Wavenumber domain near-field imaging method and equipment for synthetic aperture radiometer

Abstract

The present invention discloses a near-field imaging method and device of a synthetic aperture radiometer in the wavenumber domain, which belongs to the field of millimeter wave radiation detection. The method includes: using the antenna array of the synthetic aperture radiometer to measure the brightness temperature distribution of the near-field target area to generate a corresponding four-dimensional near-field visibility function; performing Fourier transform on the four-dimensional near-field visibility function to achieve wavenumber domain decomposition, and obtaining four-dimensional wavenumber domain information in the four-dimensional near-field visibility function; performing distance-direction phase compensation on the four-dimensional wavenumber domain information to remove distance-direction coupling, and obtaining two-dimensional wavenumber domain data; performing Fourier transform or Fourier inverse transform on the two-dimensional wavenumber domain data to generate an inversion image of the near-field target area. The method realizes near-field high-resolution, high-precision, and large-field-of-view imaging of a planar array of synthetic aperture millimeter wave radiometers, and realizes near-field imaging of synthetic aperture without distance information, and promotes the application of synthetic aperture passive millimeter wave imaging technology in the field of near-field imaging.

Description

Technical Field

[0001] The present invention belongs to the field of millimeter wave radiation detection, and more specifically, relates to a wavenumber domain near-field imaging method and device of a synthetic aperture radiometer. Background Art

[0002] According to Planck's blackbody radiation law, all substances with a temperature above absolute zero radiate energy in the form of electromagnetic waves. The millimeter wave radiometer is a highly sensitive receiver that measures the electromagnetic radiation energy of substances in the millimeter wave band. By receiving millimeter wave signals, the physical parameters or information of each observed object can be obtained, which is usually called passive millimeter wave radiation detection technology. Passive millimeter wave radiation has the advantages of strong penetration, self-concealment, and all-day and quasi-all-weather operation. Therefore, it is widely used in fields such as ocean monitoring, atmospheric remote sensing, radio astronomy, human security inspection, soil and vegetation remote sensing.

[0003] At present, there are three main types of passive millimeter wave imaging: real aperture mechanical scanning imaging, focal plane staring imaging, and synthetic aperture imaging. Synthetic aperture imaging detection technology is based on aperture synthesis, using small-aperture antennas to form an array, thereby forming an equivalent large-aperture array, which naturally has the ability of high-resolution imaging detection. Traditional synthetic aperture radiometers are mainly used in far-field imaging, such as radio astronomy and earth remote sensing. When conducting far-field observations, according to the Van Sitt-Zernike theorem, there is a Fourier transform relationship between the scene-corrected brightness temperature and the visibility function; in near-field imaging, this relationship no longer exists. Synthetic aperture radiometer imaging detection technology is less used in near-field observations, mainly for near-field human security inspections. The current technology is not mature enough and is difficult to apply on a large scale. Especially in terms of near-field imaging algorithms, traditional point source correction algorithms are difficult to achieve large field of view and high-precision imaging; and as the imaging distance shortens, the imaging performance of the point source correction algorithm further deteriorates. In previous research, the inventor first proposed to apply the wavenumber domain imaging algorithm to the near-field imaging of the synthetic aperture radiometer to achieve large field of view, close distance, and high-precision imaging of the synthetic aperture radiometer. However, the algorithm is applied to the one-to-many complex correlation method, and its array is required to be full, which is very costly. Summary of the invention

[0004] In view of the defects of the prior art and the need for improvement, the present invention provides a method and device for near-field imaging in the wavenumber domain of a synthetic aperture radiometer, which aims to achieve high-resolution, high-precision, and large-field-of-view near-field imaging of a planar array of synthetic aperture millimeter-wave radiometers, as well as to achieve near-field imaging of synthetic aperture without distance information, and to promote the application of synthetic aperture passive millimeter-wave imaging technology in the field of near-field imaging.

[0005] To achieve the above-mentioned purpose, according to one aspect of the present invention, a method for near-field imaging in wavenumber domain of a synthetic aperture radiometer is provided, comprising: S1, measuring the brightness temperature distribution of a near-field target area by using the antenna array of a synthetic aperture radiometer to generate a corresponding four-dimensional near-field visibility function; S2, performing Fourier transform on the four-dimensional near-field visibility function to achieve wavenumber domain decomposition, and obtaining four-dimensional wavenumber domain information in the near-field visibility function; S3, performing range-wise phase compensation on the four-dimensional wavenumber domain information to remove range-wise coupling, and performing dimensionality reduction accumulation on the four-dimensional wavenumber domain information after range-wise phase compensation to obtain two-dimensional wavenumber domain data; S4, performing Fourier transform or inverse Fourier transform on the two-dimensional wavenumber domain data to generate an inversion image of the near-field target area.

[0006] Furthermore, the antenna array of the synthetic aperture radiometer is a planar full-array antenna.

[0007] Furthermore, the four-dimensional near-field visibility function generated in S1 is:

[0008]

[0009]

[0010]

[0011] Among them, V(x k ,y k , x l ,y l ) is the four-dimensional near-field visibility function, T(x, y, z) is the brightness temperature distribution of the near-field target area, (x k ,y k ) is the coordinate position of one of the two antennas that make up the interferometer, (x l ,y l ) is the coordinate position of the other antenna of the two antennas that constitute the interferometer, (x, y, z) is the coordinate position of the target point in the near-field target area, R k , R l are the positions of the two antennas corresponding to the target point to the interferometer, j is the imaginary unit, k is the wave number, and s is the area of ​​the target point in the near-field target area.

[0012] Furthermore, the four-dimensional wavenumber domain information obtained in S2 is:

[0013]

[0014]

[0015]

[0016]

[0017]

[0018] in, is the four-dimensional wave number domain information, For x k The corresponding Fourier variable is, For k The corresponding Fourier variable is, For x l The corresponding Fourier variable is, For l The corresponding Fourier variable.

[0019] Furthermore, after performing range phase compensation on the four-dimensional wave number domain information in S3, the step further includes: performing dimensionality reduction accumulation processing on the four-dimensional wave number domain information after range phase compensation to obtain the two-dimensional wave number domain data.

[0020] Furthermore, when the z-formed prior distance information is obtained, the two-dimensional wavenumber domain data obtained in S3 is:

[0021]

[0022] Among them, E′(k x ,k y ) is the two-dimensional wave number domain data, k x is the first synthetic azimuth wave number, k y is the second synthetic azimuth wave number, k z is the synthetic distance wave number, is the azimuthal wave number, is the distance wave number, is the four-dimensional wave number domain information, For x k The corresponding Fourier variable is, For k The corresponding Fourier variable is, For x l The corresponding Fourier variable is, For l The corresponding Fourier variable.

[0023] Furthermore, when the z-formation priori distance information is not obtained, the two-dimensional wavenumber domain data obtained in S3 is:

[0024]

[0025] Among them, E′(k x ,k y) is the two-dimensional wave number domain data, k x is the first synthetic azimuth wave number, k y is the second synthetic azimuth wave number, is the azimuthal wave number, is the distance wave number, is the four-dimensional wave number domain information, For x k The corresponding Fourier variable is, For k The corresponding Fourier variable is, For x l The corresponding Fourier variable is, For l The corresponding Fourier variable.

[0026] Furthermore, the antenna array of the synthetic aperture radiometer is a sparse array antenna.

[0027] Furthermore, the sparse array antenna is a cross array antenna, and S1 further includes: selecting x from the generated four-dimensional near-field visibility function l ,y k dimension, and obtain the new near-field visibility function V(x l ,y k ):

[0028]

[0029]

[0030]

[0031] Among them, T(x,y,z) is the brightness temperature distribution of the near-field target area, x l is the coordinate of the horizontal array unit on the x-axis, y k is the coordinate of the vertical array unit on the y-axis, R k is the distance from the target point to each antenna of the vertical array, R l is the distance from the target point to each antenna of the horizontal array, (x, y, z) is the coordinate position of the target point in the near-field target area, j is the imaginary unit, k is the wave number, and s is the area of ​​the target point in the near-field target area.

[0032] According to another aspect of the present invention, there is provided an electronic device, comprising: a processor; and a memory storing a computer executable program, wherein when the program is executed by the processor, the processor executes the synthetic aperture radiometer wavenumber domain near-field imaging method as described above.

[0033] In general, the above technical scheme conceived by the present invention can achieve the following beneficial effects: it is proposed that the near-field visibility function of the comprehensive aperture under the planar array is four-dimensional, based on this, the four-dimensional visibility function is obtained by using the planar array, based on the four-dimensional visibility function, combined with the wavenumber domain imaging algorithm and the dimensionality reduction accumulation operation, the near-field large field of view, close distance, high-precision imaging is achieved, which can be applied to the detection of prohibited items hidden in the human body; further, based on the characteristic that the comprehensive aperture array can be sparsely imaged, a corresponding two-dimensional wavenumber domain imaging algorithm is designed for the cross array, and near-field high-precision imaging based on the cross sparse array is achieved; in addition, a corresponding near-field high-precision imaging algorithm without distance information is designed for the full array, and near-field high-precision imaging without distance information is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 A flow chart of a synthetic aperture radiometer wavenumber domain near-field imaging method provided in an embodiment of the present invention;

[0035] Figure 2 A schematic diagram of a comprehensive aperture binary interference model provided by an embodiment of the present invention;

[0036] Figure 3 A schematic diagram of a two-dimensional cross array for synthetic aperture near-field imaging provided by an embodiment of the present invention;

[0037] Figure 4A-4C A schematic diagram of an experimental setup for two-dimensional cross array imaging provided by an embodiment of the present invention;

[0038] Figure 5 A schematic diagram of a dual-source target imaging result provided by an embodiment of the present invention;

[0039] Figure 6 A schematic diagram of a three-dimensional source-target imaging result provided by an embodiment of the present invention;

[0040] Figure 7 A schematic diagram of imaging results of a point source without distance information provided by an embodiment of the present invention;

[0041] Figure 8 A schematic diagram of dual-source imaging results without distance information provided by an embodiment of the present invention;

[0042] Fig. 9 A block diagram of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0044] In the present invention, the terms "first", "second", etc. (if any) in the present invention and the accompanying drawings are used to distinguish similar objects but not necessarily to describe a specific order or sequence.

[0045] Figure 1 A flowchart of a wavenumber domain near-field imaging method for a synthetic aperture radiometer provided in an embodiment of the present invention. Figure 1 , combined with Figure 2-Figure 8 , the wavenumber domain near-field imaging method of the synthetic aperture radiometer in this embodiment is described in detail, and the method includes operations S1 to S4.

[0046] See also Figure 2 , shows a synthetic aperture binary interference model, the antenna array of the synthetic aperture radiometer is located in plane B, the near-field target area is located in plane A, and the distance between plane A and plane B is z. By using the synthetic aperture radiometer wavenumber domain near-field imaging method in this embodiment, it is possible to use the synthetic aperture radiometer at plane A to image the near-field target area at plane B.

[0047] In operation S1 , a brightness temperature distribution of a near-field target area is measured using an antenna array of a synthetic aperture radiometer to generate a corresponding four-dimensional near-field visibility function.

[0048] Operation S2: Performing Fourier transform on the four-dimensional near-field visibility function to achieve wave number domain decomposition, and obtaining four-dimensional wave number domain information in the near-field visibility function.

[0049] Operation S3 is to perform range phase compensation on the four-dimensional wave number domain information to remove the range coupling, and to perform dimensionality reduction accumulation on the four-dimensional wave number domain information after the range phase compensation to obtain two-dimensional wave number domain data.

[0050] In operation S4, Fourier transform or inverse Fourier transform is performed on the two-dimensional wavenumber domain data to generate an inversion image of the near-field target area.

[0051] According to an embodiment of the present 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 present invention is the basic principle of synthetic aperture imaging and the stationary phase principle. The following is a detailed description of the wave number domain near-field imaging method of the synthetic aperture radiometer in this embodiment based on the cross array antenna in the planar full array antenna and the sparse array antenna.

[0052] (1) For a planar full array antenna, the specific operation is as follows:

[0053] (1.1) Using a planar full array antenna to measure the brightness temperature distribution of the near-field target area, the corresponding four-dimensional near-field visibility function is generated:

[0054]

[0055]

[0056]

[0057] Among them, V(x k ,y k ,x l ,y l ) is the four-dimensional near-field visibility function, T(x,y,z) is the brightness temperature distribution of the near-field target area, (x k ,y k ) is the coordinate position of one of the two antennas that make up the interferometer, (x l ,y l ) is the coordinate position of the other antenna of the two antennas that constitute the interferometer, (x, y, z) is the coordinate position of the target point in the near-field target area, R k , R l are the positions of the two antennas corresponding to the target point to the interferometer, j is the imaginary unit, k is the wave number, and s is the area of ​​the target point in the near-field target area.

[0058] (1.2) For the four-dimensional near-field visibility function V(x k ,y k ,x l ,y l ) is Fourier transformed to obtain the four-dimensional wave number domain information:

[0059]

[0060]

[0061]

[0062]

[0063]

[0064] in, is the four-dimensional wave number domain information; For x k The corresponding Fourier variable is, For kThe corresponding Fourier variable is, For x l The corresponding Fourier variable is, For l The corresponding Fourier variable represents the coordinates of the angular spectrum data, and its physical meaning is the wave number vector, that is, the wave number k multiplied by the direction cosine function.

[0065] It should be noted that The physical meaning of is the angular spectrum in optics. Because there is no Fourier transform relationship between the visibility function and the target scene under near-field conditions, the Fourier transform of the visibility function only obtains the wave number domain information. This theory can be fully demonstrated from the stationary phase principle:

[0066]

[0067]

[0068]

[0069]

[0070]

[0071]

[0072] (1.3) Perform distance phase compensation on the four-dimensional wave number domain information, and perform dimensionality reduction accumulation processing on the four-dimensional wave number domain information after distance phase compensation to obtain two-dimensional wave number domain data.

[0073] Since the wave number domain information There is a coupling in the range direction, and the phase compensation in the range direction is required to remove the coupling term. At the same time, since the obtained wave number domain data is four-dimensional, in order to achieve near-field two-dimensional high-resolution imaging, it is necessary to perform distance term compensation and dimensionality reduction accumulation processing on the wave number domain data to obtain the two-dimensional wave number domain data E′(k x ,k y ). Where E′(k x ,k y ) is the frequency domain information of the near-field brightness temperature distribution and is a virtual synthetic angular spectrum.

[0074] (1.3.1) When the z-formation prior distance information is obtained, the two-dimensional wavenumber domain data obtained is:

[0075]

[0076] Among them, E′(k x ,k y ) is the two-dimensional wave number domain data, k xis the first synthetic azimuth wave number, k y is the second synthetic azimuth wave number, k z is the synthetic distance wave number, is the azimuthal wave number, is the distance wave number, is the four-dimensional wave number domain information, For x k The corresponding Fourier variable is, For k The corresponding Fourier variable is, For x l The corresponding Fourier variable is, For l The corresponding Fourier variable.

[0077] Since near-field observation focuses on the brightness temperature difference between the target point and the background, there is no need to obtain the real brightness temperature information and accurately quantify the image brightness temperature. For scenes that do not require accurate quantification of image brightness temperature, the two-dimensional wavenumber domain data E′(k x ,k y ) can be approximated as:

[0078]

[0079] in:

[0080]

[0081]

[0082]

[0083] (1.3.2) When the z formation prior distance information is not obtained, the two-dimensional wavenumber domain data obtained is:

[0084]

[0085] At this time, k z =0. Among them, E′(k x ,k y ) is the two-dimensional wave number domain data, k x is the first synthetic azimuth wave number, k y is the second synthetic azimuth wave number, is the azimuthal wave number, is the distance wave number, is the four-dimensional wave number domain information, For x k The corresponding Fourier variable is, For k The corresponding Fourier variable is, For x lThe corresponding Fourier variable is, For l The corresponding Fourier variable.

[0086] (1.4) For the two-dimensional wave number domain data E′(k x ,k y ) to perform Fourier transform or inverse Fourier transform to obtain an error-free inversion image of the near field

[0087]

[0088] (2) See Figure 3 , Figure 4A , shows a schematic diagram of a typical sparse array being a cross array to achieve near-field imaging. For the cross array antenna in the sparse array antenna, the specific operation is as follows:

[0089] (2.1) Use the cross array antenna to measure the brightness temperature distribution of the near-field target area and generate the corresponding four-dimensional near-field visibility function. Select x from the four-dimensional near-field visibility function. l ,y k dimension, and obtain the new near-field visibility function V(x l ,y k ):

[0090]

[0091] Assume that the multi-to-multi complex correlation operation of the cross array antenna only occurs between the vertical array and the horizontal array. In this case, R l , R k It can be expressed as:

[0092]

[0093]

[0094] Among them, T(x,y,z) is the brightness temperature distribution of the near-field target area, x l is the coordinate of the horizontal array unit on the x-axis, y k is the coordinate of the vertical array unit on the y-axis, R k is the distance from the target point to each antenna of the vertical array, R l is the distance from the target point to each antenna of the horizontal array, (x, y, z) is the coordinate position of the target point in the near-field target area, j is the 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 above processing, the data is equivalently reduced in dimension, omitting the complex and tedious dimensionality reduction and accumulation operations in the wave number domain data.

[0095] (2.2) Its four-dimensional near-field visibility function V(x l ,yk ) is transformed by Fourier to obtain its four-dimensional wave number domain information E(k x ,k y ),in:

[0096]

[0097]

[0098]

[0099] (2.3) Its four-dimensional wave number domain information E(k x ,k y ) to perform phase compensation in the range direction and eliminate the influence of kz, thereby obtaining the two-dimensional wave number domain data E′(k x ,k y ).

[0100] (2.4) For the two-dimensional wave number domain data E′(k x ,k y ) to perform Fourier transform or inverse Fourier transform to obtain an error-free inversion image of the near field

[0101] For the cross array antenna, the array is in the xoy plane, and the signals received by all the array elements on the horizontal array H are only complex correlated with the array elements on the vertical array V, based on which the four-dimensional visibility function is obtained. The experimental settings used are as follows: Figure 4A-4C As shown, Figure 4A It is a 24-channel 94GHz synthetic aperture system with a system bandwidth of 400MHz and an array spacing of 3cm; Figure 4B is a schematic diagram of a dual-source display. Figure 4C The schematic diagram of the triple-expanded source is shown in Figure 1. The distance between the target source and the antenna aperture is 4.2 m. The imaging results of the double-expanded source target and the triple-expanded source target are shown in Figure 1. Figure 5 , Figure 6 shown.

[0102] The following is an example of imaging without distance information. For two-dimensional imaging without distance information, a two-dimensional full array is required, which is very expensive. This embodiment is aimed at one-dimensional imaging and uses a one-dimensional linear array to verify the effectiveness of this method.

[0103] First, based on the horizontal line array of the cross sparse array in Figure 4, the two-dimensional visibility function data is obtained; secondly, the two-dimensional visibility function data is Fourier transformed to obtain the two-dimensional wave number domain data; then, the data of kz=0 in the two-dimensional wave number domain data is obtained, thereby achieving the equivalent of reducing the two-dimensional wave number domain data to one dimension, and Fourier transforming the one-dimensional wave number domain data to obtain the one-dimensional imaging result under the condition of no distance information. The imaging results of the point source target and the dual-expansion source target under the condition of no distance information are shown as follows: Figure 7 and Figure 8 shown. Figure 5-Figure 8 The imaging results shown verify the effectiveness of the method provided in this embodiment.

[0104] Based on the above technical solutions, this embodiment demonstrates that the near-field visibility function under a planar array is four-dimensional, based on which dimensionality reduction accumulation is performed to obtain near-field two-dimensional wavenumber domain data, and near-field large field of view, close distance, and high-precision imaging are achieved, which can be applied to the detection of prohibited items hidden in the human body. Furthermore, based on the characteristic that the comprehensive aperture array can perform sparse imaging, a corresponding two-dimensional wavenumber domain imaging algorithm is designed for the cross array to achieve near-field high-precision imaging based on the cross sparse array; in addition, a corresponding near-field high-precision imaging algorithm without distance information is designed for the full array to achieve near-field high-precision imaging without distance information.

[0105] The embodiment of the present disclosure also shows an electronic device, such as Fig. 9 As shown, the electronic device 900 includes a processor 910 and a readable storage medium 920. The electronic device 900 can execute the above Figure 1-Figure 8 The synthetic aperture radiometer wavenumber domain near-field imaging method described in.

[0106] Specifically, the processor 910 may include, for example, a general-purpose microprocessor, an instruction set processor and / or a related chipset and / or a dedicated microprocessor (e.g., an application-specific integrated circuit (ASIC)), etc. The processor 910 may also include an onboard memory for cache purposes. The processor 910 may be a processor for executing reference Figure 1-Figure 8 The described method flow according to the embodiment of the present disclosure may be a single processing unit or multiple processing units for different actions.

[0107] The readable storage medium 920 may be, for example, any medium capable of containing, storing, conveying, propagating, or transmitting instructions. For example, the readable storage medium may include, but is not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device, component, or propagation medium. Specific examples of readable storage media include: a magnetic storage device, such as a magnetic tape or a hard disk (HDD); an optical storage device, such as a compact disk (CD-ROM); a memory, such as a random access memory (RAM) or flash memory; and / or a wired / wireless communication link.

[0108] The readable storage medium 920 may include a computer program 921, which may include code / computer executable instructions, which when executed by the processor 910 causes the processor 910 to perform, for example, the above-mentioned combination Figure 1-Figure 8 The described method sequences and any variations thereof.

[0109] The computer program 921 may be configured to have, for example, computer program codes including computer program modules. For example, in an exemplary embodiment, the codes in the computer program 921 may include one or more program modules, for example, including module 921A, module 921B, ... It should be noted that the division method and number of modules are not fixed, and those skilled in the art may use appropriate program modules or program module combinations according to actual conditions. When these program module combinations are executed by the processor 910, the processor 910 may execute, for example, the above combination of Figure 1-Figure 8 The described method sequences and any variations thereof.

[0110] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A near-field imaging method in the wavenumber domain of a synthetic aperture radiometer, characterized in that: include: S1, using the antenna array of the synthetic aperture radiometer to measure the brightness temperature distribution of the near-field target area to generate the corresponding four-dimensional near-field visibility function; S2, performing Fourier transform on the four-dimensional near-field visibility function to achieve wave number domain decomposition, and obtaining four-dimensional wave number domain information in the near-field visibility function; S3, performing range phase compensation on the four-dimensional wave number domain information to remove the range coupling, and performing dimensionality reduction accumulation on the four-dimensional wave number domain information after the range phase compensation to obtain two-dimensional wave number domain data; S4, performing Fourier transform or inverse Fourier transform on the two-dimensional wavenumber domain data to generate an inversion image of the near-field target area; The antenna array of the synthetic aperture radiometer is a planar full array antenna; The four-dimensional near-field visibility function generated in S1 is: Among them, V(x k ,y k ,x l ,y l ) is the four-dimensional near-field visibility function, T(x, y, z) is the brightness temperature distribution of the near-field target area, (x k ,y k ) is the coordinate position of one of the two antennas that make up the interferometer, (x l ,y l ) is the coordinate position of the other antenna of the two antennas that constitute the interferometer, (x, y, z) is the coordinate position of the target point in the near-field target area, R k , R l are the positions of the two antennas corresponding to the target point to the interferometer, j is the imaginary unit, k is the wave number, and s is the area of ​​the target point in the near-field target area.

2. The wavenumber domain near-field imaging method of a synthetic aperture radiometer according to claim 1, characterized in that: The four-dimensional wavenumber domain information obtained in S2 is: in, is the four-dimensional wave number domain information, is the Fourier variable corresponding to xk, For k The corresponding Fourier variable is, For x l The corresponding Fourier variable is, For l The corresponding Fourier variable.

3. The wavenumber domain near-field imaging method of a synthetic aperture radiometer according to claim 1, characterized in that: When the z-formed prior distance information is obtained, the two-dimensional wavenumber domain data obtained in S3 is: Among them, E′(k x ,k y ) is the two-dimensional wavenumber domain data, kx is the first synthetic azimuth wavenumber, ky is the second synthetic azimuth wavenumber, k z is the synthetic distance wave number, is the azimuthal wave number, is the distance wave number, is the four-dimensional wave number domain information, For x k The corresponding Fourier variable is, For k The corresponding Fourier variable is, For x l The corresponding Fourier variable is, For l The corresponding Fourier variable.

4. The wavenumber domain near-field imaging method of a synthetic aperture radiometer according to claim 1, characterized in that: When the z formation prior distance information is not obtained, the two-dimensional wave number domain data obtained in S3 is: Among them, E′(k x ,k y ) is the two-dimensional wavenumber domain data, kx is the first synthetic azimuth wavenumber, ky is the second synthetic azimuth wavenumber, is the azimuthal wave number, is the distance wave number, is the four-dimensional wave number domain information, For x k The corresponding Fourier variable is, For k The corresponding Fourier variable is, For x l The corresponding Fourier variable is, For l The corresponding Fourier variable.

5. A near-field imaging method in wavenumber domain using a synthetic aperture radiometer, characterized in that: include: S1, using the antenna array of the synthetic aperture radiometer to measure the brightness temperature distribution of the near-field target area to generate a corresponding four-dimensional near-field visibility function, and selecting x from the four-dimensional near-field visibility function l ,y k dimension, and obtain the new near-field visibility function V(x l ,y k ): The antenna array of the synthetic aperture radiometer is a sparse array antenna; The sparse array antenna is a cross array antenna, and the new near-field visibility function V(x l ,y k ): Among them, T(x,y,z) is the brightness temperature distribution of the near-field target area, x l is the coordinate of the horizontal array unit on the x-axis, y k is the coordinate of the vertical array unit on the y-axis, R k is the distance from the target point to each antenna of the vertical array, R l is the distance from the target point to each antenna of the horizontal array, (x, y, z) is the coordinate position of the target point in the near-field target area, j is the imaginary unit, k is the wave number, and s is the area of ​​the target point in the near-field target area; S2, for the new near-field visibility function V(x l ,y k ) is subjected to Fourier transform to realize wave number domain decomposition, and the new near-field visibility function V(x l ,y k ) in the wavenumber domain; S3, performing range phase compensation on the wave number domain information to remove range coupling, thereby obtaining two-dimensional wave number domain data; S4, performing Fourier transform or inverse Fourier transform on the two-dimensional wavenumber domain data to generate an inversion image of the near-field target area.

6. An electronic device, characterized in that: include: processor; A memory storing a computer executable program, wherein when the program is executed by the processor, the processor executes the synthetic aperture radiometer wave number domain near-field imaging method according to any one of claims 1 to 5.

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