Method, apparatus and storage medium for generating DOM (Domain Image) for airborne interferometric synthetic aperture radar

Abstract

This invention discloses an airborne interferometric synthetic aperture radar (DOM) generation method, apparatus, and storage medium, comprising: determining the flight and processing parameters of the current slant-range imaging data block; determining the ground coverage area of ​​the current slant-range imaging data block based on the flight and processing parameters and DEM data; interpolating the DEM data according to the resolution at which the current slant-range imaging data block was imaged; calculating the position of the DEM points within the current slant-range imaging data block point by point based on the interpolated DEM data within the ground coverage area; and calculating the image grayscale value corresponding to the DEM points point by point based on the position of the DEM points within the current slant-range imaging data block, thereby obtaining the final DOM image. The airborne interferometric synthetic aperture radar DOM inversion method provided by this invention improves the continuity and effectiveness of DOM data.

Description

Technical Field

[0001] This invention relates to the field of airborne interferometric synthetic aperture radar (IASAR) remote sensing and mapping technology, and particularly to an airborne ISAR DOM generation method, apparatus, and storage medium. Background Technology

[0002] Digital Orthophoto Map (DOM) is a product of airborne interferometric synthetic aperture radar (IASAR) remote sensing mapping. DOM can be obtained through the geocoding process of ISAR. It is obtained by directly projecting the slant-range DSM (Digital Surface Model) data and geometric relationships after elevation inversion. However, directly using the slant-range DSM after elevation inversion can lead to anomalies in elevation values ​​due to issues such as water bodies, shadows, and overlays. In this case, the DOM image is prone to obvious errors such as splicing and misalignment. At the same time, due to the presence of noise, the slant-range DSM is prone to areas of elevation discontinuity, resulting in obvious problems such as misalignment of DOM data, which seriously affects the quality of DOM. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a method, apparatus and storage medium for generating DOM for airborne interferometric synthetic aperture radar, which addresses the problems existing in the prior art.

[0004] To solve the above-mentioned technical problems, the present invention provides an airborne interferometric synthetic aperture radar DOM generation method, characterized in that it includes: determining the flight and processing parameters of the current slant range imaging data block;

[0005] The ground coverage area of ​​the current slant range imaging data block is determined based on flight and processing parameters and DEM data. The DEM data is interpolated based on the resolution at which the current slant range imaging data block is imaged. The positions of DEM points within the current slant range imaging data block are obtained point by point based on the interpolated DEM data within the ground coverage area. The corresponding image grayscale values ​​of the DEM points are obtained point by point based on their positions within the current slant range imaging data block, thus obtaining the final DOM image.

[0006] To address the aforementioned technical problems, this invention also provides an airborne interferometric synthetic aperture radar (DOM) generation device, comprising: a parameter acquisition module for determining the flight and processing parameters of the current slant range imaging data block; a coverage determination module for determining the ground coverage area of ​​the current slant range imaging data block based on the flight and processing parameters and DEM data; an interpolation processing module for interpolating the DEM data according to the resolution during imaging of the current slant range imaging data block; a DEM point location determination module for determining the location of DEM points within the current slant range imaging data block point by point based on the interpolated DEM data within the ground coverage area; and a DOM image generation module for interpolating the image grayscale values ​​corresponding to the DEM points point by point based on the locations of the DEM points within the current slant range imaging data block to obtain the final DOM image.

[0007] To address the aforementioned technical problems, the present invention also provides an airborne interferometric synthetic aperture radar (DOM) generation device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, it implements the airborne interferometric synthetic aperture radar (DOM) generation method provided by the above-mentioned technical solution.

[0008] To address the aforementioned technical problems, the present invention also provides a computer-readable storage medium including instructions that, when executed on a computer, cause the computer to perform the airborne interferometric synthetic aperture radar DOM generation method provided by the above technical solution.

[0009] The beneficial effects of this invention are as follows: By determining the ground coverage area of ​​the current slant range imaging data block using flight and processing parameters and DEM (Digital Elevation Model) data, and then calculating the position of each DEM point within the current slant range imaging data block based on the interpolated DEM data within the ground coverage area, the DOM pixel value corresponding to that DEM point is obtained through interpolation using SAR images near that point in the current slant range imaging data block, thereby obtaining the DOM result for the entire image. This invention utilizes DEM data, flight and processing parameters, and geometric backprojection and error parameter correction to obtain the DOM data for the corresponding data block. This avoids DOM region anomalies caused by slant range DSM region anomalies and elevation discontinuities, effectively improving the quality of DOM data.

[0010] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0011] Figure 1 A flowchart of the airborne interferometric synthetic aperture radar DOM generation method provided in this embodiment of the invention;

[0012] Figure 2 This is a schematic diagram of flight path and data image location provided in an embodiment of the present invention;

[0013] Figure 3 This is a schematic diagram of coordinate transformation provided in an embodiment of the present invention;

[0014] Figure 4 This is a flowchart for determining the position of a DEM point in the current slope distance data block, provided in an embodiment of the present invention.

[0015] Figure 5 This is a flowchart for determining the DOM grayscale value corresponding to a DEM point, provided in an embodiment of the present invention.

[0016] Figure 6 The slant-range SAR image of the current slant-range imaging data block provided in this embodiment of the invention;

[0017] Figure 7 This is the current slant range imaging data block ground distance DSM image;

[0018] Figure 8 This is the DOM image (generated by direct geocoding) corresponding to the ground distance of the current slant range imaging data block from the DSM.

[0019] Figure 9 for Figure 8 A magnified view of the corresponding DOM image;

[0020] Figure 10 This is the current slant range imaging data block ground distance DEM image provided in this embodiment of the invention;

[0021] Figure 11 This is the DOM image corresponding to the ground distance DEM of the current slant range imaging data block provided in this embodiment of the invention;

[0022] Figure 12 for Figure 11 A magnified view of the corresponding DOM image. Detailed Implementation

[0023] The following specific examples illustrate the implementation of this disclosure. Those skilled in the art can easily understand other advantages and effects of this disclosure from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this disclosure, and not all of them. This disclosure can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this disclosure. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0024] It should be noted that various aspects of embodiments within the scope of the appended claims are described below. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any particular structure and / or function described herein is merely illustrative. Based on this disclosure, those skilled in the art will understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects set forth herein can be used to implement the device and / or practice the method. Additionally, this device and / or method can be implemented using structures and / or functionalities other than one or more of the aspects set forth herein.

[0025] Figure 1 This is a flowchart illustrating the airborne interferometric synthetic aperture radar (DOM) generation method provided in an embodiment of the present invention. Figure 1 As shown, the method includes:

[0026] S1 determines the flight and processing parameters for the current slant range imaging data block.

[0027] The flight and processing parameters of the current slant range imaging data block mainly include: the aircraft altitude H corresponding to the current slant range imaging data block, the starting latitude and longitude of the flight path (latitude B1, longitude L1, altitude H1), the latitude and longitude of the four corner points of the image, and the flight heading angle θ. h The image's nearest slant range R0, slant range resolution dR, azimuth resolution dA, range pixel Nr, azimuth pixel Na, image center downward viewing angle θ, and error parameters (including image range error ΔR). r and image orientation error ΔR a This provides parameters for subsequent DOM generation.

[0028] It should be noted that the current slant range imaging data block includes the aircraft altitude H, the starting latitude and longitude of the flight path (B1, L1, H1), and the flight heading angle θ. hThe image's closest slant range R0, slant range resolution dR, azimuth resolution dA, range pixel Nr, azimuth pixel Na, downward viewing angle θ, Doppler center frequency fdc, and aircraft speed Vst can be output during imaging; error parameters (image range error ΔR) r and image orientation error ΔR a The distance and azimuth errors can be determined by using known ground control points.

[0029] S2 determines the ground coverage of the current slant range imaging data block based on flight and processing parameters and DEM data. DEM data can be obtained from external DEM data or through interferometric processing of InSAR.

[0030] In this embodiment of the invention, the ground coverage range of the current slant range imaging data block is determined based on flight and processing parameters and DEM data, so that the obtained ground coverage range is closer to the ground coverage range of the real image.

[0031] S3, interpolate the DEM data based on the resolution of the current slant range imaging data block.

[0032] In this embodiment of the invention, the DEM data is interpolated according to the resolution of the current slant range imaging data block to improve the resolution of the DEM data, so as to ensure that the resolution of the slant range SAR image data is comparable to that of the DEM data.

[0033] S4. Based on the interpolated DEM data within the ground coverage area, determine the position of each DEM point in the current slant range imaging data block.

[0034] In this embodiment of the invention, the interpolated DEM data is converted to DEM data in the aircraft coordinate system. Then, the position of the data in the SAR image is obtained by using information such as flight parameters, image parameters, and processing error parameters. This provides position information for subsequent interpolation operations based on the image grayscale values ​​of the surrounding pixels to extract the graphic grayscale value of the corresponding DEM point.

[0035] S5. Based on the position of the DEM point in the current slant range imaging data block, interpolate the image grayscale value corresponding to the DEM point point one by one to obtain the final DOM image.

[0036] This invention determines the ground coverage of the current slant range imaging data block using flight and processing parameters and DEM (Digital Elevation Model) data. Based on the interpolated DEM data within the ground coverage area, the location of each DEM point within the current slant range imaging data block is calculated point by point. Then, the DOM pixel value corresponding to that DEM point is obtained by interpolation using SAR images near that point in the current slant range imaging data block, thus yielding the DOM result for the entire image. This invention utilizes DEM data, flight and processing parameters, and geometric backprojection and error parameter correction to obtain the DOM data for the corresponding data block. This avoids DOM region anomalies caused by slant range DSM region anomalies and elevation discontinuities, effectively improving DOM data quality.

[0037] Optionally, the ground coverage of the current slant range imaging data block is determined based on flight and processing parameters and DEM data, including: determining the initial ground coverage of the current slant range imaging data block using the latitude and longitude of the four corner points of the image in the flight and processing parameters; and determining the final ground coverage of the current slant range data block based on the initial ground coverage, the maximum value hmax and minimum value hmin of the DEM (elevation) data within the initial ground coverage, and the flight and processing parameters.

[0038] It should be noted that, Figure 2 The diagram shows the flight path and data image position. In the diagram, N and E coordinates represent the north and east directions in the Gaussian coordinate system, and X and Y represent the forward and right directions in the aircraft coordinate system. The aircraft coordinate system is rotated counterclockwise by 90°-θ in the plane containing the forward and right directions. f (θ f (where the flight heading angle is used) can be used to obtain the Gaussian plane coordinate system. Figure 2 Both the Gaussian coordinate system and the aircraft coordinate system are three-axis coordinate systems, both conforming to the right-hand screw rule. The Gaussian coordinate system has three directions: north, east, and ground, with the ground direction perpendicular to the paper and pointing inwards; the aircraft coordinate system has three directions: front, right, and down, with the down direction perpendicular to the paper and pointing inwards.

[0039] When determining the ground coverage area for the first time, the latitude and longitude of the four corner points of the image are used as the initial ground coverage area.

[0040] In the second calculation of the ground coverage area, the maximum elevation hmax and minimum elevation hmin in the DEM data within this area are determined based on the initial ground coverage area, thereby further narrowing the ground coverage area. At this time, the coordinate system of the four corner points is (0, (Rnear-hmin / cosθ)sinθ), (((Na-1)*dA, (Rnear-hmin / cosθ)sinθ), ((Na-1)*dA, (Rfar-hmax / cosθ)sinθ), (0, (Rfar-hmax / cosθ)sinθ). Where Rfar = R0 + (Nr-1)*dR, Rnear = R0, R0 is the nearest slant distance of the image, Nr is the distance pixel, Na is the azimuth pixel, dR is the slant distance resolution, dA is the azimuth resolution, θ is the downward viewing angle at the image center; hmax is the maximum value of the DEM data, and hmin is the minimum value of the DEM data.

[0041] The second calculation of the ground coverage area is performed using the coordinate transformation matrix T. 21 and T 22 The final ground coverage area is determined by converting to a latitude, longitude, and altitude coordinate system. The conversion formula is (B, L) = (X, Y) * T. 21 *T 22 Where (X, Y) are the coordinates of the four corner points of the image, and (B, L) are the latitude and longitude of the calculated ground coverage area. Where T... 21 T is the coordinate transformation matrix for converting the aircraft coordinate system to the Gaussian coordinate system. 22 This is the coordinate transformation matrix for converting from Gaussian coordinates to latitude and longitude coordinates.

[0042] In this embodiment of the invention, the ground coverage area of ​​the current slant range imaging data block is calculated twice based on flight and processing parameters and DEM data. The ground coverage area calculated twice decreases sequentially, and the ground coverage area calculated in the second step is closer to the ground coverage area of ​​the real image.

[0043] Optionally, interpolating the DEM data based on the resolution of the current slant range imaging data block includes: determining the interpolation factor of the DEM data based on the ground resolution of the DEM data, the slant range resolution dR, the azimuth resolution dA, and the downward viewing angle θ at the image center; and interpolating the DEM data using a two-dimensional linear interpolation method or a cubic convolution interpolation method based on the interpolation factor.

[0044] Specifically, based on the slant range resolution dR, azimuth resolution dA, and downward viewing angle θ of the current slant range imaging data block image, the approximate resolution ΔR of the current slant range imaging data block image on the ground can be calculated. s Then, using the ground resolution ΔR of the DEM data...dem (Obtained by combining latitude interval dlat, longitude interval dlon, etc.) and ΔR s The interpolation factor K is determined by the interpolation factor used to interpolate the DEM data grid. New DEM data is then obtained through interpolation. The formula for calculating the interpolation factor is as follows:

[0045]

[0046]

[0047]

[0048] It should be understood that if the DEM data is in latitude and longitude format, it can be converted according to the distance between the ground represented by the latitude and longitude grid.

[0049] It should be noted that the interpolation method in this step can be obtained through two-dimensional linear or cubic convolution interpolation, depending on the actual processing speed requirements (processing speed V). 线性 >V 三次卷积 ).

[0050] In this embodiment of the invention, the interpolation factor of the DEM data is determined based on the ground resolution of the DEM data, the slant range resolution dR, the azimuth resolution dA, and the downward viewing angle θ at the image center during imaging of the current slant range imaging data block. Based on the interpolation factor, the DEM data is interpolated using a two-dimensional linear interpolation method or a cubic convolution interpolation method to improve the resolution of the DEM data, thereby ensuring that the resolution of the slant range SAR image data is comparable to that of the DEM data.

[0051] Optionally, the position of the DEM point in the current slant range imaging data block is obtained point by point based on the interpolated DEM data within the ground coverage area, including: converting the interpolated DEM data point by point into DEM data in the aircraft coordinate system; and obtaining the azimuth coordinate position Na1 and range coordinate position Nr1 in the image point by point based on the position of the DEM data in the aircraft coordinate system.

[0052] It should be noted that the conversion process between latitude, longitude, and altitude coordinate system data and aircraft coordinate system data is as follows: Figure 3 As shown. According to Figure 3 It can be seen that latitude, longitude, and altitude coordinate system data need to be transformed first through the transformation matrix T. 11 Convert the data to Gaussian coordinates, and then convert it to Gaussian coordinates using the transformation matrix T. 12 Transform to the aircraft coordinate system. Similarly, the aircraft coordinate system data is first transformed using the transformation matrix T. 21 Transform to Gaussian coordinates, and then from Gaussian coordinates through the transformation matrix T 22 Convert to latitude, longitude, and altitude coordinate systems.

[0053] Among them, T11 T 22 This is a general formula for converting between Gaussian coordinates and latitude / longitude coordinates.

[0054]

[0055] like Figure 4 As shown, in this embodiment of the invention, when determining the position of a DEM point within the current slant range imaging data block, the interpolated DEM data is first transformed using the coordinate transformation matrix T. 11 The data was converted to Gaussian coordinates, with values ​​in the three directions: northeast, northeast, and north-southeast. The starting latitude and longitude (B1, L1, H1) of the flight path were then transformed using the coordinate transformation matrix T. 11 Transform to Gaussian coordinates, and then apply the coordinate transformation matrix T. 12 The conversion formula for data in the aircraft coordinate system is shown below:

[0056] data 载机 =(data DEM ·T 11 -(B1, L1, H1)·T 11 )·T 12 ;

[0057] Among them, data 载机 Each data point contains three values: X, Y, and Z, which can be represented as (data 载机_X , data 载机_Y , data 载机_z ); data DEM This is the interpolated DEM data; T 11 T is the coordinate transformation matrix between the latitude / longitude coordinate system and the Gaussian coordinate system. 12 This is the coordinate transformation matrix between the Gaussian coordinate system and the aircraft coordinate system.

[0058] Then, based on the position of the DEM data in the aircraft coordinate system and combined with flight and processing parameters (including error parameters), the azimuth coordinate position Na1 and range coordinate position Nr1 in the image are calculated point by point. The conversion formula is as follows:

[0059]

[0060]

[0061] Where, ΔR a The image orientation error, ΔR r dA represents the image range error, H represents the aircraft altitude, dR represents the slant range resolution, and R0 represents the closest slant range in the image.

[0062] like Figure 5As shown, determine whether the azimuth coordinate position Na1 and the distance coordinate position Nr1 corresponding to the DEM point are within the range of the maximum values ​​Na and Nr in the image azimuth and distance directions.

[0063] If Na1 or Nr1 is not within the image range (Na1<0 or Na1>Na or Nr1<0 or Nr1>Nr), the grayscale value of the image corresponding to the DEM is set to an invalid value (NaN value); if it is within the range, SAR image data near the point is extracted (SAR image is a two-dimensional matrix, u matrix size is [1:Nr,1:Na]), the range of extracted SAR image data is [(floor(Nr1)-Δr):(floor(Nr1)+Δr),(floor(Na1)-Δa):(floor(Na1)+Δa)]), and bilinear (Δr=1,Δa=1) or cubic spline interpolation (Δr=2,Δa=2) operations are performed on the extracted SAR image grayscale value to obtain the image grayscale value corresponding to the DEM point. floor is a rounding operation for the numerical value.

[0064] The SAR amplitude image corresponding to each DEM point is obtained point by point in the above manner, thus obtaining the final DOM image.

[0065] It should be noted that the coordinates corresponding to the NaN values ​​in the DOM images obtained by this method are outside the coordinate range after the SAR slant range image is projected to the ground distance. They are not data of the current slant range imaging data block, so setting them as NaN values ​​is within a reasonable range.

[0066] The following will provide further explanation using specific examples.

[0067] The following describes the experimental processing of the airborne interferometric synthetic aperture radar DOM generation method proposed in this embodiment of the invention, and compares it with the DOM results generated by direct geocoding to verify the effectiveness of the invention.

[0068] The slant-range SAR images from this experiment are as follows: Figure 6 As shown, the DSM and DOM images of ground distance obtained directly through elevation inversion and geocoding are respectively as follows: Figure 7 As shown and Figure 8 As shown. The DSM and DOM images obtained through direct geocoding have a one-to-one pixel correspondence. When anomalies occur in the DSM elevation, corresponding abnormal areas such as splicing or discontinuity appear in the DOM. A magnified view of a local area is shown below. Figure 9 As shown, the information on houses and buildings in the figure differs significantly from the actual situation. The experimental results show that the DOM obtained by directly performing geocoding has obvious abnormal areas.

[0069] This invention's embodiments generate a DOM based on a DEM, where the DEM image is as follows: Figure 10 As shown, the obtained DOM image is as follows. Figure 11 As shown in the enlarged view, Figure 12 As shown. Figure 11 and Figure 12 respectively with Figure 8 , Figure 9 The comparison revealed that the method of the present invention significantly reduced the DOM (Domain of Depth) area obtained, and the continuity was significantly improved, with ground feature information (houses, buildings, etc.) clearly visible. The experimental results verified the effectiveness of the method of the present invention.

[0070] This invention provides an airborne interferometric synthetic aperture radar (DOM) generation device, including a parameter acquisition module, a coverage range determination module, an interpolation processing module, a DEM point location determination module, and a DOM image generation module.

[0071] The parameter acquisition module is used to determine the flight and processing parameters of the current slant range imaging data block; the coverage determination module is used to determine the ground coverage of the current slant range imaging data block based on the flight and processing parameters and DEM data; the interpolation processing module is used to perform interpolation on the DEM data based on the resolution when the current slant range imaging data block is imaged; the DEM point location determination module is used to calculate the location of the DEM point in the current slant range imaging data block point by point based on the interpolated DEM data within the ground coverage area; the DOM image generation module is used to calculate the image grayscale value corresponding to the DEM point point point by point based on the location of the DEM point in the current slant range imaging data block, and obtain the final DOM image.

[0072] Optionally, the flight and processing parameters of the current slant range imaging data block acquired by the parameter acquisition module include: the aircraft altitude H corresponding to the current slant range imaging data block, the starting latitude and longitude of the flight path (B1, L1, H1), the latitude and longitude of the four corner points of the image, and the flight heading angle θ. h The image's nearest slant range R0, slant range resolution dR, azimuth resolution dA, range pixel Nr, azimuth pixel Na, image center downward viewing angle θ, and image range error ΔR. r and image orientation error ΔR a .

[0073] Optionally, the coverage determination module is specifically used to obtain the initial ground coverage of the current slant range imaging data block using the latitude and longitude of the four corner points of the image; and to determine the final ground coverage of the current slant range data block based on the initial ground coverage, the maximum and minimum values ​​of the DEM data within the initial ground coverage, and the flight and processing parameters.

[0074] The final ground coverage coordinates of the four corner points of the current slant range data block are: (0, (Rnear-hmin / cosθ)sinθ), (((Na-1)*dA, (Rnear-hmin / cosθ)sinθ), ((Na-1)*dA, (Rfar-hmax / cosθ)sinθ), (0, (Rfar-hmax / cosθ)sinθ);

[0075] Where Rfar = R0 + (Nr - 1) * dR, Rnear = R0, R0 is the nearest slant distance of the image, Nr is the distance pixel, Na is the azimuth pixel, dR is the slant distance resolution, θ is the viewing angle below the image center, hmax is the maximum value of the DEM data, and hmin is the minimum value of the DEM data.

[0076] Optionally, the interpolation processing module is specifically used to determine the interpolation factor of the DEM data based on the ground resolution of the DEM data, the slant range resolution dR when the current slant range imaging data block is imaged, the azimuth resolution dA, and the downward viewing angle θ at the image center; and to perform interpolation operation on the DEM data using a two-dimensional linear interpolation method or a cubic convolution interpolation method based on the interpolation factor.

[0077] The DEM point location determination module is used to convert the interpolated DEM data point by point into DEM data in the aircraft coordinate system; based on the position of the DEM data in the aircraft coordinate system, the azimuth coordinate position Na1 and the range coordinate position Nr1 in the image are calculated point by point.

[0078] Based on the position of the DEM data in the aircraft coordinate system, the azimuth coordinate position Na1 and range coordinate position Nr1 in the image are calculated point by point, as follows:

[0079]

[0080]

[0081] Among them, data 载机_X The data represents the X-direction value of the DEM data in the aircraft coordinate system. 载机_Y The data represents the Y-axis value of the DEM data in the aircraft coordinate system. 载机_z The DEM data is represented in the Z-direction in the aircraft coordinate system; ΔR a The image orientation error, ΔR r dA represents the image range error, H represents the aircraft altitude, dR represents the slant range resolution, and R0 represents the closest slant range in the image.

[0082] Optionally, the DOM image generation module is specifically used to determine whether the azimuth coordinate position Na1 and range coordinate position Nr1 corresponding to the DEM point are within the range of the maximum azimuth value Na and the maximum range value Nr of the image; if Na1 or Nr1 is not within the image range, the image grayscale value corresponding to the DEM point is set to an invalid value; if both Na1 and Nr1 are within the image range, the image grayscale value corresponding to the DEM point is determined by performing bilinear or cubic convolution interpolation on the SAR image data within a preset range near the DEM point; the image grayscale value corresponding to the DEM point is obtained point by point in the above manner, thereby obtaining the final DOM image.

[0083] This invention provides an airborne interferometric synthetic aperture radar (DOM) generation device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, it implements the airborne interferometric synthetic aperture radar (DOM) generation method provided in the above embodiment.

[0084] This invention provides a computer-readable storage medium including instructions that, when executed on a computer, cause the computer to perform the airborne interferometric synthetic aperture radar DOM generation method provided in the above embodiments.

[0085] Readers should understand that in the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0086] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working process of the above-described apparatus and unit can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0087] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative. For instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed.

[0088] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of the embodiments of the present invention, depending on actual needs.

[0089] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0090] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0091] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for generating the DOM (Domain of Expansion) for airborne interferometric synthetic aperture radar, characterized in that, include: Determine the flight and processing parameters for the current slant range imaging data block; The ground coverage area of ​​the current slant range imaging data block is determined based on the flight and processing parameters and DEM data. The DEM data is interpolated based on the resolution of the current slant range imaging data block during imaging. Based on the interpolated DEM data within the ground coverage area, the position of the DEM point in the current slant range imaging data block is determined point by point; Based on the position of the DEM point in the current slant range imaging data block, the image grayscale value corresponding to the DEM point is obtained by point-by-point interpolation to obtain the final DOM image.

2. The airborne interferometric synthetic aperture radar DOM generation method according to claim 1, characterized in that, The step of determining the ground coverage of the current slant range imaging data block based on the flight and processing parameters and DEM data includes: The initial ground coverage of the current slant range imaging data block is determined using the latitude and longitude of the four corner points of the image corresponding to the current slant range imaging data block in the flight and processing parameters. The final ground coverage of the current slant range imaging data block is determined based on the initial ground coverage area, the maximum and minimum values ​​of the DEM data within the initial ground coverage area, and the flight and processing parameters.

3. The airborne interferometric synthetic aperture radar DOM generation method according to claim 2, characterized in that, The coordinates of the four corner points of the final ground coverage area of ​​the current slant range imaging data block are: (0, (Rnear-hmin / cosθ)sinθ), ((Na-1)*dA, (Rnear-hmin / cosθ)sinθ), ((Na-1)*dA, (Rfar-hmax / cosθ)sinθ), (0, (Rfar-hmax / cosθ)sinθ); Where Rfar = R0 + (Nr - 1) * dR, Rnear = R0, R0 is the nearest slant range of the image corresponding to the current slant range imaging data block in the flight and processing parameters, Nr is the distance pixel corresponding to the current slant range imaging data block in the flight and processing parameters, Na is the azimuth pixel corresponding to the current slant range imaging data block in the flight and processing parameters, dR is the slant range resolution corresponding to the current slant range imaging data block in the flight and processing parameters, dA is the azimuth resolution corresponding to the current slant range imaging data block in the flight and processing parameters, θ is the downward viewing angle at the image center corresponding to the current slant range imaging data block in the flight and processing parameters, hmax is the maximum value of the DEM data, and hmin is the minimum value of the DEM data.

4. The airborne interferometric synthetic aperture radar DOM generation method according to claim 1, characterized in that, The step of interpolating the DEM data based on the resolution of the current slant range imaging data block includes: Based on the ground resolution of the DEM data, the slant range resolution dR, the azimuth resolution dA, and the downward viewing angle θ at the image center, the interpolation factor K of the DEM data is determined, and the calculation formula is as follows: Wherein, dR is the slant range resolution corresponding to the current slant range imaging data block in the flight and processing parameters, dA is the azimuth resolution corresponding to the current slant range imaging data block in the flight and processing parameters, θ is the image center downward viewing angle corresponding to the current slant range imaging data block in the flight and processing parameters, dlon is the precision interval, and dlat is the latitude interval; ΔR s ΔR represents the approximate resolution of the current slant range imaging data block image on the ground. dem The ground resolution of the DEM data; The DEM data is interpolated using a two-dimensional linear interpolation method or a cubic convolution interpolation method based on the interpolation factor.

5. The airborne interferometric synthetic aperture radar DOM generation method according to claim 4, characterized in that, The step of determining the position of DEM points in the current slant range imaging data block based on the interpolated DEM data within the ground coverage area includes: The interpolated DEM data is then converted point by point into DEM data in the aircraft coordinate system. The conversion formula is as follows: data 载机 =(data DEM ·T 11 -(B1、L1、H1)·T 11 )·T 12 ; Among them, data 载机 Each data point contains three values: X, Y, and Z, which can be represented as (data 载机_X , data 载机_Y , data 载机_z ); data DEM This is the interpolated DEM data; (B1, L1, H1) are the starting latitude and longitude of the flight route, T 11 T is the coordinate transformation matrix between the latitude / longitude coordinate system and the Gaussian coordinate system. 12 This is the coordinate transformation matrix between the Gaussian coordinate system and the aircraft coordinate system; Based on the position of the DEM data in the aircraft coordinate system, the azimuth coordinate position Na1 and range coordinate position Nr1 in the image are calculated point by point.

6. The airborne interferometric synthetic aperture radar DOM generation method according to claim 5, characterized in that, The azimuth coordinate position Na1 and range coordinate position Nr1 in the image are calculated point by point based on the position of the DEM data in the aircraft coordinate system, as follows: Among them, data 载机_X The data represents the X-direction value of the DEM data in the aircraft coordinate system. 载机_Y The data represents the Y-axis value of the DEM data in the aircraft coordinate system. 载机_z The DEM data is represented in the Z-direction in the aircraft coordinate system; ΔR a The image orientation error, ΔR r dA represents the image range error, H represents the aircraft altitude, dR represents the slant range resolution, and R0 represents the closest slant range in the image.

7. The airborne interferometric synthetic aperture radar DOM generation method according to claim 5, characterized in that, The step of interpolating the image grayscale values ​​corresponding to the DEM points based on their positions in the current slant range imaging data block to obtain the final DOM image includes: Determine whether the azimuth coordinate position Na1 and the range coordinate position Nr1 corresponding to the DEM point are within the range of the maximum azimuth coordinate position Na and the maximum range coordinate position Nr of the image; If Na1 or Nr1 is not within the image range, the image grayscale value corresponding to the DEM point is set to an invalid value; if both Na1 and Nr1 are within the image range, the image grayscale value corresponding to the DEM point is determined by performing bilinear or cubic convolution interpolation on the SAR image data within a preset range near the DEM point. The grayscale values ​​of the image corresponding to each DEM point are obtained point by point in the manner described above, thus obtaining the final DOM image.

8. An airborne interferometric synthetic aperture radar DOM generation device, characterized in that, include: The parameter acquisition module is used to determine the flight and processing parameters of the current slant range imaging data block; The coverage determination module is used to determine the ground coverage of the current slant range imaging data block based on the flight and processing parameters and DEM data. An interpolation processing module is used to perform interpolation operations on the DEM data based on the resolution when the current slant range imaging data block is imaged. The DEM point location determination module is used to determine the position of the DEM point in the current slant range imaging data block by point based on the interpolated DEM data within the ground coverage area. The DOM image generation module is used to interpolate the image grayscale values ​​corresponding to the DEM points point by point according to the positions of the DEM points in the current slant range imaging data block, so as to obtain the final DOM image.

9. An airborne interferometric synthetic aperture radar DOM generation device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the airborne interferometric synthetic aperture radar DOM generation method as described in any one of claims 1 to 7.

10. A computer-readable storage medium comprising instructions, characterized in that, When the instructions are executed on a computer, the computer performs the airborne interferometric synthetic aperture radar DOM generation method according to any one of claims 1 to 7.

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