A fusion optimization method and system for different precision DEMs

Abstract

The application provides a fusion optimization method and system for different precision DEMs, comprising: generating an elevation correction surface through ground control points, performing elevation reference conversion on low-precision L_DEM to GL_DEM; establishing a boundary optimization transition zone, resampling GL_DEM to high-precision H_DEM based on the transition zone range, and outputting GH_DEM; performing terrain inlaying on H_DEM and GH_DEM in priority through reservation of high-precision elevation, generating P_DEM to be smoothed and corrected; deleting discontinuous parts in the area where there is a height difference step problem at the boundary of P_DEM, filling the deleted area by using bilinear interpolation, and performing Gaussian smoothing optimization processing; and outputting seamless and continuous DEM fusion tiles for application of a digital twin system. The application solves the problems of inconsistent elevation, abrupt boundary and discontinuous data and the like existing in the fusion of DEM data with different elevation references and low precision and high precision in a digital twin system of a watershed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of digital twin application of river basin, and particularly relates to a fusion optimization method and system for DEMs of different accuracies. BACKGROUND

[0002] Digital Elevation Model (DEM) is an important basic data for terrain modeling and spatial analysis in digital twin system, and is widely used in fields such as river basin hydrological simulation, disaster warning, and environmental monitoring. Digital twin system requires accurate digital modeling of the real world, and in particular in the river basin digital twin system, high-precision DEM data is crucial for simulation, analysis and decision-making. However, the acquisition of river basin DEM usually relies on multiple data sources, including satellite remote sensing, aerial photography, ground measurement, etc., which have different spatial resolutions and elevation benchmarks. If the difference between the elevation benchmark and the spatial resolution is large, direct fusion will cause obvious step-shaped abnormal terrain, affecting the visualization effect and consistency of the fused DEM. Digital twin system requires seamless fusion of DEM data, especially in the fine simulation of river basins, the boundary transition, joints and height steps have a more significant impact on the results. Especially in micro scenarios (such as small-scale river basin modeling) and close-up views, the joint flaws between data are easily exposed, causing significant visual and analytical errors. How to efficiently fuse and optimize these data to meet the high-precision requirements of river basin digital twin systems has become a key problem in the current technical field.

[0003] In order to solve the above problems, some technical methods have been proposed, but there are still some deficiencies. For example, the invention patent CN114612806A proposes to use elevation control points to correct the elevation of DEM data. This method requires the collection of a large number of high-precision elevation control points. If the distribution of control points is uneven, or the number of control points is small, the correction effect may be affected, resulting in a decline in fusion effect; the invention patent CN110874613A proposes to assign different weights to DEM data from different sources for weighted averaging. When using the weighted method to correct DEM, the elevation values in the boundary area are often affected by the differences between different data sources, especially when the boundary height difference is too large, height steps or unsmooth transitions may still occur. Especially when fusing low-precision and high-precision data, the transition in the boundary area may produce significant errors; in addition, the invention patent CN112084280A proposes to use different scales of terrain for interpolation to solve fusion. The interpolation method essentially relies on existing elevation data to calculate the elevation of unknown points, and is often suitable for cases where the elevation difference is small. When the difference between the elevation benchmark and the resolution is very large, the interpolation effect in the boundary area is often poor, and unnatural transitions or height steps may still occur in the boundary area.

[0004] Therefore, how to realize effective fusion for different precision DEMs needs to be proposed. SUMMARY

[0005] The application provides a fusion optimization method and system for different precision DEMs, to solve the defects that different precision DEMs cannot be well fused and converted in the prior art of digital twin of a river basin, so as to realize high-precision fusion of DEM data of different resolutions and benchmarks with only a small number of control points, especially for the case that the height difference is very large, and to perform smoothing processing on the step effect of the boundary area, and finally generate a seamless and continuous high-precision digital elevation model.

[0006] In a first aspect, the application provides a fusion optimization method for different precision DEMs, comprising:

[0007] obtaining preset high-precision DEM data of a first elevation reference and preset low-precision DEM data of a second elevation reference;

[0008] generating an elevation correction surface based on ground control points, converting the elevation reference corresponding to the preset low-precision DEM data into an elevation reference consistent with the preset high-precision DEM data, and generating corrected low-precision DEM data;

[0009] extracting a specified high-precision range from the preset high-precision DEM data, establishing a boundary optimization transition zone, resampling the corrected low-precision DEM data based on the boundary optimization transition zone, and generating corrected high-precision DEM data consistent with the resolution of the preset high-precision DEM data;

[0010] performing terrain inlaying on the corrected high-precision DEM data and the preset high-precision DEM data by a sampling method that gives priority to high precision, and generating DEM data to be smoothed and corrected;

[0011] deleting discontinuous regions at the boundary of the DEM data to be smoothed and corrected, filling the deleted regions by using a bilinear interpolation algorithm, removing discontinuity and noise in the terrain by using a Gaussian smoothing optimization, and generating boundary smoothing transition DEM data;

[0012] outputting seamless and continuous DEM fusion tiles for application by a digital twin system.

[0013] According to the fusion optimization method for different precision DEMs provided by the application, an elevation correction surface is generated based on ground control points, the elevation reference corresponding to the preset low-precision DEM data is converted into an elevation reference consistent with the preset high-precision DEM data, and corrected low-precision DEM data is generated, comprising:

[0014] According to the ground control point containing the first elevation, a control point vector layer is established, and a new field is stored to store the first elevation control point;

[0015] Load the preset low-precision DEM data which needs to be corrected in elevation, and ensure that the preset low-precision DEM data and the projection coordinate system of the first elevation control point are consistent;

[0016] The first elevation control point coordinates are used to extract the control point corresponding geodetic elevation value on the preset low-precision DEM data, and the value is stored in the control point vector layer field;

[0017] The control point vector layer is subjected to field operation, and the elevation difference value is obtained by subtracting the geodetic elevation value corresponding to the preset low-precision DEM data extracted by the control point from the first elevation control point elevation value;

[0018] According to the elevation difference value, an elevation correction surface layer with the same range and resolution as the preset low-precision DEM data is interpolated and generated;

[0019] The preset low-precision DEM data corresponding layer and the elevation correction surface layer are subjected to grid value superposition operation to generate the corrected low-precision DEM data.

[0020] According to the fusion optimization method for different precision DEMs provided by the application, a specified high-precision range is extracted from the preset high-precision DEM data, a boundary optimization transition zone is established, and the modified low-precision DEM data is resampled based on the boundary optimization transition zone to generate modified high-precision DEM data with the same resolution as the preset high-precision DEM data, including:

[0021] The outer boundary range is extracted from the preset high-precision DEM data to generate a first vector range surface;

[0022] Based on the first vector range surface, a buffer zone analysis is performed to obtain the boundary optimization transition zone after the first preset distance is expanded, and a second vector range surface containing the preset high-precision DEM data range and the transition zone range is generated;

[0023] Based on the second vector range surface, the modified low-precision DEM data is cut and resampled to regenerate the modified high-precision DEM data with the same resolution as the preset high-precision DEM data.

[0024] According to the fusion optimization method for different precision DEMs provided by the application, the modified high-precision DEM data and the preset high-precision DEM data are topographically inlaid by a sampling method which gives priority to high-precision to generate DEM data to be smoothed and corrected, including:

[0025] Add the preset high-precision DEM data and the corrected high-precision DEM data respectively, and superimpose the layer corresponding to the preset high-precision DEM data on the layer corresponding to the corrected high-precision DEM data.

[0026] The preset high-precision DEM data and the corrected high-precision DEM data are subjected to terrain inlay processing in an upper layer sampling mode, and are combined into the DEM data to be smoothed and corrected.

[0027] According to the fusion optimization method for different precision DEMs provided by the application, the upper layer sampling mode comprises:

[0028] The elevation of the overlapping area is valued according to the first terrain layer, and the elevation of the non-overlapping area is valued according to the respective terrain layer.

[0029] According to the fusion optimization method for different precision DEMs provided by the application, the discontinuous region is deleted in the area with a height difference step problem at the boundary of the DEM data to be smoothed and corrected, the deleted area is filled by using a bilinear interpolation algorithm, the discontinuity and noise in the terrain are removed by using a Gaussian smoothing optimization, and the boundary smoothed transition DEM data is generated, comprising:

[0030] The first smoothed boundary line on the side of the preset high-precision terrain area is generated by moving the first vector range inward by a second preset distance.

[0031] The second smoothed boundary line on the side of the preset low-precision terrain area is generated by moving the first vector range outward by a third preset distance.

[0032] In the interval range of the first smoothed boundary line and the second smoothed boundary line, the segmented terrain deletion is performed on the existing height difference step area, wherein the segmentation of the mountainous area is taken as an interval with a variable slope point, and the segmentation of the flat area is taken as an interval with different elevation planes.

[0033] The deleted blank area is filled by using a bilinear interpolation algorithm based on local terrain features, so that the terrain with a step boundary is smoothly transitioned, and a seamless and continuous terrain is generated.

[0034] The interpolated terrain is subjected to Gaussian smoothing optimization processing, and the discontinuity and noise in the terrain are removed, so that the boundary smoothed transition DEM data is generated.

[0035] According to the fusion optimization method for different precision DEMs provided by the application, a seamless and continuous DEM fusion tile is output, comprising:

[0036] The fusion slice is performed by a slice tool, terrain slices of layers corresponding to the DEM data after boundary smoothing and layers corresponding to the modified low-precision DEM data are performed, and the DEM fusion tile is output.

[0037] In a second aspect, the present application further provides a fusion optimization system for different precision DEMs, comprising:

[0038] An acquisition module is configured to acquire preset high-precision DEM data of a first height reference and preset low-precision DEM data of a second height reference;

[0039] A conversion module is configured to generate a height correction surface based on ground control points, convert a height reference corresponding to the preset low-precision DEM data into a height reference consistent with the preset high-precision DEM data, and generate modified low-precision DEM data;

[0040] A building module is configured to extract a specified high-precision range from the preset high-precision DEM data, build a boundary optimization transition zone, resample the modified low-precision DEM data based on the boundary optimization transition zone, and generate modified high-precision DEM data consistent with the resolution of the preset high-precision DEM data;

[0041] A tiling module is configured to perform terrain tiling on the modified high-precision DEM data and the preset high-precision DEM data by a sampling method that gives priority to high precision, and generate DEM data to be smoothed and corrected;

[0042] An optimization module is configured to delete discontinuous regions at a high-difference step problem area at a boundary of the DEM data to be smoothed and corrected, fill the deleted regions by using a bilinear interpolation algorithm, remove discontinuity and noise in the terrain by using a Gaussian smoothing optimization, and generate boundary smoothing transition DEM data;

[0043] An output module is configured to output seamless and continuous DEM fusion tiles for application by a digital twin system.

[0044] In a third aspect, the present application further provides an electronic device, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein the processor implements the fusion optimization method for different precision DEMs as described above when executing the program.

[0045] In a fourth aspect, the present application further provides a non-transitory computer readable storage medium having a computer program stored thereon, wherein the computer program is executable by a processor to implement the fusion optimization method for different precision DEMs as described above.

[0046] The application provides a fusion optimization method and system for DEMs with different precisions.

[0047] The application can effectively process the conversion between low-precision and high-precision DEM data, especially in the case of large elevation difference between different references, thereby improving the data fusion precision, smoothly integrating different source data and eliminating the problems caused by inconsistent elevations. BRIEF DESCRIPTION OF DRAWINGS

[0048] In order to more clearly illustrate the technical solutions in the application or prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are some embodiments of the application, and other drawings can be obtained by those skilled in the art without any creative effort based on these drawings.

[0049] Figure 1 Fig. 1 is one of the flow diagrams of the fusion optimization method for DEMs with different precisions provided by the application;

[0050] Figure 2 Fig. 2 is another of the flow diagrams of the fusion optimization method for DEMs with different precisions provided by the application;

[0051] Figure 3is a height reference conversion flowchart provided by the present application;

[0052] Figure 4 is a boundary smoothing transition C_DEM flowchart provided by the present application;

[0053] Figure 5 is an embodiment study area map provided by the present application;

[0054] Figure 6 is a three-dimensional rendering map and an elevation profile map of the embodiment of the present application before the high-precision terrain (H_DEM) of the national height reference 85 of China and the low-precision terrain (L_DEM) of the reference ellipsoid reference are fused;

[0055] Figure 7 is a three-dimensional rendering map and an elevation profile map of the embodiment of the present application after the L_DEM is corrected by the height reference to generate the GL_DEM and the H_DEM is superimposed;

[0056] Figure 8 is a final effect map of the DEM fusion and boundary optimization method of different references and precisions provided by the present application;

[0057] Figure 9 is a comparison map after the terrain boundary is smoothed and optimized in the embodiment of the present application;

[0058] Figure 10 is a structural schematic diagram of the fusion and optimization system for DEMs of different precisions provided by the present application;

[0059] Figure 11 is a structural schematic diagram of an electronic device provided by the present application. DETAILED DESCRIPTION

[0060] In order to make the purpose, technical scheme and advantages of the present application clearer, the technical scheme in the present application will be described clearly and completely below in combination with the drawings in the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0061] Figure 1 is one of the process schematic diagrams of the fusion and optimization method for DEMs of different precisions provided by the embodiment of the present application, as shown in Figure 1 , comprising:

[0062] Step 100: obtaining preset high-precision DEM data of a first height reference and preset low-precision DEM data of a second height reference;

[0063] Step 200: Generate an elevation correction front based on ground control points, convert the elevation datum corresponding to the preset low-precision DEM data into an elevation datum consistent with the preset high-precision DEM data, and generate corrected low-precision DEM data.

[0064] Step 300: Extract a specified high-precision range from the preset high-precision DEM data, establish a boundary optimization transition zone, and resample the corrected low-precision DEM data based on the boundary optimization transition zone to generate corrected high-precision DEM data with the same resolution as the preset high-precision DEM data.

[0065] Step 400: The corrected high-precision DEM data and the preset high-precision DEM data are mosaicked using a sampling method that prioritizes high precision to generate DEM data to be smoothed and corrected.

[0066] Step 500: For the DEM data to be smoothed and corrected, delete the discontinuous areas at the boundary of the area with elevation steps, fill in the deleted areas using the bilinear interpolation algorithm, and use Gaussian smoothing optimization to remove discontinuities and noise in the terrain, generating DEM data with smooth boundary transition.

[0067] Step 600: Output seamless and continuous DEM fusion tiles for use in digital twin systems.

[0068] Specifically, such as Figure 2 As shown, the specific steps of the overall implementation process of this invention include:

[0069] (1) In this embodiment, the DEM data of the study area are from high-precision H_DEM and low-precision L_DEM respectively. The H_DEM data adopts the national 85 elevation datum and has high accuracy, while the L_DEM data adopts the reference ellipsoid datum and has low accuracy. Based on this, a modified front face is established by using ground control points (image control points collected by GPS RTK) through the difference algorithm. This modified front face represents the correction value of the low-precision L_DEM under the target elevation datum, which is used to convert the datum of the L_DEM data to a datum consistent with the H_DEM, and generate a low-precision GL_DEM;

[0070] (2) Extract specified high-precision regions from the H_DEM data and establish boundary optimization transition zones based on these regions. The design of the transition zones considers the smooth transition of boundary elevation differences, ensuring that the data gradually transitions to high-precision data within the transition zones. On this basis, the GL_DEM is resampled to generate a GH_DEM with the same resolution as the H_DEM. The resampling method uses a bilinear interpolation algorithm to ensure the accuracy and continuity of the data;

[0071] (3) The resampled GH DEM and H DEM are terrain mosaicked. A high-precision elevation priority sampling strategy is adopted to retain the data of high-precision H DEM in the mosaicking process, ensuring the accuracy of the high-precision area. The final P DEM contains the fusion results from two different precision data, but further optimization is still needed to eliminate the boundary height difference;

[0072] (4) In the boundary part of P DEM, there is a height difference step problem. The discontinuous part is deleted, the discontinuous area is filled using a bilinear interpolation algorithm, and the data is further optimized using a Gaussian smoothing algorithm to generate a C DEM with smooth transition of the boundary. The C DEM can be used to accurately display rivers and roads and other infrastructure in the digital twin system;

[0073] (5) Finally, seamless and continuous DEM fusion tiles are output, which meet the needs of the digital twin system for high-precision and detailed display. Rivers can be normally laid, highways are connected smoothly, and slopes conform to the actual situation, ensuring efficient operation of the digital twin system in terrain modeling and visualization applications.

[0074] Optionally, as shown in Figure 3 step (1), the process of height reference conversion includes the following steps:

[0075] (1-1) Import the ground control points containing the national 85 elevation, establish a control point vector layer, and create a new field to store the control point national 85 elevation N_Height;

[0076] (1-2) Load the low-precision L DEM data of the geodetic height reference that needs to be corrected, and ensure that the projection coordinate system is consistent with the control points.

[0077] (1-3) Extract the control point corresponding geodetic elevation value on the L DEM data to be corrected using the control point coordinates, and store it to the control point vector layer field G_Height;

[0078] (1-4) Perform field operation on the control point vector layer to calculate the elevation difference Dh, and the calculation method is:

[0079] Dh=N_Height-G_Height

[0080] In the above formula, N_Height is the control point national 85 elevation value, and G_Height is the control point extracted low-precision L DEM corresponding geodetic elevation value;

[0081] (1-5) According to the elevation difference Dh, a high-precision L DEM corresponding to the range and resolution of L DEM is interpolated to generate a high-precision L DEM corresponding to the range and resolution of L DEM.

[0082] (1-6) After the to-be-corrected large-geodetic-height L_DEM layer is subjected to a grid value superposition operation with the elevation correction surface layer C_DEM, a topographic data GL_DEM of the national 85 elevation datum is generated.

[0083] Optionally, in step (2), the process of generating GH_DEM consistent with the resolution of H_DEM includes the following steps:

[0084] (2-1) A vector range surface H_POLYGON is generated by extracting an outer boundary range from the high-precision H_DEM data.

[0085] (2-2) A buffer analysis is performed based on the vector range surface H_POLYGON to obtain an optimized transition zone after the boundary is expanded by a certain distance, and a vector range surface B_POLYGON containing the H_DEM range and the transition zone range is generated.

[0086] (2-3) The low-precision GL_DEM of the national 85 elevation datum is cut based on the range surface B_POLYGON, and resampling processing is performed to regenerate GH_DEM consistent with the resolution of H_DEM.

[0087] Optionally, in step (3), the process of generating the to-be-smoothed correction P_DEM includes the following steps:

[0088] (3-1) The high-precision H_DEM and the resampled GH_DEM are added respectively, and the layer order is adjusted to be H_DEM superimposed on GH_DEM, so as to ensure that the high-precision topography covers the low-precision topography.

[0089] (3-2) The topography inlay processing is performed on H_DEM and GH_DEM in the sampling mode of the upper layer, and is combined into a to-be-smoothed correction P_DEM.

[0090] The sampling mode of the upper layer is that the elevation in the overlapping area is taken according to the first topographic layer, and the elevation in the non-overlapping area is taken according to the respective topographic layer.

[0091] As a preferred embodiment of the present application, as shown in Figure 4 in step (4), the process of generating the boundary smooth transition C_DEM includes the following steps:

[0092] (4-1) A smooth boundary line S_POLYGON on the side of the high-precision topography is generated by retaining as many high-precision topography parts as possible within a certain distance (about 1-2 grid distances of high-precision topography) from the H_POLYGON range boundary.

[0093] (4-2), generating a smooth boundary line E_POLYGON outside the H_POLYGON range boundary by a certain distance (about 1 grid distance of low-precision terrain);

[0094] (4-3), performing segmented terrain deletion on the existing high-difference step region within the range of S_POLYGON and E_POLYGON, with the segments of the mountainous part being the intervals of the variable slope points and the segments of the flat part being the intervals of different elevation planes;

[0095] (4-4), reasonably filling the deleted blank area by bilinear interpolation based on local terrain features, smoothing the terrain transition at the step boundary, and generating seamless and continuous terrain;

[0096] (4-5), performing Gaussian smoothing optimization processing on the interpolated terrain to remove discontinuities and noise in the terrain, making the DEM data smoother and more natural, and finally generating a boundary-smoothed terrain C_DEM.

[0097] Optionally, in step (5), the process of outputting the seamless and continuous DEM fusion tile includes:

[0098] The DEM fusion tile is output by performing terrain slicing according to the layer order of C_DEM and GL_DEM together through the fusion slicing tool, for application in a digital twin system.

[0099] In one embodiment, as shown in Figure 5 , the study area is located in the upstream reservoir and downstream flooded area of a certain watershed, and contains multiple important geographical elements such as rivers, roads, and artificial facilities. The terrain in this area is complex, with hills and plains alternating, and rivers flowing along the valley. The DEM data in this area is derived from two different precision and reference topographic data: one is high-precision DEM (H_DEM), which uses unmanned aerial vehicles equipped with laser radar equipment to collect three-dimensional point cloud data, and after filtering, ground point classification, registration, and simplification, generates high-precision DEM results. The results use the national 85 elevation reference, have high precision, and are suitable for precise terrain modeling and digital twin applications; the other is low-precision DEM (L_DEM), which is obtained by remote sensing satellite. This data uses a reference ellipsoid reference, has lower precision, is easier to obtain, is lower in price, and due to the use of the reference ellipsoid reference, there is an elevation difference between the high-precision DEM.

[0100] In this area, due to the differences in different elevation references and precision, the two DEMs will have very obvious fault phenomena at the boundary after superimposition (as Figure 6As shown in the left-middle figure, the elevation difference ranges from 10 to 40 meters, posing certain challenges to the application of digital twins for the watershed. Furthermore, the study area contains numerous rivers and highways, requiring a high degree of terrain continuity; data discontinuity and elevation inconsistencies can prevent the accurate representation of these important geographical features.

[0101] like Figure 6 As shown, Figure 6 The left-middle image shows the 3D effect of overlaying the high-precision topographic data (H_DEM) of the National 85 Elevation Datum with the low-precision topographic data (L_DEM) of the reference ellipsoidal datum. Due to the significant difference in the datum values, obvious faulting occurs at the boundaries of the two topographic data. Figure 6 The right image shows an elevation profile at the boundary of two terrain features, with a height difference of more than 20 meters, resulting in an abnormal terrain elevation.

[0102] like Figure 7 As shown, Figure 7 The left-middle image shows the corrected front view generated from the low-precision terrain L_DEM through control points (Table 1). The resulting 3D effect is achieved by overlaying the GL_DEM and H_DEM after elevation datum correction. As can be seen from the image, the obvious terrain faults have largely disappeared, but terrain discontinuities and seams still exist. Figure 7 The right-hand image shows the elevation profiles at the two terrain boundaries after elevation datum correction. The large elevation difference at the boundaries has been corrected to a smaller range, approximately 2 meters, laying the foundation for smooth, seamless integration later. See Table 1 for details.

[0103] Table 1 Coordinates of Elevation Control Points

[0104]

[0105] like Figure 8 As shown, Figure 8 The left-middle image shows the result of removing discontinuous terrain sections and filling in the discontinuous areas using a bilinear interpolation algorithm, generating a 3D rendering of the terrain fusion. As can be seen from the image, a smooth and seamless terrain transition at the boundaries was achieved. Figure 8 The right-middle figure shows the elevation profile after merging two terrains with different references and accuracies. As can be seen from the figure, there are no elevation anomalies at the terrain boundaries, the slope is normal, and the transition at the boundaries is smooth and natural, indicating a good fusion effect. This verifies the practicality and effectiveness of the present invention.

[0106] like Figure 9 As shown, Figure 9 The left-middle image shows the effect before Gaussian smoothing optimization. Figure 9 The middle right image shows the effect after Gaussian smoothing optimization. As can be seen from the image, if there are some terrain noise or slight discontinuities after terrain fusion, Gaussian windows can be used for further optimization.

[0107] The fusion optimization system for DEMs with different precisions provided by the present application is described below, and the fusion optimization system for DEMs with different precisions described below can be mutually referred to the fusion optimization method for DEMs with different precisions described above.

[0108] Figure 10 is a structural schematic diagram of the fusion optimization system for DEMs with different precisions provided by the present application, as Figure 10 shown, comprising: an acquisition module 1001, a conversion module 1002, an establishment module 1003, an inlay module 1004, an optimization module 1005 and an output module 1006, wherein:

[0109] The acquisition module 1001 is configured to acquire preset high-precision DEM data of a first height reference and preset low-precision DEM data of a second height reference; the conversion module 1002 is configured to generate a height correction surface based on ground control points, convert the height reference corresponding to the preset low-precision DEM data into a height reference consistent with the preset high-precision DEM data, and generate corrected low-precision DEM data; the establishment module 1003 is configured to extract a specified high-precision range from the preset high-precision DEM data, establish a boundary optimization transition zone, resample the corrected low-precision DEM data based on the boundary optimization transition zone, and generate corrected high-precision DEM data consistent with the resolution of the preset high-precision DEM data; the inlay module 1004 is configured to perform terrain inlaying on the corrected high-precision DEM data and the preset high-precision DEM data by a sampling method that gives priority to preserving high precision, and generate DEM data to be smoothed and corrected; the optimization module 1005 is configured to delete discontinuous regions at the boundary of the DEM data to be smoothed and corrected, fill the deleted regions by using a bilinear interpolation algorithm, remove discontinuities and noise in the terrain by using a Gaussian smoothing optimization, and generate boundary-smoothed transition DEM data; and the output module 1006 is configured to output seamless and continuous DEM fusion tiles for application by a digital twin system.

[0110] Figure 11 An example of an entity structure schematic diagram of an electronic device is shown in Figure 11As shown, the electronic device can include a processor 1110, a communications interface 1120, a memory 1130, and a communications bus 1140, wherein the processor 1110, the communications interface 1120, and the memory 1130 complete mutual communication through the communications bus 1140. The processor 1110 can invoke a logical instruction in the memory 1130 to execute a fusion optimization method for different precision DEMs, which includes: obtaining preset high-precision DEM data of a first elevation reference and preset low-precision DEM data of a second elevation reference; generating an elevation correction surface based on a ground control point, converting the elevation reference corresponding to the preset low-precision DEM data into an elevation reference consistent with the preset high-precision DEM data to generate corrected low-precision DEM data; extracting a specified high-precision range from the preset high-precision DEM data, establishing a boundary optimization transition zone, resampling the corrected low-precision DEM data based on the boundary optimization transition zone to generate corrected high-precision DEM data consistent with the resolution of the preset high-precision DEM data; performing terrain inlaying on the corrected high-precision DEM data and the preset high-precision DEM data through a sampling method that gives priority to high precision, to generate DEM data to be smoothed and corrected; deleting discontinuous regions at the boundary of the DEM data to be smoothed and corrected, filling the deleted regions using a bilinear interpolation algorithm, removing discontinuity and noise in the terrain using a Gaussian smoothing optimization, to generate boundary-smoothed transition DEM data; and outputting seamless and continuous DEM fusion tiles for application by a digital twin system.

[0111] In addition, the logical instructions in the memory 1130 described above can be implemented in the form of a software functional unit and sold or used as an independent product, and can be stored in a computer-readable storage medium. Based on this understanding, the technical solutions of the present application or the part of the technical solutions that essentially contribute to the prior art or the part of the technical solutions can be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in various embodiments of the present application. The aforementioned storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and various program code storage media.

[0112] In another aspect, the present application also provides a non-transitory computer readable storage medium having stored thereon a computer program, which, when executed by a processor, implements the fusion optimization method for DEMs of different accuracies provided by the above method, and the method comprises: obtaining preset high-precision DEM data of a first height reference and preset low-precision DEM data of a second height reference; generating an elevation correction surface based on ground control points, converting the height reference corresponding to the preset low-precision DEM data into a height reference consistent with the preset high-precision DEM data to generate corrected low-precision DEM data; extracting a specified high-precision range from the preset high-precision DEM data, establishing a boundary optimized transition zone, resampling the corrected low-precision DEM data based on the boundary optimized transition zone to generate corrected high-precision DEM data consistent with the resolution of the preset high-precision DEM data; performing terrain inlaying on the corrected high-precision DEM data and the preset high-precision DEM data by a sampling method that gives priority to high precision to generate DEM data to be smoothed and corrected; deleting discontinuous regions at the boundary of the DEM data to be smoothed and corrected where there are height difference steps, filling the deleted regions using a bilinear interpolation algorithm, removing discontinuities and noise in the terrain using a Gaussian smoothing optimization, and generating boundary smoothed transition DEM data; and outputting seamless and continuous DEM fusion tiles for application by a digital twin system.

[0113] The device embodiments described above are merely illustrative, wherein the units illustrated as separate components can or can not be physically separated, and the components illustrated as units can or can not be physical units, i.e., can be located in one place or distributed on multiple network units. Part or all of the modules can be selected to achieve the purpose of the embodiment scheme according to actual needs. Those skilled in the art can understand and implement without creative labor.

[0114] From the above description of the embodiments, those skilled in the art can clearly understand that the embodiments can be implemented by means of software and the necessary general hardware platform, and of course can also be implemented by hardware. Based on such understanding, the above technical solutions can be embodied in the form of a software product, which can be stored in a computer readable storage medium, such as a ROM / RAM, a magnetic disk, an optical disk, etc., and includes a number of instructions to make a computer device (which can be a personal computer, a server, or a network device, etc.) execute the methods described in each embodiment or some parts of the embodiments.

[0115] It should be pointed out finally that the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit the same; and although the present application has been described in detail with reference to the foregoing embodiments, it should be appreciated by those skilled in the art that the technical solutions recorded in the foregoing embodiments can be modified, or some technical features thereof can be replaced equivalently; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A fusion optimization method for different precision DEMs, characterized in that, The method comprises the following steps: acquire pre-set high-precision DEM data of first elevation datum and pre-set low-precision DEM data of second elevation datum; generate an elevation correction surface based on ground control points, convert the elevation datum corresponding to the pre-set low-precision DEM data into an elevation datum consistent with the pre-set high-precision DEM data, and generate corrected low-precision DEM data; establish a control point vector layer according to the ground control points containing the first elevation, and newly create a field to store the first elevation control points; load the pre-set low-precision DEM data that needs to be corrected in elevation, and ensure that the projection coordinate system of the pre-set low-precision DEM data is consistent with the first elevation control points; extract the geodetic height value corresponding to the control points on the pre-set low-precision DEM data using the first elevation control point coordinates, and store it in the control point vector layer field; perform field operation on the control point vector layer, subtract the geodetic height value of the control point extracted from the pre-set low-precision DEM data from the first elevation control point height value to obtain the elevation difference value; interpolate to generate an elevation correction surface layer with the same range and resolution as the pre-set low-precision DEM data according to the elevation difference value; perform raster value overlay operation on the layer corresponding to the pre-set low-precision DEM data and the elevation correction surface layer to generate the corrected low-precision DEM data; extract a specified high-precision range from the pre-set high-precision DEM data, establish a boundary optimized transition zone, and resample the corrected low-precision DEM data based on the boundary optimized transition zone to generate corrected high-precision DEM data with the same resolution as the pre-set high-precision DEM data; extract the outer boundary range from the pre-set high-precision DEM data to generate a first vector range surface; perform buffer zone analysis based on the first vector range surface to obtain the boundary optimized transition zone after expanding by a first preset distance, and generate a second vector range surface containing the range of the pre-set high-precision DEM data and the range of the transition zone; based on the second vector range surface, cut and resample the corrected low-precision DEM data to regenerate the corrected high-precision DEM data with the same resolution as the pre-set high-precision DEM data; perform terrain inlaying on the corrected high-precision DEM data and the pre-set high-precision DEM data by retaining high-precision priority to generate DEM data to be smoothed and corrected; delete the discontinuous area at the boundary of the DEM data to be smoothed and corrected, fill the deleted area by using a bilinear interpolation algorithm, remove the discontinuity and noise in the terrain by using a Gaussian smoothing optimization, and generate boundary smoothed transition DEM data; output seamless and continuous DEM fusion tiles for application by a digital twin system.

2. The fusion optimization method for different precision DEMs according to claim 1, characterized in that, The method for performing terrain inlaying on the corrected high-precision DEM data and the pre-set high-precision DEM data by retaining high-precision priority to generate DEM data to be smoothed and corrected comprises the following steps: add the pre-set high-precision DEM data and the corrected high-precision DEM data respectively, and superimpose the layer corresponding to the pre-set high-precision DEM data on the layer corresponding to the corrected high-precision DEM data. The preset high-precision DEM data and the corrected high-precision DEM data are subjected to terrain inlay processing in an upper layer sampling mode to be combined into the DEM data to be smoothed and corrected.

3. The fusion optimization method for different precision DEMs according to claim 2, characterized in that, The upper layer sampling mode comprises: The elevation of the overlapping area is valued according to the first terrain layer, and the elevation of the non-overlapping area is valued according to the respective terrain layer.

4. The fusion optimization method for different precision DEMs of claim 1, wherein, The discontinuous region of the area with the problem of height difference steps at the boundary of the DEM data to be smoothed and corrected is deleted, the deleted region is filled by using a bilinear interpolation algorithm, and the discontinuity and noise in the terrain are removed by using Gaussian smoothing optimization to generate the boundary smooth transition DEM data, comprising: A first smooth boundary line on the side of the preset high-precision terrain region is generated by moving the first vector range inward by a second preset distance; A second smooth boundary line on the side of the preset low-precision terrain region is generated by moving the first vector range outward by a third preset distance; The segmented terrain of the existing height difference step area in the interval range of the first smooth boundary line and the second smooth boundary line is deleted, wherein the segmentation of the mountainous area is taken as the interval, and the segmentation of the flat area is taken as the interval of different elevation planes; The deleted blank area is filled by using a bilinear interpolation algorithm based on local terrain characteristics to make the terrain at the step boundary smooth transition to generate seamless and continuous terrain; The interpolated terrain is subjected to Gaussian smoothing optimization to remove the discontinuity and noise in the terrain to generate the boundary smooth transition DEM data.

5. The method for fusion optimization for different precision DEMs according to claim 1, characterized in that, The seamless and continuous DEM fusion tiles are output, comprising: The DEM fusion tiles are output by performing fusion slicing through a slicing tool, performing terrain slicing on the layers corresponding to the boundary smooth transition DEM data and the layers corresponding to the corrected low-precision DEM data, and outputting the DEM fusion tiles.

6. A system for fusion optimization for different accuracy DEMs based on the method for fusion optimization for different accuracy DEMs according to any one of claims 1 to 5, characterized in that, Comprising: An acquisition module is configured to acquire preset high-precision DEM data of a first elevation reference and preset low-precision DEM data of a second elevation reference; A conversion module is configured to generate an elevation correction surface based on ground control points, convert the elevation reference corresponding to the preset low-precision DEM data into an elevation reference consistent with the preset high-precision DEM data, and generate corrected low-precision DEM data; An establishment module is configured to extract a specified high-precision range from the preset high-precision DEM data, establish a boundary optimization transition zone, resample the corrected low-precision DEM data based on the boundary optimization transition zone, and generate corrected high-precision DEM data consistent with the resolution of the preset high-precision DEM data; An inlay module is configured to perform terrain inlaying on the corrected high-precision DEM data and the preset high-precision DEM data by using a sampling mode that gives priority to high precision to generate DEM data to be smoothed and corrected; An optimization module is configured to delete the discontinuous region of the area with the problem of height difference steps at the boundary of the DEM data to be smoothed and corrected, fill the deleted region by using a bilinear interpolation algorithm, and remove the discontinuity and noise in the terrain by using Gaussian smoothing optimization to generate the boundary smooth transition DEM data; An output module is configured to output seamless and continuous DEM fusion tiles for application by a digital twin system.

7. An electronic device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, The processor implements the fusion optimization method for DEMs with different precisions as claimed in any one of claims 1 to 5 when executing the program.

8. A non-transitory computer-readable storage medium having stored thereon a computer program, characterized in that, The computer program implements the fusion optimization method for DEMs with different precisions as claimed in any one of claims 1 to 5 when executed by the processor.

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