prior art exists, the invention provides one and can improve room and time resolution The holographic microwave imaging system of rate and formation method thereof.

For realizing object above, the technical solution adopted in the present invention is: a kind of holographic microwave imaging system includes signal Generating unit, signal transmitter unit, signal receiving unit, signaling control unit, signal show with image conversion unit and image Show unit；

The microwave signal in the single-frequency territory of generation is launched to treating by described signal generating unit by described signal transmitter unit Survey thing, around determinand, form scattering electric field；

Described signal receiving unit measures scattering electric field, and the change of determinand inside and around electric field information, described Signal receiving unit transmits measurement result to described signaling control unit；

Described signaling control unit obtains the scattering electric field visibility distribution of determinand, and transmits to described signal and image Converting unit；

Described signal and image conversion unit build the four-dimensional image obtaining determinand, and by four-dimension image transmitting to described Image-display units shows.

Further, described signal generating unit includes radio-frequency signal generator and multi-way contral switching circuit board, institute State signal transmitter unit, signal receiving unit, signaling control unit and multi-way contral switching circuit board respectively with described radio frequency Signal generator connects, and described multi-way contral switching circuit board is connected with signal receiving unit.

Further, described signal transmitter unit and signal receiving unit are realized by one or two aerial array.

Further, when described signal transmitter unit and signal receiving unit are realized by an aerial array, described letter Number transmitter unit includes one or more transmitting antenna, and described signal receiving unit includes more than three reception antennas, described Penetrate antenna and reception antenna is respectively positioned on equal height.

Further, when described signal transmitter unit and signal receiving unit are realized by two aerial arrays, described letter Number transmitter unit uses transmitting antenna array, and described signal receiving unit uses receiving antenna array；Described transmitting antenna array Including a transmitting antenna, described receiving antenna array includes at least three reception antenna；Described transmitting antenna array and reception Aerial array is uneven distribution, and is positioned at identical or different height；Described transmitting antenna array and receiving antenna array set Put at the same side of determinand or not homonymy；All described reception antennas are positioned at sustained height.

Further, between described transmitting antenna, between reception antenna and launch between antenna and reception antenna all Microwave absorbing material or medium are set.

A kind of formation method based on described holographic microwave imaging system, it comprises the following steps:

Arrange one include signal generating unit, signal transmitter unit, signal receiving unit, signaling control unit, signal with Image conversion unit and the holographic microwave imaging system of image-display units；Signal generating unit and signal transmitter unit and letter Number control unit connects, and signal transmitter unit and signal receiving unit carry out radio communication, signaling control unit by signal with Image conversion unit is connected with image-display units；

Determinand is arranged on distance signal transmitter unit and signal receiving unit exceeds well over the position of a wavelength；

Signal generating unit launches single-frequency territory microwave signal by signal transmitter unit to determinand；

Under the effect of single-frequency territory microwave signal, forming scattered field around determinand, scattered field is entered by signal receiving unit Row receives, and transmits the scattered field received to signaling control unit；

Signaling control unit obtains amplitude and Phase delay information, and transmits to signal and image conversion unit；

Signal and image conversion unit are according to the scattering electric field distributed intelligence being consecutively detected, it is achieved four-dimensional image reconstruction.

Further, the process that described signal and image conversion realize four-dimensional image reconstruction is:

The reconstruction of two-dimensional images of determinand is realized according to the scattering electric field distributed intelligence being consecutively detected；

Two dimensional image based on reconstruct, moves up and down scanning to the reception antenna in signal receiving unit, and acquisition is treated The medium of survey thing intensity distributions under different depth, it is achieved 3-D view reconstructs；

3-D view based on reconstruct, the different time points in a domain gathers different 3-D views, the most each The difference of 3-D view, obtains the temporal information of determinand, it is achieved four-dimensional image reconstruction.

Further, the reconstructing method of two dimensional image is:

Assume that (x, y, z) be positioned in determinand certain point P, and (x, y z) are positioned at this P to two in signal receiving unit r_iAnd r_gThe scattering electric field visibility of reception antenna be:

$G(r_i,r_g)=<E_{scat}\left(r_i\right)\&CenterDot;E_{scat}^{*}\left(r_g\right)>---\left(1\right)$

In formula (1), E_scat(r_i) represent be positioned at r_iThe scattering electric field of reception antenna,Represent and be positioned at r_gReception The conjugation of the scattering electric field of antenna,<>represents average time, r_iRepresent that in the determinand of target area, arbitrfary point receives sky to i-th The distance vector of line, r_gRepresent that in the determinand of target area, arbitrfary point is to the distance vector of g reception antenna；

Under far field condition, scattering electric field is expressed as:

$E_{scat}\left(r\right)=\left(\frac{k_0^2}{4\mathrm{\&pi;}}\right)\underset{V}{\&Integral;}\left(\mathrm{\&epsiv;}\right(s)-{\mathrm{\&epsiv;}}_b)E_T\left(s\right)\frac{e^{-{\mathrm{jk}}_b|s-r|}}{|s-r|}dV---\left(2\right)$

In formula (2),k₀=2 π/λ₀Represent the wave number of free space；k_b=2 π/λ_bRepresent background media matter Wave number, λ₀Represent the wavelength of free space, λ_bThe wavelength of background media matter, ε (s) represents the complicated relative dielectric constant of object Distribution, ε_bRepresenting the complicated relative dielectric constant distribution of background media, r represents that in the determinand of target area, arbitrfary point is to receiving sky The distance vector of line, E_TS () represents the determinand incident electric fields of any point and total electric field of scattering electric field on direction vector s Sum, V represents the volume of determinand；

Formula (2) is substituted in formula (1), obtains:

$G(r_i,r_g)={\left(\frac{k_0^2}{4\mathrm{\&pi;}}\right)}^2\underset{V}{\&Integral;\&Integral;\&Integral;}\underset{V^{\&prime;}}{\&Integral;\&Integral;\&Integral;}\left(\mathrm{\&epsiv;}\right(s)-{\mathrm{\&epsiv;}}_b){\left(\mathrm{\&epsiv;}\right(s^{\&prime;})-{\mathrm{\&epsiv;}}_b)}^{*}{E}_T\left(s\right)\&CenterDot;E_T^{*}\left(s^{\&prime;}\right)\frac{e^{-{\mathrm{jk}}_b(R-R^{\&prime;})}}{{\mathrm{RR}}^{\&prime;}}{\mathrm{dVdV}}^{\&prime;}---\left(3\right)$

In formula (3), R represents a P, and (x, y, z) to reception antenna r_iDistance, R=| r_i-s|；R' is different in representing determinand With a P (x, y, another P'(x' z), y', z') to reception antenna r_iDistance, R'=| r_gIn-s'|, s' represent determinand Point P'(x', y', z') to the distance of zero；V' represents around a P'(x', y', z') the volume of determinand；

In far-field region, (x, y, z) to reception antenna r for some P_iDistance be far longer than the size of aerial array, i.e. R ＞ ＞ | r_i |, obtain:

$R=\left|R\right|=\sqrt{(r_i-s)\&CenterDot;(r_g-s)}=\sqrt{r_i^2+s^2-2r_i\&CenterDot;s}\&cong;s-\frac{r_i\&CenterDot;s}{s}=s-r_i\&CenterDot;\hat{s}---\left(4\right)$

In formula (4), ". " represents scalar,Representation unit vector；

In like manner obtain, another P'(x' in target area, y', z') arrive reception antenna r_gDistance be:

$R^{\&prime;}=\left|R^{\&prime;}\right|=s^{\&prime;}-r_g\&CenterDot;\widehat{s^{\&prime;}}---\left(5\right)$

Obtained by formula (4) and formula (5):

$\frac{e^{-{\mathrm{jk}}_b(R-R^{\&prime;})}}{{\mathrm{RR}}^{\&prime;}}\&ap;\frac{1}{{\mathrm{ss}}^{\&prime;}}{e}^{-{\mathrm{jk}}_b(s-s^{\&prime;})}{e}^{{\mathrm{jk}}_b(r_g\&CenterDot;\widehat{s^{\&prime;}}-r_i\&CenterDot;\hat{s})}---\left(6\right)$

Formula (6) being brought in formula (3), the visibility function obtaining target area determinand is:

$G(r_i,r_g)={\left(\frac{k_0^2}{4\mathrm{\&pi;}}\right)}^2\&Integral;\&Integral;{\&Integral;}_V\left(\right|\mathrm{\&epsiv;}\left(s\right)-{\mathrm{\&epsiv;}}_b{|}^2)E_T\left(s\right)\&CenterDot;E_T^{*}\left(s\right)\frac{e^{-{\mathrm{jk}}_b(r_g-r_i)\&CenterDot;\underset{\&OverBar;}{\hat{s}}}}{s^2}dV---\left(7\right)$

The Strength Equation of the target determinand of definition s position is:

$I\left(s\right)={\left(\frac{k_0^2}{4\mathrm{\&pi;}}\right)}^2|\mathrm{\&epsiv;}\left(s\right)-{\mathrm{\&epsiv;}}_b{|}^2{E}_T\left(s\right)\&CenterDot;E_T^{*}\left(s\right)---\left(8\right)$

Formula (8) is brought in formula (7), then, it is seen that degree functional equation is transformed to:

$G(u_{ig},v_{ig},w_{ig})=\underset{l}{\&Integral;}\underset{m}{\&Integral;}\underset{s}{\&Integral;}\frac{I(s,l,m)}{\sqrt{1-l^2-m^2}}{e}^{-j2{\mathrm{\&pi;\&Phi;}}_{ig}}dldmds---\left(9\right)$

In formula (9),u_ig=(x_g-x_i)/λ_b, v_ig=(y_g-y_i)/λ_b, w_ig= (z_g-z_i)/λ_b, l=sin θ cos φ, m=sin θ sin φ, D_igRepresent reception antenna r_iWith reception antenna r_gBetween baseline, (l, m n) represent the coordinate in spherical coordinate system；

All arranging at sustained height if all of reception antenna, radially the line integral of coordinate p is:

$\tilde{I}(l,m)=\underset{p}{\&Integral;}\frac{I(s,l,m)}{\sqrt{1-l^2-m^2}}dp---\left(10\right)$

The visibility function equation utilizing formula (10) to represent formula (9) carries out two-dimensional Fourier transform, obtains:

$G(u_{ig},v_{ig})=\&Integral;\&Integral;\tilde{I}(l,m)e^{-j2\mathrm{\&pi;}(u_{ig}l+v_{ig}m)}dldm---\left(11\right)$

Formula (11) is carried out inverse Fourier transform, obtains the two dimensional image of determinand, it may be assumed that

$\tilde{I}(l,m)=\&Integral;\&Integral;G(u_{ig},v_{ig})e^{j2\mathrm{\&pi;}(u_{ig}l+v_{ig}m)}dudv---\left(12\right).$

Further, the reconstructing method of 3-D view is: by aerial array from height H₁(mm) height H is moved to_n(mm), In target determinand, any point depth location in target area is:

z_n=p_ncos(θ_n) (13)

In formula (13), θ_nRepresent that in aerial array, same antenna is at position p_nTransmitting or acceptance angle to target determinand Degree；

According to formula (13), in formula (10), dp is transformed to:

$dp=\frac{dz}{cos\left({\mathrm{\&theta;}}_n\right)}=\frac{dz}{\sqrt{1-l^2-m^2}}---\left(14\right)$

Formula (14) is carried out calculus, and the three-dimensional description of the determinand intensity function of arbitrary height is:

$I(H=z_n,l,m)=\frac{d\tilde{I}(l,m)\&CenterDot;(1-l^2-m^2)}{dz}---\left(15\right)$

Under differing heights, the vision intensity distribution of the difference of determinand is:

$\frac{d\tilde{I}}{dz}=\frac{{\tilde{I}}_{z_n}-{\tilde{I}}_{z_{n-1}}}{z_n-z_{n-1}}---\left(16\right)$

By calculating the vision intensity distribution of the difference of determinand under differing heights, and compare under differing heights two-by-two visible Strength difference, forms one group of complete data, thus realizes 3-D view reconstruct.

Owing to using above technical scheme, the invention have the benefit that holography microwave imaging system of the present invention can have Effect improves spatial resolution and temporal resolution, it is achieved four-dimensional image, improves picture quality；3-D view is overcome to detect organism The problem that sensitivity is low, can obtain more stable image according to the size of detection object.Holography microwave imaging method of the present invention There is the advantages such as noncontact, noinvasive, multidimensional image, high-resolution.The Medical Instruments developed according to formation method of the present invention, can With forms such as the curve relevant by display, image, numerical value, it is achieved continuous, the noinvasive to organism dielectric constant changes in distribution Monitoring, thus monitoring organism pathophysiologic features in time, it is achieved the cancers such as detection disease such as breast carcinoma, disease of brain, skin carcinoma.

Present invention can be suitably applied to the non-contact monitoring of multiple organism pathophysiologic features, the present invention may be used for having Jie Electrical organism physiological and pathological detects such as mastocarcinoma, skin carcinoma etc., it is also possible to for the cerebral edema of open injury initiation Detection and monitoring, the particularly detection of head war wound and monitoring；Use the present invention can also carry out foggara crack detection, wheel Tire abrasion detection, nondestructively soil attribute is descended to detect, remote metal and/or weapon detection etc..

Accompanying drawing explanation

Fig. 1 is the schematic diagram of holography microwave imaging system of the present invention；

Fig. 2 is the geometry arrangement schematic diagram of a pair reception antenna in holography microwave imaging system of the present invention；

Fig. 3 is spherical coordinate system；

Fig. 4 is receiving antenna array scattering signatures schematic diagram of object under test when being listed in differing heights；

Fig. 5 is four-dimensional reconstruction image schematic diagram based on time orientation.

In figure: 1, signal generating unit；2, signal transmitter unit；3, signal receiving unit；4, signaling control unit；5, letter Number and image conversion unit；6, image-display units.

Detailed description of the invention

The present invention will be described in detail with embodiment below in conjunction with the accompanying drawings.

As it is shown in figure 1, the invention provides a kind of holographic microwave imaging system, it includes that signal generating unit 1, signal are sent out Penetrate unit 2, signal receiving unit 3, signaling control unit 4, signal and image conversion unit 5 and image-display units 6.

Signal generating unit 1 includes radio-frequency signal generator and multi-way contral switching circuit board, signal transmitter unit 2, Signal receiving unit 3, signaling control unit 4 and multi-way contral switching circuit board are connected with radio-frequency signal generator respectively, many Passage controls switching circuit board and is connected with signal receiving unit 3.Wherein, radio-frequency signal generator uses Network Analyzer.Signal Transmitter unit 2 and signal receiving unit 3 are realized by one or two aerial array.

When signal transmitter unit 2 and signal receiving unit 3 are realized by an aerial array, signal transmitter unit 2 includes One or more transmitting antennas, signal receiving unit 3 includes more than three reception antennas；Wherein, antenna and reception antenna are launched It is respectively positioned on equal height, and is arranged near determinand.

When signal transmitter unit 2 and signal receiving unit 3 are realized by two aerial arrays, two aerial arrays are respectively Transmitting antenna array and receiving antenna array；Wherein, transmitting antenna array includes a transmitting antenna, and receiving antenna array includes At least three reception antenna.Transmitting antenna array and receiving antenna array are uneven distribution, and may be located at identical or different Height.Transmitting antenna array and receiving antenna array can be arranged on the same side or the not homonymy of determinand.All reception skies Line is positioned at sustained height.

Further, for reducing the coupling between antenna, reduce signal noise, launch between antenna, between reception antenna with And it is respectively provided with microwave absorbing material or medium between transmitting antenna and reception antenna.

Signal generating unit 1 produces the microwave signal in single-frequency territory, and the microwave signal produced is passed through signal transmitter unit 2 Launch to determinand.Utilize the electromagnetic property of organism and the penetrance of microwave, around determinand, form scattering electric field.

The operating frequency of holographic microwave imaging system is single-frequency territory, and it may be used for organism imaging particularly human body imaging Detecting pathophysiologic features, when being used for detecting mastocarcinoma, best effort frequency range is 5GHz-10GHz；It may be used for Brain diseases is detected by head imaging, and when being used for detecting brain diseases, best effort frequency range is 1GHz-3GHz；It can For industrial nondestructive testing, when for industrial nondestructive testing, work frequency domain is 0.3GHz-300GHz.

Signal receiving unit 3 measures scattering electric field, and measures the change of the determinand inside and around electric field information of target area Changing, signal receiving unit 3 transmits measurement result to signaling control unit 4.

Signaling control unit 4 obtains the scattering electric field visibility distribution of determinand according to the measurement result received, and will Scattering electric field visibility Distributed Transmission is to signal and image conversion unit 5.

The scattering electric field visibility of determinand is distributed and carries out two dimension Fourier's inverse operation by signal and image conversion unit 5, Obtain reconstruction of two-dimensional images；The 3-D view of determinand is built by changing the distance between signal receiving unit 3 and determinand； By the 3-D view in a time window is compared two-by-two, calculate the difference of electromagnetic attributes in 3-D view, and Build the four-dimensional image of determinand.

The four-dimensional image transmitting of the determinand of structure is shown to image-display units 6 by signal with image conversion unit 5 Show.

A kind of holographic microwave imaging system provided based on the present invention, present invention also offers a kind of holographic microwave imaging side Method, it comprises the following steps:

S1, arrange one include signal generating unit 1, signal transmitter unit 2, signal receiving unit 3, signaling control unit 4, Signal and image conversion unit 5 and the holographic microwave imaging system of image-display units 6；Signal generating unit 1 is sent out with signal Penetrating unit 2 and signaling control unit 4 connects, signal transmitter unit 2 and signal receiving unit 3 carry out radio communication, and signal controls Unit 4 is connected with image-display units 6 with image conversion unit 5 by signal.

S2, determinand (such as breast) is arranged on distance signal transmitter unit 2 and signal receiving unit 3 exceeds well over one The position of wavelength.

S3, signal generating unit 1 launch single-frequency territory microwave signal by signal transmitter unit 2 to determinand.

S4, under the effect of single-frequency territory microwave signal, around determinand formed scattered field, signal receiving unit 3 is to scattering Field is received, and transmits the scattered field received to signaling control unit 4.

Due to penetrability and the dielectricity of determinand of microwave signal, under the effect of electromagnetic field, shape around determinand Becoming scattered field, this scattered field is received by different reception antenna in signal receiving unit 3.

S5, signaling control unit 4, by measuring the scattering electric field of different reception antennas in receiving antenna array, utilize holography The principle of imaging, obtains amplitude and Phase delay information, and amplitude and Phase delay information is transmitted to signal and image conversion Unit 5.

Amplitude and Phase delay information can reflect the dielectric constant distribution of determinand.When there is disease, organism Dielectric constant generation great variety, the image reconstructed by organism can observe the change of organism physiological and pathological.

S6, signal and image conversion unit 5 are according to the scattering electric field distributed intelligence being consecutively detected, it is achieved four-dimensional image weight Structure.

The restructuring procedure of four-dimensional image particularly as follows:

The scattering electric field distributed intelligence that S601, basis are consecutively detected realizes the reconstruction of two-dimensional images of determinand.

The reconstructing method of two dimensional image is:

(x, y, z) be positioned in determinand, and (x, y, z) to signal receiving unit 3 for this P as illustrated in fig. 2, it is assumed that certain point P In two be positioned at r_iAnd r_gThe scattering electric field visibility of reception antenna be:

$G(r_i,r_g)=<E_{scat}\left(r_i\right)\&CenterDot;E_{scat}^{*}\left(r_g\right)>---\left(1\right)$

In formula (1), E_scat(r_i) represent be positioned at r_iThe scattering electric field of reception antenna,Represent and be positioned at r_gReception The conjugation of the scattering electric field of antenna,<>represents average time, r_iRepresent that in the determinand of target area, arbitrfary point receives sky to i-th The distance vector of line, r_gRepresent that in the determinand of target area, arbitrfary point is to the distance vector of g reception antenna.

Formula (1) can be expressed as follows:

Scattering electric field can be expressed as the volume integral of a scattering object, and scattering object relates to induced polarization electric current, induced polarization Electric current occurs in the complex dielectric permittivity compared with host medium.Under far field condition, scattering electric field can be expressed as follows:

$E_{scat}\left(r\right)=\left(\frac{k_0^2}{4\mathrm{\&pi;}}\right)\underset{V}{\&Integral;}\left(\mathrm{\&epsiv;}\right(s)-{\mathrm{\&epsiv;}}_b)E_T\left(s\right)\frac{e^{-{\mathrm{jk}}_b|s-r|}}{|s-r|}dV---\left(2\right)$

In formula (2),k₀=2 π/λ₀Represent the wave number of free space；k_b=2 π/λ_bRepresent background media matter Wave number, λ₀Represent the wavelength of free space, λ_bThe wavelength of background media matter, ε (s) represents the complicated relative dielectric constant of object Distribution, ε_bRepresenting the complicated relative dielectric constant distribution of background media, r represents that in the determinand of target area, arbitrfary point is to receiving sky The distance vector of line, E_TS () represents the determinand incident electric fields of any point and total electric field of scattering electric field on direction vector s Sum, V represents the volume of determinand.

Formula (2) is substituted in formula (1), obtains:

$G(r_i,r_g)={\left(\frac{k_0^2}{4\mathrm{\&pi;}}\right)}^2\underset{V}{\&Integral;\&Integral;\&Integral;}\underset{V^{\&prime;}}{\&Integral;\&Integral;\&Integral;}\left(\mathrm{\&epsiv;}\right(s)-{\mathrm{\&epsiv;}}_b){\left(\mathrm{\&epsiv;}\right(s^{\&prime;})-{\mathrm{\&epsiv;}}_b)}^{*}{E}_T\left(s\right)\&CenterDot;E_T^{*}\left(s^{\&prime;}\right)\frac{e^{-{\mathrm{jk}}_b(R-R^{\&prime;})}}{{\mathrm{RR}}^{\&prime;}}{\mathrm{dVdV}}^{\&prime;}---\left(3\right)$

In formula (3), R represents a P, and (x, y, z) to reception antenna r_iDistance, R=| r_i-s|；R' is different in representing determinand With a P (x, y, another P'(x' z), y', z') to reception antenna r_iDistance, R'=| r_gIn-s'|, s' represent determinand Point P'(x', y', z') to the distance of zero；V' represents around a P'(x', y', z') the volume of determinand.

In far-field region, (x, y, z) to reception antenna r for some P_iDistance be far longer than the size of aerial array, i.e. R ＞ ＞ | r_i |, can obtain

$R=\left|R\right|=\sqrt{(r_i-s)\&CenterDot;(r_g-s)}=\sqrt{r_i^2+s^2-2r_i\&CenterDot;s}\&cong;s-\frac{r_i\&CenterDot;s}{s}=s-r_i\&CenterDot;\hat{s}---\left(4\right)$

In formula (4), ". " represents scalar,Representation unit vector.

In like manner can obtain, another P'(x' in target area, y', z') arrive reception antenna r_gDistance be:

$R^{\&prime;}=\left|R^{\&prime;}\right|=s^{\&prime;}-r_g\&CenterDot;\widehat{s^{\&prime;}}---\left(5\right)$

Obtained by formula (4) and formula (5):

$\frac{e^{-{\mathrm{jk}}_b(R-R^{\&prime;})}}{{\mathrm{RR}}^{\&prime;}}\&ap;\frac{1}{{\mathrm{ss}}^{\&prime;}}{e}^{-{\mathrm{jk}}_b(s-s^{\&prime;})}{e}^{{\mathrm{jk}}_b(r_g\&CenterDot;\widehat{s^{\&prime;}}-r_i\&CenterDot;\hat{s})}---\left(6\right)$

Formula (6) being brought in formula (3), the visibility function obtaining target area determinand is:

$G(r_i,r_g)={\left(\frac{k_0^2}{4\mathrm{\&pi;}}\right)}^2\&Integral;\&Integral;{\&Integral;}_V\left(\right|\mathrm{\&epsiv;}\left(s\right)-{\mathrm{\&epsiv;}}_b{|}^2)E_T\left(s\right)\&CenterDot;E_T^{*}\left(s\right)\frac{e^{-{\mathrm{jk}}_b(r_g-r_i)\&CenterDot;\underset{\&OverBar;}{\hat{s}}}}{s^2}dV---\left(7\right)$

The Strength Equation of the target determinand of definition s position is:

$I\left(s\right)={\left(\frac{k_0^2}{4\mathrm{\&pi;}}\right)}^2|\mathrm{\&epsiv;}\left(s\right)-{\mathrm{\&epsiv;}}_b{|}^2{E}_T\left(s\right)\&CenterDot;E_T^{*}\left(s\right)---\left(8\right)$

Formula (8) is brought in formula (7), then, it is seen that degree functional equation is transformed to:

$G(u_{ig},v_{ig},w_{ig})=\underset{l}{\&Integral;}\underset{m}{\&Integral;}\underset{s}{\&Integral;}\frac{I(s,l,m)}{\sqrt{1-l^2-m^2}}{e}^{-j2{\mathrm{\&pi;\&Phi;}}_{ig}}dldmds---\left(9\right)$

In formula (9),u_ig=(x_g-x_i)/λ_b, v_ig=(y_g-y_i)/λ_b, w_ig= (z_g-z_i)/λ_b, l=sin θ cos φ, m=sin θ sin φ, D_igRepresent reception antenna r_iWith reception antenna r_gBetween baseline, (l, m n) represent the seat in spherical coordinate system as shown in Figure 3 Mark.

All arranging at sustained height if all of reception antenna, radially the line integral of coordinate p is:

$\tilde{I}(l,m)=\underset{p}{\&Integral;}\frac{I(s,l,m)}{\sqrt{1-l^2-m^2}}dp---\left(10\right)$

The visibility function equation utilizing formula (10) to represent formula (9) carries out two-dimensional Fourier transform, obtains:

$G(u_{ig},v_{ig})=\&Integral;\&Integral;\tilde{I}(l,m)e^{-j2\mathrm{\&pi;}(u_{ig}l+v_{ig}m)}dldm---\left(11\right)$

Formula (11) is carried out inverse Fourier transform, obtains the two dimensional image of determinand, it may be assumed that

$\tilde{I}(l,m)=\&Integral;\&Integral;G(u_{ig},v_{ig})e^{j2\mathrm{\&pi;}(u_{ig}l+v_{ig}m)}dudv---\left(12\right)$

Formula (12) shows that the two dimensional image of a three-dimensional determinand can be by Fourier's inversion of space visibility function Change reconstruction to obtain.

S602, two dimensional image based on reconstruct, move up and down scanning to the reception antenna in signal receiving unit 3, The medium of acquisition determinand intensity distributions under different depth, it is achieved 3-D view reconstructs.

When an aerial array, aerial array is moved up and down uniformly scanning, can obtain different high The spatial information of degree, i.e. obtains the medium of the three-dimensional body intensity distributions under different depth, can carry out 3-D view reconstruct.

When two aerial arrays, transmitting antenna array is placed in level altitude, launches microwave signal to be measured Thing, moves up and down scanning to receiving antenna array, it is thus achieved that the two dimensional image of differing heights, at the altitude range of scanning, and can The spatial information of the determinand obtained, i.e. obtains the medium of the three-dimensional body intensity distributions under different depth, thus realizes three-dimensional Image reconstruction.

The reconstructing method of 3-D view is:

For the determinand of target area being realized the antenna in three-dimensional imaging, signal transmitter unit 2 and signal receiving unit 3 Array can move up and down scanning.As shown in Figure 4, by this aerial array from height H₁(mm) height H is moved to_n(mm), target In determinand, any point depth location in target area is:

z_n=p_ncos(θ_n) (13)

In formula, θ_nRepresent that in aerial array, same antenna is at position p_nTransmitting or receiving angle to target determinand.

According to formula (13), in formula (10), dp is transformed to:

$dp=\frac{dz}{cos\left({\mathrm{\&theta;}}_n\right)}=\frac{dz}{\sqrt{1-l^2-m^2}}---\left(14\right)$

Formula (14) is carried out calculus, and the three-dimensional description of the determinand intensity function of arbitrary height is:

$I(H=z_n,l,m)=\frac{d\tilde{I}(l,m)\&CenterDot;(1-l^2-m^2)}{dz}---\left(15\right)$

Under differing heights, the vision intensity distribution of the difference of determinand is:

$\frac{d\tilde{I}}{dz}=\frac{{\tilde{I}}_{z_n}-{\tilde{I}}_{z_{n-1}}}{z_n-z_{n-1}}---\left(16\right)$

From formula (16), by calculating the vision intensity distribution of the difference of determinand under differing heights, and ratio is less two-by-two With the vision intensity difference under height, form one group of complete data, thus realize 3-D view reconstruct.The space of 3-D view Resolution is affected by antenna distribution shape, scanning speed, scanning height.For qualitative assessment imaging results, zoom function formula Can apply to strengthen picture contrast:

${\tilde{I}}_m(H,l,m)={\&lsqb;\tilde{I}(H,l,m)\&rsqb;}^Q---\left(17\right)$

Formula (17) represents that determinand reconstruct image zooms in or out the situation of Q times.

S603,3-D view based on reconstruct, the different time points in a domain gathers different 3-D views, enters And compare the difference of each 3-D view, obtain the temporal information of determinand, it is achieved four-dimensional image reconstruction.

The reconstructing method of four-dimensional image is:

As it is shown in figure 5, obtain one group of complete 3 d image data in a domain d of time orientation,

$\tilde{I}=\&lsqb;{\tilde{I}}_{m0},{\tilde{I}}_{m1},{\tilde{I}}_{m2},...,{\tilde{I}}_{md-1},{\tilde{I}}_{md}\&rsqb;---\left(18\right)$

Under different time direction, the 3-D view distribution of the difference of determinand is:

$d\tilde{I}/dt=({\tilde{I}}_{md}-{\tilde{I}}_{md-1})/(t_{md}-t_{md-1})---\left(19\right)$

From formula (19), by calculating the three-dimensional vision intensity distribution of the difference of the determinand in different time direction, formed One group of complete data, thus realize four-dimensional image reconstruction.

The present invention is not limited to above-mentioned preferred forms, and those skilled in the art can draw under the enlightenment of the present invention Other various forms of products, no matter but in its shape or structure, make any change, every have same as the present application or phase The technical scheme of approximation, within all falling within protection scope of the present invention.

Claims (10)

1. a holographic microwave imaging system, it is characterised in that: it includes that signal generating unit, signal transmitter unit, signal connect Receive unit, signaling control unit, signal and image conversion unit and image-display units；

The microwave signal in the single-frequency territory produced is launched to determinand by described signal generating unit by described signal transmitter unit, Scattering electric field is formed around determinand；

Described signal receiving unit measures scattering electric field, and the change of determinand inside and around electric field information, described signal Receive unit and transmit measurement result to described signaling control unit；

Described signaling control unit obtains the scattering electric field visibility distribution of determinand, and transmission is changed to described signal with image Unit；

Described signal and image conversion unit build the four-dimensional image obtaining determinand, and by four-dimension image transmitting to described image Display unit shows.

2. a kind of holographic microwave imaging system as claimed in claim 1, it is characterised in that: described signal generating unit includes penetrating Frequently signal generator and multi-way contral switching circuit board, described signal transmitter unit, signal receiving unit, signaling control unit Be connected with described radio-frequency signal generator respectively with multi-way contral switching circuit board, described multi-way contral switching circuit board with Signal receiving unit connects.

3. microwave imaging system as claimed in claim 1 or 2 a kind of holographic, it is characterised in that: described signal transmitter unit and Signal receiving unit is realized by one or two aerial array.

4. a kind of holographic microwave imaging system as claimed in claim 3, it is characterised in that: described signal transmitter unit and signal When reception unit is realized by an aerial array, described signal transmitter unit includes one or more transmitting antenna, described signal Receive unit and include that more than three reception antennas, described transmitting antenna and reception antenna are respectively positioned on equal height.

5. a kind of holographic microwave imaging system as claimed in claim 3, it is characterised in that: described signal transmitter unit and signal When reception unit is realized by two aerial arrays, described signal transmitter unit uses transmitting antenna array, and described signal receives single Unit uses receiving antenna array；Described transmitting antenna array includes a transmitting antenna, and described receiving antenna array includes at least Three reception antennas；Described transmitting antenna array and receiving antenna array are uneven distribution, and are positioned at identical or different height Degree；Described transmitting antenna array and receiving antenna array are arranged on the same side or the not homonymy of determinand；All described reception skies Line is positioned at sustained height.

6. a kind of holographic microwave imaging system as described in claim 4 or 5, it is characterised in that: between described transmitting antenna, connect Receive between antenna and launch and be respectively provided with microwave absorbing material or medium between antenna and reception antenna.

7. a formation method based on microwave imaging system holographic described in described any one of claim 1～6, it includes following Step:

Arrange one and include signal generating unit, signal transmitter unit, signal receiving unit, signaling control unit, signal and image Converting unit and the holographic microwave imaging system of image-display units；Signal generating unit and signal transmitter unit and signal control Unit processed connects, and signal transmitter unit and signal receiving unit carry out radio communication, and signaling control unit passes through signal and image Converting unit is connected with image-display units；

Determinand is arranged on distance signal transmitter unit and signal receiving unit exceeds well over the position of a wavelength；

Signal generating unit launches single-frequency territory microwave signal by signal transmitter unit to determinand；

Under the effect of single-frequency territory microwave signal, forming scattered field around determinand, scattered field is connect by signal receiving unit Receive, and the scattered field received is transmitted to signaling control unit；

Signaling control unit obtains amplitude and Phase delay information, and transmits to signal and image conversion unit；

Signal and image conversion unit are according to the scattering electric field distributed intelligence being consecutively detected, it is achieved four-dimensional image reconstruction.

8. a kind of holographic microwave imaging method as claimed in claim 7, it is characterised in that: described signal realizes with image conversion The process of four-dimensional image reconstruction is:

The reconstruction of two-dimensional images of determinand is realized according to the scattering electric field distributed intelligence being consecutively detected；

Two dimensional image based on reconstruct, moves up and down scanning to the reception antenna in signal receiving unit, obtains determinand Medium intensity distributions under different depth, it is achieved 3-D view reconstructs；

3-D view based on reconstruct, the different time points in a domain gathers different 3-D views, relatively each three-dimensional The difference of image, obtains the temporal information of determinand, it is achieved four-dimensional image reconstruction.

9. a kind of holographic microwave imaging method as claimed in claim 8, it is characterised in that: the reconstructing method of two dimensional image is:

Assume that (x, y, z) be positioned in determinand certain point P, and (x, y z) are positioned at r to two in signal receiving unit to this P_iWith r_gThe scattering electric field visibility of reception antenna be:

$G(r_i,r_g)=<E_{scat}\left(r_i\right)\&CenterDot;E_{scat}^{*}\left(r_g\right)>---\left(1\right)$

In formula (1), E_scat(r_i) represent be positioned at r_iThe scattering electric field of reception antenna,Represent and be positioned at r_gReception antenna The conjugation of scattering electric field,<>represents average time, r_iRepresent that in the determinand of target area, arbitrfary point is to i-th reception antenna Distance vector, r_gRepresent that in the determinand of target area, arbitrfary point is to the distance vector of g reception antenna；

Under far field condition, scattering electric field is expressed as:

$E_{scat}\left(r\right)=\left(\frac{k_0^2}{4\mathrm{\&pi;}}\right)\underset{V}{\&Integral;}\left(\mathrm{\&epsiv;}\right(s)-{\mathrm{\&epsiv;}}_b)E_T\left(s\right)\frac{e^{-{\mathrm{jk}}_b|s-r|}}{|s-r|}dV---\left(2\right)$

In formula (2),k₀=2 π/λ₀Represent the wave number of free space；k_b=2 π/λ_bRepresent the wave number of background media matter, λ₀Represent the wavelength of free space, λ_bThe wavelength of background media matter, ε (s) represents the complicated relative dielectric constant distribution of object, ε_bRepresenting the complicated relative dielectric constant distribution of background media, r represents that in the determinand of target area, reception antenna is arrived in arbitrfary point Distance vector, E_T(s) represent determinand on direction vector s the total electric field of the incident electric fields of any point and scattering electric field it With, V represents the volume of determinand；

Formula (2) is substituted in formula (1), obtains:

$G\left(r_i,r_g\right)={\left(\frac{k_0^2}{4\mathrm{\&pi;}}\right)}^2\underset{V}{\&Integral;\&Integral;\&Integral;}\underset{V^{\&prime;}}{\&Integral;\&Integral;\&Integral;}\left(\mathrm{\&epsiv;}\left(s\right)-{\mathrm{\&epsiv;}}_b\right){\left(\mathrm{\&epsiv;}\left(s^{\&prime;}\right)-{\mathrm{\&epsiv;}}_b\right)}^{*}{E}_T\left(s\right)\&CenterDot;E_T^{*}\left(s^{\&prime;}\right)\frac{e^{-{\mathrm{jk}}_b\left(R-R^{\&prime;}\right)}}{{\mathrm{RR}}^{\&prime;}}{\mathrm{dVdV}}^{\&prime;}---\left(3\right)$

In formula (3), R represents a P, and (x, y, z) to reception antenna r_iDistance, R=| r_i-s|；R' is different and point in representing determinand P (x, y, another P'(x' z), y', z') arrives reception antenna r_iDistance, R'=| r_g-s'|, s' put P' in representing determinand (x', y', z') is to the distance of zero；V' represents around a P'(x', y', z') the volume of determinand；

In far-field region, (x, y, z) to reception antenna r for some P_iDistance be far longer than the size of aerial array, i.e. R ＞ ＞ | r_i|, Arrive:

$R=\left|R\right|=\sqrt{(r_i-s)\&CenterDot;(r_g-s)}=\sqrt{r_i^2+s^2-2r_i\&CenterDot;s}\&cong;s-\frac{r_i\&CenterDot;s}{s}=s-r_i\&CenterDot;\hat{s}---\left(4\right)$

In formula (4), ". " represents scalar,Representation unit vector；

In like manner obtain, another P'(x' in target area, y', z') arrive reception antenna r_gDistance be:

$R^{\&prime;}=\left|R^{\&prime;}\right|=s^{\&prime;}-r_g\&CenterDot;\widehat{s^{\&prime;}}---\left(5\right)$

Obtained by formula (4) and formula (5):

$\frac{e^{-{\mathrm{jk}}_b(R-R^{\&prime;})}}{{\mathrm{RR}}^{\&prime;}}\&ap;\frac{1}{{\mathrm{ss}}^{\&prime;}}{e}^{-{\mathrm{jk}}_b\left(s-s^{\&prime;}\right)}{e}^{{\mathrm{jk}}_b\left(r_g\&CenterDot;\widehat{s^{\&prime;}}-r_i\&CenterDot;\hat{s}\right)}---\left(6\right)$

Formula (6) being brought in formula (3), the visibility function obtaining target area determinand is:

The Strength Equation of the target determinand of definition s position is:

Formula (8) is brought in formula (7), then, it is seen that degree functional equation is transformed to:

$G(u_{ig},v_{ig},w_{ig})=\underset{l}{\&Integral;}\underset{m}{\&Integral;}\underset{s}{\&Integral;}\frac{I(s,l,m)}{\sqrt{1-l^2-m^2}}{e}^{-j2{\mathrm{\&pi;\&Phi;}}_{ig}}dldmds---\left(9\right)$

In formula (9),u_ig=(x_g-x_i)/λ_b, v_ig=(y_g-y_i)/λ_b, w_ig=(z_g- z_i)/λ_b, l=sin θ cos φ, m=sin θ sin φ, D_igRepresent reception antenna r_iWith reception antenna r_gBetween baseline, (l, m n) represent the coordinate in spherical coordinate system；

All arranging at sustained height if all of reception antenna, radially the line integral of coordinate p is:

$\tilde{I}(l,m)=\underset{p}{\&Integral;}\frac{I(s,l,m)}{\sqrt{1-l^2-m^2}}dp---\left(10\right)$

The visibility function equation utilizing formula (10) to represent formula (9) carries out two-dimensional Fourier transform, obtains:

$G(u_{ig},v_{ig})=\&Integral;\&Integral;\tilde{I}(l,m)e^{-j2\mathrm{\&pi;}(u_{ig}l+v_{ig}m)}dldm---\left(11\right)$

Formula (11) is carried out inverse Fourier transform, obtains the two dimensional image of determinand, it may be assumed that

$\tilde{I}(l,m)=\&Integral;\&Integral;G(u_{ig},v_{ig})e^{j2\mathrm{\&pi;}(u_{ig}l+v_{ig}m)}dudv---\left(12\right).$

10. a kind of holographic microwave imaging method as claimed in claim 9, it is characterised in that: the reconstructing method of 3-D view is: By aerial array from height H₁(mm) height H is moved to_n(mm), in target determinand any point in the degree of depth position of target area It is set to:

z_n=p_ncos(θ_n) (13)

In formula (13), θ_nRepresent that in aerial array, same antenna is at position p_nTransmitting or receiving angle to target determinand；

According to formula (13), in formula (10), dp is transformed to:

$dp=\frac{dz}{cos\left({\mathrm{\&theta;}}_n\right)}=\frac{dz}{\sqrt{1-l^2-m^2}}---\left(14\right)$

Formula (14) is carried out calculus, and the three-dimensional description of the determinand intensity function of arbitrary height is:

$I(H=z_n,l,m)=\frac{d\tilde{I}\left(l,m\right)\&CenterDot;\left(1-l^2-m^2\right)}{dz}---\left(15\right)$

Under differing heights, the vision intensity distribution of the difference of determinand is:

$\frac{d\tilde{I}}{dz}=\frac{{\tilde{I}}_{z_n}-{\tilde{I}}_{z_{n-1}}}{z_n-z_{n-1}}---\left(16\right)$

By calculating the vision intensity distribution of the difference of determinand under differing heights, and compare the vision intensity under differing heights two-by-two Difference, forms one group of complete data, thus realizes 3-D view reconstruct.