Multi-center polar coordinate system interpolation-free image fusion method and device

Abstract

The invention discloses a multi-center polar coordinate system interpolation-free image fusion method and device, and the method comprises the steps: obtaining a multi-center polar coordinate BP image of each receiving platform in a distributed one-transmitting-multiple-receiving foresight configuration, and obtaining N multi-center polar coordinate BP images, the distributed one-transmitting multi-receiving foresight configuration comprises a transmitting platform and N receiving platforms; for each multi-center polar coordinate BP image, sequentially performing frequency spectrum center compensation and frequency spectrum broadening compensation on the multi-center polar coordinate BP image to obtain a frequency spectrum alignment signal; performing up-sampling processing on the frequency spectrum alignment signal to obtain an up-sampled signal; performing frequency spectrum broadening inverse compensation and frequency spectrum center inverse compensation on the up-sampled signal to obtain a preprocessed image; and carrying out fast coherent fusion on the obtained N preprocessed images to obtain a foresight high-resolution image. According to the invention, accurate and rapid fusion of the front-view images of the multiple receiving platforms can be realized.

Description

Technical Field

[0001] The present invention belongs to the field of radar imaging technology, and in particular relates to a multi-center polar coordinate system interpolation-free image fusion method and device. Background Art

[0002] The traditional fast factorized back projection (FFBP) algorithm is a typical fast time-domain algorithm suitable for achieving high-performance focusing in multistatic SARs of any configuration. The FFBP algorithm employs multi-stage recursive image fusion, which significantly improves the processing efficiency of traditional time-domain algorithms. Its fast time-domain processing architecture is particularly well-suited for image fusion on multiple platforms of distributed SARs. However, image fusion in the FFBP algorithm is achieved through two-dimensional interpolation. Compared to traditional monostatic and bistatic SARs, single-transmitter, multi-receiver distributed forward-looking SARs are equipped with significantly more moving platforms. Two-dimensional interpolation fusion involves a large number of complex addition and multiplication operations, which reduces the algorithm's computational efficiency. This inevitably leads to the accumulation of errors during image fusion, making it difficult to quickly achieve precise focusing of high-resolution forward-looking images. Summary of the Invention

[0003] In order to solve the above problems existing in the prior art, the present invention provides a multi-center polar coordinate system non-interpolation image fusion method and device.

[0004] The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0005] The present invention provides a multi-center polar coordinate system interpolation-free image fusion method, comprising:

[0006] Acquire multi-center polar coordinate BP images of each receiving platform in a distributed one-transmitter-multiple-receiver forward-looking configuration to obtain N multi-center polar coordinate BP images, wherein the distributed one-transmitter-multiple-receiver forward-looking configuration includes one transmitting platform and N receiving platforms, and N is a positive integer greater than 2;

[0007] For each multi-center polar coordinate BP image, performing spectrum center compensation and spectrum broadening compensation on the multi-center polar coordinate BP image in sequence to obtain a spectrum alignment signal;

[0008] performing upsampling processing on the spectrum aligned signal to obtain an upsampled signal;

[0009] performing spectrum broadening inverse compensation and spectrum center inverse compensation on the upsampled signal to obtain a preprocessed image;

[0010] The N pre-processed images are quickly coherently fused to obtain a forward-looking high-resolution image.

[0011] The present invention also provides a multi-center polar coordinate system non-interpolation image fusion device, comprising a processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory communicate with each other via the communication bus;

[0012] The memory is used to store computer programs;

[0013] The processor is used to implement the steps of the above-mentioned multi-center polar coordinate system non-interpolation image fusion method when executing the program stored in the memory.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] The present invention designs a spectral preprocessing function (i.e., a function of a filter used for compensation and inverse compensation) based on a multi-center polar coordinate system, and uses Fourier transform to replace two-dimensional interpolation operations, which significantly improves the accuracy and efficiency of multi-platform image fusion, avoids the accumulation of interpolation errors, and realizes the precise and rapid fusion of forward-looking images from multiple receiving platforms, providing a more efficient and accurate solution for distributed SAR forward-looking high-resolution imaging.

[0016] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a flowchart of a method for multi-center polar coordinate system interpolation-free image fusion provided by an embodiment of the present invention;

[0018] Figure 2 It is a schematic diagram of the relationship between the multi-center polar coordinate system and the reference coordinates;

[0019] Figure 3 This is another flowchart of a multi-center polar coordinate system non-interpolation image fusion method provided by an embodiment of the present invention;

[0020] Figure 4 It is a schematic diagram of the spectrum of the image of the receiving platform before and after preprocessing and fusion using traditional methods;

[0021] Figure 5 Schematic diagram of the spectrum of the image of the receiving platform before and after preprocessing and fusion using the method of the present invention;

[0022] Figure 6 It is a comparison diagram of surface target simulation results using the traditional method and the method of the present invention respectively. DETAILED DESCRIPTION

[0023] The present invention will be further described in detail below with reference to specific examples, but the embodiments of the present invention are not limited thereto.

[0024] Figure 1 FIG. 1 is a flow chart of a multi-center polar coordinate system non-interpolation image fusion method provided by an embodiment of the present invention. Figure 1 As shown, the method includes:

[0025] S101. Acquire multi-center polar coordinate BP images of each receiving platform in a distributed one-transmitter-multi-receiver forward-looking configuration to obtain N multi-center polar coordinate BP images, where the distributed one-transmitter-multi-receiver forward-looking configuration includes one transmitting platform and N receiving platforms; N is a positive integer greater than 2.

[0026] S102 : For each multi-center polar coordinate BP image, perform spectrum center compensation and spectrum broadening compensation on the multi-center polar coordinate BP image in sequence to obtain a spectrum alignment signal.

[0027] S103 : Upsampling the spectrum aligned signal to obtain an upsampled signal.

[0028] S104 , performing spectrum broadening inverse compensation and spectrum center inverse compensation on the upsampled signal to obtain a preprocessed image.

[0029] S105 , performing rapid coherent fusion on the obtained N pre-processed images to obtain a forward-looking high-resolution image.

[0030] In the present invention, the multi-center polar coordinate BP image of the nth receiving platform is an image obtained by reconstructing the echo signal of the nth receiving platform into the multi-center polar coordinate grid using the BP algorithm, where n is a positive integer and the value of n ranges from 1 to N. For example, the final expression of the multi-center polar coordinate BP image of the nth receiving platform is: n (ρ,θ)=∫∫exp[j(ρ-ρ p )k ρ ]×exp[j(θ-θ p )k θ ]dk ρ dk θ , where i n (ρ,θ) represents the multi-center polar coordinate BP image of the nth receiving platform, θ represents θ r and θ t Mapped to the equivalent angle in the reference coordinate system, ρ represents ρ r and ρ t Equivalent radial distance mapped to the reference coordinate system, k θ Indicates the azimuthal wavenumber of the multi-center polar coordinate BP image spectrum, k ρ Represents the distance wave number of the multi-center polar coordinate BP image spectrum, ρ p Represents ρ rp and ρ tpThe equivalent radial distance mapped from the multi-center polar coordinate system to the reference coordinate system, θ p represents θ rp and θ tp Mapped to the equivalent angle in the reference coordinate system. It should be noted that the above-mentioned multi-center polar coordinate system is a coordinate system composed of a local polar coordinate constructed according to the polar position of the transmitting platform and another local polar coordinate constructed according to the polar position of N receiving platforms. The multi-center polar coordinate system is composed of a multi-center polar coordinate system grid. The above-mentioned reference coordinate system is a global coordinate system obtained by fusing the above-mentioned two local polar coordinates using a unified polar coordinate rule. It should be noted that the imaging system grids corresponding to different platforms are uniformly represented under a reference imaging system in order to facilitate derivation when deriving formulas. For example, Figure 2 It is a schematic diagram of the relationship between the multi-center polar coordinate system and the reference coordinate system. Figure 2 As shown, O r and O t Represents the two poles of the multi-center polar coordinate system, O r are the poles of N receiving platforms, where O t is the pole of the launch platform, O is the midpoint of the pole, and OXY represents the reference coordinate system. Figure 2 It can be clearly seen that θ p is θ rp and θ tp Equivalent angle mapped to the reference coordinate system, ρ p is ρ rp and ρ tp Mapped to the equivalent radial distance in the reference coordinate system, θ is θ r and θ t Mapped to the equivalent angle in the reference coordinate system, ρ is ρ r and ρ t Mapped to the equivalent radial distance in the reference coordinate system.

[0031] Here, I n The expression of (ρ,θ) is obtained from the initial expression of the image obtained by reconstructing the echo signal of the nth receiving platform into a multi-center polar coordinate grid. The specific principle is as follows:

[0032] First, let E(ρ r ,θ r )(hereinafter referred to as E) and F(ρ t ,θ t ) (hereinafter referred to as F) together represent the multi-center polar coordinate grid, θ r represents the oblique angle from the nth receiving platform to the multi-center polar coordinate grid, θ t represents the oblique angle from the launch platform to the multi-center polar coordinate grid, ρ rrepresents the radial distance from the nth receiving platform to the multi-center polar coordinate grid, ρ t represents the radial distance from the launch platform to the multi-center polar coordinate grid, E p (ρ rp ,θ rp )(Subsequent use of E p indicates) and F p (ρ tp ,θ tp )(Subsequently adopt F p represents the position mapping of the real target point P0 in the multi-center polar coordinate system, ρ rp represents the radial distance from the nth receiving platform to the true target point P0, θ rp represents the oblique angle from the nth receiving platform to the real target point P0, ρ tp Represents the radial distance from the receiving platform to the true target point P0, θ tp represents the oblique angle from the transmitting platform to the real target point P0. At time η, the position of the antenna phase center of the nth receiving platform is expressed as (Subsequent adoption The position of the antenna phase center of the transmitting platform is represented by P t [x t (η),y t (η)] (subsequently using P t express), and x t (η) are all horizontal coordinates, and y t (η) are all ordinates. Using the BP algorithm, the echo signal of the nth receiving platform is reconstructed into a multi-center polar coordinate grid. The initial expression of the multi-center polar coordinate BP image of the nth receiving platform can be obtained:

[0033]

[0034] in, Indicates from to F p The wave number vector of the direction, Indicates that from P t to E p The wave number vector in the direction of and The order of magnitude is the same as that of , denoted as k. Indicates from The distance vector to the E direction, Indicates that from P t The distance vector to the direction of F. Indicates from The distance vector to the E direction, Indicates that from Pt The distance vector to the direction of F. Indicates from to E p The distance vector of the direction, Indicates that from P t to F p The distance vector of the direction.

[0035] Next, i n In the expression Expressed as (ρ r -ρ rp ,θ r -θ rp ), Expressed as (ρ t -ρ tp ,θ t -θ tp ), and introduce the and The parameters obtained by orthogonal wave number vector decomposition can be expressed as follows:

[0036] i n =∫∫exp[j(ρ r -ρ rp )k ρr +j(ρ t -ρ tp )k ρt ]×exp[j(θ r -θ rp )k θr +j(θ t -θ tp )k θt ]dk ρ dk θ ;

[0037] in, and Yes The orthogonal wave number vector decomposition is obtained. and The order of magnitude is k ρr and k θr , and Yes The orthogonal wave number vector decomposition is obtained. and The order of magnitude is k ρt and k θt According to the stationary phase principle, E(ρ r ,θ r ) and F(ρt ,θ t ) to i n The contribution of the expression of (ρ r -ρ rp ) and (ρ t -ρ tp ) is uniformly expressed as ρ-ρ p , and (θ r -θ rp ) and (θ t -θ tp ) is uniformly expressed as θ-θ p On this basis, the multi-center polar coordinate BP image of the nth receiving platform can be finally expressed as:

[0038] i n (ρ,θ)=∫∫exp[j(ρ-ρ p )k ρ ]×exp[j(θ-θ p )k θ ]dk ρ dk θ ;

[0039] Among them, k ρ =k ρr +k ρt , k θ =k θr +k θt .

[0040] For example, Figure 3 This is another flowchart of a multi-center polar coordinate system non-interpolation image fusion method. Figure 3 It can be seen that the above S102 is implemented through steps S1021 to S1023:

[0041] S1021. Using a spectrum center filter designed based on the multi-center polar coordinate BP image, the multi-center polar coordinate BP image is compensated to obtain a spectrum center compensated signal.

[0042] Here, the spectrum center filter can be used to compensate the multi-center polar coordinate BP image in the range time domain and the azimuth time domain. For example, the expression of the spectrum center filter is as follows:

[0043]

[0044] Among them, H1 represents the spectrum center filter, Indicates the position of the nth receiving platform at the azimuth center moment, (x tc ,y tc ) represents the position of the launch platform at the azimuth center, k θc represents kθ The wave number center, k ρc represents k ρ The wave number center [θ min ,θ max ] represents the range of θ, [ρ min ,ρ max ] represents the range of ρ, k c =4π / λ, λ represents the wavelength.

[0045] Here, the expression of the spectrum center filter is obtained according to the following principle:

[0046] First, for i n The expression of (ρ,θ) is Fourier transformed to obtain the image spectrum of the nth receiving platform in the multi-center polar coordinate system. The expression of the spectrum is: I n (k ρ ,k θ )≈exp(-jρ p k ρ -jθ p k θ ). Next, define The gradient direction is the direction of the maximum rate of change of the wave number spectrum energy. Find the partial derivative of ρ and get k ρ The rate of change of direction, Find the partial derivative of θ and get k θ The rate of change of direction. According to k ρ The rate of change of direction and k θ The rate of change of direction can be obtained by n (k ρ ,k θ )’s frequency distribution expression: Next, the center k of wave number k c The receiving platform position and the transmitting platform position at the center of the azimuth and (x tc ,y tc )Substitute into I n (k ρ ,k θ ) in the frequency distribution expression, we can get k θ and k ρ The wave number center k θc and k ρc , thus the expression of the spectrum center filter can be constructed.

[0047] S1022 , after performing range FFT transformation on the spectrum center compensated signal, a spectrum stretching filter designed based on a multi-center polar coordinate BP image is used to compensate the range FFT transformed signal to obtain a spectrum stretch compensated signal.

[0048] Here, after spectrum center compensation, k θ and k ρ The wave number width can be expressed as Δk θ and Δk ρ Since Δk θ right and (x tc ,y tc ) is relatively sensitive, showing azimuth spectrum broadening. In order to achieve spectrum broadening compensation, it is necessary to construct a spectrum broadening filter H2 to further compensate the signal that has undergone spectrum center compensation and range FFT transformation in the range frequency domain-azimuth time domain. For example, the expression of the spectrum broadening filter is as follows:

[0049]

[0050] Where H2 represents the spectrum broadening filter, Δk θ represents k θ The wave number width, Δk ρ represents k ρ The wave number width is Δk=2πB / c, where B represents the bandwidth and c represents the speed of light.

[0051] S1023 : Perform azimuth FFT transformation on the signal that has undergone spectrum broadening compensation to obtain a spectrum aligned signal.

[0052] Combined with the above Figure 3 It can be seen that, in the present invention, the above S103 is specifically implemented as: performing N-fold upsampling processing on the spectrum aligned signal to obtain an upsampled signal.

[0053] Combined with the above Figure 3 It can be seen that in the present invention, the above S104 is implemented through steps S1041 to S1042:

[0054] S1041 , after performing azimuth IFFT transformation on the upsampled signal, inverse compensation is performed on the azimuth IFFT transformed signal using a filter for spectrum broadening inverse compensation to obtain a spectrum broadening inverse compensated signal.

[0055] Here, the function of the filter for inverse compensation of spectrum broadening and the function of the filter for compensating spectrum broadening are a pair of conjugate functions.

[0056] S1042 , after performing range IFFT transformation on the signal that has undergone spectrum broadening inverse compensation, inverse compensation is performed on the signal that has undergone range IFFT transformation using a filter for spectrum center inverse compensation to obtain a preprocessed image.

[0057] Here, the function of the filter used for spectrum center inverse compensation and the function of the filter used for spectrum center compensation are a pair of conjugate functions.

[0058] Here, through spectrum broadening inverse compensation and spectrum center inverse compensation, the multi-center polar coordinate BP image spectra corresponding to different receiving platforms can be moved to the correct frequency position, which facilitates the subsequent coherent accumulation of the image.

[0059] The multi-center polar coordinate system interpolation-free image fusion method provided by the present invention designs a spectrum preprocessing function based on the multi-center polar coordinate system and uses Fourier transform to replace traditional two-dimensional interpolation fusion. This avoids a large number of complex addition and multiplication operations, eliminates the problem of interpolation error accumulation, and achieves accurate and rapid fusion of forward-looking images from multiple receiving platforms. Thanks to the advantages of the multi-center polar coordinate system, the wave number vector in the forward-looking configuration of a single-transmitter, multi-receiver distributed SAR always satisfies orthogonal decomposition. Therefore, the present invention derives a spectrum preprocessing function based on the multi-center polar coordinate imaging system, can obtain a narrower spectrum region, can significantly reduce the multi-platform image sampling requirements, and thus achieve accurate and rapid fusion of multi-platform images.

[0060] The present invention also provides a multi-center polar coordinate system non-interpolation image fusion device, comprising a processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory communicate with each other via the communication bus;

[0061] Memory for storing computer programs;

[0062] The processor is configured to implement the steps of the above-mentioned multi-center polar coordinate system non-interpolation image fusion method when executing the program stored in the memory.

[0063] The technical effects of the present invention are verified through experiments below.

[0064] The traditional method (i.e., FFBP algorithm) and the method of the present invention are used to preprocess and fuse the images of the receiving platform in the single-transmitter, multiple-receiver distributed forward-looking SAR configuration, and the preprocessing effect and fusion effect are compared. Surface target imaging simulation is also performed using the traditional method and the method of the present invention.

[0065] Figure 4 It is a schematic diagram of the spectrum of the image of the receiving platform before and after preprocessing and fusion using traditional methods. Figure 5 It is a schematic diagram of the spectrum of the image of the receiving platform before and after preprocessing and fusion using the method of the present invention. Figure 6 is a comparison chart of the simulation results of the surface target using the conventional method and the method of the present application. Specifically, Figure 4 (a) of is a schematic diagram of the original frequency spectrum of the image signal used by the conventional method, which is an elliptical polar coordinate BP image signal; (b) is a schematic diagram of the frequency spectrum after the image signal shown in (a) is preprocessed using the conventional method; and (c) is a schematic diagram of the frequency spectrum of the image signal obtained after the preprocessed image signals of multiple receiving platforms are fused using the conventional method. Figure 5 (a) of is a schematic diagram of the original frequency spectrum of the image signal used by the present application, which is a multi-center polar coordinate BP image signal; (b) is a schematic diagram of the frequency spectrum after the image signal shown in (a) is preprocessed using the method of the present application; and (c) is a schematic diagram of the frequency spectrum of the image signal obtained after the preprocessed image signals of multiple receiving platforms are fused using the method of the present application. Figure 6 (a) of is a schematic diagram of the imaging result of the conventional method, and (b) is a schematic diagram of the imaging result of the method of the present application.

[0066] According to Figure 4 , 5 and 6, the pre-processing effect, the fusion effect and the imaging effect of the method of the present application are all superior to those of the conventional method.

[0067] It should be noted that the terms “first”, “second” are only used for description purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with “first”, “second” can explicitly or implicitly include one or more features. In the description of the present application, the meaning of “multiple” is two or more, unless otherwise specifically limited.

[0068] In the description of the present application, the description of the terms “one embodiment”, “some embodiments”, “example”, “specific example” or “some examples” means that the specific features or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the description of the present application, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in the present application.

[0069] In the description, the word “comprising” does not exclude other components or steps, and “one” or “a” does not exclude multiple cases. Some measures are described in different embodiments, but this does not mean that these measures cannot be combined to produce good results.

[0070] The above is a further detailed description of the present invention in conjunction with specific preferred embodiments, and the specific implementation of the present invention should not be considered to be limited to these descriptions. For those skilled in the art of the present invention, without departing from the concept of the present invention, several simple deductions or substitutions can be made, which should be considered to fall within the scope of protection of the present invention.

Claims

1. A multi-center polar coordinate system non-interpolation image fusion method, characterized in that: include: Acquire multi-center polar coordinate BP images of each receiving platform in a distributed one-transmitter-multiple-receiver forward-looking configuration to obtain N multi-center polar coordinate BP images, wherein the distributed one-transmitter-multiple-receiver forward-looking configuration includes one transmitting platform and N receiving platforms, and N is a positive integer greater than 2; For each multi-center polar coordinate BP image, performing spectrum center compensation and spectrum broadening compensation on the multi-center polar coordinate BP image in sequence to obtain a spectrum alignment signal; performing upsampling processing on the spectrum aligned signal to obtain an upsampled signal; performing spectrum broadening inverse compensation and spectrum center inverse compensation on the upsampled signal to obtain a preprocessed image; The N pre-processed images are quickly coherently fused to obtain a forward-looking high-resolution image.

2. The method according to claim 1, characterized in that The step of sequentially performing spectrum center compensation and spectrum broadening compensation on the multi-center polar coordinate BP image to obtain a spectrum alignment signal includes: Using a spectrum center filter designed based on the multi-center polar coordinate BP image, the multi-center polar coordinate BP image is compensated to obtain a spectrum center compensated signal; After performing a range FFT transform on the spectrum center compensated signal, a spectrum stretching filter designed based on the multi-center polar coordinate BP image is used to compensate the range FFT transformed signal to obtain a spectrum stretch compensated signal; Performing azimuth FFT transformation on the signal that has undergone spectrum broadening compensation to obtain a spectrum aligned signal.

3. The method according to claim 1, characterized in that The upsampling the spectrum aligned signal to obtain an upsampled signal includes: Perform N-fold upsampling processing on the spectrum aligned signal to obtain an upsampled signal.

4. The method according to claim 1, characterized in that The performing spectrum broadening inverse compensation and spectrum center inverse compensation on the upsampled signal to obtain a preprocessed image includes: After performing azimuth IFFT transformation on the upsampled signal, inverse compensation is performed on the azimuth IFFT transformed signal using a filter for spectrum broadening inverse compensation to obtain a spectrum broadening inverse compensated signal; After performing distance IFFT transformation on the signal that has undergone spectrum broadening inverse compensation, the filter used for spectrum center inverse compensation is used to perform inverse compensation on the signal that has undergone range IFFT transformation to obtain a preprocessed image.

5. The method according to claim 1, characterized in that: The multi-center polar coordinate BP image of the nth receiving platform is an image obtained by reconstructing the echo signal of the nth receiving platform into a multi-center polar coordinate system grid using the BP algorithm, where n is a positive integer and the value of n ranges from 1 to N.

6. The method according to claim 2, characterized in that: The expression of the spectrum center filter is as follows: Wherein, H1 represents the spectrum center filter, Indicates the position of the nth receiving platform at the azimuth center moment, n is a positive integer, and the value of n ranges from 1 to N, (x tc ,y tc ) represents the position of the launch platform at the azimuth center moment, θ r represents the oblique angle from the nth receiving platform to the multi-center polar coordinate grid, θ t represents the oblique viewing angle from the launch platform to the multi-center polar coordinate grid, ρ r represents the radial distance from the nth receiving platform to the multi-center polar coordinate grid, ρ t represents the radial distance from the launch platform to the multi-center polar coordinate grid, k θc represents k θ The wave number center, k θ Indicates the azimuthal wavenumber of the multi-center polar coordinate BP image spectrum, k ρc represents k ρ The wave number center, k ρ Represents the distance wave number of the multi-center polar coordinate BP image spectrum, [θ min ,θ max ] represents the range of θ, θ represents θ r and θ t Mapped to the equivalent angle in the reference coordinate system, [ρ min ,ρ max ] represents the range of ρ, ρ represents ρ r and ρ t Equivalent radial distance mapped to the reference coordinate system, k c =4π / λ, λ represents the wavelength.

7. The method according to claim 2, characterized in that: The spectrum broadening filter is expressed as follows: Wherein, H2 represents the spectrum broadening filter, Indicates the position of the nth receiving platform at the azimuth center moment, n is a positive integer, and the value of n ranges from 1 to N, (x tc ,y tc ) represents the position of the launch platform at the azimuth center moment, θ r represents the oblique angle from the nth receiving platform to the multi-center polar coordinate grid, θ t represents the oblique viewing angle from the launch platform to the multi-center polar coordinate grid, ρ r represents the radial distance from the nth receiving platform to the multi-center polar coordinate grid, ρ t represents the radial distance from the launch platform to the multi-center polar coordinate grid, Δk θ represents k θ The wave number width, k θ represents the azimuthal wavenumber of the multi-center polar coordinate BP image spectrum, Δk ρ represents k ρ The wave number width, k ρ Represents the distance wave number of the multi-center polar coordinate BP image spectrum, [θ min ,θ max ] represents the range of θ, θ represents θ r and θ t Mapped to the equivalent angle in the reference coordinate system, [ρ min ,ρ max ] represents the range of ρ, ρ represents ρ r and ρ t Mapped to the equivalent radial distance in the reference coordinate system, Δk = 2πB / c, where B represents the bandwidth and c represents the speed of light.

8. The method according to claim 4, characterized in that: The function of the filter used for inverse compensation of spectrum broadening and the function of the filter used for compensation of spectrum broadening are a pair of conjugate functions.

9. The method according to claim 4, characterized in that: The function of the filter used for spectrum center inverse compensation and the function of the filter used for spectrum center compensation are a pair of conjugate functions.

10. A multi-center polar coordinate system non-interpolation image fusion device, comprising a processor, a communication interface, a memory and a communication bus, characterized in that: The processor, the communication interface and the memory communicate with each other via the communication bus; The memory is used to store computer programs; The processor is configured to implement the method steps described in any one of claims 1 to 9 when executing a program stored in the memory.

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