CN113848547A - Digital holographic fast imaging method - Google Patents

Digital holographic fast imaging method Download PDF

Info

Publication number
CN113848547A
CN113848547A CN202111123894.XA CN202111123894A CN113848547A CN 113848547 A CN113848547 A CN 113848547A CN 202111123894 A CN202111123894 A CN 202111123894A CN 113848547 A CN113848547 A CN 113848547A
Authority
CN
China
Prior art keywords
imaging
phase
weighting
array
target
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
CN202111123894.XA
Other languages
Chinese (zh)
Other versions
CN113848547B (en
Inventor
张继康
张艺恒
张继龙
俞晓琳
宋雨花
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Suzhou Weimo Electronic Information Technology Co ltd
Original Assignee
Suzhou Weimo Electronic Information Technology Co ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Suzhou Weimo Electronic Information Technology Co ltd filed Critical Suzhou Weimo Electronic Information Technology Co ltd
Priority to CN202111123894.XA priority Critical patent/CN113848547B/en
Publication of CN113848547A publication Critical patent/CN113848547A/en
Priority to PCT/CN2022/118463 priority patent/WO2023045804A1/en
Application granted granted Critical
Publication of CN113848547B publication Critical patent/CN113848547B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/88—Radar or analogous systems specially adapted for specific applications
    • G01S13/89—Radar or analogous systems specially adapted for specific applications for mapping or imaging
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/88—Radar or analogous systems specially adapted for specific applications
    • G01S13/89—Radar or analogous systems specially adapted for specific applications for mapping or imaging
    • G01S13/90—Radar or analogous systems specially adapted for specific applications for mapping or imaging using synthetic aperture techniques, e.g. synthetic aperture radar [SAR] techniques
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/88—Radar or analogous systems specially adapted for specific applications
    • G01S13/89—Radar or analogous systems specially adapted for specific applications for mapping or imaging
    • G01S13/90—Radar or analogous systems specially adapted for specific applications for mapping or imaging using synthetic aperture techniques, e.g. synthetic aperture radar [SAR] techniques
    • G01S13/9021—SAR image post-processing techniques
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/88—Radar or analogous systems specially adapted for specific applications
    • G01S13/89—Radar or analogous systems specially adapted for specific applications for mapping or imaging
    • G01S13/90—Radar or analogous systems specially adapted for specific applications for mapping or imaging using synthetic aperture techniques, e.g. synthetic aperture radar [SAR] techniques
    • G01S13/904—SAR modes
    • G01S13/9064—Inverse SAR [ISAR]
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S15/00—Systems using the reflection or reradiation of acoustic waves, e.g. sonar systems
    • G01S15/88—Sonar systems specially adapted for specific applications
    • G01S15/89—Sonar systems specially adapted for specific applications for mapping or imaging
    • G01S15/8906—Short-range imaging systems; Acoustic microscope systems using pulse-echo techniques
    • G01S15/8965—Short-range imaging systems; Acoustic microscope systems using pulse-echo techniques using acousto-optical or acousto-electronic conversion techniques
    • G01S15/897—Short-range imaging systems; Acoustic microscope systems using pulse-echo techniques using acousto-optical or acousto-electronic conversion techniques using application of holographic techniques
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S15/00—Systems using the reflection or reradiation of acoustic waves, e.g. sonar systems
    • G01S15/88—Sonar systems specially adapted for specific applications
    • G01S15/89—Sonar systems specially adapted for specific applications for mapping or imaging
    • G01S15/8906—Short-range imaging systems; Acoustic microscope systems using pulse-echo techniques
    • G01S15/8977—Short-range imaging systems; Acoustic microscope systems using pulse-echo techniques using special techniques for image reconstruction, e.g. FFT, geometrical transformations, spatial deconvolution, time deconvolution
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S15/00—Systems using the reflection or reradiation of acoustic waves, e.g. sonar systems
    • G01S15/88—Sonar systems specially adapted for specific applications
    • G01S15/89—Sonar systems specially adapted for specific applications for mapping or imaging
    • G01S15/8906—Short-range imaging systems; Acoustic microscope systems using pulse-echo techniques
    • G01S15/8997—Short-range imaging systems; Acoustic microscope systems using pulse-echo techniques using synthetic aperture techniques
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/88—Lidar systems specially adapted for specific applications
    • G01S17/89—Lidar systems specially adapted for specific applications for mapping or imaging
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/88—Lidar systems specially adapted for specific applications
    • G01S17/89—Lidar systems specially adapted for specific applications for mapping or imaging
    • G01S17/90—Lidar systems specially adapted for specific applications for mapping or imaging using synthetic aperture techniques
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F17/00—Digital computing or data processing equipment or methods, specially adapted for specific functions
    • G06F17/10—Complex mathematical operations
    • G06F17/14—Fourier, Walsh or analogous domain transformations, e.g. Laplace, Hilbert, Karhunen-Loeve, transforms
    • G06F17/141—Discrete Fourier transforms
    • G06F17/142—Fast Fourier transforms, e.g. using a Cooley-Tukey type algorithm

Abstract

The invention relates to the technical field of optical imaging, microwave imaging, radar detection, wireless communication, sonar, ultrasonic imaging, target detection and imaging identification based on media such as sound, light, electricity and the like, in particular to a digital holographic rapid imaging method and application thereof in the fields. The method is based on the lens imaging principle, combines the electromagnetic field theory, and obtains the image field distribution corresponding to the target by the amplitude and phase weighting of unit signals and the efficient parallel algorithm according to the target signals received by the antenna array. The invention has the advantages of small operation amount, low hardware cost, high imaging speed, suitability for remote imaging and the like, and can be widely applied to the fields of optical imaging, microwave imaging, radar detection, sonar imaging, ultrasonic imaging, target detection, imaging identification and wireless communication taking sound, light, electricity and the like as media.

Description

Digital holographic fast imaging method
Technical Field
The invention relates to the technical fields of optical imaging, microwave imaging, radar detection, sonar, ultrasonic imaging, target detection based on media such as sound, light, electricity and the like, imaging identification and wireless communication, in particular to a digital holographic rapid imaging method and application thereof in the fields.
Background
The digital holographic imaging technology evolved from the laser holographic imaging technology has high imaging resolution, is one of the first-choice technologies of millimeter wave active imaging at present, and related products are popularized and applied in different fields at home and abroad.
However, the conventional digital holographic imaging technology still has many defects and shortcomings, mainly including:
1) large computation, high cost and low speed
In the existing digital holographic imaging technology, two operations of Fast Fourier Transform (FFT) and Inverse Fast Fourier Transform (IFFT) are required to be performed in sequence during imaging, the operation amount is extremely large, the configuration requirements on hardware environment and computing resources are high, the hardware price and the operation cost are high, and in addition, the two operations of FFT and IFFT are required to be performed in sequence, so the imaging speed is low.
2) Can not image for a long distance
In the existing digital holographic imaging technology, when the target distance is long, the phase compensation can be ignored, which is equivalent to performing "FFT-IFFT" operation, and imaging distortion and even imaging failure can be caused.
In addition, the present inventors have developed a "microwave array fast imaging method" (CN 112612024a), but this method is not suitable for short-distance digital holography imaging applications, and when the imaging distance is close, this method cannot obtain satisfactory imaging effect due to poor imaging effect and low resolution.
Disclosure of Invention
In order to overcome the defects and shortcomings of the traditional digital holographic imaging technology, the invention provides a set of solutions.
As shown in fig. 1, a coordinate system of an imaging system is established, wherein: p is the target, Q is the image of the target, the antenna array is located on the plane where z is 0, and X denotes the transmit and receive antenna elements. And sequentially opening the receiving and transmitting antenna units, recording the scattering signals of the target, obtaining the holographic data of the target when the whole antenna array is scanned, and carrying out imaging processing on the holographic data to obtain the image of the target.
The propagation phase shift introduced when a signal propagates through a single pass of R1, R2 is:
Figure BDA0003278014220000021
among the components useful for imaging focusing are:
Figure BDA0003278014220000022
wherein phi is1Is the propagation phase shift, phi, of the scattering source P to the array elements2For the propagation phase shift of the array element to the image point Q,
Figure BDA0003278014220000023
is the wave number, U is the object distance, V is the image distance;
Figure BDA0003278014220000026
the target coordinates, (x, y) are the array element coordinates, and (δ, σ) are the image point coordinates.
By equating the antenna array as a lens with focal length F, the effective phase shift of the lens elements is:
Figure BDA0003278014220000024
wherein phi isLF is the focal length for the lens phase shift of the array element.
In the holographic imaging system, a signal is transmitted from an antenna unit, reflected to a target and received by the antenna unit, the signal undergoes two-pass transmission with a path R1, and the corresponding phase delay is 2 phi1. In the imaging process, the lens unit phase shift and the R2 propagation phase shift are processed in two passes: the receiving and transmitting antenna units sequentially transmit detection signals, and the signals reflected by the target P are subjected to secondary scattering in the form of spherical waves after reaching the receiving and transmitting antenna units and then pass through different transmission paths R1、R2And the field strength reaching the image plane after the two-way phase shift is as follows:
Figure BDA0003278014220000025
wherein the content of the first and second substances,
Figure BDA0003278014220000031
in order to be the image field distribution,
Figure BDA0003278014220000032
is the target reflected signal. Substitution of phi1、φ2、φLThe expression of (A) is obtained after the arrangement:
Figure BDA0003278014220000033
wherein the content of the first and second substances,
Figure BDA0003278014220000034
when the imaging conditions are satisfied:
Figure BDA0003278014220000035
at this time there is Ψ10, order
Figure BDA0003278014220000036
Finishing to obtain:
Figure BDA0003278014220000037
for an ideal rectangular lens front:
Figure BDA0003278014220000038
substituting the formula to carry out definite integration to obtain:
Figure BDA0003278014220000039
where Sinc represents the Sinc function. It can be seen that there is a good mapping between the image field distribution and the object.
For an actual holographic imaging discrete array system, assuming that a target transmission signal received by a transceiving antenna unit is E, a reflected signal received by an array needs to be subjected to the following two-way phase shift processing during imaging:
Figure BDA00032780142200000310
wherein the content of the first and second substances,
Figure BDA00032780142200000311
for the field received by the array element, AmnThe amplitude weighting coefficients of the array elements. The formula is developed and finished to obtain:
Figure BDA00032780142200000312
wherein the content of the first and second substances,
Figure BDA00032780142200000313
when the imaging conditions are satisfied:
Figure BDA00032780142200000314
at this time has psi1＝0。
Figure BDA00032780142200000315
Let xm＝x0+mΔx，yn＝y0+nΔyM and n are respectively the serial numbers of the array units in the x direction and the y direction, deltax、ΔyArray unit spacing in x-direction and y-direction respectively, (x)0,y0) Is the array starting cell coordinate. The formula is simplified and arranged as follows:
Figure BDA00032780142200000316
wherein the content of the first and second substances,
Figure BDA00032780142200000317
the right coefficient of the above formula satisfies
Figure BDA0003278014220000041
The spatial fluctuation characteristic of an image field is reflected, and the influence on imaging is basically avoided and can be ignored. The summation operation can be rapidly solved by using two-dimensional IFFT, and then the image field calculation formula is as follows:
Figure BDA0003278014220000042
where IFFT represents a two-dimensional inverse fast fourier transform. Omega corresponding to IFFT calculation resultδ、ωσThe value range is as follows: omegaδ∈[0,2π]、ωσ∈[0,2π]After fftshift operation, the value of ω is calculatedδ、ωσThe value range is transformed into: omegaδ∈[-π,π]、ωσ∈[-π,π]The image at this time is the image which is in accordance with the actual distribution, and has a good linear mapping relation with the source field.
Figure BDA0003278014220000043
Bonding ofTheory of array antenna, with omegaδ＝2kΔxsinθδ、ωσ＝2kΔysinθσThe condition that the directional diagram has no grating lobe is as follows:
Figure BDA0003278014220000044
and finally, correcting the scanning angular coordinate of the image point by adopting an array antenna theory:
Figure BDA0003278014220000045
on the basis of the knowledge, the invention provides a digital holographic rapid imaging method, which is based on a lens imaging principle, combines an electromagnetic field theory, and adopts an efficient parallel algorithm to obtain image field distribution corresponding to a target by weighting the amplitude and the phase of a unit signal according to a target signal received by an antenna array.
Further, in the method, the image field distribution corresponding to the target is obtained by weighting the amplitude and the phase of the unit signal and adopting an efficient parallel algorithm, and the specific algorithm is as follows:
Figure BDA0003278014220000046
wherein: j is an imaginary unit, e is an Euler constant,
Figure BDA0003278014220000047
in order to be the image field distribution,
Figure BDA0003278014220000048
for the target signal received by the array unit, AmnIs a weighting coefficient for the array element amplitude,
Figure BDA0003278014220000049
in order to focus the phase weighting coefficients,
Figure BDA00032780142200000410
for scanning the phase weighting coefficients, M is the number of array elements in the x-direction, and N is the number of array elements in the y-direction, (x)m，yn) Is the coordinate of the array unit, (delta, sigma) is the coordinate of the image point, V is the image distance, i.e. the distance from the image plane to the array plane, m, n are the serial numbers of the array unit in the x direction and the y direction respectively,
Figure BDA00032780142200000411
in wavenumber, λ is the wavelength, and the symbol Σ represents the summation operation.
Specifically, the digital holographic rapid imaging method comprises the following steps:
the method comprises the following steps: carrying out amplitude weighting on the array unit signals to reduce side lobe levels;
step two: carrying out scanning phase weighting on the array unit signals to adjust the central visual angle direction of the imaging system;
step three: carrying out focusing phase weighting on the array unit signals to realize imaging focusing;
step four: performing rapid imaging processing on signals of the array unit by adopting an efficient parallel algorithm;
step five: and resolving the image field coordinates, and performing coordinate inversion on the image field to obtain the position of the real target.
Further, the amplitude weighting method in step one of the method of the present invention includes, but is not limited to, uniform distribution, cosine weighting, hamming window, Taylor distribution, chebyshev distribution, and hybrid weighting method.
Further, in step two of the method of the present invention, the scanning phase is weighted to adjust the central view direction of the imaging system, and the phase calculation formula of the scanning phase weighting is as follows:
Figure BDA0003278014220000051
wherein:
Figure BDA0003278014220000052
adjacent to each other in x and y directionsThe calculation formula of the phase difference between the units is respectively as follows:
Figure BDA0003278014220000053
Figure BDA0003278014220000054
wherein: deltax、ΔyThe array unit pitch theta in the x direction and the y directionζ、θξThe x and y scanning angle coordinates when the central visual angle direction points to the source coordinates (zeta, xi) are respectively calculated as follows:
Figure BDA0003278014220000055
Figure BDA0003278014220000056
wherein: u is the object distance, i.e., the distance from the plane of the target to the plane of the array.
Further, the method comprises the following steps: and carrying out focusing phase weighting on the array unit signals by using a focusing phase weighting method to realize imaging focusing, wherein:
the autofocus phase weighted focus phase calculation formula is:
Figure BDA0003278014220000057
the zoom or fixed focus phase weighted focus phase calculation formula is:
Figure BDA0003278014220000058
wherein F is the focal length, and F < U, F < V.
Further, the method of the invention comprises the following fourth step: performing rapid imaging processing on the signals after the amplitude and the phase of the array unit are weighted by adopting an efficient parallel algorithm; the efficient parallel algorithm includes, but is not limited to, two-dimensional or three-dimensional FFT, IFFT, non-uniform FFT, sparse FFT, and the calculation formula is:
Figure BDA0003278014220000061
wherein:
Figure BDA0003278014220000062
is like, symbol
Figure BDA0003278014220000063
Represents an efficient parallel algorithm function and is,
Figure BDA0003278014220000064
is a target scattered field received by the array unit, A is an array unit amplitude weighting coefficient, phiFFor focusing the phase weighting coefficients, [ phi ]sWeighting coefficients for the scanning phases;
ω corresponding to the image field calculation resultδ、ωσThe value range is as follows: omegaδ∈[0,2π]、ωσ∈[0,2π]After fftshift operation, the value of ω is calculatedδ、ωσThe value range is transformed into: omegaδ∈[-π,π]、ωσ∈[-π,π]The image at this time is an image conforming to the actual distribution:
Figure BDA0003278014220000065
further, the method of the invention comprises the following step five: carrying out coordinate calculation on an image field obtained by the efficient parallel algorithm, and carrying out coordinate inversion on the image field to obtain the distribution condition of a real target; wherein:
for the efficient parallel algorithm of the IFFT class, the calculation formula of the angular coordinate of the image field scanning is as follows:
Figure BDA0003278014220000066
Figure BDA0003278014220000067
for the FFT-like efficient parallel algorithm, the calculation formula of the image field scanning angle coordinate is as follows:
Figure BDA0003278014220000068
Figure BDA0003278014220000069
the rectangular coordinate calculation formula of the image is as follows:
δ＝V tanθδ，
σ＝V tanθσ；
the coordinate inversion calculation formula of the real target is as follows:
Figure BDA00032780142200000610
Figure BDA0003278014220000071
furthermore, the method of the invention sets the unit spacing of the transmitting and receiving antenna
Figure BDA0003278014220000072
To avoid image aliasing.
Meanwhile, the invention also relates to the application of the method in the fields of optical imaging, microwave imaging, radar detection, sonar, ultrasonic imaging, sound, light and electric target detection, imaging identification and wireless communication.
In addition, the bookThe invention also provides a digital holographic fast imaging method, which is used for remote imaging and comprises the following steps: if U is ∞, then phiFA simplified formula suitable for long range imaging is 0:
Figure BDA0003278014220000073
and calculating an image field by adopting the efficient parallel algorithm, and obtaining the target distribution condition in a wide visual angle range through one-time operation.
In summary, the digital holographic fast imaging method of the invention has the following advantages:
1) small operation amount, low hardware cost and high imaging speed
Compared with the traditional holographic imaging algorithm, the phase compensation-IFFT algorithm framework is adopted, the FFT operation link with high requirement on hardware resources and low operation speed is removed, the operation amount is greatly reduced, and the operation speed is improved.
2) Can be used for long-distance imaging
In the invention, when the remote imaging is carried out, the phase compensation can be ignored, and the IFFT operation is equivalently carried out, so that the imaging of the remote target can be realized.
In addition, the method has good application prospect, can be widely applied to the technical field of target detection and wireless communication taking sound, light, electricity and the like as media, and when the detection media are electromagnetic waves, the technology is suitable for microwave imaging, radar detection, wireless communication, synthetic aperture radar and inverse synthetic aperture radar; when the detection medium is sound wave and ultrasonic wave, the technology is suitable for sonar, ultrasonic imaging and synthetic aperture sonar; when the detection medium is light, the technology is suitable for optical imaging and synthetic aperture optical imaging.
Drawings
In order to more clearly illustrate the technical solutions of the prior art and the embodiments of the present invention, the drawings needed to be used in the description of the prior art and the embodiments of the present invention will be briefly described below, it is obvious that the following drawings are only some embodiments described in the present invention, and it is obvious for those skilled in the art that other drawings can be obtained based on these drawings without creative efforts.
FIG. 1 is a coordinate system of a digital holographic imaging system according to the present invention.
FIG. 2 is an algorithm block diagram of the digital holographic imaging method of the present invention.
Fig. 3 is a comparison of the results of conventional holographic imaging and holographic imaging of the present invention in close range (U ═ 1m), where: (a) for conventional holographic imaging and (b) for holographic imaging according to the invention.
Fig. 4 shows the comparison between the conventional holographic imaging and the holographic imaging remote imaging (U1000 m), in which: (a) for conventional holographic imaging and (b) for holographic imaging according to the invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be described in detail and completely with reference to the following embodiments and accompanying drawings. It is to be understood that the embodiments described are merely illustrative of some, but not all, of the present invention and that the invention may be embodied or carried out in various other specific forms, and that various modifications and changes in the details of the specification may be made without departing from the spirit of the invention.
Also, it should be understood that the scope of the invention is not limited to the particular embodiments described below; it is also to be understood that the terminology used in the examples is for the purpose of describing particular embodiments only, and is not intended to limit the scope of the present invention.
Example 1: a digital holographic fast imaging method (refer to the attached figures 1-2) is based on the lens imaging principle, combines the electromagnetic field theory, and obtains the image field distribution corresponding to the target by the amplitude and phase weighting of unit signals and the high-efficiency parallel algorithm according to the target signals received by an antenna array, and the specific algorithm is as follows:
Figure BDA0003278014220000081
wherein: j is an imaginary unit, e is an Euler constant,
Figure BDA0003278014220000091
in order to be the image field distribution,
Figure BDA0003278014220000092
for the target signal received by the array unit, AmnIs a weighting coefficient for the array element amplitude,
Figure BDA0003278014220000093
in order to focus the phase weighting coefficients,
Figure BDA0003278014220000094
for scanning the phase weighting coefficients, M is the number of array elements in the x-direction, and N is the number of array elements in the y-direction, (x)m，yn) Is the coordinate of the array unit, (delta, sigma) is the coordinate of the image point, V is the image distance, i.e. the distance from the image plane to the array plane, m, n are the serial numbers of the array unit in the x direction and the y direction respectively,
Figure BDA0003278014220000095
in wavenumber, λ is the wavelength, and the symbol Σ represents the summation operation.
Specifically, the method comprises the following steps:
the method comprises the following steps: carrying out amplitude weighting on the array unit signals to reduce side lobe levels;
the amplitude weighting method comprises a uniform distribution method, a cosine weighting method, a Hamming window method, a Taylor distribution method, a Chebyshev distribution method and a mixed weighting method.
Step two: carrying out scanning phase weighting on the array unit signals to adjust the central visual angle direction of the imaging system;
wherein, the scanning phase weighting adjusts the central view angle direction of the imaging system, and the phase calculation formula of the scanning phase weighting is as follows:
Figure BDA0003278014220000096
wherein: m and n are respectively the serial numbers of the array units in the x direction and the y direction,
Figure BDA0003278014220000097
the phase difference between the adjacent cells of the array in the x direction and the y direction respectively has the following calculation formula:
Figure BDA0003278014220000098
Figure BDA0003278014220000099
wherein: deltax、ΔyThe array unit spacing in the x-direction and the y-direction respectively, the symbol sin represents a sine function, thetaζ、θξThe x and y scanning angle coordinates when the central visual angle direction points to the source coordinates (zeta, xi) are respectively calculated as follows:
Figure BDA00032780142200000910
Figure BDA00032780142200000911
wherein: u is the object distance, i.e. the distance from the plane of the target to the plane of the array, and the symbol tan-1Representing the arctan function.
Step three: carrying out focusing phase weighting on the array unit signals to realize imaging focusing;
the method specifically comprises the following steps: and carrying out focusing phase weighting on the array unit signals by using a focusing phase weighting method to realize imaging focusing, wherein:
the autofocus phase weighted focus phase calculation formula is:
Figure BDA0003278014220000101
the zoom or fixed focus phase weighted focus phase calculation formula is:
Figure BDA0003278014220000102
wherein F is the focal length, and F < U, F < V.
Step four: performing rapid imaging processing on signals of the array unit by adopting an efficient parallel algorithm;
the method specifically comprises the following steps: performing rapid imaging processing on the signals after the amplitude and the phase of the array unit are weighted by adopting an efficient parallel algorithm; the efficient parallel algorithm comprises two-dimensional or three-dimensional FFT, IFFT, non-uniform FFT and sparse FFT, and the calculation formula is as follows:
Figure BDA0003278014220000103
wherein:
Figure BDA0003278014220000104
is like, symbol
Figure BDA0003278014220000105
Represents an efficient parallel algorithm function and is,
Figure BDA0003278014220000106
is a target scattered field received by the array unit, A is an array unit amplitude weighting coefficient, phiFFor focusing the phase weighting coefficients, [ phi ]SWeighting coefficients for the scanning phases;
ω corresponding to the image field calculation resultδ、ωσThe value range is as follows: omegaδ∈[0,2π]、ωσ∈[0,2π]After fftshift operation, the value of ω is calculatedδ、ωσThe value range is transformed into: omegaδ∈[-π,π]、ωσ∈[-π,π]At this timeIs the image that fits the actual distribution:
Figure BDA0003278014220000107
step five: resolving an image field coordinate, and performing coordinate inversion on the image field to obtain the position of a real target;
the method specifically comprises the following steps: carrying out coordinate calculation on an image field obtained by the efficient parallel algorithm, and carrying out coordinate inversion on the image field to obtain the distribution condition of a real target; wherein:
for the efficient parallel algorithm of the IFFT class, the calculation formula of the angular coordinate of the image field scanning is as follows:
Figure BDA0003278014220000108
Figure BDA0003278014220000109
for the FFT-like efficient parallel algorithm, the calculation formula of the image field scanning angle coordinate is as follows:
Figure BDA0003278014220000111
Figure BDA0003278014220000112
the rectangular coordinate calculation formula of the image is as follows:
δ＝V tanθδ，
σ＝V tanθσ；
the coordinate inversion calculation formula of the real target is as follows:
Figure BDA0003278014220000113
Figure BDA0003278014220000114
in addition, the unit distance of the transmitting and receiving antenna is set in the method of the invention
Figure BDA0003278014220000115
To avoid image aliasing.
Example 2: the digital holographic fast imaging (embodiment 1 method) of the invention is compared with the short-distance imaging result of the traditional holographic imaging (U is 1m), and the method comprises the following steps:
the working frequency is 30GHz, the antenna unit spacing is half wavelength, the array scale is 32 x 32, one target is located in the normal direction of the array, the other target deviates from the normal direction by 20 degrees, the distance between the target and the plane where the antenna array is located is 1m, and the imaging result is contrasted with that shown in figure 3.
Example 3: the digital holographic fast imaging (embodiment 1 method) of the invention is compared with the remote imaging result of the traditional holographic imaging (U is 1000m), and the method comprises the following steps:
the working frequency is 30GHz, the antenna unit spacing is half wavelength, the array scale is 32 x 32, one target is located in the normal direction of the array, the other target deviates from the normal direction by 20 degrees, the distance between the target and the plane where the antenna array is located is 1000m, and the imaging result is contrasted with that shown in figure 4.
Example 4: a digital holographic fast imaging method for remote imaging, comprising: if U is ∞, then phiFA simplified formula suitable for long range imaging is 0:
Figure BDA0003278014220000121
and calculating an image field by adopting the efficient parallel algorithm, and obtaining the target distribution condition in a wide visual angle range through one-time operation.
The embodiments of the present invention are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.
The above description is only an example of the present invention, and is not intended to limit the present invention. Various modifications and alterations to this invention will become apparent to those skilled in the art. Any modification, replacement, or the like that comes within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.

Claims (11)

1. A digital holographic rapid imaging method is characterized in that the method is based on a lens imaging principle, combines an electromagnetic field theory, and obtains image field distribution corresponding to a target by adopting an efficient parallel algorithm through amplitude and phase weighting of unit signals according to target signals received by an antenna array.
2. The method according to claim 1, wherein the image field distribution corresponding to the target is obtained by weighting the amplitude and the phase of the unit signal and adopting an efficient parallel algorithm, and the specific algorithm is as follows:
Figure FDA0003278014210000011
wherein: j is an imaginary unit, e is an Euler constant,
Figure FDA0003278014210000012
in order to be the image field distribution,
Figure FDA0003278014210000013
for the target signal received by the array unit, AmnIs a weighting coefficient for the array element amplitude,
Figure FDA0003278014210000014
in order to focus the phase weighting coefficients,
Figure FDA0003278014210000015
for scanning phase weighting coefficients, M being in x-directionThe number of array elements, N being the number of array elements in the y-direction, (x)m，yn) Is the coordinate of the array unit, (delta, sigma) is the coordinate of the image point, V is the image distance, i.e. the distance from the image plane to the array plane, m, n are the serial numbers of the array unit in the x direction and the y direction respectively,
Figure FDA0003278014210000016
in wavenumber, λ is the wavelength, and the symbol Σ represents the summation operation.
3. Method according to claim 2, characterized in that it comprises the following steps:
the method comprises the following steps: carrying out amplitude weighting on the array unit signals to reduce side lobe levels;
step two: carrying out scanning phase weighting on the array unit signals to adjust the central visual angle direction of the imaging system;
step three: carrying out focusing phase weighting on the array unit signals to realize imaging focusing;
step four: performing rapid imaging processing on signals of the array unit by adopting an efficient parallel algorithm;
step five: and resolving the image field coordinates, and performing coordinate inversion on the image field to obtain the position of the real target.
4. The method of claim 3, wherein the amplitude weighting method in step one comprises uniform distribution, cosine weighting, Hamming window, Taylor distribution, Chebyshev distribution and hybrid weighting method.
5. The method of claim 3, wherein the scan phase weighting adjusts the central view direction of the imaging system in step two, and the phase calculation formula of the scan phase weighting is:
Figure FDA0003278014210000017
wherein:
Figure FDA0003278014210000018
the phase difference between the adjacent cells of the array in the x direction and the y direction respectively has the following calculation formula:
Figure FDA0003278014210000021
Figure FDA0003278014210000022
wherein: deltax、ΔyThe array unit spacing in the x-direction and the y-direction respectively, the symbol sin represents a sine function, thetaζ、θξThe x and y scanning angle coordinates when the central visual angle direction points to the source coordinates (zeta, xi) are respectively calculated as follows:
Figure FDA0003278014210000023
Figure FDA0003278014210000024
wherein: u is the object distance, i.e. the distance from the plane of the target to the plane of the array, and the symbol tan-1Representing the arctan function.
6. The method of claim 3, wherein step three comprises: and carrying out focusing phase weighting on the array unit signals by using a focusing phase weighting method to realize imaging focusing, wherein:
the autofocus phase weighted focus phase calculation formula is:
Figure FDA0003278014210000025
the zoom or fixed focus phase weighted focus phase calculation formula is:
Figure FDA0003278014210000026
wherein F is the focal length, and F < U, F < V.
7. The method of claim 3, wherein step four comprises: performing rapid imaging processing on the signals after the amplitude and the phase of the array unit are weighted by adopting an efficient parallel algorithm; the efficient parallel algorithm comprises two-dimensional or three-dimensional FFT, IFFT, non-uniform FFT and sparse FFT, and the calculation formula is as follows:
Figure FDA0003278014210000027
wherein:
Figure FDA0003278014210000028
is like, symbol
Figure FDA00032780142100000210
Represents an efficient parallel algorithm function and is,
Figure FDA0003278014210000029
is a target scattered field received by the array unit, A is an array unit amplitude weighting coefficient, phiFFor focusing the phase weighting coefficients, [ phi ]SWeighting coefficients for the scanning phases;
ω corresponding to the image field calculation resultδ、ωσThe value range is as follows: omegaδ∈[0,2π]、ωσ∈[0,2π]After fftshift operation, the value of ω is calculatedδ、ωσThe value range is transformed into: omegaδ∈[-π,π]、ωσ∈[-π,π]The image at this time is an image conforming to the actual distribution:
Figure FDA0003278014210000031
8. the method of claim 3, wherein step five comprises: carrying out coordinate calculation on an image field obtained by the efficient parallel algorithm, and carrying out coordinate inversion on the image field to obtain the distribution condition of a real target; wherein:
for the efficient parallel algorithm of the IFFT class, the calculation formula of the angular coordinate of the image field scanning is as follows:
Figure FDA0003278014210000032
Figure FDA0003278014210000033
for the FFT-like efficient parallel algorithm, the calculation formula of the image field scanning angle coordinate is as follows:
Figure FDA0003278014210000034
Figure FDA0003278014210000035
the rectangular coordinate calculation formula of the image is as follows:
δ＝V tanθδ，
σ＝V tanθσ；
the coordinate inversion calculation formula of the real target is as follows:
Figure FDA0003278014210000036
Figure FDA0003278014210000037
9. a method according to claim 3, characterized in that the element spacing of the transceiving antennas is set
Figure FDA0003278014210000038
Figure FDA0003278014210000039
To avoid image aliasing.
10. Use of the method according to any one of claims 1 to 9 in the fields of optical imaging, microwave imaging, radar detection, sonar, ultrasound imaging, and acoustic, optical, electrical object detection, image recognition, wireless communication.
11. A digital holographic fast imaging method, wherein the fast imaging method is used for long-distance imaging, comprising:
if U is ∞, then phiFA simplified formula suitable for long range imaging is 0:
Figure FDA0003278014210000041
the image field is calculated by adopting the efficient parallel algorithm according to claim 7, and the distribution condition of the targets in the wide visual angle range is obtained through one operation.
CN202111123894.XA 2021-09-24 2021-09-24 Digital holographic fast imaging method Active CN113848547B (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
CN202111123894.XA CN113848547B (en) 2021-09-24 2021-09-24 Digital holographic fast imaging method
PCT/CN2022/118463 WO2023045804A1 (en) 2021-09-24 2022-09-13 Digital holographic high-speed imaging method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202111123894.XA CN113848547B (en) 2021-09-24 2021-09-24 Digital holographic fast imaging method

Publications (2)

Publication Number Publication Date
CN113848547A true CN113848547A (en) 2021-12-28
CN113848547B CN113848547B (en) 2022-09-16

Family

ID=78979372

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202111123894.XA Active CN113848547B (en) 2021-09-24 2021-09-24 Digital holographic fast imaging method

Country Status (2)

Country Link
CN (1) CN113848547B (en)
WO (1) WO2023045804A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2023045804A1 (en) * 2021-09-24 2023-03-30 苏州威陌电子信息科技有限公司 Digital holographic high-speed imaging method

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116609794B (en) * 2023-07-21 2023-09-26 中国人民解放军国防科技大学 Single-pixel imaging method, device and equipment based on radial Chebyshev light field

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6517490B1 (en) * 2000-06-08 2003-02-11 Advanced Diagnostics Systems, Inc. Apparatus and process for enhancing imaging of subtle structures
CN108271410A (en) * 2015-02-27 2018-07-10 布里格姆女子医院有限公司 Imaging system and the method using the imaging system
CN109471193A (en) * 2018-11-19 2019-03-15 博微太赫兹信息科技有限公司 A kind of microwave and millimeter wave 3D hologram imaging system signal processing imaging method
CN109581388A (en) * 2018-12-20 2019-04-05 华中科技大学 A kind of near field wide viewing angle Beamforming Method of real time three-dimensional imaging sonar
CN109581526A (en) * 2018-11-12 2019-04-05 北京航空航天大学 A kind of real-time tracking fast imaging method applied to camera shooting type millimeter wave human body safety check instrument
CN110892733A (en) * 2017-05-18 2020-03-17 埃尔瓦有限公司 System and method for acoustic mode conversion
CN112612024A (en) * 2020-12-13 2021-04-06 张艺恒 Microwave array rapid imaging method
CN112987025A (en) * 2019-08-23 2021-06-18 长沙天仪空间科技研究院有限公司 Laser imaging device and imaging method based on synthetic aperture

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113848547B (en) * 2021-09-24 2022-09-16 苏州威陌电子信息科技有限公司 Digital holographic fast imaging method

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6517490B1 (en) * 2000-06-08 2003-02-11 Advanced Diagnostics Systems, Inc. Apparatus and process for enhancing imaging of subtle structures
CN108271410A (en) * 2015-02-27 2018-07-10 布里格姆女子医院有限公司 Imaging system and the method using the imaging system
CN110892733A (en) * 2017-05-18 2020-03-17 埃尔瓦有限公司 System and method for acoustic mode conversion
CN109581526A (en) * 2018-11-12 2019-04-05 北京航空航天大学 A kind of real-time tracking fast imaging method applied to camera shooting type millimeter wave human body safety check instrument
CN109471193A (en) * 2018-11-19 2019-03-15 博微太赫兹信息科技有限公司 A kind of microwave and millimeter wave 3D hologram imaging system signal processing imaging method
CN109581388A (en) * 2018-12-20 2019-04-05 华中科技大学 A kind of near field wide viewing angle Beamforming Method of real time three-dimensional imaging sonar
CN112987025A (en) * 2019-08-23 2021-06-18 长沙天仪空间科技研究院有限公司 Laser imaging device and imaging method based on synthetic aperture
CN112612024A (en) * 2020-12-13 2021-04-06 张艺恒 Microwave array rapid imaging method

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
张继龙 等: "微波透镜成像技术在目标识别中的应用研究", 《中国电子科学研究院学报》 *
王云新 等: "基于数字全息显微成像的微光学元件三维面形检测", 《光学学报》 *
贾昉: "数字全息原理及应用的研究", 《中国优秀博硕士学位论文全文数据库(硕士)基础科学辑》 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2023045804A1 (en) * 2021-09-24 2023-03-30 苏州威陌电子信息科技有限公司 Digital holographic high-speed imaging method

Also Published As

Publication number Publication date
CN113848547B (en) 2022-09-16
WO2023045804A1 (en) 2023-03-30

Similar Documents

Publication Publication Date Title
CN113820711B (en) Array rapid imaging method and application thereof
CN113848546B (en) Rapid imaging method suitable for passive imaging and active imaging
CN113848547B (en) Digital holographic fast imaging method
CN113933834B (en) Cylindrical scanning microwave imaging method
CN108828593B (en) Random radiation radar correlation imaging method
CN103728591A (en) MIMO radar near-field target efficient real beam direction focusing method
CN113917461B (en) MIMO radar imaging method and system
CN109884627B (en) Short-range millimeter wave rapid three-dimensional imaging method of any linear array configuration
CN110687538A (en) Near-field focusing-based super-beam forming method
CN103513238B (en) A kind of target azimuth direction-finding method of Regularization least square subspace intersection
Frid et al. Determining direction-of-arrival accuracy for installed antennas by postprocessing of far-field data
US11754973B2 (en) Fast imaging method suitable for passive imaging and active imaging
CN114002664A (en) Sum and difference beam imaging target detection and accurate angle measurement method
CN111239747B (en) Sonar high-resolution low-sidelobe two-dimensional imaging method based on deconvolution
CN116679306A (en) Extended aperture sonar imaging method based on coefficient correction
CN113835222A (en) Curved surface array rapid imaging method
CN115201821A (en) Small target detection method based on strong target imaging cancellation
CN1773307A (en) Small size antenna array aperture expanding and space signal processing method
CN113820654A (en) S-band radar target low elevation DOA estimation method based on beam domain dimension reduction
CN114994668A (en) Semi-holographic curved surface array rapid imaging method
CN114966675B (en) MIMO array rapid imaging method based on distance compensation
CN114994667A (en) Rapid imaging method of semi-holographic array
CN112710983A (en) Electromagnetic vector co-prime area array multidimensional parameter estimation method based on multiplicative tensor beam scanning
CN114994666A (en) Semi-holographic cylindrical scanning imaging method
CN113917465B (en) SAR radar imaging method and system

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant