Curved array rapid imaging method

Abstract

The present invention relates to the fields of optical imaging, microwave imaging, radar detection, sonar, ultrasonic imaging, and target detection, imaging recognition, and wireless communication technologies based on acoustic, optical, and electrical media. Specifically, it relates to a method for rapid imaging of curved arrays and its applications in these fields. The method of the present invention enables rapid imaging of curved arrays and is applicable to various non-planar and conformal arrays, enabling rapid imaging and target detection. Furthermore, the method of the present invention has the advantages of good compatibility, low computational complexity, excellent imaging quality, and a wide range of applications.

Description

Technical Field

[0001] The present invention relates to the fields of optical imaging, microwave imaging, radar detection, sonar, ultrasonic imaging, and target detection, imaging recognition, and wireless communication technologies based on sound, light, electricity, and other media, and more particularly to a method for rapid imaging of a curved array and its applications in the above-mentioned fields. Background Art

[0002] Curved arrays are widely used in target detection and wireless communications, especially in radar detection technology. For example, many ground-based radars use spherical or cylindrical arrays, while shipborne and airborne radars increasingly employ conformal arrays. These non-planar arrays are collectively referred to as curved arrays. For curved arrays, the use of imaging detection technology can greatly improve detection efficiency.

[0003] The virtual lens imaging algorithm is a novel array imaging technology. The inventor's previous patent applications, "Rapid Imaging Method for Passive and Active Imaging" and "Cylindrical Scanning Microwave Imaging Method," are applicable only to planar and cylindrical arrays and cannot be applied to general curved arrays. Therefore, a rapid imaging technology applicable to general curved arrays is needed to address this challenge. Summary of the Invention

[0004] In order to apply virtual lens imaging technology to curved array imaging, the present invention provides a solution.

[0005] As attached Figure 1 As shown, a coordinate system of the curved array imaging system is established, where P is the target, Q is the image of the target, and the center of the curved array is located on the plane of z=0.

[0006] Without loss of generality, assume that the distance error between the curved array unit and the ideal array plane is Δ z , the ideal array plane refers to the plane passing through the center of the curved array and perpendicular to the normal direction of the curved array. Use (x, y, z) to represent the coordinates of the array unit, then Δ z =z, z>0 when Δ z is a positive value, when z<0, Δ z is a negative value.

[0007] The propagation phase shift introduced when the signal propagates through R1 and R2 in a single path is:

[0008]

[0009] Where: φ1 is the propagation phase shift from the scattering source P to the array element, φ2 is the propagation phase shift from the array element to the image point Q, is the wave number, U is the object distance, V is the image distance, (ζ,ξ) are the coordinates of the scattering source, (x,y,z) are the coordinates of the array unit, and (δ,σ) are the coordinates of the image point.

[0010] Ignore the constant components in φ1 and φ2 that are not helpful for imaging, and only take the coordinate-related change components that are useful for imaging and focusing:

[0011]

[0012] The curved array is equivalent to a lens with a focal length of F, and the effective phase shift of the lens unit is:

[0013]

[0014] Where: φ L is the lens phase shift of the array unit, and F is the focal length.

[0015] In passive imaging, the antenna unit does not transmit a detection signal, but is only used to receive the scattered signal of the target. After receiving the scattered signal of the target, the antenna performs secondary scattering in the form of a spherical wave. Then, after passing through different transmission paths R1 and R2 and the phase shift of the lens unit, the field intensity reaching the image plane is:

[0016]

[0017] During holographic imaging, a signal is emitted from the antenna unit, reflected by the target, and then received by the antenna unit. The signal undergoes a two-way transmission of distance R1, and the corresponding phase delay is 2φ1. During imaging processing, both the lens unit phase shift and the R2 propagation phase shift need to be processed in two directions: the transmitting and receiving antenna units transmit the detection signal in sequence. After the signal is reflected by the target P and reaches the transmitting and receiving antenna units, it is secondary scattered in the form of a spherical wave. Then, after the two-way phase shift through different transmission paths R1 and R2, the field strength reaching the image plane is:

[0018]

[0019] Comparing the imaging formulas in the above two cases, by introducing the auxiliary object selectivity parameter η, the above two formulas can be unified as follows:

[0020]

[0021] Among them, η=1 is applicable to passive imaging, and η=2 is applicable to active holographic imaging.

[0022] In actual imaging, only the following processing is required:

[0023]

[0024] The target signal received by the antenna unit is E, and A is the amplitude weighting coefficient. Substitute φL After simplifying the expression of φ2, we can get:

[0025]

[0026] in, φ C =ηkΔ z .

[0027] When the imaging conditions are met When , the above formula can be simplified to:

[0028]

[0029] For actual discrete systems, (x m ,y n ,z mn ) represents the coordinates of the array unit, then the distance error from the array unit to the ideal array plane is Where m and n are the array unit numbers in the x-direction and y-direction respectively. Discretizing the above equation yields:

[0030]

[0031] The symbol exp represents the exponential function with Euler's constant e as the base. is the signal received by the array unit, A mn is the array element amplitude weighting coefficient, is the array unit focusing phase weighting coefficient, is the phase compensation coefficient of the array unit;

[0032] Let x m =x0+mΔ x ,y n =y0+nΔ y , put it into the above formula and simplify it to get:

[0033]

[0034] in,

[0035] The coefficients on the right side of the above equation satisfy It reflects the spatial fluctuation characteristics of the image field and has little effect on imaging and can be ignored. Without considering the influence of the coefficient, the summation operation can be solved by a fast algorithm represented by the inverse fast Fourier transform (IFFT), and the image field calculation formula is:

[0036]

[0037] in, is the image field, symbol Represents an efficient and fast algorithm function, which can be implemented using the Inverse Fast Fourier Transform (IFFT) or the Fast Fourier Transform (FFT); is the signal received by the array, A is the array amplitude weighting coefficient, φ F is the array focusing phase weighting coefficient, φ C is the array phase compensation coefficient, φ S is the array scanning phase weighting coefficient.

[0038] The spatial spectrum ω corresponding to the above calculation results δ 、ω σ The value range is: δ ∈[0,2π],ω σ ∈[0,2π], after fftshift operation, ω δ 、ω σ The value range is transformed into: ω δ ∈[-π,π],ω σ ∈[-π,π], the image at this time is consistent with the actual distribution and has a good linear mapping relationship with the source field.

[0039]

[0040] in, To match the actual distribution.

[0041] Combining array antenna theory to analyze spatial spectrum ω δ 、ω σ Correction, there is ω δ =ηkΔ x sinθ δ 、ω σ =ηkΔ y sinθ σ .

[0042] Since the repetition period of discrete FFT transformation is 2π, if image aliasing is required to be avoided, then:

[0043] |ω|≤π;

[0044] Assuming the unit spacing is Δ, we have:

[0045]

[0046] Usually the effective range of θ is [-π / 2,π / 2], and the condition to ensure that the above formula is always valid is:

[0047]

[0048] The alias-free condition for semi-spatial images is:

[0049] The array antenna theory is used to correct the image point scanning angle coordinates:

[0050]

[0051] Using the target slant distance R instead of the object distance parameter U can improve the imaging performance at large angles:

[0052]

[0053] Based on the above understanding, the present invention provides a method for rapid imaging of curved arrays. This method is based on the principle of lens imaging and combines electromagnetic field theory. Based on the target signal received by the antenna array, the amplitude and phase weighting of the unit signal are weighted, and an efficient parallel algorithm is used to obtain the image field distribution corresponding to the target. The specific algorithm is as follows:

[0054]

[0055] Where: j is the imaginary unit, e is Euler's constant, is the image field distribution, is the target signal received by the array unit, A mn is the array element amplitude weighting coefficient, is the array unit focusing phase weighting coefficient, is the array unit phase compensation coefficient, is the array unit scanning phase weighting coefficient, M is the number of array units in the x direction, N is the number of array units in the y direction, (x m ,y n ) are the coordinates of the array unit, (δ, σ) are the coordinates of the image point, V is the image distance, that is, the distance from the imaging plane to the array plane, η is the object selectivity parameter, and different values ​​are selected according to the characteristics of the imaging system. m and n are the serial numbers of the array unit in the x and y directions, respectively. is the wave number, λ is the wavelength, and the symbol ∑ represents the summation operation.

[0056] Furthermore, the method of the present invention can be applied to different imaging systems by selecting different values ​​of the parameter η. Specifically:

[0057] When η = 1, it is applicable to passive imaging systems, semi-active imaging systems, and conventional phased array systems;

[0058] When η=2 is selected, it is applicable to active holographic imaging systems and synthetic aperture imaging systems.

[0059] Furthermore, the method of the present invention comprises the following steps:

[0060] Step 1: Amplitude weighting of array element signals to reduce sidelobe levels;

[0061] Step 2: Perform focusing phase weighting on the array unit signal to achieve imaging focusing;

[0062] Step 3: Perform curved array phase compensation on the array unit signal to improve imaging performance;

[0063] Step 4: Perform beam scanning phase weighting on the array unit signal to adjust the central viewing direction of the imaging system;

[0064] Step 5: Use efficient parallel algorithms to quickly process the array unit signals;

[0065] Step 6: Calculate the image field coordinates and perform coordinate inversion on the image field to obtain the position of the real target.

[0066] Furthermore, the amplitude weighting method in step 1 of the method of the present invention includes but is not limited to uniform distribution, cosine weighting, Hamming window, Taylor distribution, Chebyshev distribution and mixed weighting method.

[0067] Furthermore, in step 2 of the method of the present invention, focusing phase weighting is performed on the array unit signal to achieve imaging focusing, wherein:

[0068] The formula for calculating the focus phase of autofocus phase weighting is:

[0069]

[0070] Where R is the target slant range, that is, the distance from the target to the center of the array;

[0071] The formula for calculating the focus phase of zoom or fixed focus phase weighting is:

[0072]

[0073] Among them, F is the focal length, V is the image distance, that is, the distance from the imaging plane to the plane where the receiving array is located, and F <U、F<V。

[0074] Furthermore, in step 3 of the method of the present invention, curved array phase compensation is performed on the array unit signal to improve the imaging performance, wherein:

[0075] The calculation formula of the array unit phase compensation coefficient is:

[0076]

[0077] in, Indicates the distance error between the curved array unit and the ideal array plane. The ideal array plane refers to the plane passing through the center of the curved array and perpendicular to the normal direction of the curved array.

[0078] Furthermore, the scanning phase weighting in step 4 of the method of the present invention adjusts the central viewing direction of the imaging system, and the phase calculation formula of the scanning phase weighting is:

[0079]

[0080] in: are the phase differences between adjacent array units in the x and y directions, respectively. Their calculation formulas are:

[0081]

[0082]

[0083] Where: Δ x is the array element spacing in the x direction, Δ y is the array element spacing in the y direction, θ ζ ,θ ξ The scanning angle coordinates in the x and y directions when the central viewing direction points to the source coordinates (ζ, ξ) are calculated as follows:

[0084]

[0085]

[0086] Where: U is the object distance, that is, the distance from the target plane to the array plane.

[0087] Furthermore, in step 5 of the method of the present invention, an efficient parallel algorithm is used to perform rapid imaging processing on the array unit signal; the efficient parallel algorithm includes two-dimensional or three-dimensional FFT, IFFT, non-uniform FFT, and sparse FFT, and its calculation formula is:

[0088]

[0089] in: is the image field, the symbol F represents the efficient parallel algorithm function, is the signal received by the array, A is the array amplitude weighting coefficient, φ F is the array focusing phase weighting coefficient, φ C is the array phase compensation coefficient, φ S is the array scanning phase weighting coefficient;

[0090] The spatial spectrum ω corresponding to the above image field calculation results δ 、ω σ The value range is: δ ∈[0,2π],ω σ ∈[0,2π], after fftshift operation, ω δ 、ω σThe value range is transformed into: ω δ ∈[-π,π],ω σ ∈[-π,π], the image at this time is consistent with the actual distribution:

[0091]

[0092] Furthermore, step six of the method of the present invention includes: performing coordinate calculation on the image field obtained by the efficient parallel algorithm, and performing coordinate inversion on the image field to obtain the position of the real target; wherein:

[0093] For efficient parallel algorithms such as IFFT, the image field scanning angle coordinate calculation formula is:

[0094]

[0095]

[0096] For efficient parallel algorithms such as FFT, the image field scanning angle coordinate calculation formula is:

[0097]

[0098]

[0099] The rectangular coordinate calculation formula of the image is:

[0100] δ=Vtanθ δ ,

[0101] σ=Vtanθ σ ;

[0102] The coordinate inversion calculation formula of the real target is:

[0103]

[0104]

[0105] Furthermore, in the method of the present invention, the spacing between the transmitting and receiving antennas satisfies: To avoid imaging aliasing.

[0106] In addition, the curved array rapid imaging method of the present invention can also be used for long-distance imaging, including: selecting U = ∞, then φ F =0, the simplified formula applicable to long-distance imaging is:

[0107]

[0108] The image field is calculated using the above-mentioned efficient parallel algorithm, and the target distribution within a wide viewing angle range is obtained through a single operation.

[0109] Note: The parameters in the above formulas with subscripts mn refer specifically to the data of the mth and nth units and are applicable to discrete systems; those without subscripts mn represent the data of the entire array, are not limited to a certain unit, and are applicable to continuous systems; the two are the difference between individual and overall.

[0110] At the same time, the present invention also relates to the application of the above method in the fields of optical imaging, microwave imaging, radar detection, sonar, ultrasonic imaging, as well as acoustic, optical, and electrical target detection, imaging recognition, and wireless communication.

[0111] In summary, the curved array rapid imaging method of the present invention has the following advantages:

[0112] 1) Created a fast imaging method suitable for curved arrays

[0113] The present invention realizes a low-cost, fast curved array imaging, the computational complexity of which is much lower than that of active holographic imaging system, digital beam synthesis system and traditional synthetic aperture system, which can greatly save hardware resources and improve imaging speed.

[0114] 2) Created a curved array imaging method that is compatible with both passive and active imaging

[0115] By adopting the method of the present invention, passive imaging technology can be used to achieve ultra-fast scanning of the target. When a suspicious object is found, active imaging technology can be used to observe the details of the object in detail. The two imaging methods can share a signal processing system, thereby greatly reducing hardware costs, improving scanning speed, and providing great convenience for practical applications.

[0116] In addition, the method of the present invention has good application prospects and can be widely used in the fields of target detection and wireless communication technology using sound, light, electricity, etc. as media. When the detection medium is electromagnetic waves, this technology is suitable for microwave imaging, radar detection, wireless communication, synthetic aperture radar, and inverse synthetic aperture radar; when the detection medium is sound waves or ultrasonic waves, this technology is suitable for sonar, ultrasonic imaging, and synthetic aperture sonar; when the detection medium is light, this technology is suitable for optical imaging and synthetic aperture optical imaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0117] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following is a brief introduction to the drawings required for use in describing the embodiments of the present invention. Obviously, the following drawings are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0118] Figure 1 Schematic diagram of the imaging system coordinate system of the curved array imaging method of the present invention.

[0119] Figure 2 This is an algorithm block diagram of the curved array imaging method of the present invention.

[0120] Figure 3 The following are the simulation results of curved array imaging using the imaging method of the present invention, where: (a) is the electromagnetic simulation model, and (b) is the curved array imaging result. DETAILED DESCRIPTION

[0121] To make the objectives, technical solutions, and advantages of the present invention more clearly apparent, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The present invention may also be implemented or applied through different specific implementation methods, and the details in this specification may be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0122] At the same time, it should be understood that the scope of protection of the present invention is not limited to the specific embodiments described below; it should also be understood that the terms used in the embodiments of the present invention are for describing specific embodiments rather than for limiting the scope of protection of the present invention.

[0123] Example 1: A method for rapid imaging of a curved array (see attached Figure 1-2 This method is based on the principle of lens imaging and combines electromagnetic field theory. According to the target signal received by the antenna array, the amplitude and phase weighting of the unit signal are weighted, and an efficient parallel algorithm is used to obtain the image field distribution corresponding to the target. The specific algorithm is as follows:

[0124]

[0125] Where: j is the imaginary unit, e is Euler's constant, is the image field distribution, is the target signal received by the array unit, A mn is the array element amplitude weighting coefficient, is the array unit focusing phase weighting coefficient, is the array unit phase compensation coefficient, is the array unit scanning phase weighting coefficient, M is the number of array units in the x direction, N is the number of array units in the y direction, (x m ,y n) are the coordinates of the array elements, (δ, σ) are the coordinates of the image point, V is the image distance, that is, the distance from the imaging plane to the array plane, η is the object selectivity parameter, and different values ​​are selected according to the characteristics of the imaging system (when η = 1, it is suitable for passive imaging systems, semi-active imaging systems, and conventional phased array systems; when η = 2, it is suitable for active holographic imaging systems and synthetic aperture imaging systems), m and n are the serial numbers of the array elements in the x and y directions, respectively. is the wave number, λ is the wavelength, and the symbol ∑ represents the summation operation.

[0126] Specifically, the imaging method includes the following steps:

[0127] Step 1: Amplitude weighting of array element signals to reduce sidelobe levels;

[0128] Amplitude weighting methods include, but are not limited to, uniform distribution, cosine weighting, Hamming window, Taylor distribution, Chebyshev distribution, and mixed weighting methods.

[0129] Step 2: Perform focusing phase weighting on the array unit signal to achieve imaging focusing;

[0130] Among them: The calculation formula of the autofocus phase weighted focus phase is:

[0131]

[0132] Where R is the target slant range, that is, the distance from the target to the center of the array;

[0133] The formula for calculating the focus phase of zoom or fixed focus phase weighting is:

[0134]

[0135] Among them, F is the focal length, V is the image distance, that is, the distance from the imaging plane to the plane where the receiving array is located, and F <U、F<V。

[0136] Step 3: Perform curved array phase compensation on the array unit signal to improve imaging performance;

[0137] The calculation formula of the array unit phase compensation coefficient is:

[0138]

[0139] in, Indicates the distance error between the curved array unit and the ideal array plane. The ideal array plane refers to the plane passing through the center of the curved array and perpendicular to the normal direction of the curved array.

[0140] Step 4: Perform beam scanning phase weighting on the array unit signal to adjust the central viewing direction of the imaging system;

[0141] The phase calculation formula of the scanning phase weight is:

[0142]

[0143] in: are the phase differences between adjacent array units in the x and y directions, respectively. Their calculation formulas are:

[0144]

[0145]

[0146] Where: Δ x is the array element spacing in the x direction, Δ y is the array element spacing in the y direction, θ ζ ,θ ξ The scanning angle coordinates in the x and y directions when the central viewing direction points to the source coordinates (ζ, ξ) are calculated as follows:

[0147]

[0148]

[0149] Where: U is the object distance, that is, the distance from the target plane to the array plane.

[0150] Step 5: Use efficient parallel algorithms to quickly process the array unit signals;

[0151] The efficient parallel algorithm includes two-dimensional or three-dimensional FFT, IFFT, non-uniform FFT, and sparse FFT. Its calculation formula is:

[0152]

[0153] in: is the image field, symbol represents an efficient parallel algorithm function, is the signal received by the array, A is the array amplitude weighting coefficient, φ F is the array focusing phase weighting coefficient, φ C is the array phase compensation coefficient, φ S is the array scanning phase weighting coefficient;

[0154] The spatial spectrum ω corresponding to the above image field calculation results δ 、ω σ The value range is: δ ∈[0,2π],ω σ ∈[0,2π], after fftshift operation, ω δ 、ωσ The value range is transformed into: ω δ ∈[-π,π],ω σ ∈[-π,π], the image at this time is consistent with the actual distribution:

[0155]

[0156] Step 6: Calculate the image field coordinates and perform coordinate inversion on the image field to obtain the position of the real target;

[0157] Among them: For the efficient parallel algorithm of IFFT type, the calculation formula of the image field scanning angle coordinate is:

[0158]

[0159]

[0160] For efficient parallel algorithms such as FFT, the image field scanning angle coordinate calculation formula is:

[0161]

[0162]

[0163] The rectangular coordinate calculation formula of the image is:

[0164] δ=Vtanθ δ ,

[0165] σ=Vtanθ σ ;

[0166] The coordinate inversion calculation formula of the real target is:

[0167]

[0168]

[0169] In addition, the spacing between the transmitting and receiving antennas in this imaging method satisfies: To avoid imaging aliasing.

[0170] Example 2: Imaging effect verification test of this imaging method (method of Example 1)

[0171] Test conditions: operating frequency 10 GHz, array is a hemispherical array with a radius of 1 m, unit spacing is half a wavelength, the target is a "V" shaped metal object, see attached Figure 3 (a) During the test, a plane wave was used to illuminate a V-shaped metal object, and the field distribution of the array unit was calculated. Then, the method of the present invention was used to perform curved array imaging. The imaging results are shown in the attached figure. Figure 3 (b).

[0172] Example 3: A method for rapid imaging of a curved array, which is used for long-distance imaging, comprising: selecting U = ∞, then φ F =0, the simplified formula applicable to long-distance imaging is:

[0173]

[0174] The image field is calculated using the efficient parallel algorithm in the method of Example 1, and the distribution of all targets within a wide viewing angle can be obtained through a single operation.

[0175] The various embodiments of the present invention are described in a progressive manner. Each embodiment focuses on the differences from other embodiments, and the same or similar parts between the various embodiments can be referred to in detail.

[0176] The foregoing is merely an embodiment of the present invention and is not intended to limit the present invention. It will be apparent to those skilled in the art that various modifications and variations of the present invention are possible. Any modifications, substitutions, etc. made within the spirit and principles of the present invention are intended to be included within the scope of the claims of the present invention.

Claims

1. A method for rapid imaging of a curved array, characterized in that: The method is based on the principle of lens imaging and electromagnetic field theory. According to the target signal received by the antenna array, the amplitude and phase weighting of the unit signal are weighted, and an efficient parallel algorithm is used to obtain the image field distribution corresponding to the target. The specific algorithm is as follows: ； in: j is the imaginary unit, e is Euler's constant, is the image field distribution, is the target signal received by the array unit, A mn is the array element amplitude weighting coefficient, is the array unit focusing phase weighting coefficient, is the array unit phase compensation coefficient, Scanning phase weighting coefficients for array elements, M is the number of array elements in the x direction, N is the number of array elements in the y direction, ( x m ，y n ) is the coordinate of the array element, ( δ, σ ) are the coordinates of the image point, V is the image distance, i.e. the distance from the imaging plane to the array plane, η is the object selectivity parameter, which is selected according to the characteristics of the imaging system, m and n are the numbers of the array units in the x and y directions, respectively. is the wave number, λ is the wavelength, and the symbol ∑ represents the summation operation; The method can be applied to different imaging systems by selecting different parameter η values; The method comprises the following steps: Step 1: Calculate the array element amplitude weighting coefficient A mn , amplitude weighting is performed on the array element signals to reduce the sidelobe level; Step 2: Calculate the array unit focusing phase weighting coefficient , performing focusing phase weighting on the array unit signal to achieve imaging focusing; Step 3: Calculate the phase compensation coefficient of the array element , perform curved array phase compensation on the array unit signal to improve the imaging performance, where: The calculation formula of the array unit phase compensation coefficient is: ； in, Represents the distance error between the curved array unit and the ideal array plane, where the ideal array plane is a plane passing through the center of the curved array and perpendicular to the normal direction of the curved array; Step 4: Calculate the array unit scanning phase weighting coefficient , performing beam scanning phase weighting on the array unit signal to adjust the central viewing direction of the imaging system; Step 5: Use efficient parallel algorithms to quickly process the array unit signals; Step 6: Calculate the image field coordinates and perform coordinate inversion on the image field to obtain the position of the real target.

2. The method according to claim 1, characterized in that In the method: When η = 1, it is applicable to passive imaging systems, semi-active imaging systems, and conventional phased array systems; When η=2 is selected, it is applicable to active holographic imaging systems and synthetic aperture radar systems.

3. The method according to claim 2, characterized in that The amplitude weighting methods described in step 1 include uniform distribution, cosine weighting, Hamming window, Taylor distribution, Chebyshev distribution and mixed weighting methods.

4. The method according to claim 2, characterized in that In step 2, the array unit signal is subjected to focusing phase weighting to achieve imaging focusing, wherein: The formula for calculating the focus phase of autofocus phase weighting is: ； in, R is the target slant range, that is, the distance from the target to the center of the array; The formula for calculating the focus phase of zoom or fixed focus phase weighting is: ； in, F is the focal length, V is the image distance, that is, the distance from the imaging plane to the plane where the receiving array is located, and F < U 、 F < V .

5. The method according to claim 2, characterized in that The scanning phase weighting in step 4 adjusts the central viewing angle direction of the imaging system. The phase calculation formula of the scanning phase weighting is: ； in: are the phase differences between adjacent array units in the x and y directions, respectively. Their calculation formulas are: ， ； in: is the array element spacing in the x direction, is the array element spacing in the y direction, θ ζ ,θ ξ The center view direction points to the source coordinates ( ζ,ξ ) when the scanning angle coordinates in the x and y directions are calculated as follows: Where: U is the object distance, that is, the distance from the target plane to the ideal array plane.

6. The method according to claim 2, characterized in that In step 5, an efficient parallel algorithm is used to perform rapid imaging processing on the array unit signal; the efficient parallel algorithm includes two-dimensional or three-dimensional FFT, IFFT, non-uniform FFT, and sparse FFT, and its calculation formula is: ； in: is the image field, symbol represents an efficient parallel algorithm function, is the target signal received by the array, A is the array amplitude weighting coefficient, is the array focusing phase weighting coefficient, is the array phase compensation coefficient, is the array scanning phase weighting coefficient; The above image field calculation results The corresponding spatial spectrum The value range is: 、 , after fftshift operation, The value range is transformed into: , the image at this time is consistent with the actual distribution: 。 7. The method according to claim 2, characterized in that Step 6 includes: performing coordinate calculation on the image field obtained by the efficient parallel algorithm and performing coordinate inversion on the image field to obtain the position of the real target; wherein: For efficient parallel algorithms such as IFFT, the image field scanning angle coordinate calculation formula is: For efficient parallel algorithms such as FFT, the image field scanning angle coordinate calculation formula is: The rectangular coordinate calculation formula of the image is: The coordinate inversion calculation formula of the real target is:

8. The method according to claim 2, characterized in that Set the antenna spacing to meet the following requirements: 、 , to avoid imaging aliasing.

9. The method according to claim 1, characterized in that The rapid imaging method is used for long-distance imaging, comprising: Select , then , the simplified formula applicable to long-distance imaging is: ； The image field is calculated using the efficient parallel algorithm as claimed in claim 7, and the target distribution within a wide viewing angle range is obtained through a single operation.

10. Application of the method according to any one of claims 1 to 9 in the fields of optical imaging, microwave imaging, radar detection, sonar, ultrasonic imaging, imaging recognition, and wireless communication.

Images