Interactively-based arbitrary-angle squinted sar point target evaluation method and device

Abstract

The application relates to an interactive arbitrary-angle squint SAR point target evaluation method and device, which comprises the following steps: extracting the global peak point position coordinates from the two-dimensional complex data containing a target point to be evaluated after preprocessing; obtaining two local regions corresponding to the azimuth direction and the range direction respectively on the two-dimensional complex data after preprocessing through an interactive interception mode; extracting the strongest value points in the two local regions as the azimuth direction control point and the range direction control point respectively; calculating the corresponding slice slope according to the global peak point position coordinates, the azimuth direction control point coordinates and the range direction control point coordinates; extracting the azimuth direction profile data and the range direction profile data on the two-dimensional complex data through corresponding modes after judging the slice slope; and finally calculating the evaluation parameters according to the azimuth direction profile data and the range direction profile data, so as to realize the evaluation of the arbitrary-angle squint SAR point target.

Description

Technical Field

[0001] This application relates to the field of microwave remote sensing technology, and in particular to an interactive arbitrary-angle oblique-view SAR point target evaluation method and apparatus. Background Technology

[0002] SAR is a high-resolution air-to-ground remote sensing technology applicable to all-weather, all-day conditions. To evaluate the performance of a synthetic aperture radar (SAR) system, image performance metrics of point targets are commonly used. The typical procedure involves first extracting the range and azimuth profiles of the point targets, then interpolating them to obtain high-precision evaluation metrics, followed by calculating metrics such as resolution, integrated sidelobe ratio (ISLR), and integrated sidelobe ratio (PSLR).

[0003] In oblique-looking SAR systems with frontal or very small angles, the range and azimuth profiles can be considered perpendicular. However, in large-angle oblique-looking SAR systems, the range data becomes tilted, leading to differences in profile data extraction and parameter calculation compared to frontal and side-looking systems. Existing oblique-looking SAR point target evaluation methods have certain angle limitations, making them unsuitable for large-angle oblique-looking SAR imaging. Furthermore, the target range and azimuth profile tilt angles differ for SAR systems with different oblique angles, and the same oblique-looking SAR data may also exhibit different target range and azimuth profile tilt angles after processing with different imaging algorithms. Therefore, a widely applicable point target evaluation method and device are needed. Summary of the Invention

[0004] Therefore, it is necessary to provide an interactive, arbitrary-angle squint SAR point target evaluation method and apparatus that addresses the aforementioned technical problems.

[0005] An interactive, arbitrary-angle squint SAR point target evaluation method, the method comprising:

[0006] Two-dimensional complex data containing the target point to be evaluated is obtained. The two-dimensional complex data is obtained by imaging the target echo data obtained by SAR radar from arbitrary angle detection of the target point to be evaluated.

[0007] After preprocessing the two-dimensional complex data, the coordinates of the global peak points are extracted:

[0008] By using an interactive cropping method, two local regions corresponding to the azimuth and range directions are obtained from the preprocessed two-dimensional complex data.

[0009] The two strongest points in the local regions are extracted as azimuth control points and range control points, respectively. The corresponding slice slope is calculated based on the coordinates of the global peak point and the coordinates of the azimuth control points and range control points.

[0010] By judging the slope of the slice, azimuth profile data and range profile data are extracted from the two-dimensional complex data in a corresponding manner.

[0011] The resolution, integral sidelobe ratio, and peak sidelobe ratio are calculated based on the azimuth profile data and range profile data, respectively, to enable the evaluation of SAR point targets at any angle of oblique look-out.

[0012] In one embodiment, preprocessing the two-dimensional complex data includes:

[0013] Centered on the target point to be evaluated, the two-dimensional complex data is truncated according to a preset size to obtain the truncated two-dimensional complex data;

[0014] The truncated two-dimensional complex data is upsampled to obtain a complex data matrix, and the global peak position coordinates are extracted from the complex data matrix.

[0015] In one embodiment, before obtaining two local regions corresponding to the azimuth and range directions on the complex data matrix through interactive cropping:

[0016] The corresponding target region image is also generated based on the complex data matrix;

[0017] A Cartesian coordinate system is established on the target region image with the global peak point location coordinates as the origin.

[0018] In one embodiment, the two local regions are two local regions of the same size arbitrarily cropped in the azimuth and distance directions from the target region image.

[0019] In one embodiment, the slice slope is calculated by comparing the coordinates of the global peak point with the coordinates of the azimuth control point and the coordinates of the range control point, respectively, using the following formula:

[0020] k a =(y max -y a ) / (x max -x a )

[0021] In the above formula, (x max y max (x) represents the coordinates of the global peak point.a y a ) represents the coordinates of the azimuth control point or the distance control point.

[0022] In one embodiment, by determining the slope of the slice, azimuth profile data and range profile data are extracted from the two-dimensional complex data using corresponding methods, including:

[0023] When the slope of the slice meets the first preset range, the azimuth profile data and the range profile data are extracted row by row from the two-dimensional complex data.

[0024] When the slope of the slice meets the second preset range, the azimuth profile data and range profile data are extracted row by row from the two-dimensional complex data.

[0025] In one embodiment, the first preset range is: the absolute value of the slice slope is greater than or equal to -1;

[0026] The second preset range is: the absolute value of the slope of the slice is greater than or equal to 0 and less than 1.

[0027] In one embodiment, the resolution is calculated based on the azimuth profile data and the range profile data, respectively, using the following formula:

[0028]

[0029] In the above formula, B represents the 3dB bandwidth in the azimuth or range direction, Δa and Δr represent the sampling intervals in the azimuth and range directions, respectively, and k represents the slice slope.

[0030] This application also provides an interactive arbitrary-angle squint SAR point target evaluation device, the device comprising:

[0031] The module for obtaining the data to be evaluated is used to acquire two-dimensional complex data containing the target point to be evaluated. The two-dimensional complex data is obtained by imaging the target echo data obtained by SAR radar from detecting the target point at any angle.

[0032] The peak point location coordinate extraction module is used to extract the global peak point location coordinates from the two-dimensional complex data after preprocessing.

[0033] The local region acquisition module is used to obtain two local regions corresponding to the azimuth and distance directions respectively on the preprocessed two-dimensional complex data through interactive interception.

[0034] The slice slope acquisition module is used to extract the strongest value points in the two local regions as azimuth control points and range control points, respectively, and calculate the corresponding slice slope based on the coordinates of the global peak point and the coordinates of the azimuth control points and range control points, respectively.

[0035] The profile data acquisition module is used to extract azimuth profile data and range profile data from the two-dimensional complex data by judging the slope of the slice and using corresponding methods respectively.

[0036] The point target evaluation module is used to calculate the resolution, integral sidelobe ratio, and peak sidelobe ratio based on the azimuth profile data and range profile data, respectively, so as to evaluate SAR point targets at any angle of oblique look-out.

[0037] A computer device includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program performing the following steps:

[0038] Two-dimensional complex data containing the target point to be evaluated is obtained. The two-dimensional complex data is obtained by imaging the target echo data obtained by SAR radar from arbitrary angle detection of the target point to be evaluated.

[0039] After preprocessing the two-dimensional complex data, the coordinates of the global peak points are extracted:

[0040] By using an interactive cropping method, two local regions corresponding to the azimuth and range directions are obtained from the preprocessed two-dimensional complex data.

[0041] The two strongest points in the local regions are extracted as azimuth control points and range control points, respectively. The corresponding slice slope is calculated based on the coordinates of the global peak point and the coordinates of the azimuth control points and range control points.

[0042] By judging the slope of the slice, azimuth profile data and range profile data are extracted from the two-dimensional complex data in a corresponding manner.

[0043] The resolution, integral sidelobe ratio, and peak sidelobe ratio are calculated based on the azimuth profile data and range profile data, respectively, to enable the evaluation of SAR point targets at any angle of oblique look-out.

[0044] A computer-readable storage medium having a computer program stored thereon, the computer program performing the following steps when executed by a processor:

[0045] Two-dimensional complex data containing the target point to be evaluated is obtained. The two-dimensional complex data is obtained by imaging the target echo data obtained by SAR radar from arbitrary angle detection of the target point to be evaluated.

[0046] After preprocessing the two-dimensional complex data, the coordinates of the global peak points are extracted:

[0047] By using an interactive cropping method, two local regions corresponding to the azimuth and range directions are obtained from the preprocessed two-dimensional complex data.

[0048] The two strongest points in the local regions are extracted as azimuth control points and range control points, respectively. The corresponding slice slope is calculated based on the coordinates of the global peak point and the coordinates of the azimuth control points and range control points.

[0049] By judging the slope of the slice, azimuth profile data and range profile data are extracted from the two-dimensional complex data in a corresponding manner.

[0050] The resolution, integral sidelobe ratio, and peak sidelobe ratio are calculated based on the azimuth profile data and range profile data, respectively, to enable the evaluation of SAR point targets at any angle of oblique look-out.

[0051] The aforementioned interactive arbitrary-angle squint SAR point target evaluation method and apparatus preprocesses two-dimensional complex data containing the target point to be evaluated, extracts the global peak point coordinates, and then uses an interactive cropping method to obtain two local regions corresponding to the azimuth and range directions on the preprocessed two-dimensional complex data. The strongest points in these two local regions are then extracted as azimuth and range control points, respectively. The corresponding slice slopes are calculated based on the global peak point coordinates, the azimuth control point coordinates, and the range control point coordinates. After judging the slice slopes, azimuth and range profile data are extracted from the two-dimensional complex data using appropriate methods. Finally, the resolution, integral sidelobe ratio, and peak sidelobe ratio are calculated based on the azimuth and range profile data to achieve evaluation of arbitrary-angle squint SAR point targets. Attached Figure Description

[0052] Figure 1 This is a flowchart illustrating an interactive arbitrary-angle oblique-look SAR point target evaluation method in one embodiment.

[0053] Figure 2 This is a schematic diagram of a target region image in one embodiment;

[0054] Figure 3This is a schematic diagram illustrating the results of an experimental simulation using this method on a 50-degree oblique-look SAR point target. Figure 3 (a) represents the SAR point target simulation results. Figure 3 (b) shows a schematic diagram of the distance profile. Figure 3 (c) shows a schematic diagram of the azimuth profile;

[0055] Figure 4 This is a schematic diagram illustrating the results of an experimental simulation using this method on a 30-degree oblique-look SAR point target. Figure 4 (a) represents the SAR point target simulation results. Figure 4 (b) shows a schematic diagram of the distance profile. Figure 4 (c) shows a schematic diagram of the azimuth profile;

[0056] Figure 5 This is a schematic diagram illustrating the results of an experimental simulation using this method on a 10-degree oblique-look SAR point target. Figure 5 (a) represents the SAR point target simulation results. Figure 5 (b) shows a schematic diagram of the distance profile. Figure 5 (c) shows a schematic diagram of the azimuth profile;

[0057] Figure 6 This is a structural block diagram of an interactive arbitrary-angle oblique-view SAR point target evaluation device in one embodiment;

[0058] Figure 7 This is an internal structural diagram of a computer device in one embodiment. Detailed Implementation

[0059] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0060] For a front-looking SAR system, the range and azimuth profiles of a point target are perpendicular to each other and parallel to the coordinate axes, respectively. Assume the coordinates of the peak point are (x... max ,y max ), where x and y are the indices of the azimuth and range directions, respectively. The sampling intervals for the azimuth and range directions are Δa and Δr, respectively. At this time, the column vector (x, y) max ) represents azimuth profile data, row vector (x max (,y) represents the range profile data. The 3dB bandwidths for the azimuth and range directions are B and B, respectively. a and B r Then the resolution in the azimuth and range directions can be expressed as:

[0061]

[0062] For point targets in oblique-looking SAR, the 3dB bandwidths of the range and azimuth profiles are non-orthogonal.

[0063] Existing methods for evaluating point targets in oblique-looking SAR are limited by angle, making them unsuitable for large-angle oblique-looking SAR imaging. Furthermore, they suffer from difficulties in extracting point target profiles and calculating performance indicators. In this embodiment, for example... Figure 1 As shown, an interactive arbitrary-angle squint SAR point target evaluation method is provided, including the following steps:

[0064] Step S100: Obtain two-dimensional complex data containing the target point to be evaluated. This two-dimensional complex data is obtained by imaging the target echo data obtained by SAR radar from detecting the target point at any angle.

[0065] Step S110: After preprocessing the two-dimensional complex data, extract the coordinates of the global peak points.

[0066] Step S120: Using an interactive capture method, two local regions corresponding to the azimuth and distance directions are obtained from the preprocessed two-dimensional complex data.

[0067] Step S130: Extract the strongest value points in the two local regions as azimuth control points and range control points respectively. Calculate the corresponding slice slopes based on the coordinates of the global peak point and the coordinates of the azimuth and range control points respectively.

[0068] Step S140: By judging the slope of the slice, azimuth profile data and range profile data are extracted from the two-dimensional complex data using the corresponding methods.

[0069] Step S150: Calculate the resolution, integral sidelobe ratio, and peak sidelobe ratio based on the azimuth profile data and range profile data, respectively, to evaluate SAR point targets at any angle of oblique look-out.

[0070] In this embodiment, control points are established by truncating a local area. The slope of the straight line is calculated based on the control points, which can accurately extract profile data. Furthermore, the resolution and other indicators are calculated for different angles of squint, which can quickly and effectively evaluate the SAR imaging performance of any angle of squint.

[0071] In step S100, the acquired two-dimensional complex data is the data obtained after SAR imaging of the target echo data. The target point to be evaluated is not a specific target being detected, but rather the point with the strongest value in the image data obtained after target imaging.

[0072] In this embodiment, the two-dimensional complex data can be obtained from measured data or from simulation data.

[0073] In step S110, the preprocessing of the two-dimensional complex data includes: taking the target point to be evaluated as the center, truncating the two-dimensional complex data according to a preset size to obtain truncated two-dimensional complex data, then performing an upsampling operation on the truncated two-dimensional complex data to obtain a complex data matrix, and extracting the global peak position coordinates from the complex data matrix.

[0074] Specifically, after upsampling the two-dimensional complex data containing the points to be evaluated, an N (azimuth) × N (distance) complex data matrix is ​​obtained, and the peak position in the complex data matrix is ​​used as the center of the point target slice. The peak position (x... max ,y max Establish a Cartesian coordinate system with the origin as the coordinate origin.

[0075] In this embodiment, before obtaining the two local regions corresponding to the azimuth and range directions on the complex data matrix through interactive cropping, the complex data matrix is ​​converted into a target region image. Various conversion methods are available, and existing programs can be used to process the data to obtain the desired image. Figure 2 As shown, a Cartesian coordinate system is established on the target region image with the global peak point location coordinates as the origin.

[0076] In step 120, interactive interception is performed in the following manner: Figure 2 The following calculations are performed on two identical local regions arbitrarily cropped from the target region image, one in the upper direction and the other in the lower direction. For example... Figure 2 The two local regions shown are captured.

[0077] In step S130, the strongest value points in the two local regions are extracted as control points. The corresponding slice slopes are then calculated based on the coordinates of the global peak point, the coordinates of the azimuth control points, and the coordinates of the range control points, using the following formula:

[0078] k a =(y max -y a ) / (x max -x a (2)

[0079] In formula (2), (x max y max (x) represents the coordinates of the global peak point. a y a ) represents the coordinates of the azimuth control point or the distance control point.

[0080] In step S140, by judging the slope of the slice, azimuth profile data and range profile data are extracted from the two-dimensional complex data using appropriate methods, including:

[0081] When the slice slope meets the first preset range, azimuth profile data and range profile data are extracted row by row from the two-dimensional complex data. When the slice slope meets the second preset range, azimuth profile data and range profile data are extracted row by row from the two-dimensional complex data.

[0082] In this embodiment, the first preset range is: the absolute value of the slice slope is greater than or equal to -1. The second preset range is: the absolute value of the slice slope is greater than or equal to 0 and less than 1.

[0083] In step S150, when calculating the resolution in the evaluation parameters, the resolution is calculated by extracting profile data column by column or row by row, depending on the different slopes of the cross section. On the one hand, the target range and azimuth profile tilt angle differ for SAR systems with different oblique viewing angles. On the other hand, the target range and azimuth profile tilt angle may also differ after processing the same oblique-view SAR data using different imaging algorithms. This method does not impose any pre-restrictions on the values ​​of the target range and azimuth profile slope; that is, the slope value range is k∈(-∞,+∞), making it more widely applicable.

[0084] Taking the azimuth direction as an example, when the slice slope is less than or equal to -1, some column vectors do not contain azimuth profile data. In this case, the azimuth profile data is extracted row by row. That is, for each row y, the profile data can be represented as data[round(x',y)], where data represents two-dimensional complex data, x' = (yy max ) / k a +x max The round(·) function performs a rounding approximation. The azimuth resolution can then be calculated using the following formula:

[0085]

[0086] When the slope of the slice is greater than or equal to -1 and less than 0, the azimuth profile data is extracted column by column. The profile data is then represented as data[round(x,y')], where y' = k a (xx max )+y max At this point, the azimuth resolution can be calculated using the following formula:

[0087]

[0088] Similarly, the resolution of the range profile can also be calculated by selecting control points and calculating the slope. In summary, the expressions for calculating the resolution can be uniformly divided into:

[0089]

[0090] In formula (5), B represents the 3dB bandwidth in the azimuth or range direction, Δa and Δr represent the sampling intervals in the azimuth and range directions, respectively, and k represents the slice slope.

[0091] From formula (5), it can be seen that the resolution calculation is only related to the slice slope, which further simplifies the resolution calculation and makes the application scenarios of this method wider.

[0092] Next, when calculating the integral sidelobe ratio and peak sidelobe ratio in the evaluation parameters, the integral sidelobe ratio refers to the ratio of the sidelobe energy to the main lobe energy of the target impulse response, and its mathematical expression is:

[0093]

[0094] In formula (6), E s and E m These are the sidelobe energy and main lobe energy of the impulse response (IRF), respectively. ISLR characterizes the degree to which a locally darker region (weak signal) is "overwhelmed" by the signal energy from the surrounding bright region (strong signal), or characterizes the ability to suppress image grayscale changes caused by adjacent surface targets.

[0095] The peak-to-sidelobe ratio refers to the ratio of the highest sidelobe peak value to the main lobe peak value in the target impulse response. The mathematical expression is:

[0096]

[0097] In formula (7), P smax The peak value of the highest sidelobe of the impulse response (IRF). P m The main lobe peak value of the impulse response. PSLR characterizes the ability of a SAR system to suppress the "masking" of weak targets by adjacent strong targets, or to characterize the ability to detect weak targets.

[0098] The obtained resolution, integral sidelobe ratio, and peak sidelobe ratio are used to evaluate the oblique-looking SAR point target.

[0099] In this paper, simulation experiments were also conducted to demonstrate the effectiveness of the method described herein. Profile extraction and index calculation were performed on point targets at oblique angles of 50 degrees, 30 degrees, and 10 degrees, respectively. The simulation results and distance and azimuth profiles are attached. Figure 3 , 4 As shown in Figure 5. Table 1 lists the resolution, PSLR, and ISLR results for the three cases, which are close to the ideal resolution, demonstrating that this method can well meet the needs of engineering applications.

[0100] Table 1. Point target evaluation results under different oblique angles.

[0101]

[0102] In the aforementioned interactive arbitrary-angle squint SAR point target evaluation method, the method and apparatus extract the global peak point coordinates from the two-dimensional complex data containing the target point to be evaluated. Then, through interactive cropping, two local regions corresponding to the azimuth and range directions are obtained from the preprocessed two-dimensional complex data. The strongest point in the two local regions is then extracted as the azimuth control point and the range control point, respectively. The corresponding slice slope is calculated based on the global peak point coordinates and the coordinates of the azimuth and range control points. After judging the slice slope, the azimuth profile data and the range profile data are extracted from the two-dimensional complex data in an appropriate manner. Finally, the resolution, integral sidelobe ratio, and peak sidelobe ratio are calculated based on the azimuth profile data and the range profile data, respectively, to achieve the evaluation of arbitrary-angle squint SAR point targets.

[0103] It should be understood that, although Figure 1 The steps in the flowchart are shown sequentially as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order in which these steps are executed, and they can be performed in other orders. Figure 1 At least some of the steps in the process may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least some of the sub-steps or stages of other steps.

[0104] In one embodiment, such as Figure 6 As shown, an interactive arbitrary-angle oblique-view SAR point target evaluation device is provided, including: a data acquisition module 200, a peak point location coordinate extraction module 210, a local region acquisition module 220, a slice slope acquisition module 230, a profile data acquisition module 240, and a point target evaluation module 250, wherein:

[0105] The evaluation data acquisition module 200 is used to acquire two-dimensional complex data containing the target point to be evaluated. The two-dimensional complex data is obtained by imaging the target echo data obtained by SAR radar from arbitrary angle detection of the target point to be evaluated.

[0106] Peak point location coordinate extraction module 210 is used to extract the global peak point location coordinates from the two-dimensional complex data after preprocessing.

[0107] The local region acquisition module 220 is used to obtain two local regions corresponding to the azimuth and range directions respectively on the preprocessed two-dimensional complex data through an interactive interception method;

[0108] The slice slope acquisition module 230 is used to extract the strongest value points in the two local regions as azimuth control points and range control points, respectively, and calculate the corresponding slice slope based on the coordinates of the global peak point and the coordinates of the azimuth control points and range control points, respectively.

[0109] The profile data acquisition module 240 is used to extract azimuth profile data and range profile data from the two-dimensional complex data by judging the slope of the slice and using corresponding methods respectively.

[0110] The point target evaluation module 250 is used to calculate the resolution, integral sidelobe ratio and peak sidelobe ratio based on the azimuth profile data and range profile data, respectively, so as to evaluate the SAR point target at any angle of oblique look-out.

[0111] Specific limitations regarding the interactive arbitrary-angle squint SAR point target evaluation device can be found in the limitations of the interactive arbitrary-angle squint SAR point target evaluation method described above, and will not be repeated here. Each module in the aforementioned interactive arbitrary-angle squint SAR point target evaluation device can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device, or stored in the memory of a computer device as software, so that the processor can call and execute the corresponding operations of each module.

[0112] In one embodiment, a computer device is provided, which may be a terminal, and its internal structure diagram may be as follows: Figure 7As shown, the computer device includes a processor, memory, network interface, display screen, and input devices connected via a system bus. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The network interface is used for communication with external terminals via a network connection. When executed by the processor, the computer program implements an interactive, arbitrary-angle oblique-look SAR point target evaluation method. The display screen can be a liquid crystal display (LCD) or an e-ink display. The input devices can be a touch layer covering the display screen, buttons, a trackball, or a touchpad mounted on the computer device casing, or an external keyboard, touchpad, or mouse.

[0113] Those skilled in the art will understand that Figure 7 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0114] In one embodiment, a computer device is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to perform the following steps:

[0115] Two-dimensional complex data containing the target point to be evaluated is obtained. The two-dimensional complex data is obtained by imaging the target echo data obtained by SAR radar from arbitrary angle detection of the target point to be evaluated.

[0116] After preprocessing the two-dimensional complex data, the coordinates of the global peak points are extracted:

[0117] By using an interactive cropping method, two local regions corresponding to the azimuth and range directions are obtained from the preprocessed two-dimensional complex data.

[0118] The two strongest points in the local regions are extracted as azimuth control points and range control points, respectively. The corresponding slice slope is calculated based on the coordinates of the global peak point and the coordinates of the azimuth control points and range control points.

[0119] By judging the slope of the slice, azimuth profile data and range profile data are extracted from the two-dimensional complex data in a corresponding manner.

[0120] The resolution, integral sidelobe ratio, and peak sidelobe ratio are calculated based on the azimuth profile data and range profile data, respectively, to enable the evaluation of SAR point targets at any angle of oblique look-out.

[0121] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon, the computer program performing the following steps when executed by a processor:

[0122] Two-dimensional complex data containing the target point to be evaluated is obtained. The two-dimensional complex data is obtained by imaging the target echo data obtained by SAR radar from arbitrary angle detection of the target point to be evaluated.

[0123] After preprocessing the two-dimensional complex data, the coordinates of the global peak points are extracted:

[0124] By using an interactive cropping method, two local regions corresponding to the azimuth and range directions are obtained from the preprocessed two-dimensional complex data.

[0125] The two strongest points in the local regions are extracted as azimuth control points and range control points, respectively. The corresponding slice slope is calculated based on the coordinates of the global peak point and the coordinates of the azimuth control points and range control points.

[0126] By judging the slope of the slice, azimuth profile data and range profile data are extracted from the two-dimensional complex data in a corresponding manner.

[0127] The resolution, integral sidelobe ratio, and peak sidelobe ratio are calculated based on the azimuth profile data and range profile data, respectively, to enable the evaluation of SAR point targets at any angle of oblique look-out.

[0128] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), Rambus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0129] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0130] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for evaluating point targets using interactive, arbitrary-angle oblique-look SAR, characterized in that, The method includes: Two-dimensional complex data containing the target point to be evaluated is obtained. The two-dimensional complex data is obtained by imaging the target echo data obtained by SAR radar from arbitrary angle detection of the target point to be evaluated. After preprocessing the two-dimensional complex data, the coordinates of the global peak points are extracted: By using an interactive cropping method, two local regions corresponding to the azimuth and range directions are obtained from the preprocessed two-dimensional complex data. The two strongest points in the local regions are extracted as azimuth control points and range control points, respectively. The corresponding slice slope is calculated based on the coordinates of the global peak point and the coordinates of the azimuth control points and range control points. By judging the slope of the slice, azimuth profile data and range profile data are extracted from the two-dimensional complex data in a corresponding manner. Specifically, when the slope of the slice meets the first preset range, the azimuth profile data and range profile data are extracted row by row from the two-dimensional complex data. When the slope of the slice meets the second preset range, the azimuth profile data and range profile data are extracted column by column from the two-dimensional complex data. The first preset range is: the absolute value of the slope of the slice is greater than or equal to 1. The second preset range is: the absolute value of the slope of the slice is greater than or equal to 0 and less than 1. The resolution, integral sidelobe ratio, and peak sidelobe ratio are calculated based on the azimuth profile data and range profile data, respectively, to enable the evaluation of SAR point targets at any angle of oblique look-out.

2. The arbitrary-angle oblique-view SAR point target evaluation method according to claim 1, characterized in that, Preprocessing the two-dimensional complex data includes: Centered on the target point to be evaluated, the two-dimensional complex data is truncated according to a preset size to obtain the truncated two-dimensional complex data; The truncated two-dimensional complex data is upsampled to obtain a complex data matrix, and the coordinates of the global peak point are extracted from the complex data matrix.

3. The arbitrary-angle oblique-view SAR point target evaluation method according to claim 2, characterized in that, Before obtaining two local regions corresponding to the azimuth and range directions on the complex data matrix through interactive cropping: The corresponding target region image is also generated based on the complex data matrix; A Cartesian coordinate system is established on the target region image with the global peak point location coordinates as the origin.

4. The arbitrary angle oblique-view SAR point target evaluation method according to claim 3, characterized in that, The two local regions are two local regions of the same size arbitrarily cropped from the target region image in terms of azimuth and distance.

5. The arbitrary-angle oblique-view SAR point target evaluation method according to claim 4, characterized in that, The slice slope is calculated based on the coordinates of the global peak point and the coordinates of the azimuth control point and the coordinates of the range control point, respectively, using the following formula: In the above formula, This represents the coordinates of the global peak point. This indicates the coordinates of the azimuth control point or the distance control point.

6. The arbitrary-angle oblique-view SAR point target evaluation method according to claim 5, characterized in that, The resolution is calculated based on the azimuth profile data and the range profile data, respectively, using the following formula: In the above formula, This indicates the 3dB bandwidth in the azimuth or range direction. and These represent the sampling intervals in the azimuth and range directions, respectively. This indicates the slope of the slice.

7. An interactive, arbitrary-angle oblique-look SAR point target evaluation device, characterized in that, The device includes: The module for obtaining the data to be evaluated is used to acquire two-dimensional complex data containing the target point to be evaluated. The two-dimensional complex data is obtained by imaging the target echo data obtained by SAR radar from detecting the target point at any angle. The peak point location coordinate extraction module is used to extract the global peak point location coordinates from the two-dimensional complex data after preprocessing. The local region acquisition module is used to obtain two local regions corresponding to the azimuth and distance directions respectively on the preprocessed two-dimensional complex data through interactive interception. The slice slope acquisition module is used to extract the strongest value points in the two local regions as azimuth control points and range control points, respectively, and calculate the corresponding slice slope based on the coordinates of the global peak point and the coordinates of the azimuth control points and range control points, respectively. The profile data acquisition module is used to extract azimuth profile data and range profile data from the two-dimensional complex data by judging the slope of the slice and using corresponding methods. Specifically, when the slope of the slice meets a first preset range, the azimuth profile data and range profile data are extracted row by row from the two-dimensional complex data. When the slope of the slice meets a second preset range, the azimuth profile data and range profile data are extracted column by column from the two-dimensional complex data. The first preset range is: the absolute value of the slope of the slice is greater than or equal to 1, and the second preset range is: the absolute value of the slope of the slice is greater than or equal to 0 and less than 1. The point target evaluation module is used to calculate the resolution, integral sidelobe ratio, and peak sidelobe ratio based on the azimuth profile data and range profile data, respectively, so as to evaluate SAR point targets at any angle of oblique look-out.

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