CN114200448A - Synthetic aperture radiometer wavenumber domain near-field imaging method and equipment - Google Patents

Synthetic aperture radiometer wavenumber domain near-field imaging method and equipment Download PDF

Info

Publication number
CN114200448A
CN114200448A CN202111381927.0A CN202111381927A CN114200448A CN 114200448 A CN114200448 A CN 114200448A CN 202111381927 A CN202111381927 A CN 202111381927A CN 114200448 A CN114200448 A CN 114200448A
Authority
CN
China
Prior art keywords
dimensional
wave number
field
synthetic aperture
distance
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.)
Pending
Application number
CN202111381927.0A
Other languages
Chinese (zh)
Inventor
胡飞
付鹏
朱冬
苏金龙
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.)
Huazhong University of Science and Technology
Original Assignee
Huazhong University of Science and Technology
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 Huazhong University of Science and Technology filed Critical Huazhong University of Science and Technology
Priority to CN202111381927.0A priority Critical patent/CN114200448A/en
Publication of CN114200448A publication Critical patent/CN114200448A/en
Pending legal-status Critical Current

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
    • 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
    • G01S13/887—Radar or analogous systems specially adapted for specific applications for detection of concealed objects, e.g. contraband or weapons
    • 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
    • G01S13/9023—SAR image post-processing techniques combined with interferometric 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

Landscapes

  • Engineering & Computer Science (AREA)
  • Remote Sensing (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Mathematical Physics (AREA)
  • Electromagnetism (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Mathematical Analysis (AREA)
  • Computational Mathematics (AREA)
  • Mathematical Optimization (AREA)
  • Pure & Applied Mathematics (AREA)
  • Data Mining & Analysis (AREA)
  • Theoretical Computer Science (AREA)
  • Discrete Mathematics (AREA)
  • Algebra (AREA)
  • Databases & Information Systems (AREA)
  • Software Systems (AREA)
  • General Engineering & Computer Science (AREA)
  • Radiation Pyrometers (AREA)

Abstract

The invention discloses a synthetic aperture radiometer wavenumber domain near-field imaging method and equipment, belonging to the field of millimeter wave radiation detection, wherein the method comprises the following steps: measuring the brightness temperature distribution of a near-field target area by using an antenna array of the synthetic aperture radiometer to generate a corresponding four-dimensional near-field visibility function; carrying out Fourier transform on the four-dimensional near field visibility function to realize wave number domain decomposition to obtain four-dimensional wave number domain information in the four-dimensional near field visibility function; performing distance direction phase compensation on the four-dimensional wave number domain information to remove distance direction coupling to obtain two-dimensional wave number domain data; and carrying out Fourier transform or inverse Fourier transform on the two-dimensional wave number domain data to generate an inverted image of the near-field target area. The method realizes near-field high-resolution, high-precision and large-view-field imaging of the planar array of the synthetic aperture millimeter wave radiometer, realizes near-field imaging of synthetic aperture without distance information, and promotes application of the synthetic aperture passive millimeter wave imaging technology in the field of near-field imaging.

Description

Synthetic aperture radiometer wavenumber domain near-field imaging method and equipment
Technical Field
The invention belongs to the field of millimeter wave radiation detection, and particularly relates to a synthetic aperture radiometer wavenumber domain near-field imaging method and equipment.
Background
According to the Planck's blackbody radiation law, all substances with a temperature higher than absolute zero radiate energy outwards in the form of electromagnetic waves, and a millimeter wave radiometer is a high-sensitivity receiver for measuring the electromagnetic radiation energy of the substances in a millimeter wave band. By receiving the millimeter wave signal, physical parameters or information of each observation object is acquired, which is generally called as a passive millimeter wave radiation detection technique. The passive millimeter wave radiation has the advantages of strong penetrability, self concealment, and full-time and quasi-all-weather work, so the passive millimeter wave radiation is widely applied to the fields such as ocean monitoring, atmospheric remote sensing, radio astronomy, human body security inspection, soil and vegetation remote sensing, and the like.
At present, three passive millimeter wave imaging modes, namely real-aperture mechanical scanning imaging, focal plane staring imaging and synthetic aperture imaging, are mainly available. The synthetic aperture imaging detection technology is based on aperture synthesis, and an array is formed by small-aperture antennas, so that an equivalent large-aperture array is formed, and the synthetic aperture imaging detection technology naturally has high resolution imaging detection capability. The traditional synthetic aperture radiometer is mainly applied to far-field imaging, such as radio astronomy and remote ground sensing. During far field observation, according to the Van Satt-Zernike theorem, a Fourier transform relation exists between the scene correction brightness temperature and the visibility function; this relationship no longer exists in near field imaging. The imaging detection technology of the synthetic aperture radiometer is less applied to near-field observation, mainly faces to near-field human body security inspection, is not high in maturity of the current technology, and is difficult to be applied in a large scale. Particularly in the aspect of a near-field imaging algorithm, the traditional point source correction algorithm is difficult to realize large-view-field and high-precision imaging; and the imaging performance of the point source correction algorithm deteriorates further as the imaging distance is shortened. In the previous research work, the inventor firstly proposes that the wave number domain imaging algorithm is applied to near-field imaging of the synthetic aperture radiometer, and large-view-field, close-range and high-precision imaging of the synthetic aperture radiometer is achieved. However, the algorithm is applied to a single-to-multiple correlation mode, the array requirement is full array, and the cost is very high.
Disclosure of Invention
Aiming at the defects and improvement requirements of the prior art, the invention provides a near-field imaging method and equipment for a wavenumber domain of a synthetic aperture radiometer, and aims to realize near-field imaging with high resolution, high precision and large field of view of a planar array of the synthetic aperture millimeter wave radiometer, realize near-field imaging of synthetic aperture without distance information and promote the application of a synthetic aperture passive millimeter wave imaging technology in the field of near-field imaging.
To achieve the above object, according to one aspect of the present invention, there is provided a synthetic aperture radiometer wavenumber domain near field imaging method, comprising: s1, measuring the brightness temperature distribution of the near-field target area by using the antenna array of the synthetic aperture radiometer to generate a corresponding four-dimensional near-field visibility function; s2, carrying out Fourier transform on the four-dimensional near field visibility function to realize wave number domain decomposition, and obtaining four-dimensional wave number domain information in the near field visibility function; s3, performing distance direction phase compensation on the four-dimensional wave number domain information to remove distance direction coupling, and performing dimensionality reduction accumulation on the four-dimensional wave number domain information subjected to distance direction phase compensation to obtain two-dimensional wave number domain data; s4, carrying out Fourier transform or inverse Fourier transform on the two-dimensional wave number domain data to generate an inversion image of the near-field target area.
Furthermore, the antenna array of the synthetic aperture radiometer is a planar full-array antenna.
Further, the four-dimensional near-field visibility function generated in S1:
Figure BDA0003364017730000021
Figure BDA0003364017730000022
Figure BDA0003364017730000023
wherein, V (x)k，yk，xl，yl) For the four-dimensional near-field visibility function, T (x, y, z) is the near-field eye(x) luminous temperature distribution of target areak，yk) (x) to form the coordinate position of one of the two antennas to which the interferometer correspondsl,yl) (x, y, z) is the coordinate position of the target point in the near field target area, Rk、RlThe positions from the target point to the two antennas corresponding to the constituent interferometers are respectively shown, j is an imaginary unit, k is a wave number, and s is the area of the target point in the near-field target area.
Further, the four-dimensional wave number domain information obtained in S2 is:
Figure BDA0003364017730000031
Figure BDA0003364017730000032
Figure BDA0003364017730000033
Figure BDA0003364017730000034
Figure BDA0003364017730000035
wherein the content of the first and second substances,
Figure BDA0003364017730000036
for the information of the four-dimensional wave number domain,
Figure BDA0003364017730000037
is equal to xkThe corresponding fourier variable is used as a reference,
Figure BDA0003364017730000038
is given askThe corresponding fourier variable is used as a reference,
Figure BDA0003364017730000039
is equal to xlThe corresponding fourier variable is used as a reference,
Figure BDA00033640177300000310
is given aslThe corresponding fourier variable.
Further, the distance-phase compensation of the four-dimensional wavenumber domain information in S3 further includes: and performing dimensionality reduction accumulation processing on the four-dimensional wave number domain information subjected to the distance-direction phase compensation to obtain the two-dimensional wave number domain data.
Further, when the z-formation prior distance information is acquired, the two-dimensional wavenumber domain data obtained in S3 is:
Figure BDA00033640177300000311
wherein, E' (k)x,ky) For the two-dimensional wavenumber domain data, kxIs the first resultant azimuth wave number, kyIs the second resultant azimuth wave number, kzIn order to synthesize the distance wave number,
Figure BDA0003364017730000041
in the form of an azimuth wave number,
Figure BDA0003364017730000042
in order to be a distance wave number,
Figure BDA0003364017730000043
for the information of the four-dimensional wave number domain,
Figure BDA0003364017730000044
is equal to xkThe corresponding fourier variable is used as a reference,
Figure BDA0003364017730000045
is given askThe corresponding fourier variable is used as a reference,
Figure BDA0003364017730000046
is equal to xlThe corresponding fourier variable is used as a reference,
Figure BDA0003364017730000047
is given aslThe corresponding fourier variable.
Further, when the z-formation prior distance information is not acquired, the two-dimensional wavenumber domain data obtained in S3 is:
Figure BDA0003364017730000048
wherein, E' (k)x,ky) For the two-dimensional wavenumber domain data, kxIs the first resultant azimuth wave number, kyFor the second synthesized azimuth wavenumber,
Figure BDA0003364017730000049
in the form of an azimuth wave number,
Figure BDA00033640177300000410
in order to be a distance wave number,
Figure BDA00033640177300000411
for the information of the four-dimensional wave number domain,
Figure BDA00033640177300000412
is equal to xkThe corresponding fourier variable is used as a reference,
Figure BDA00033640177300000413
is given askThe corresponding fourier variable is used as a reference,
Figure BDA00033640177300000414
is equal to xlThe corresponding fourier variable is used as a reference,
Figure BDA00033640177300000415
is given aslCorresponding FourierLeaf variables.
Further, the antenna array of the synthetic aperture radiometer is a sparse array antenna.
Further, the sparse array antenna is a cross array antenna, and the S1 further includes: selecting x from the generated four-dimensional near-field visibility functionl、ykDimension to obtain a new near field visibility function V (x)l,yk)：
Figure BDA00033640177300000416
Figure BDA00033640177300000417
Figure BDA00033640177300000418
Wherein T (x, y, z) is the bright temperature distribution of the near-field target area, xlIs the coordinate of the horizontal array element in the x-axis, ykIs the coordinate of the vertical array element in the y-axis, RkDistance of target point to each antenna of vertical array, RlThe distance from the target point to each antenna of the horizontal array is given as (x, y, z) the coordinate position of the target point in the near field target area, j is an imaginary unit, k is the wave number, and s is the area of the target point in the near field target area.
According to another aspect of the present invention, there is provided an electronic apparatus including: a processor; a memory storing a computer executable program which, when executed by the processor, causes the processor to perform the synthetic aperture radiometer wavenumber domain near field imaging method as described above.
Generally, by the above technical solution conceived by the present invention, the following beneficial effects can be obtained: the comprehensive aperture near-field visibility function under the planar array is proposed to be four-dimensional, on the basis, the four-dimensional visibility function is obtained by utilizing the planar array, on the basis of the four-dimensional visibility function, the near-field large-view-field, close-range and high-precision imaging is realized by combining a wave number domain imaging algorithm and dimension reduction accumulation operation, and the near-field large-view-field, close-range and high-precision imaging method can be applied to detection of human body hidden prohibited articles; furthermore, based on the characteristic that the synthetic aperture array can be used for sparse imaging, a corresponding two-dimensional wave number domain imaging algorithm is designed for the cross array, and near-field high-precision imaging based on the cross sparse array is realized; in addition, a corresponding near-field high-precision distance information-free imaging algorithm is designed for the full array, and near-field high-precision imaging without distance information is achieved.
Drawings
FIG. 1 is a flow chart of a synthetic aperture radiometer wavenumber domain near field imaging method provided by an embodiment of the present invention;
FIG. 2 is a schematic diagram of a synthetic aperture binary interference model provided by an embodiment of the present invention;
FIG. 3 is a schematic diagram of a synthetic aperture near-field imaging two-dimensional cross array provided by an embodiment of the present invention;
4A-4C are schematic diagrams of experimental setup for two-dimensional cross array imaging provided by embodiments of the present invention;
FIG. 5 is a schematic diagram of a dual spread source target imaging result provided by an embodiment of the present invention;
fig. 6 is a schematic diagram of a three-spread source target imaging result provided by an embodiment of the present invention;
FIG. 7 is a schematic diagram of imaging result of a point source without distance information provided by an embodiment of the invention;
fig. 8 is a schematic diagram of a dual-spread-source imaging result without distance information according to an embodiment of the present invention;
fig. 9 is a block diagram of an electronic device provided in an embodiment of the invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.
In the present application, the terms "first," "second," and the like (if any) in the description and the drawings are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order.
Fig. 1 is a flowchart of a synthetic aperture radiometer wavenumber domain near-field imaging method according to an embodiment of the present invention. Referring to fig. 1, the details of the synthetic aperture radiometer wavenumber domain near-field imaging method in this embodiment are described with reference to fig. 2 to 8, and the method includes operations S1 to S4.
Referring to fig. 2, a synthetic aperture binary interference model is shown, with the antenna array of the synthetic aperture radiometer at plane B, the near field target area at plane a, and the distance between plane a and plane B being z. By adopting the near-field imaging method of the synthetic aperture radiometer wavenumber domain in the embodiment, the imaging of the near-field target area at the plane B by using the synthetic aperture radiometer at the plane A can be realized.
In operation S1, a bright temperature distribution of the near-field target area is measured using an antenna array of the synthetic aperture radiometer to generate a corresponding four-dimensional near-field visibility function.
In operation S2, a fourier transform is performed on the four-dimensional near-field visibility function to perform a wave number domain decomposition, so as to obtain four-dimensional wave number domain information in the near-field visibility function.
Operation S3 is performed to perform distance-to-phase compensation on the four-dimensional wavenumber domain information to remove distance-to-phase coupling, and perform dimensionality reduction and accumulation on the four-dimensional wavenumber domain information after the distance-to-phase compensation to obtain two-dimensional wavenumber domain data.
In operation S4, fourier transform or inverse fourier transform is performed on the two-dimensional wavenumber domain data to generate an inverted image of the near-field target area.
According to the embodiment of the invention, the antenna array of the synthetic aperture radiometer is a planar full-array antenna or a sparse array antenna. The theoretical basis of the embodiment of the invention is the synthetic aperture imaging basic principle and the stationary phase principle. The following describes in detail the synthetic aperture radiometer wavenumber domain near-field imaging method in this embodiment based on a planar full-array antenna and a cross-array antenna in a sparse array antenna.
(1) For a planar full-array antenna, the specific operation is as follows:
(1.1) measuring the brightness temperature distribution of a near-field target area by using a planar full-array antenna, and generating a corresponding four-dimensional near-field visibility function:
Figure BDA0003364017730000071
Figure BDA0003364017730000072
Figure BDA0003364017730000073
wherein, V (x)k,yk,xl,yl) For a four-dimensional near-field visibility function, T (x, y, z) is the bright temperature distribution of the near-field target area, (x)k,yk) (x) to form the coordinate position of one of the two antennas to which the interferometer correspondsl,yl) (x, y, z) is the coordinate position of the target point in the near field target area, Rk、RlThe positions from the target point to the two antennas corresponding to the constituent interferometers are respectively shown, j is an imaginary unit, k is a wave number, and s is the area of the target point in the near-field target area.
(1.2) to the four-dimensional near-field visibility function V (x)k,yk,xl,yl) Performing Fourier transform to obtain four-dimensional wave number domain information:
Figure BDA0003364017730000074
Figure BDA0003364017730000075
Figure BDA0003364017730000076
Figure BDA0003364017730000077
Figure BDA0003364017730000078
wherein the content of the first and second substances,
Figure BDA0003364017730000081
is four-dimensional wave number domain information;
Figure BDA0003364017730000082
is equal to xkThe corresponding fourier variable is used as a reference,
Figure BDA0003364017730000083
is given askThe corresponding fourier variable is used as a reference,
Figure BDA0003364017730000084
is equal to xlThe corresponding fourier variable is used as a reference,
Figure BDA0003364017730000085
is given aslThe corresponding fourier variable, representing the coordinates of the angular spectrum data, has the physical meaning of a wave number vector, i.e. the wave number k multiplied by a direction cosine function.
It should be noted that, in the following description,
Figure BDA0003364017730000086
the physical meaning of (a) is angular spectrum in optics. Under the near field condition, the visibility function and the target scene do not have a Fourier transform relationship, and only wave number domain information is obtained by performing Fourier transform on the visibility function, so that the theory can be fully demonstrated from a stationary phase principle:
Figure BDA0003364017730000087
Figure BDA0003364017730000088
Figure BDA0003364017730000089
Figure BDA00033640177300000810
Figure BDA00033640177300000811
Figure BDA00033640177300000812
and (1.3) performing distance-direction phase compensation on the four-dimensional wave number domain information, and performing dimensionality reduction accumulation processing on the four-dimensional wave number domain information subjected to distance-direction phase compensation to obtain two-dimensional wave number domain data.
Due to wavenumber domain information
Figure BDA00033640177300000813
There is a coupling in the range direction, and a compensation in the range direction and phase is needed, so that the coupling term is removed. Meanwhile, because the acquired wave number domain data are four-dimensional, distance item compensation and dimension reduction accumulation processing are required to be carried out on the wave number domain data to acquire two-dimensional wave number domain data E' (k) in order to realize near-field two-dimensional high-resolution imagingx,ky). Wherein E' (k)x,ky) The frequency domain information of the near-field brightness temperature distribution is a virtual synthesized angular spectrum.
(1.3.1) when obtaining the prior distance information formed by z, the obtained two-dimensional wave number domain data is as follows:
Figure BDA0003364017730000091
wherein, E' (k)x,ky) For two-dimensional wavenumber domain data, kxIs the first resultant azimuth wave number, kyIs the second resultant azimuth wave number, kzIn order to synthesize the distance wave number,
Figure BDA0003364017730000092
in the form of an azimuth wave number,
Figure BDA0003364017730000093
in order to be a distance wave number,
Figure BDA0003364017730000094
is the information of the four-dimensional wave number domain,
Figure BDA0003364017730000095
is equal to xkThe corresponding fourier variable is used as a reference,
Figure BDA0003364017730000096
is given askThe corresponding fourier variable is used as a reference,
Figure BDA0003364017730000097
is equal to xlThe corresponding fourier variable is used as a reference,
Figure BDA0003364017730000098
is given aslThe corresponding fourier variable.
Because the near-field observation focuses on the brightness temperature difference between the target point and the background, the real brightness temperature information does not need to be acquired, and the image brightness temperature does not need to be accurately quantized. For scenes that do not require accurate quantification of image brightness temperature, two-dimensional wavenumber domain data E' (k)x,ky) Can be approximated as:
Figure BDA0003364017730000099
wherein:
Figure BDA00033640177300000910
Figure BDA00033640177300000911
Figure BDA00033640177300000912
(1.3.2) when the prior distance information formed by z is not acquired, the obtained two-dimensional wave number domain data is as follows:
Figure BDA00033640177300000913
at this time, k z0. Wherein, E' (k)x,ky) For two-dimensional wavenumber domain data, kxIs the first resultant azimuth wave number, kyFor the second synthesized azimuth wavenumber,
Figure BDA00033640177300000914
in the form of an azimuth wave number,
Figure BDA00033640177300000915
in order to be a distance wave number,
Figure BDA00033640177300000916
is the information of the four-dimensional wave number domain,
Figure BDA00033640177300000917
is equal to xkThe corresponding fourier variable is used as a reference,
Figure BDA00033640177300000918
is given askThe corresponding fourier variable is used as a reference,
Figure BDA0003364017730000101
is equal to xlThe corresponding fourier variable is used as a reference,
Figure BDA0003364017730000102
is given aslThe corresponding fourier variable.
(1.4) for two-dimensional wavenumber domain data E' (k)x,ky) Fourier transform or inverse Fourier transform is carried out to obtain near-field error-free inversion image
Figure BDA0003364017730000103
Figure BDA0003364017730000104
(2) Referring to fig. 3 and 4A, schematic diagrams of a typical sparse array when implementing near-field imaging for a cross array are shown. For a cross array antenna in a sparse array antenna, the specific operation is as follows:
(2.1) measuring the brightness temperature distribution of the near-field target area by using the cross array antenna to generate a corresponding four-dimensional near-field visibility function, and selecting x from the four-dimensional near-field visibility functionl、ykDimension to obtain a new near field visibility function V (x)l,yk)：
Figure BDA0003364017730000105
Assuming that the many-to-many correlation operation of the cross-shaped antenna only occurs between the vertical linear array and the horizontal linear array, R at the momentl、RkCan be expressed as:
Figure BDA0003364017730000106
Figure BDA0003364017730000107
wherein T (x, y, z) is the bright temperature distribution of the near-field target area, xlIs the coordinate of the horizontal array element in the x-axis, ykIs the coordinate of the vertical array element in the y-axis, RkDistance of target point to each antenna of vertical array, RlThe distance from the target point to each antenna of the horizontal array is given as (x, y, z) the coordinate position of the target point in the near field target area, j is an imaginary unit, k is the wave number, and s is the area of the target point in the near field target area. Based on the processing, the equivalent dimension reduction is carried out on the data, and the complex dimension reduction accumulation operation carried out in the wave number domain data is omitted.
(2.2) for which the four-dimensional near-field visibility function V (x)l,yk) Fourier transform is carried out to obtain four-dimensional wave number domain information E (k)x,ky) Wherein:
Figure BDA0003364017730000111
Figure BDA0003364017730000112
Figure BDA0003364017730000113
(2.3) the information E (k) of the four-dimensional wave number domainx,ky) Compensating the distance direction phase, correcting and eliminating the influence of kz, thereby obtaining two-dimensional wave number domain data E' (k)x,ky)。
(2.4) for two-dimensional wavenumber domain data E' (k)x,ky) Fourier transform or inverse Fourier transform is carried out to obtain near-field error-free inversion image
Figure BDA0003364017730000114
For the cross array antenna, the array is on the xoy plane, signals received by all array elements on the horizontal linear array H are only in complex correlation with the array elements on the vertical linear array V, and a four-dimensional visibility function is obtained based on the complex correlation. The experimental setup used is shown in fig. 4A-4C, where fig. 4A is a 24-channel 94GHz synthetic aperture system with 400MHz system bandwidth and 3cm array spacing; FIG. 4B is a schematic diagram of a dual-spread source, and FIG. 4C is a schematic diagram of a triple-spread source; the distance between the spread source target and the antenna aperture is 4.2 m. The imaging results of the double-spread source target and the triple-spread source target are respectively shown in fig. 5 and fig. 6.
An example of distance information-free imaging is described below. For two-dimensional non-distance information imaging, a two-dimensional full array is needed, the cost is huge, and the method is used for verifying the effectiveness of the method by using the one-dimensional linear array for one-dimensional imaging.
Firstly, acquiring two-dimensional visibility function data based on a horizontal linear array of the cross sparse array in FIG. 4; secondly, performing Fourier transform on the two-dimensional visibility function data to acquire two-dimensional wave number domain data; and then, acquiring data with kz being 0 in the two-dimensional wavenumber domain data, so that the two-dimensional wavenumber domain data is equivalently reduced to one dimension, and performing Fourier transform on the one-dimensional wavenumber domain data to acquire a one-dimensional imaging result under the condition of no distance information. The imaging results of the point source target and the double-spread source target under the condition of no distance information are respectively shown in fig. 7 and fig. 8. The imaging results shown in fig. 5-8 verify the effectiveness of the method provided by the present embodiment.
By combining the technical scheme, the embodiment demonstrates that the near field visibility function under the planar array is four-dimensional, dimension reduction accumulation is carried out on the basis of the function, near field two-dimensional wave number domain data are obtained, near field large-view field, near field and high-precision imaging is realized, and the near field two-dimensional wave number domain data can be applied to detection of forbidden articles hidden in a human body. Furthermore, based on the characteristic that the synthetic aperture array can be used for sparse imaging, a corresponding two-dimensional wave number domain imaging algorithm is designed for the cross array, and near-field high-precision imaging based on the cross sparse array is realized; in addition, a corresponding near-field high-precision distance information-free imaging algorithm is designed for the full array, and near-field high-precision imaging without distance information is achieved.
Embodiments of the present disclosure also show an electronic device, as shown in fig. 9, the electronic device 900 includes a processor 910 and a readable storage medium 920. The electronic device 900 can perform the synthetic aperture radiometer wavenumber domain near field imaging methods described above in fig. 1-8.
In particular, processor 910 may include, for example, a general purpose microprocessor, an instruction set processor and/or related chip set and/or a special purpose microprocessor (e.g., an Application Specific Integrated Circuit (ASIC)), and/or the like. The processor 910 may also include onboard memory for caching purposes. Processor 910 may be a single processing unit or a plurality of processing units for performing the different actions of the method flows according to embodiments of the present disclosure described with reference to fig. 1-8.
Readable storage medium 920 may be, for example, any medium that can contain, store, communicate, propagate, or transport the instructions. For example, a readable storage medium may include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, device, or propagation medium. Specific examples of the readable storage medium include: magnetic storage devices, such as magnetic tape or Hard Disk Drives (HDDs); optical storage devices, such as compact disks (CD-ROMs); a memory, such as a Random Access Memory (RAM) or a flash memory; and/or wired/wireless communication links.
Readable storage medium 920 may include a computer program 921, which computer program 921 may include code/computer-executable instructions that, when executed by processor 910, cause processor 910 to perform a method flow, such as described above in connection with fig. 1-8, and any variations thereof.
The computer program 921 may be configured with, for example, computer program code comprising computer program modules. For example, in an example embodiment, code in computer program 921 may include one or more program modules, including, for example, module 921A, module 921B, … …. It should be noted that the division and number of modules are not fixed, and those skilled in the art may use suitable program modules or program module combinations according to actual situations, which when executed by the processor 910, enable the processor 910 to perform the method flows described above in connection with fig. 1-8, for example, and any variations thereof.
It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims (10)

1. A method of synthetic aperture radiometer wavenumber domain near field imaging, comprising:
s1, measuring the brightness temperature distribution of the near-field target area by using the antenna array of the synthetic aperture radiometer to generate a corresponding four-dimensional near-field visibility function;
s2, carrying out Fourier transform on the four-dimensional near field visibility function to realize wave number domain decomposition, and obtaining four-dimensional wave number domain information in the near field visibility function;
s3, performing distance direction phase compensation on the four-dimensional wave number domain information to remove distance direction coupling, and performing dimensionality reduction accumulation on the four-dimensional wave number domain information subjected to distance direction phase compensation to obtain two-dimensional wave number domain data;
s4, carrying out Fourier transform or inverse Fourier transform on the two-dimensional wave number domain data to generate an inversion image of the near-field target area.
2. The method of claim 1 wherein the array antenna of the synthetic aperture radiometer is a planar full array antenna.
3. The synthetic aperture radiometer wavenumber domain near field imaging method of claim 2, wherein the four-dimensional near field visibility function generated in S1:
Figure FDA0003364017720000011
Figure FDA0003364017720000012
Figure FDA0003364017720000013
wherein, V (x)k,yk,xl,yl) For the four-dimensional near-field visibility function, T (x, y, z) is the bright temperature distribution of the near-field target area, (xk,yk) (x) to form the coordinate position of one of the two antennas to which the interferometer correspondsl,yl) (x, y, z) is the coordinate position of the target point in the near field target area, Rk、RlThe positions from the target point to the two antennas corresponding to the constituent interferometers are respectively shown, j is an imaginary unit, k is a wave number, and s is the area of the target point in the near-field target area.
4. The synthetic aperture radiometer wavenumber domain near field imaging method of claim 3, wherein said four dimensional wavenumber domain information obtained in S2 is:
Figure FDA0003364017720000021
Figure FDA0003364017720000022
Figure FDA0003364017720000023
Figure FDA0003364017720000024
Figure FDA0003364017720000025
wherein the content of the first and second substances,
Figure FDA0003364017720000026
for the information of the four-dimensional wave number domain,
Figure FDA0003364017720000027
is equal to xkThe corresponding fourier variable is used as a reference,
Figure FDA0003364017720000028
is given askThe corresponding fourier variable is used as a reference,
Figure FDA0003364017720000029
is equal to xlThe corresponding fourier variable is used as a reference,
Figure FDA00033640177200000210
is given aslThe corresponding fourier variable.
5. The synthetic aperture radiometer wavenumber domain near field imaging method of claim 3, wherein said distance phase compensating said four dimensional wavenumber domain information at S3 further comprises: and performing dimensionality reduction accumulation processing on the four-dimensional wave number domain information subjected to the distance-direction phase compensation to obtain the two-dimensional wave number domain data.
6. The synthetic aperture radiometer wavenumber domain near-field imaging method of claim 5, wherein when acquiring z-formation prior distance information, the two-dimensional wavenumber domain data obtained in S3 is:
Figure FDA00033640177200000211
wherein, E' (k)x,ky) For the two-dimensional wavenumber domain data, kxIs the first resultant azimuth wave number, kyIs the second resultant azimuth wave number, kzIn order to synthesize the distance wave number,
Figure FDA0003364017720000031
in the form of an azimuth wave number,
Figure FDA0003364017720000032
in order to be a distance wave number,
Figure FDA0003364017720000033
for the information of the four-dimensional wave number domain,
Figure FDA0003364017720000034
is equal to xkThe corresponding fourier variable is used as a reference,
Figure FDA0003364017720000035
is given askThe corresponding fourier variable is used as a reference,
Figure FDA0003364017720000036
is equal to xlThe corresponding fourier variable is used as a reference,
Figure FDA0003364017720000037
is given aslThe corresponding fourier variable.
7. The synthetic aperture radiometer wavenumber domain near-field imaging method of claim 5, wherein when z-formation prior distance information is not acquired, the two-dimensional wavenumber domain data obtained in S3 is:
Figure FDA0003364017720000038
wherein, E' (k)x,ky) For the two-dimensional wavenumber domain data, kxIs the first resultant azimuth wave number, kyFor the second synthesized azimuth wavenumber,
Figure FDA0003364017720000039
in the form of an azimuth wave number,
Figure FDA00033640177200000310
in order to be a distance wave number,
Figure FDA00033640177200000311
for the information of the four-dimensional wave number domain,
Figure FDA00033640177200000312
is equal to xkThe corresponding fourier variable is used as a reference,
Figure FDA00033640177200000313
is given askThe corresponding fourier variable is used as a reference,
Figure FDA00033640177200000314
is equal to xlThe corresponding fourier variable is used as a reference,
Figure FDA00033640177200000315
is given aslThe corresponding fourier variable.
8. The method of claim 1 wherein the antenna array of the synthetic aperture radiometer is a sparse array antenna.
9. The synthetic aperture radiometer wavenumber domain near field imaging method of claim 8, wherein said sparse array antenna is a cross array antenna, said S1 further comprising: selecting x from the generated four-dimensional near-field visibility functionl、ykDimension to obtain a new near field visibility function V (x)l,yk)：
Figure FDA00033640177200000316
Figure FDA00033640177200000317
Figure FDA00033640177200000318
Wherein T (x, y, z) is the bright temperature distribution of the near-field target area, xlIs the coordinate of the horizontal array element in the x-axis, ykIs the coordinate of the vertical array element in the y-axis, RkDistance of target point to each antenna of vertical array, RlThe distance from the target point to each antenna of the horizontal array is given as (x, y, z) the coordinate position of the target point in the near field target area, j is an imaginary unit, k is the wave number, and s is the area of the target point in the near field target area.
10. An electronic device, comprising:
a processor;
a memory storing a computer executable program which, when executed by the processor, causes the processor to perform the synthetic aperture radiometer wavenumber domain near field imaging method of any of claims 1-9.
CN202111381927.0A 2021-11-19 2021-11-19 Synthetic aperture radiometer wavenumber domain near-field imaging method and equipment Pending CN114200448A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202111381927.0A CN114200448A (en) 2021-11-19 2021-11-19 Synthetic aperture radiometer wavenumber domain near-field imaging method and equipment

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202111381927.0A CN114200448A (en) 2021-11-19 2021-11-19 Synthetic aperture radiometer wavenumber domain near-field imaging method and equipment

Publications (1)

Publication Number Publication Date
CN114200448A true CN114200448A (en) 2022-03-18

Family

ID=80648083

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202111381927.0A Pending CN114200448A (en) 2021-11-19 2021-11-19 Synthetic aperture radiometer wavenumber domain near-field imaging method and equipment

Country Status (1)

Country Link
CN (1) CN114200448A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116365219A (en) * 2023-04-14 2023-06-30 佛山市迪安通讯设备有限公司 Ultra-small radiation caliber radiating unit and ultra-low sidelobe square antenna

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116365219A (en) * 2023-04-14 2023-06-30 佛山市迪安通讯设备有限公司 Ultra-small radiation caliber radiating unit and ultra-low sidelobe square antenna
CN116365219B (en) * 2023-04-14 2024-04-19 佛山市迪安通讯设备有限公司 Ultra-small radiation caliber radiating unit and ultra-low sidelobe square antenna

Similar Documents

Publication Publication Date Title
JP6660857B2 (en) Method of generating image of region of interest using radar system
CN111650585B (en) Near-field millimeter wave sparse MIMO scanning array full-focusing imaging method and device
CN102590640A (en) Millimeter-wave\submillimeter-wave near-field amplitude and phase measuring method
CN107607945B (en) Scanning radar foresight imaging method based on spatial embedding mapping
Gennarelli et al. RF/microwave imaging of sparse targets in urban areas
Farsaei et al. Improved two-dimensional millimeter-wave imaging for concealed weapon detection through partial Fourier sampling
Zvolensky et al. W-band sparse imaging system using frequency diverse cavity-fed metasurface antennas
CN202735513U (en) Holographic active microwave imaging device
Liao et al. Plane-wave synthesis and RCS extraction via 3-D linear array SAR
CN107797110B (en) System imaging method of synthetic aperture projection radiation and synthetic aperture projection radiometer
CN107942326B (en) Two-dimensional active millimeter wave imaging method with high universality
CN102798858B (en) Holographic active microwave imaging method
CN114200448A (en) Synthetic aperture radiometer wavenumber domain near-field imaging method and equipment
Skouroliakou et al. Towards Real-Time Three-Dimensional (3D) Imaging using Dynamic Metasurface Antennas
Hu et al. Advanced thz mimo sparse imaging scheme using multipass synthetic aperture focusing and low-rank matrix completion techniques
Wei et al. Learning-based split unfolding framework for 3-D mmW radar sparse imaging
CN109581526A (en) A kind of real-time tracking fast imaging method applied to camera shooting type millimeter wave human body safety check instrument
CN110231625B (en) Synthetic aperture imaging method based on multi-scale fusion
Marks et al. Near‐field multistatic radar reconstruction with stretched‐phase Fourier accelerated multistatic imaging
CN108375767B (en) Mirror image synthetic aperture radiometer imaging method based on reflecting plate combination
An et al. A Nsst-Based Fusion Method For Airborne Dual-Frequency, High-Spatial-Resolution Sar Images
Salmon et al. Near-field and three-dimensional aperture synthesis imaging
Kazemi et al. Blind calibration for radio interferometry using convex optimization
Lu et al. Spatial spectrum-based imaging for UWB through-the-wall MIMO arrays
Zhu et al. Frequency-domain algorithm for short-range MIMO-SAR imaging

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