Radar echo image generation method and device, equipment and medium

Abstract

The invention provides a radar echo image generation method and device, equipment and a medium, is used for the technical field of radar scattering echo testing, and can solve the problem of low radar echo accuracy caused by existing clutters. Comprising the following steps: determining a clutter spectrum image, and determining an initial mixed wave two-dimensional image and a mixed wave spectrum image corresponding to the initial mixed wave two-dimensional image; according to an energy value corresponding to the clutter frequency spectrum image, determining a frequency threshold value, and performing zero setting on the clutter frequency spectrum area to obtain a zero-set hybrid wave frequency spectrum image and a corresponding zero-set hybrid wave two-dimensional image; calculating an energy loss value according to the energy values of the target scattering area in the zero-set mixed wave two-dimensional imaging and the initial mixed wave two-dimensional imaging, and determining a target frequency threshold according to the energy loss value, a loss threshold and a frequency threshold; carrying out zero setting on the mixed wave spectrum image to obtain a target spectrum image, and carrying out IFFT (Inverse Fast Fourier Transform) to obtain a target mixed wave two-dimensional image; therefore, the accuracy of the radar echo test is improved.

Description

Technical Field

[0001] This application relates to the field of radar scattering echo testing technology, and in particular to a method, apparatus, device and medium for generating radar echo images. Background Technology

[0002] Radar cross section (RCS) is a core parameter reflecting the electromagnetic scattering characteristics of a target. It is a physical quantity that measures the target's ability to scatter incident radar waves. It can be understood as the target's ability to reflect radar waves back to the radar receiver. It has important reference value for equipment stealth performance evaluation, system design, and target identification. Traditional far-field testing methods are limited by issues such as anechoic chamber size and cost. In contrast, near-field testing, which calculates far-field characteristics through scanning and data post-processing, is not only an efficient and reliable solution, but also effectively overcomes the bottlenecks of space and cost.

[0003] In existing practical near-field RCS tests, in addition to receiving the target echo signal, the system inevitably introduces environmental interference clutter, which will directly affect the radar imaging results and reduce the accuracy of RCS tests.

[0004] Therefore, existing methods for generating radar echo images suffer from low accuracy. Summary of the Invention

[0005] This application provides a method, apparatus, device, and medium for generating radar echo images, in order to solve the problem that existing radar echo image generation methods have low accuracy.

[0006] In a first aspect, this application provides a method for generating radar echo images, the method comprising: For radar echoes in a pure clutter detection environment, determine the clutter spectrum image, and based on the mixed radar echoes in a target detection environment, determine the initial mixed wave two-dimensional imaging and its corresponding mixed wave spectrum image; Based on the energy value corresponding to the clutter spectrum image, the frequency threshold is determined, and based on the frequency threshold, the clutter spectrum region in the mixed wave spectrum image is zeroed to obtain the zeroed mixed wave spectrum image and its corresponding zeroed mixed wave two-dimensional image. Based on the energy values ​​corresponding to the target scattering region in the zero-mixed wave 2D imaging and the initial mixed wave 2D imaging, respectively, the energy loss value is calculated, and the target frequency threshold is determined based on the energy loss value, the loss threshold, and the frequency threshold. Based on the target frequency threshold, the mixed wave spectrum image is zeroed to obtain the target spectrum image, and then an IFFT transform is performed on the target spectrum image to obtain a two-dimensional image of the target mixed wave.

[0007] In some embodiments of this application, determining the corresponding clutter spectrum image for radar echoes in a pure clutter detection environment includes: For pure clutter detection environments, radar echoes at various azimuth angles are collected to obtain corresponding radar echo data. Then, IFFT transformation is performed on the radar echo data to obtain multiple one-dimensional range images. Based on the one-dimensional distance image, the corresponding imaging region is determined, and the imaging region is divided into grids to obtain multiple imaging grids and the grid center corresponding to each imaging grid. Based on the distance between the antenna phase center of the acquisition antenna and the center of each grid, the corresponding phase compensation value is calculated, and the phase of each grid center is compensated according to the phase compensation value. The signal values ​​at the centers of each compensated grid are accumulated to obtain a two-dimensional image, and an FFT transform is performed on the two-dimensional image to obtain a clutter spectrum image.

[0008] In some embodiments of this application, determining a frequency threshold based on the energy value corresponding to the clutter spectrum image includes: Based on the energy values ​​corresponding to the clutter spectrum image, calculate the corresponding energy mean and energy standard deviation, and obtain the frequency threshold based on the sum of the energy mean and energy standard deviation.

[0009] In some embodiments of this application, based on a frequency threshold, the clutter spectrum region in the mixed wave spectrum image is zeroed out to obtain a zeroed mixed wave spectrum image and its corresponding zeroed mixed wave two-dimensional image, including: Based on the frequency threshold, the frequencies in the mixed wave spectrum image that are greater than the frequency threshold are determined to obtain the clutter spectrum region. All energy values ​​in the clutter spectrum region are then set to zero to obtain the zeroed mixed wave spectrum image. An IFFT transform is performed on the null-set hybrid wave spectrum image to obtain a two-dimensional image of the null-set hybrid wave.

[0010] In some embodiments of this application, the energy loss value is calculated based on the energy values ​​corresponding to the target scattering region in the nulled mixed-wave two-dimensional imaging and the initial mixed-wave two-dimensional imaging, respectively, including: Based on the preset scattering region corresponding to the target detection environment, determine the energy values ​​of the preset scattering region in the initial mixed-wave two-dimensional imaging; By comparing the energy value with the energy threshold, the target energy value that is greater than the energy threshold is obtained, and the target scattering area is determined based on the pixel position corresponding to the target energy value. Based on the energy values ​​corresponding to the target scattering region in the zero-mixed wave 2D imaging and the initial mixed wave 2D imaging, the corresponding zero-total energy value and initial total energy value are determined, and the difference between the zero-total energy value and the initial total energy value is calculated to obtain the energy loss value.

[0011] In some embodiments of this application, determining a target frequency threshold based on energy loss value, a loss threshold, and a frequency threshold includes: Determine whether the energy loss value is greater than the loss threshold; If not, then the frequency threshold is determined to be the target frequency threshold; If so, determine the preset frequency increment, and determine the target frequency threshold based on the preset frequency increment and the frequency threshold.

[0012] In some embodiments of this application, determining a target frequency threshold based on a preset frequency increment and a frequency threshold includes: Based on the sum of the preset frequency increment and the frequency threshold, the incremental frequency threshold is obtained. Based on the incremental frequency threshold, the clutter spectrum region in the mixed wave spectrum image is zeroed out according to the frequency threshold, resulting in a zeroed mixed wave spectrum image and its corresponding zeroed mixed wave two-dimensional imaging. The process continues until the energy loss value is less than the loss threshold. The incremental frequency threshold is determined as the target frequency threshold.

[0013] Secondly, this application provides a radar echo image generation apparatus, the apparatus comprising: The determination module is used to determine the clutter spectrum image for radar echoes in a pure clutter detection environment, and to determine the initial mixed wave two-dimensional imaging and its corresponding mixed wave spectrum image based on the mixed radar echoes in a target detection environment. The nulling module is used to determine the frequency threshold based on the energy value corresponding to the clutter spectrum image, and to nullify the clutter spectrum region in the mixed wave spectrum image according to the frequency threshold, so as to obtain the nulled mixed wave spectrum image and its corresponding nulled mixed wave two-dimensional image. The calculation module is used to calculate the energy loss value based on the energy values ​​corresponding to the target scattering region in the nulled mixed wave two-dimensional imaging and the initial mixed wave two-dimensional imaging, and to determine the target frequency threshold based on the energy loss value, the loss threshold, and the frequency threshold. The transformation module is used to zero out the mixed wave spectrum image according to the target frequency threshold to obtain the target spectrum image, and to perform IFFT transformation on the target spectrum image to obtain the target mixed wave two-dimensional image.

[0014] Thirdly, this application provides a computer device, including: a processor, and a memory communicatively connected to the processor; The memory stores instructions that the computer executes; The processor executes computer execution instructions stored in memory to implement the method of this application.

[0015] Fourthly, this application provides a computer-readable storage medium storing program code, which, when executed by a processor, is used to implement the method of this application.

[0016] This application provides a method, apparatus, device, and medium for generating radar echo images. It determines a clutter spectrum image based on radar echoes in a pure clutter detection environment, and determines an initial mixed-wave two-dimensional image and its corresponding mixed-wave spectrum image based on mixed radar echoes in a target detection environment. A frequency threshold is determined based on the energy value corresponding to the clutter spectrum image, and the clutter spectrum region in the mixed-wave spectrum image is zeroed out according to the frequency threshold to obtain a zeroed mixed-wave spectrum image and its corresponding zeroed mixed-wave two-dimensional image. An energy loss value is calculated based on the energy values ​​corresponding to the target scattering region in the zeroed mixed-wave two-dimensional image and the initial mixed-wave two-dimensional image, respectively. A target frequency threshold is determined based on the energy loss value, the loss threshold, and the frequency threshold. The mixed-wave spectrum image is zeroed out according to the target frequency threshold to obtain a target spectrum image, and an IFFT transform is performed on the target spectrum image to obtain a target mixed-wave two-dimensional image.

[0017] Thus, by analyzing radar echoes in a pure clutter detection environment, a clutter spectrum image is determined, enabling precise capture of the energy distribution characteristics of pure clutter in the frequency domain, such as the frequency range where clutter energy is concentrated. This facilitates subsequent differentiation between clutter and target spectra, avoiding false or missed clutter suppression due to a lack of clutter reference. Simultaneously, based on mixed radar echoes in a target detection environment, an initial mixed-wave two-dimensional image and corresponding mixed-wave spectrum image are determined. This acquires complete spatial domain imaging information containing both the target and clutter, facilitating subsequent target scattering region localization, and also provides frequency domain data, achieving dual-dimensional data support in both the spatial and frequency domains. Furthermore, based on the energy values ​​of the clutter spectrum image, a frequency threshold is determined, and the clutter spectrum region of the mixed-wave spectrum image is set to zero, thereby… Based on predetermined clutter characteristics, the energy of the clutter signal is directly cut off in the frequency domain, initially filtering out most of the clutter interference in the mixed wave. Simultaneously, a two-dimensional image of the zeroed mixed wave is obtained, allowing the clutter suppression effect to be visually presented in the spatial domain, such as a significant reduction in background clutter brightness. This enables subsequent verification of target energy loss based on the preliminarily optimized imaging samples. Furthermore, by selectively filtering clutter in the spatial frequency domain based on the differences in scattering characteristics between the target and clutter, the imaging clarity can be effectively improved. Moreover, only one target-free clutter test is added before the formal test, making the operation simple and easy to implement in engineering. This lays the foundation for improving the performance of existing near-field RCS testing systems, has application value, reduces clutter interference, and improves the accuracy of radar echo testing. Attached Figure Description

[0018] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0019] Figure 1 A schematic flowchart illustrating a method for generating radar echo images provided in an embodiment of this application; Figure 2 A flowchart illustrating another method for generating radar echo images provided in this application embodiment; Figure 3 A schematic diagram of a radar echo image generation device provided in an embodiment of this application; Figure 4 This is a structural block diagram of an apparatus for performing a radar echo image generation method according to an embodiment of this application. Detailed Implementation

[0020] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0021] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0022] Figure 1 This is a schematic flowchart illustrating a method for generating radar echo images provided in an embodiment of this application. Figure 1 As shown, the method for generating a radar echo image may include the following steps: S110. For radar echoes in a pure clutter detection environment, determine the clutter spectrum image, and based on the mixed radar echoes in a target detection environment, determine the initial mixed wave two-dimensional imaging and its corresponding mixed wave spectrum image.

[0023] Among them, the pure clutter detection environment refers to the near-field RCS test scenario in which there is no test target and only the inherent clutter of the environment exists. That is, the radar detection scenario in which only clutter signals exist and there are no echoes of the test target. It is a test environment specifically set up to obtain pure clutter characteristic benchmarks. In the near-field RCS test scenario, the test target refers to the specific physical object placed in the test environment whose radar cross section needs to be accurately measured and analyzed, such as the object to be detected, such as aircraft, ships, and vehicles, so as to determine the scattering capability of the target object through the radar echo.

[0024] Clutter spectrum image refers to the visualization of pure clutter in the spatial frequency domain after a series of signal processing steps are performed on the collected pure clutter echo data in a pure clutter detection environment. It is also the energy distribution spectrum of the clutter signal in the spatial frequency domain. It has the characteristics of rich high-frequency components and wide energy distribution range. The horizontal axis is usually the azimuth spatial frequency, the vertical axis is the distance unit, and the pixel gray level represents the clutter energy intensity at the corresponding frequency-distance position.

[0025] The target detection environment refers to a near-field RCS test scenario in which a test target is placed and both target echo and environmental clutter are present. This allows for the acquisition of the target's scattering characteristics in the actual environment, which is then used to generate target images and extract target spectral characteristics. This environment must maintain completely consistent test parameters (transmitted signal, antenna scanning method, environmental conditions, etc.) with the pure clutter detection environment, with only the addition of a test target (such as a fighter jet model, missile model, etc.) to ensure that the target echo and clutter are collected under the same interference background.

[0026] Hybrid radar echo refers to the superimposed echo data received by the radar system in a target detection environment, which simultaneously contains the target reflection signal and the environmental clutter signal, and fully preserves the temporal and spatial characteristics of the target and clutter.

[0027] Initial mixed-wave 2D imaging refers to a spatial domain visualization image containing superimposed information of the target and clutter, obtained by applying the same signal processing procedure as pure clutter 2D image to mixed radar echoes. Its horizontal axis is the azimuth direction, corresponding to the antenna scanning angle, and the vertical axis is the range direction. The pixel grayscale represents the scattered energy intensity at the corresponding azimuth and range positions. It has the characteristics of relatively concentrated energy in the target area, but is covered by clutter noise and has blurred boundaries. For example, in the imaging of fighter jet models, the fuselage outline is interfered with by background clutter and is difficult to clearly identify.

[0028] A mixed wave spectrum image refers to the energy distribution map of the target and clutter in the spatial frequency domain obtained after performing an FFT (Fast Fourier Transform) on the initial mixed wave two-dimensional image along the azimuth direction. It is the superposition result of the target spectrum and the clutter spectrum. Its horizontal axis is the spatial frequency in the azimuth direction, and the vertical axis is the range cell. The pixel gray level represents the total energy intensity of the corresponding frequency and range position. It has the characteristics of the target spectrum (energy concentration) in the low-frequency narrow band region and the clutter spectrum (energy dispersion) in the high-frequency wide range region. However, the two may overlap in some frequency ranges due to multiple reflections and coupling.

[0029] Therefore, in practical applications, the RCS testing scenario cannot completely eliminate the influence of clutter on the test target. In addition to receiving the target echo signal, the system inevitably introduces environmental interference clutter, which will directly affect the imaging results and reduce the accuracy of RCS testing. Therefore, by acquiring radar echoes in a pure clutter detection environment and a target detection environment with the target, the clutter spectrum image corresponding to the pure clutter and the mixed radar echo corresponding to the target are determined. The initial mixed wave two-dimensional imaging and mixed wave spectrum image corresponding to the target are determined so that the mixed wave spectrum image can be further suppressed and optimized based on the clutter spectrum image, thereby improving the test accuracy and precision.

[0030] S120. Determine the frequency threshold based on the energy value corresponding to the clutter spectrum image, and zero out the clutter spectrum region in the mixed wave spectrum image based on the frequency threshold to obtain the zeroed mixed wave spectrum image and its corresponding zeroed mixed wave two-dimensional image.

[0031] Among them, the energy value refers to the quantified value of the electromagnetic signal intensity corresponding to a specific spatial frequency and distance cell position in a clutter spectrum image or a mixed wave spectrum image. It is usually expressed in the form of power (such as milliwatts) or relative energy (such as normalized decibels). In a clutter spectrum image, the energy value reflects the intensity distribution of pure clutter at different spatial frequencies. The energy in the high-frequency region is dispersed and the overall intensity is relatively high. In a mixed wave spectrum image, the energy value is the result of the superposition of the target signal energy and the clutter signal energy. The low-frequency region is dominated by the target energy, and the high-frequency region is dominated by the clutter energy.

[0032] A frequency threshold is a spatial frequency critical value set based on the statistical characteristics of energy values ​​in a clutter spectrum image to distinguish between clutter and target spectrum regions. It is a quantitative standard for determining whether a certain frequency belongs to the clutter range. For example, if a specific frequency value in the high-frequency band is f0, and f0 is the frequency threshold, then the region in the clutter spectrum image with a frequency higher than f0 is determined to be a clutter region. In order to clearly define the high-frequency clutter region and the low-frequency target region in the mixed wave spectrum image by means of the frequency threshold, thereby distinguishing the spectral superposition region of the target and clutter.

[0033] The clutter spectrum region refers to a specific frequency range in the mixed wave spectrum image where the spatial frequency exceeds the frequency threshold and the energy value mainly comes from clutter. It is the concentrated distribution range of clutter signals in the frequency domain. Its boundary is clearly defined by the frequency threshold. The core feature of this region is that the energy value is mainly contributed by clutter, the target energy accounts for a very low proportion (or there is no target energy), and it is highly matched with the frequency distribution range of clutter in the clutter spectrum image.

[0034] Zeroing refers to the process of setting the energy values ​​of all spatial frequencies and range cells in the mixed wave spectrum image that have been identified as clutter spectrum regions to zero. This means forcibly setting the quantized value of the electromagnetic signal intensity in that region to 0 (or a minimum value close to 0). The zeroing operation only applies to the clutter spectrum region in the frequency domain and does not change the energy value of the target spectrum region. By setting the energy value of the clutter spectrum region to zero, the interference of clutter signals on the target signal is eliminated from the frequency domain. Since only the clutter region is zeroed, the energy value of the low-frequency spectrum region where the target is located remains unchanged, ensuring that key information such as the energy and phase of the target scattering center is not lost. The mixed wave spectrum image after zeroing has been freed from clutter interference, so that a clear two-dimensional image of the target can be generated subsequently.

[0035] A zeroed hybrid spectrum image refers to a new spatial frequency domain map obtained after zeroing the clutter spectrum region in a hybrid spectrum image. It is a visual representation of the frequency domain data after clutter removal.

[0036] Zero-mixed wave 2D imaging refers to performing IFFT (Inverse Fast Fourier Transform) along the azimuth direction on the zero-mixed wave spectrum image to restore the clutter-free data in the frequency domain to a visual image in the spatial domain. It is the final result of target imaging after clutter removal in near-field RCS testing.

[0037] Based on this, by using the clutter spectrum image determined in a pure clutter environment, the corresponding frequency threshold is determined according to the clutter distribution characteristics. The region above the frequency threshold can be understood as the main distribution range of clutter. In order to determine the clutter spectrum region in the mixed wave spectrum image according to the frequency threshold, and set it to zero, the interference of clutter signal on the target signal is eliminated from the frequency domain. Since only the clutter region is set to zero, the energy value of the low frequency spectrum region where the target is located remains unchanged, ensuring that key information such as the energy and phase of the target scattering center is not lost. The corresponding zeroed mixed wave spectrum image and its corresponding zeroed mixed wave two-dimensional imaging are obtained, so as to further generate the final output target image.

[0038] S130. Calculate the energy loss value based on the energy values ​​corresponding to the target scattering region in the zero-mixed wave two-dimensional imaging and the initial mixed wave two-dimensional imaging, and determine the target frequency threshold based on the energy loss value, the loss threshold, and the frequency threshold.

[0039] The target scattering region refers to the specific spatial region where the electromagnetic scattering signal of the test target itself is concentrated in the initial mixed wave two-dimensional imaging or the zero mixed wave two-dimensional imaging. It is the core region reflecting the scattering characteristics of the target. It is usually a continuous region in the imaging where the energy value is significantly higher than the background clutter. It is highly matched with the physical structure of the target. For example, in the imaging of fighter jet models, the target scattering region corresponds to the spatial position of physical structures such as fuselage, wings, and tail fins; in the imaging of component-level targets, it corresponds to the position of key scattering components such as radomes and engine exhaust nozzles.

[0040] The energy loss value refers to the difference in energy value of the target scattering region in the nulled mixed-wave 2D imaging and the initial mixed-wave 2D imaging. It is usually expressed as an absolute energy difference or a relative energy loss percentage. For example, if the energy value of the target scattering region in the nulled mixed-wave 2D imaging is A and the energy value in the initial mixed-wave 2D imaging is B, then the corresponding energy loss value can be AB.

[0041] The loss threshold is a pre-set critical value used to determine whether the energy loss of a target is acceptable. It is usually expressed in decibels (dB) and is a critical standard for measuring whether clutter suppression operations have exceeded the limit. For example, the loss threshold can be Q. If the energy loss value is greater than the loss threshold Q, it indicates that the energy difference between the current target scattering region in the zero-mixed wave 2D imaging and the initial mixed wave 2D imaging exceeds the critical value, that is, the energy loss value is large and does not meet the actual requirements. In practical applications, the loss threshold can generally be 1 dB, that is, the energy loss value is required to not exceed 1 dB.

[0042] The target frequency threshold refers to the spatial frequency critical value that can simultaneously satisfy effective clutter suppression and target energy loss compliance after iterative optimization of the initially set frequency threshold based on the constraint that energy loss value ≤ loss threshold. In practical applications, if the initial frequency threshold is too low, i.e. the clutter suppression range is too large, it will lead to excessive energy loss. In this case, the target frequency threshold needs to be increased to narrow the clutter suppression range and reduce the false zeroing of the target spectrum. If the initial threshold is too high, i.e. the clutter suppression is incomplete, but the energy loss meets the standard, the threshold can be appropriately reduced to expand the clutter suppression range and improve the clutter filtering effect. Finally, the optimal critical value that balances both is obtained, i.e., the target frequency threshold, so that clutter can be zeroed based on this threshold, ensuring that most clutter is removed without causing excessive loss of target energy.

[0043] Based on this, by determining a specific spatial region where the electromagnetic scattering signal of the test target is concentrated, i.e., the target scattering region, the energy loss value is calculated according to the energy values ​​corresponding to the target scattering region in the zeroed mixed-wave two-dimensional imaging and the initial mixed-wave two-dimensional imaging, respectively. The energy loss value can reflect whether the determination of the clutter spectrum region meets the actual requirements. That is, after zeroing the clutter spectrum region, whether the energy loss corresponding to the target scattering region is within the preset loss threshold range. If it is, it indicates that the scattered echo of the test target meets the requirements and the clutter spectrum region is correct; if it is not, it indicates that the current determination of the clutter spectrum region is incorrect, which has caused part of the radar echo of the test target to be zeroed, affecting the scattering of the test target. It is necessary to redetermine the corresponding frequency threshold in order to determine the correct clutter spectrum region, so as to achieve the correct removal of clutter.

[0044] S140. Based on the target frequency threshold, the mixed wave spectrum image is zeroed to obtain the target spectrum image, and the target spectrum image is subjected to IFFT transformation to obtain the target mixed wave two-dimensional image.

[0045] The target spectrum image refers to the frequency domain image obtained by zeroing the clutter spectrum region (i.e., the region with frequency exceeding the target frequency threshold) in the mixed wave spectrum image based on the target frequency threshold. This retains only the target spectrum information, thus completely preserving the energy value of the target spectrum region with frequency below the target frequency threshold and forcibly zeroing the energy value of the clutter spectrum region with frequency above the target frequency threshold, thereby achieving frequency domain separation between the target spectrum and the clutter spectrum.

[0046] The Inverse Fast Fourier Transform (IFFT) is an efficient mathematical transformation method for converting frequency domain data (such as a target spectral image) into spatial domain data. It is the inverse operation of the FFT (which converts the spatial domain to the frequency domain).

[0047] Two-dimensional imaging of target mixed waves refers to the spatial domain visualization image containing only the electromagnetic scattering information of the target after performing IFFT transformation on the target spectrum image along the azimuth direction. It is the final result of the clutter suppression process in near-field RCS testing. Its background region (original clutter distribution area) has energy close to 0 (no clutter interference), the target region has a clear outline and a clear scattering center, and the energy loss of the main scattering center of the target is ≤ the loss threshold (usually ≤ 1dB).

[0048] Based on this, by determining the target frequency threshold, the regions in the mixed wave spectrum image that are greater than the target frequency threshold are set to zero in order to suppress and optimize clutter scattering, thereby obtaining the target spectrum image. Then, an IFFT transformation is performed on the target spectrum image to obtain a two-dimensional image of the target mixed wave, thus completing the clutter removal for the near-field RCS test of the target.

[0049] Based on the feasible implementation of S110 described above, this application further provides a method for determining the corresponding clutter spectrum image of radar echoes in a pure clutter detection environment, including: For pure clutter detection environments, radar echoes at various azimuth angles are collected to obtain corresponding radar echo data. Then, IFFT transformation is performed on the radar echo data to obtain multiple one-dimensional range images. Based on the one-dimensional distance image, the corresponding imaging region is determined, and the imaging region is divided into grids to obtain multiple imaging grids and the grid center corresponding to each imaging grid. Based on the distance between the antenna phase center of the acquisition antenna and the center of each grid, the corresponding phase compensation value is calculated, and the phase of each grid center is compensated according to the phase compensation value. The signal values ​​at the centers of each compensated grid are accumulated to obtain a two-dimensional image, and an FFT transform is performed on the two-dimensional image to obtain a clutter spectrum image.

[0050] In this context, azimuth refers to the angle between the line connecting the acquisition antenna and the scattering object in the environment and the preset reference direction (such as the central axis of the test anechoic chamber) during near-field RCS testing. It is usually expressed in degrees (°). During the test, the antenna will rotate along a preset trajectory (such as a horizontal circle or an elevation plane). Each rotation at a fixed angle interval (such as 0.1°) corresponds to an azimuth. Radar echo data will be acquired independently at each azimuth, forming a one-to-one correspondence between azimuth and echo data.

[0051] Radar echo data refers to the raw data of electromagnetic signals reflected by scatterers in a pure clutter environment after the antenna emits electromagnetic waves at each azimuth angle. It is usually stored in the form of time-domain sampled values ​​(such as voltage and time series) or frequency-domain sampled values ​​(such as the amplitude or phase of each frequency component of a stepped frequency signal).

[0052] A one-dimensional range profile refers to a one-dimensional image that reflects clutter distribution only in the range dimension after processing radar echo data at a single azimuth angle, such as range windowing, frequency domain zero-padding interpolation, and IFFT transformation. The horizontal axis represents the range (unit: m, corresponding to the straight-line distance between the scatterer and the antenna), and the vertical axis represents the signal amplitude (unit: V or dB, corresponding to the reflection intensity of the scatterer). Each azimuth angle corresponds to a one-dimensional range profile, and each range and amplitude point in the image represents the reflection intensity of the clutter scatterer at a certain range under that azimuth angle.

[0053] The imaging region refers to the spatial range that needs to be constructed for two-dimensional imaging, which is comprehensively determined based on the one-dimensional range images of all azimuth angles. It is usually represented by a rectangular area of ​​range x azimuth angle, such as a range of 0-5m and an azimuth angle of -30° to +30°. It is the spatial boundary for subsequent grid division and two-dimensional imaging. It covers all range segments in the one-dimensional range images where clutter signals exist, as well as the azimuth angle range of all acquired echo data, to ensure that the imaging region completely contains all effective scattering information of the pure clutter environment.

[0054] An imaging grid refers to a small spatial unit that is uniformly divided within the imaging area according to a preset spatial resolution (such as a distance resolution of 0.01m and an azimuth resolution of 0.1°). Each imaging grid corresponds to a unique small cubic space within the imaging area (usually simplified to a two-dimensional planar unit in near-field testing), and is the pixel-level basic unit for constructing two-dimensional imaging.

[0055] The grid center refers to the geometric center of each imaging grid, which is the reference point representing the spatial position of that grid.

[0056] A data acquisition antenna is an electromagnetic device used in near-field RCS testing to transmit electromagnetic wave signals and receive clutter reflection echo signals. It is usually a microwave antenna, such as a horn antenna or a phased array antenna.

[0057] The antenna phase center refers to the equivalent electromagnetic signal phase reference point when collecting electromagnetic waves emitted or received by the antenna. That is, the electromagnetic waves radiated by the antenna can be regarded as originating from this point, and the received electromagnetic waves can also be regarded as converging at this point. It is the only reference point for calculating the distance from the antenna to the scatterer.

[0058] Phase compensation value refers to the phase correction amount calculated to correct the electromagnetic wave phase delay caused by the distance difference between the antenna phase center and the grid center. It is usually measured in radians (rad) and is used to eliminate phase distortion caused by distance difference. In practical applications, the distance between different grid centers and the antenna is different, and the phase delay of electromagnetic waves propagating to the antenna is different. If compensation is not made, the signals of the same scatterer will not be coherently superimposed due to phase disorder at different azimuth angles, resulting in blurred two-dimensional imaging.

[0059] The signal value refers to the quantized value of the electromagnetic signal intensity at the center of the corresponding grid at each azimuth angle after phase compensation. It is usually expressed in the form of complex values ​​(including amplitude and phase information). The amplitude reflects the signal intensity, and the phase reflects the phase state of the signal. The total signal value obtained by summing the signal values ​​at all azimuth angles at the same grid center is the pixel gray value of that grid in two-dimensional imaging, which directly determines the brightness of the two-dimensional imaging. The larger the signal value, the brighter the pixel, and the stronger the clutter.

[0060] Two-dimensional imaging refers to the coherent summation of the compensated signal values ​​at all azimuth angles from the same imaging grid center, resulting in a two-dimensional visualization image in the range and azimuth directions. The horizontal axis represents the azimuth angle (corresponding to the antenna scanning direction), and the vertical axis represents the range (corresponding to the distance between the scatterer and the antenna). The pixel grayscale (or color depth) represents the clutter scattering intensity at that range and azimuth angle. The darker the grayscale, the stronger the clutter, fully presenting the distribution characteristics of clutter at different ranges and azimuth angles.

[0061] The Fast Fourier Transform (FFT) is an efficient mathematical transformation method for converting azimuth spatial domain data of two-dimensional imaging into azimuth spatial frequency domain data.

[0062] Based on this, radar echoes at various azimuth angles are collected in a pure clutter environment. The radar echoes are then preprocessed, such as windowing in the azimuth and range directions, and zero-padding in the frequency domain to achieve interpolation. The preprocessed radar echo data is then subjected to IFFT transformation to obtain multiple one-dimensional range images. Phase compensation is achieved by dividing the one-dimensional range images into grids, and the signal values ​​are accumulated to obtain two-dimensional images. Finally, FFT transformation is performed on the two-dimensional images to obtain clutter spectrum images.

[0063] Based on the feasible implementation of S120 described above, this application further provides a method for determining a frequency threshold based on the energy value corresponding to the clutter spectrum image, including: Based on the energy values ​​corresponding to the clutter spectrum image, calculate the corresponding energy mean and energy standard deviation, and obtain the frequency threshold based on the sum of the energy mean and energy standard deviation.

[0064] Among them, the energy mean refers to the value obtained by arithmetically averaging the clutter energy values ​​of all effective frequency units (or within a specified frequency range) in the clutter spectrum image, thus reflecting the concentration trend of clutter energy. The energy mean can directly quantify the average interference intensity of the clutter environment. If the mean is high, it indicates that the clutter is strong overall, such as dense signal scattering from the anechoic chamber support or walls; if the mean is low, it indicates that the clutter is weak overall, such as an optimized low-clutter anechoic chamber environment, so as to identify significant clutter areas and thus achieve the suppression and optimization of clutter areas.

[0065] The energy standard deviation is the standard deviation corresponding to the energy value. It refers to the value obtained by statistically calculating the degree of deviation between the clutter energy value and the energy mean of all effective frequency units in the clutter spectrum image. It reflects the dispersion trend of clutter energy. The larger the standard deviation, the more dispersed the clutter energy is in different frequency units, such as some frequency units having extremely high energy and some having extremely low energy. The smaller the standard deviation, the more uniform the clutter energy is distributed, and the energy of each frequency unit is close to the mean.

[0066] Based on this, the mean energy and standard deviation of energy can reflect the distribution characteristics of clutter, thereby calculating the corresponding frequency threshold, so as to divide the corresponding clutter spectrum region according to the frequency threshold.

[0067] Based on the feasible implementation of S120 described above, this application further provides a method for zeroing out clutter spectral regions in a mixed wave spectral image according to a frequency threshold, to obtain a zeroed mixed wave spectral image and its corresponding zeroed mixed wave two-dimensional image, including: Based on the frequency threshold, the frequencies in the mixed wave spectrum image that are greater than the frequency threshold are determined to obtain the clutter spectrum region. All energy values ​​in the clutter spectrum region are then set to zero to obtain the zeroed mixed wave spectrum image. An IFFT transform is performed on the null-set hybrid wave spectrum image to obtain a two-dimensional image of the null-set hybrid wave.

[0068] Based on this, by using a frequency threshold, the region in the mixed wave spectrum image that is greater than the frequency threshold is determined, which is the main distribution area of ​​clutter, i.e., the clutter spectrum region. Then, the energy value in the clutter spectrum region is set to zero in order to determine the zeroed mixed wave spectrum image and the zeroed mixed wave two-dimensional imaging.

[0069] Based on the feasible implementation of S130 described above, this application further provides a method for calculating energy loss values ​​based on the energy values ​​corresponding to the target scattering region in nulled mixed-wave two-dimensional imaging and initial mixed-wave two-dimensional imaging, including: Based on the preset scattering region corresponding to the target detection environment, determine the energy values ​​of the preset scattering region in the initial mixed-wave two-dimensional imaging; By comparing the energy value with the energy threshold, the target energy value that is greater than the energy threshold is obtained, and the target scattering area is determined based on the pixel position corresponding to the target energy value. Based on the energy values ​​corresponding to the target scattering region in the zero-mixed wave 2D imaging and the initial mixed wave 2D imaging, the corresponding zero-total energy value and initial total energy value are determined, and the difference between the zero-total energy value and the initial total energy value is calculated to obtain the energy loss value.

[0070] The preset scattering region refers to a spatial region that is pre-defined in the initial mixed-wave two-dimensional imaging based on prior information about the target detection environment, such as the target's physical size, placement position, and typical scattering characteristics. This region is likely to contain the target's scattering signal. It is usually represented by a rectangular region of distance range × azimuth angle range, or an irregular region that matches the target's contour. For example, if the test target is a fighter jet model with a length of 1m and placed 3-4m away from the antenna, the preset scattering region can be defined as a rectangular region of 3-4m distance and azimuth angle of -5° to +5°. This region needs to cover the entire spatial range in which the target may generate scattering signals, while minimizing irrelevant background areas.

[0071] The energy threshold is a predetermined critical threshold used to determine whether a region is the main coverage area of ​​a detection target based on its energy value. This allows for the selection of pixels with energy values ​​greater than the threshold, which represent the distribution points corresponding to the detection target. This integrates scattered suspected target pixels into a continuous target scattering region, thereby determining the scattering region corresponding to the detection target.

[0072] The target energy value refers to the specific energy value of a pixel that exceeds the energy threshold within the preset scattering area of ​​the initial mixed-wave 2D imaging. For example, if the energy of a pixel in the preset scattering area is 35dB (exceeding the energy threshold of 30dB), then 35dB is a target energy value.

[0073] Pixel position refers to the spatial coordinates of each pixel in two-dimensional imaging, used to identify the specific location of the pixel in the imaging plane.

[0074] The initial total energy value refers to the sum of the energy values ​​of all pixels in the target scattering area (including the target energy value and a small amount of clutter energy values ​​that were not excluded by the threshold) in the initial mixed-wave two-dimensional imaging. The initial total energy value is obtained by summing the energy values ​​of each pixel in the target scattering area (such as 35dB, 32dB, 30.5dB, etc.) (e.g., assuming a total of 100 pixels, the sum is 3100dB).

[0075] The zero-value total energy refers to the sum of all energy values ​​corresponding to the pixel positions that are exactly the same as the target scattering region in the initial mixed-wave 2D imaging.

[0076] Based on this, the target scattering region is determined by identifying the pixel positions corresponding to energy values ​​greater than the energy threshold within the preset scattering region. Then, based on the energy values ​​corresponding to the target scattering region in the zero-mixed wave 2D imaging and the initial mixed wave 2D imaging, the corresponding zero-total energy value and the initial total energy value are determined, thereby calculating the energy difference and obtaining the energy loss value.

[0077] Based on the feasible implementation of S130 described above, this application further provides a method for determining a target frequency threshold based on energy loss value, loss threshold, and frequency threshold, including: Determine whether the energy loss value is greater than the loss threshold; If not, then the frequency threshold is determined to be the target frequency threshold; If so, determine the preset frequency increment, and determine the target frequency threshold based on the preset frequency increment and the frequency threshold.

[0078] Among them, the preset frequency increment refers to the fixed frequency increment value of the frequency boundary used to adjust the clutter to zero, i.e., the frequency threshold, which is consistent with the frequency axis of the spatial frequency domain, such as Hz, kHz, etc. The preset frequency increment is used to adjust the current frequency threshold when the energy loss value is greater than the loss threshold, so that the energy loss value obtained according to the adjusted frequency threshold can be less than the loss threshold.

[0079] Based on this, by comparing the energy loss value and loss threshold of the target scattering region in the zero-mixed wave two-dimensional imaging and the initial mixed wave two-dimensional imaging, it is determined whether the frequency threshold needs to be further adjusted according to the comparison results, thereby obtaining the target frequency threshold.

[0080] Based on the feasible implementation of S130 described above, this application further provides a method for determining a target frequency threshold based on a preset frequency increment and a frequency threshold, including: Based on the sum of the preset frequency increment and the frequency threshold, the incremental frequency threshold is obtained. Based on the incremental frequency threshold, the clutter spectrum region in the mixed wave spectrum image is zeroed out according to the frequency threshold, resulting in a zeroed mixed wave spectrum image and its corresponding zeroed mixed wave two-dimensional imaging. The process continues until the energy loss value is less than the loss threshold. The incremental frequency threshold is determined as the target frequency threshold.

[0081] The incremental frequency threshold refers to the new frequency threshold calculated by the sum of the initial frequency threshold and the preset frequency increment during the adjustment of the frequency threshold for clutter suppression. It is the critical threshold used to define the range for zeroing clutter after each iteration. It can be understood as a gradual correction value to the initial frequency threshold. For example, if the initial frequency threshold is 600Hz and the preset increment is 50Hz, it will be 650Hz after the first increment and 700Hz after the second increment.

[0082] Based on this, by increasing the preset increment each time, the boundary of clutter nulling is pushed towards the high frequency direction, so as to reduce the false nulling of the target's low-frequency signal and reduce the target's energy loss. After obtaining the increment frequency threshold each time, the process of clutter nulling, generating null images, and calculating energy loss values ​​should be re-executed based on it to determine whether the current threshold satisfies the condition that energy loss ≤ loss threshold. When the energy loss value corresponding to a certain increment frequency threshold is less than the loss threshold, the increment frequency threshold becomes the final target frequency threshold, ensuring a balance between clutter suppression effect and target information preservation.

[0083] Please refer to Figure 2 , Figure 2 A flowchart illustrating another method for generating radar echo images provided in this application embodiment; as shown. Figure 2 As shown, firstly, pure clutter echo data without a target is acquired and its spatial spectrum is calculated. Then, clutter echo data containing a target is acquired and two-dimensional imaging is performed. Subsequently, an azimuth-directed FFT transform is performed on the two-dimensional image to obtain the imaging spatial spectrum. Based on the difference in spectral characteristics between the target and clutter, the data in the clutter distribution area is set to zero. Finally, an IFFT transform is performed on the processed spatial spectrum to obtain the two-dimensional imaging result after clutter removal. This achieves effective suppression of clutter in near-field RCS testing and accurately obtains the target scattering characteristics.

[0084] In some embodiments of this application, for radar echoes in a pure clutter detection environment, a clutter spectrum image is determined, and based on the mixed radar echoes in a target detection environment, an initial mixed wave two-dimensional image and its corresponding mixed wave spectrum image are determined; based on the energy value corresponding to the clutter spectrum image, a frequency threshold is determined, and based on the frequency threshold, the clutter spectrum region in the mixed wave spectrum image is zeroed to obtain a zeroed mixed wave spectrum image and its corresponding zeroed mixed wave two-dimensional image; based on the energy values ​​corresponding to the target scattering region in the zeroed mixed wave two-dimensional image and the initial mixed wave two-dimensional image, an energy loss value is calculated, and based on the energy loss value, the loss threshold, and the frequency threshold, a target frequency threshold is determined; based on the target frequency threshold, the mixed wave spectrum image is zeroed to obtain a target spectrum image, and an IFFT transform is performed on the target spectrum image to obtain a target mixed wave two-dimensional image.

[0085] Thus, by analyzing radar echoes in a pure clutter detection environment, a clutter spectrum image is determined, enabling precise capture of the energy distribution characteristics of pure clutter in the frequency domain, such as the frequency range where clutter energy is concentrated. This facilitates subsequent differentiation between clutter and target spectra, avoiding false or missed clutter suppression due to a lack of clutter reference. Simultaneously, based on mixed radar echoes in a target detection environment, an initial mixed-wave two-dimensional image and corresponding mixed-wave spectrum image are determined. This acquires complete spatial domain imaging information containing both the target and clutter, facilitating subsequent target scattering region localization, and also provides frequency domain data, achieving dual-dimensional data support in both the spatial and frequency domains. Furthermore, based on the energy values ​​of the clutter spectrum image, a frequency threshold is determined, and the clutter spectrum region of the mixed-wave spectrum image is set to zero, thereby… Based on predetermined clutter characteristics, the energy of the clutter signal is directly cut off in the frequency domain, initially filtering out most of the clutter interference in the mixed wave. Simultaneously, a two-dimensional image of the zeroed mixed wave is obtained, allowing the clutter suppression effect to be visually presented in the spatial domain, such as a significant reduction in background clutter brightness. This enables subsequent verification of target energy loss based on the preliminarily optimized imaging samples. Furthermore, by selectively filtering clutter in the spatial frequency domain based on the differences in scattering characteristics between the target and clutter, the imaging clarity can be effectively improved. Moreover, only one target-free clutter test is added before the formal test, making the operation simple and easy to implement in engineering. This lays the foundation for improving the performance of existing near-field RCS testing systems, has application value, reduces clutter interference, and improves the accuracy of radar echo testing.

[0086] Figure 3 This is a schematic diagram of the structure of a radar echo image generation device 300 provided in an embodiment of this application. Figure 3 As shown, the radar echo image generation device 300 includes: a determination module 310, a zeroing module 320, a calculation module 330, and a transformation module 340; wherein: The determination module 310 is used to determine the clutter spectrum image for radar echoes in a pure clutter detection environment, and to determine the initial mixed wave two-dimensional imaging and its corresponding mixed wave spectrum image based on the mixed radar echoes in a target detection environment. The nulling module 320 is used to determine the frequency threshold based on the energy value corresponding to the clutter spectrum image, and to nullify the clutter spectrum region in the mixed wave spectrum image based on the frequency threshold, so as to obtain the nulled mixed wave spectrum image and its corresponding nulled mixed wave two-dimensional image. The calculation module 330 is used to calculate the energy loss value based on the energy values ​​corresponding to the target scattering region in the nulled mixed wave two-dimensional imaging and the initial mixed wave two-dimensional imaging, and to determine the target frequency threshold based on the energy loss value, the loss threshold, and the frequency threshold. The transformation module 340 is used to zero out the mixed wave spectrum image according to the target frequency threshold to obtain the target spectrum image, and to perform IFFT transformation on the target spectrum image to obtain the target mixed wave two-dimensional image.

[0087] In this embodiment of the application, the determining module 310 can also be specifically used for: For pure clutter detection environments, radar echoes at various azimuth angles are collected to obtain corresponding radar echo data. Then, IFFT transformation is performed on the radar echo data to obtain multiple one-dimensional range images. Based on the one-dimensional distance image, the corresponding imaging region is determined, and the imaging region is divided into grids to obtain multiple imaging grids and the grid center corresponding to each imaging grid. Based on the distance between the antenna phase center of the acquisition antenna and the center of each grid, the corresponding phase compensation value is calculated, and the phase of each grid center is compensated according to the phase compensation value. The signal values ​​at the centers of each compensated grid are accumulated to obtain a two-dimensional image, and an FFT transform is performed on the two-dimensional image to obtain a clutter spectrum image.

[0088] In this embodiment of the application, the zeroing module 320 can also be specifically used for: Based on the energy values ​​corresponding to the clutter spectrum image, calculate the corresponding energy mean and energy standard deviation, and obtain the frequency threshold based on the sum of the energy mean and energy standard deviation.

[0089] In this embodiment of the application, the zeroing module 320 can also be specifically used for: Based on the frequency threshold, the frequencies in the mixed wave spectrum image that are greater than the frequency threshold are determined to obtain the clutter spectrum region. All energy values ​​in the clutter spectrum region are then set to zero to obtain the zeroed mixed wave spectrum image. An IFFT transform is performed on the null-set hybrid wave spectrum image to obtain a two-dimensional image of the null-set hybrid wave.

[0090] In this embodiment of the application, the calculation module 330 can also be specifically used for: Based on the preset scattering region corresponding to the target detection environment, determine the energy values ​​of the preset scattering region in the initial mixed-wave two-dimensional imaging; By comparing the energy value with the energy threshold, the target energy value that is greater than the energy threshold is obtained, and the target scattering area is determined based on the pixel position corresponding to the target energy value. Based on the energy values ​​corresponding to the target scattering region in the zero-mixed wave 2D imaging and the initial mixed wave 2D imaging, the corresponding zero-total energy value and initial total energy value are determined, and the difference between the zero-total energy value and the initial total energy value is calculated to obtain the energy loss value.

[0091] In this embodiment of the application, the calculation module 330 can also be specifically used for: Determine whether the energy loss value is greater than the loss threshold; If not, then the frequency threshold is determined to be the target frequency threshold; If so, determine the preset frequency increment, and determine the target frequency threshold based on the preset frequency increment and the frequency threshold.

[0092] In this embodiment of the application, the calculation module 330 can also be specifically used for: Based on the sum of the preset frequency increment and the frequency threshold, the incremental frequency threshold is obtained. Based on the incremental frequency threshold, the clutter spectrum region in the mixed wave spectrum image is zeroed out according to the frequency threshold, resulting in a zeroed mixed wave spectrum image and its corresponding zeroed mixed wave two-dimensional imaging. The process continues until the energy loss value is less than the loss threshold. The incremental frequency threshold is determined as the target frequency threshold.

[0093] Figure 4 This is a schematic diagram of the structure of an apparatus for performing a radar echo image generation method according to an embodiment of this application. Figure 4 As shown, the device 400 includes: The device 400 may include a processor 401 with one or more processing cores, a memory 402 with one or more computer-readable storage media, a communication component 403, and other components. The processor 401, memory 402, and communication component 403 are connected via a bus 404.

[0094] In the specific implementation process, at least one processor 401 executes computer execution instructions stored in memory 402, causing at least one processor 401 to execute the radar echo image generation method described above.

[0095] The specific implementation process of processor 401 can be found in the above method embodiments, and its implementation principle and technical effect are similar. It will not be repeated here.

[0096] Furthermore, the processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), etc. A general-purpose processor can be a microprocessor or any conventional processor. The steps of the method disclosed in this application can be directly implemented by a hardware processor, or implemented by a combination of hardware and software modules within the processor.

[0097] The memory may include random access memory (RAM) and may also include non-volatile memory (NVM), such as at least one disk storage device.

[0098] The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. Buses can be categorized as address buses, data buses, control buses, etc. For ease of illustration, the buses shown in the accompanying drawings are not limited to a single bus or a single type of bus.

[0099] In some embodiments, a computer program product is also provided, comprising a computer program or instructions that, when executed by a processor, implement the steps in any of the radar echo image generation methods described above.

[0100] For details on the implementation of each of the above operations, please refer to the previous examples, which will not be repeated here.

[0101] Those skilled in the art will understand that all or part of the steps in the various methods of the above embodiments can be performed by instructions, or by instructions controlling related hardware. These instructions can be stored in a computer-readable storage medium and loaded and executed by a processor.

[0102] Therefore, embodiments of this application provide a computer-readable storage medium storing a plurality of program codes that can be loaded by a processor to execute the steps in any of the radar echo image generation methods provided in embodiments of this application.

[0103] The storage medium may include: read-only memory (ROM), random access memory (RAM), disk or optical disk, etc.

[0104] According to one aspect of this application, a computer program product or computer program is provided, the computer program product or computer program including computer instructions stored in a computer-readable storage medium.

[0105] Since the instructions stored in the storage medium can execute the steps in any of the radar echo image generation methods provided in the embodiments of this application, the beneficial effects that any of the radar echo image generation methods provided in the embodiments of this application can achieve can be realized. For details, please refer to the previous embodiments, which will not be repeated here.

[0106] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this application are indicated by the appended claims.

[0107] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope.

Claims

1. A method for generating radar echo images, characterized in that, The method includes: For radar echoes in a pure clutter detection environment, determine the clutter spectrum image, and based on the mixed radar echoes in a target detection environment, determine the initial mixed wave two-dimensional imaging and its corresponding mixed wave spectrum image; Based on the energy value corresponding to the clutter spectrum image, a frequency threshold is determined, and based on the frequency threshold, the clutter spectrum region in the mixed wave spectrum image is zeroed out to obtain a zeroed mixed wave spectrum image and its corresponding zeroed mixed wave two-dimensional image. Based on the energy values ​​corresponding to the target scattering region in the nulled mixed-wave two-dimensional imaging and the initial mixed-wave two-dimensional imaging, respectively, the energy loss value is calculated, and the target frequency threshold is determined based on the energy loss value, the loss threshold, and the frequency threshold. Based on the target frequency threshold, the mixed wave spectrum image is zeroed to obtain the target spectrum image, and the target spectrum image is then subjected to IFFT transformation to obtain a two-dimensional image of the target mixed wave.

2. The method according to claim 1, characterized in that, The determination of the corresponding clutter spectrum image for radar echoes in a pure clutter detection environment includes: For the pure clutter detection environment, the radar echoes at various azimuth angles are collected to obtain the corresponding radar echo data, and the radar echo data are transformed by IFFT to obtain multiple one-dimensional range images. Based on the one-dimensional distance image, the corresponding imaging region is determined, and the imaging region is divided into grids to obtain multiple imaging grids and the grid center corresponding to each imaging grid. Based on the distance between the antenna phase center of the acquisition antenna and each of the grid centers, the corresponding phase compensation value is calculated, and the phase of each of the grid centers is compensated based on the phase compensation value. The signal values ​​at each of the compensated grid centers are accumulated to obtain a two-dimensional image, and the two-dimensional image is then subjected to an FFT transformation to obtain the clutter spectrum image.

3. The method according to claim 1, characterized in that, The step of determining the frequency threshold based on the energy value corresponding to the clutter spectrum image includes: Based on the energy values ​​corresponding to the clutter spectrum image, the corresponding energy mean and energy standard deviation are calculated, and the frequency threshold is obtained based on the sum of the energy mean and the energy standard deviation.

4. The method according to claim 1, characterized in that, The step of zeroing out the clutter spectrum region in the mixed wave spectrum image according to the frequency threshold to obtain a zeroed mixed wave spectrum image and its corresponding zeroed mixed wave two-dimensional image includes: Based on the frequency threshold, determine the frequencies in the mixed wave spectrum image that are greater than the frequency threshold to obtain the clutter spectrum region, and set all energy values ​​in the clutter spectrum region to zero to obtain the zeroed mixed wave spectrum image; An IFFT transform is performed on the null-set hybrid wave spectrum image to obtain the null-set hybrid wave two-dimensional image.

5. The method according to claim 1, characterized in that, The step of calculating the energy loss value based on the energy values ​​corresponding to the target scattering region in the nulled mixed-wave two-dimensional imaging and the initial mixed-wave two-dimensional imaging, respectively, includes: Based on the preset scattering region corresponding to the target detection environment, determine the energy values ​​of the preset scattering region in the initial mixed-wave two-dimensional imaging; By comparing the energy value with the energy threshold, a target energy value greater than the energy threshold is obtained, and the target scattering region is determined based on the pixel position corresponding to the target energy value. Based on the energy values ​​corresponding to the target scattering region in the zero-wave mixed-wave two-dimensional imaging and the initial mixed-wave two-dimensional imaging, the corresponding zero-energy total value and initial energy total value are determined, and the difference between the zero-energy total value and the initial energy total value is calculated to obtain the energy loss value.

6. The method according to claim 1, characterized in that, The step of determining the target frequency threshold based on the energy loss value, the loss threshold, and the frequency threshold includes: Determine whether the energy loss value is greater than the loss threshold; If not, then the frequency threshold is determined to be the target frequency threshold; If so, then a preset frequency increment is determined, and the target frequency threshold is determined based on the preset frequency increment and the frequency threshold.

7. The method according to claim 6, characterized in that, Determining the target frequency threshold based on the preset frequency increment and the frequency threshold includes: Based on the sum of the preset frequency increment and the frequency threshold, the adjusted frequency threshold is iteratively calculated, and based on the adjusted frequency threshold, the adjusted energy loss value is determined. Determine whether the adjusted energy loss value is greater than the loss threshold; If so, continue iteratively calculating the adjusted frequency threshold; If not, stop the iteration and determine the adjusted frequency threshold as the target frequency threshold.

8. A device for generating radar echo images, characterized in that, The device includes: The determination module is used to determine the clutter spectrum image for radar echoes in a pure clutter detection environment, and to determine the initial mixed wave two-dimensional imaging and its corresponding mixed wave spectrum image based on the mixed radar echoes in a target detection environment. The zeroing module is used to determine a frequency threshold based on the energy value corresponding to the clutter spectrum image, and to zero out the clutter spectrum region in the mixed wave spectrum image based on the frequency threshold, so as to obtain a zeroed mixed wave spectrum image and its corresponding zeroed mixed wave two-dimensional image. The calculation module is used to calculate the energy loss value based on the energy values ​​corresponding to the target scattering region in the nulled mixed-wave two-dimensional imaging and the initial mixed-wave two-dimensional imaging, and to determine the target frequency threshold based on the energy loss value, the loss threshold, and the frequency threshold. The transformation module is used to zero out the hybrid wave spectrum image according to the target frequency threshold to obtain the target spectrum image, and to perform IFFT transformation on the target spectrum image to obtain a two-dimensional image of the target hybrid wave.

9. A computer device, characterized in that, include: One or more processors; Memory; One or more programs, wherein the one or more programs are stored in memory and configured to be executed by one or more processors, the one or more programs being configured to perform the method as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores program code that can be called by a processor to perform the method as described in any one of claims 1 to 7.

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