CN117953172A - Terrain model generation method, device, equipment and storage medium - Google Patents

Abstract

The disclosure provides a terrain model generation method, a terrain model generation device, terrain model generation equipment and a storage medium. The method comprises the following steps: acquiring elevation data of a target terrain area; generating a first terrain model of the non-grid structure according to the elevation data; determining a plurality of first areas in a first terrain model according to the actual terrain state of the target terrain area; determining a first depth value of each first region, wherein the first depth value represents the number of times that the grid surface in the corresponding first region is divided according to a quadtree division mode; performing quadtree recursive partitioning operation on the corresponding first region according to each first depth value until the depth values of the grid planes obtained by partitioning in all the first partitioned regions are matched with the first depth values of the corresponding regions; and performing grid smoothing operation on the divided first terrain model to generate a target terrain model corresponding to the target terrain area. By the method, the precision of generating the terrain model can be improved, and the target terrain model which is closer to the actual terrain state of the actual terrain area is obtained.

Description

Terrain model generation method, device, equipment and storage medium

The application claims priority of China patent application filed at 2023, 12 and 26 months with application number 2023118132358 and entitled "method, device, apparatus and storage Medium for generating terrain model", which is incorporated herein by reference in its entirety.

Technical Field

The disclosure relates to the technical field of three-dimensional digital terrain modeling, in particular to a terrain model generation method, a device, equipment and a storage medium.

Background

When the three-dimensional terrain model is constructed, in order to vividly reflect the terrain features, the corresponding areas in the terrain grid surface are generally subdivided into grids with different numbers according to the fluctuation states of different areas in the actual terrain, so that the three-dimensional terrain model corresponding to the actual terrain features is constructed through the sparseness and the density degree of the grid numbers in the different areas in the whole terrain grid surface.

In general, the grid subdivision operation employs a manner of grid subdivision of a terrain grid surface based on a fixed grid edge or grid subdivision of a terrain grid surface according to a fixed resolution. Although the method is easy to realize, for different areas in the same terrain grid surface, the phenomenon that the constructed terrain grid surface is discontinuous is caused by conducting grid subdivision operation to different degrees in different areas while ensuring that the surface smoothness is excessive between the different areas.

Disclosure of Invention

In order to improve accuracy and visual effect of a terrain model, the disclosure provides a terrain model generation method, a device, equipment and a storage medium.

In a first aspect, an embodiment of the present disclosure provides a terrain model generating method, including: acquiring elevation data of a target terrain area; generating a first terrain model of a non-grid structure according to the elevation data; determining a plurality of first areas in a first terrain model according to the actual terrain state of the target terrain area; determining a first depth value of each first region, wherein the first depth value represents the number of times that the grid surface in the corresponding first region is divided according to a quadtree division mode; performing quadtree recursive partitioning operation on the corresponding first region according to each first depth value until the depth values of the grid planes obtained by partitioning in all the first regions are matched with the first depth values of the corresponding first regions; and performing grid smoothing operation on the divided first terrain model to generate a target terrain model corresponding to the target terrain area.

In an alternative embodiment, generating a first terrain model of the non-mesh structure from the elevation data includes: generating a second terrain model comprising a plurality of grid surfaces according to the elevation data; based on the dimensions and the vertex coordinates of the second terrain model, a first terrain model of a non-mesh structure having the same dimensions and vertex coordinates as the second terrain model is generated.

In an alternative embodiment, determining a plurality of first regions in a first terrain model based on an actual terrain state of a target terrain region includes: determining a plurality of second areas in a second terrain model according to the actual terrain state of the target terrain area; and determining a plurality of first areas corresponding to the plurality of second areas in the first terrain model according to the corresponding relation of the first terrain model and the second terrain model in the space position.

In an alternative embodiment, determining the first depth value for each first region includes: determining a curvature value of each grid surface in the second terrain model; determining a second depth value of the corresponding second region according to the curvature values of the grid surfaces in each second region; and taking the second depth value of each second area as the first depth value of the corresponding first area.

In an alternative embodiment, determining the second depth value of each second region according to the curvature values of the plurality of grid surfaces in each second region includes: inputting curvature values of a plurality of grid planes in each second area into a preset mapping function, and receiving depth values output by the preset mapping function for each grid plane in the corresponding second area; and determining a second depth value of the corresponding second region according to the depth value of each grid surface in each second region.

In an alternative embodiment, determining the second depth value of each second region according to the curvature values of the plurality of grid surfaces in each second region includes: determining curvature values of the corresponding second areas according to curvature values of the grid surfaces in each second area; and inputting the curvature value of each second region into a preset mapping function, and receiving a second depth value output by the preset mapping function for the corresponding second region.

In an alternative embodiment, performing a mesh smoothing operation on the divided first terrain model to generate a target terrain model corresponding to the target terrain area, including: performing grid smoothing operation on the divided first terrain model to obtain a third terrain model; performing detail level division on the third terrain model according to different viewpoint positions to obtain a plurality of target grid surfaces corresponding to different detail levels; a target terrain model corresponding to the target terrain area is generated based on the plurality of target mesh surfaces.

In a second aspect, an embodiment of the present disclosure provides a terrain model generating apparatus, including: the acquisition module is used for acquiring elevation data of the target terrain area; the generation module is used for generating a first terrain model of a non-grid structure according to the elevation data; a determining module for determining a plurality of first areas in a first terrain model according to an actual terrain state of the target terrain area; determining a first depth value of each first region, wherein the first depth value represents the number of times that the grid surface in the corresponding first region is divided according to a quadtree division mode; the first processing module is used for executing the quadtree recursive division operation on the corresponding first area according to each first depth value until the depth values of the grid surfaces obtained by division in all the first areas are matched with the first depth values of the corresponding first areas; and the second processing module is used for carrying out grid smoothing operation on the divided first terrain model and generating a target terrain model corresponding to the target terrain area.

In an alternative embodiment, the generating module is configured to generate, according to the elevation data, a first terrain model of a non-grid structure, specifically: the generation module is used for: generating a second terrain model comprising a plurality of grid surfaces according to the elevation data; based on the dimensions and the vertex coordinates of the second terrain model, a first terrain model of a non-mesh structure having the same dimensions and vertex coordinates as the second terrain model is generated.

In an alternative embodiment, the determining module is configured to determine a plurality of first areas in the first terrain model according to an actual terrain state of the target terrain area, specifically: the determining module is used for: determining a plurality of second areas in a second terrain model according to the actual terrain state of the target terrain area; and determining a plurality of first areas corresponding to the plurality of second areas in the first terrain model according to the corresponding relation of the first terrain model and the second terrain model in the space position.

In an alternative embodiment, the determining module is configured to determine a first depth value of each first area, specifically: the determining module is used for: determining a curvature value of each grid surface in the second terrain model; determining a second depth value of the corresponding second region according to the curvature values of the grid surfaces in each second region; and taking the second depth value of each second area as the first depth value of the corresponding first area.

In an optional embodiment, the determining module is configured to determine, according to curvature values of the plurality of grid planes in each second area, a second depth value of the corresponding second area, specifically: the determining module is used for: inputting curvature values of a plurality of grid planes in each second area into a preset mapping function, and receiving depth values output by the preset mapping function for each grid plane in the corresponding second area; and determining a second depth value of the corresponding second region according to the depth value of each grid surface in each second region.

In an optional embodiment, the determining module is configured to determine, according to curvature values of the plurality of grid planes in each second area, a second depth value of the corresponding second area, specifically: the determining module is used for: determining curvature values of the corresponding second areas according to curvature values of the grid surfaces in each second area; and inputting the curvature value of each second region into a preset mapping function, and receiving a second depth value output by the preset mapping function for the corresponding second region.

In an optional implementation manner, the second processing module is configured to perform a grid smoothing operation on the divided first terrain model, and generate a target terrain model corresponding to the target terrain area, where the method specifically includes: the second processing module is used for: performing grid smoothing operation on the divided first terrain model to obtain a third terrain model; performing detail level division on the third terrain model according to different viewpoint positions to obtain a plurality of target grid surfaces corresponding to different detail levels; a target terrain model corresponding to the target terrain area is generated based on the plurality of target mesh surfaces.

In a third aspect, an embodiment of the present disclosure provides an electronic device, including: a memory for storing a computer program product; and a processor for executing the computer program product stored in the memory, and when the computer program product is executed, implementing the terrain model generation method.

In a fourth aspect, embodiments of the present disclosure provide a computer readable storage medium having stored thereon computer program instructions that, when executed, implement the terrain model generation method described above.

In the embodiment of the disclosure, an initial terrain model generated according to elevation data corresponding to a target terrain area can initially reflect an actual terrain state of the target terrain area; further, according to actual terrain states of different areas in the target terrain area, curvature value calculation is carried out on each grid surface in the initial terrain model, depth values of grid surface recursion division operation on different areas in the intermediate model can be determined, so that after grid surface recursion division operation is carried out on different areas according to corresponding depth values, the target terrain model which comprises a plurality of areas and is different in grid surface division degree in different areas is obtained, and the target terrain model is higher in precision and is closer to the actual terrain states of different areas in the target terrain area. And before the target terrain model is generated, grid surface smoothing treatment, detail level division and other operations can be performed on the intermediate terrain model, so that the final generated target terrain model is more true in surface morphology and more in line with visual effect.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings required for the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present disclosure, and other drawings may be obtained according to these drawings without inventive effort for a person of ordinary skill in the art.

Fig. 1 is a flowchart of a terrain model generating method according to an embodiment of the present disclosure.

Fig. 2a is a schematic diagram of a terrain model of a grid structure based on elevation data generation according to an embodiment of the present disclosure.

Fig. 2b is a schematic diagram of determining a depth value of a mesh surface in a terrain model according to an embodiment of the present disclosure.

Fig. 2c is a schematic diagram of a terrain model after performing a meshing operation according to an embodiment of the present disclosure.

Fig. 2d is a schematic diagram for handling a T-shaped structure problem in a terrain model according to an embodiment of the present disclosure.

Fig. 2e is a schematic diagram of detail level classification of a terrain model according to an embodiment of the present disclosure.

Fig. 3 is a flowchart of another terrain model generation method provided in an embodiment of the present disclosure.

Fig. 4 is a schematic structural diagram of a terrain model generating device according to an embodiment of the present disclosure.

Fig. 5 is a schematic structural diagram of an electronic device according to an embodiment of the present disclosure.

Detailed Description

The present disclosure is further described in detail below with reference to the drawings and examples. The features and advantages of the present disclosure will become more apparent from the description.

The word "exemplary" is used herein to mean "serving as an example, embodiment, or illustration. Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. Although various aspects of the embodiments are illustrated in the accompanying drawings, the drawings are not necessarily drawn to scale unless specifically indicated.

In addition, technical features described below in the different embodiments of the present disclosure may be combined with each other as long as they do not collide with each other.

Fig. 1 is a flowchart of a terrain model generating method according to an embodiment of the present disclosure, where, as shown in fig. 1, the method includes:

s1, acquiring elevation data of a target terrain area;

s2, generating a first terrain model of a non-grid structure according to elevation data;

s3, determining a plurality of first areas in a first terrain model according to the actual terrain state of the target terrain area;

s4, determining a first depth value of each first area, wherein the first depth value represents the number of times that the grid surface in the corresponding first area is divided according to a quadtree division mode;

S5, performing quadtree recursive partitioning operation on the corresponding first region according to each first depth value until the depth values of the grid surfaces obtained by partitioning in all the first regions are matched with the first depth values of the corresponding first regions;

and S6, performing grid smoothing operation on the divided first terrain model to generate a target terrain model corresponding to the target terrain area.

The following describes the execution of the above steps in detail with reference to specific embodiments.

For step S1:

In the embodiment of the present disclosure, in order to generate a terrain model, for example, a terrain model of a target terrain area, or may also be referred to as a target terrain model corresponding to the target terrain area, and may be hereinafter referred to as a target terrain model for short, elevation data of the target terrain area, that is, elevation data corresponding to an actual terrain state of the target terrain area, needs to be acquired first to generate a terrain model corresponding to the actual terrain state, that is, a target terrain model, according to the acquired elevation data. The source of the elevation data is not limited in the embodiments of the present disclosure, and optionally, the elevation data may be any one or more of remote sensing satellite data, aviation measurement data, and ground measurement data, and of course, may also be other data, which may be specifically determined according to actual requirements.

Further optionally, after the elevation data is obtained, the elevation data may be further subjected to oversampling, so as to improve the accuracy of the elevation data. Alternatively, the resolution of the elevation data may be set based on the desired accuracy value corresponding to the terrain model, i.e., the resolution of the elevation data of the target terrain area may be set based on the desired accuracy value of the target terrain model. The specific determination mode of the expected accuracy value is not limited, and the embodiment of the disclosure can be determined according to the specific application scene of the terrain model, and can also be determined according to actual design requirements. For example, if the terrain model is used for reflecting urban terrain environment, the expected accuracy value of the terrain model can be determined according to urban planning requirements; for another example, if the terrain model is applied to a game environment scene, the expected precision value of the terrain model can be determined according to game development requirements; for another example, if the terrain model is applied to a geographic information system, a desired accuracy value of the terrain model may be determined based on the usage requirements of the geographic information system, and so on.

In the embodiment of the disclosure, when the elevation data is subjected to the oversampling process, an appropriate interpolation algorithm may be selected according to actual requirements to insert additional data points between original data points, for example, alternative interpolation algorithms include, but are not limited to, a nearest neighbor interpolation algorithm, a bilinear interpolation algorithm, a bicubic interpolation algorithm, and the like. After the processing, elevation data with denser data points can be obtained, and on the basis of the elevation data, the accuracy of a terrain model generated according to the elevation data is higher, and detail information is richer.

It should be noted that, in the above-mentioned process of oversampling, in order to increase the density of the elevation data, a balance is found between the data value of the high-level data and the true value of the actual terrain state to avoid introducing excessive noise or unrealistic terrain features. The specific data density condition after specific processing is not limited, and the requirements of the embodiments of the disclosure can be met as long as the elevation data after the oversampling processing can reflect the actual terrain state as much as possible.

For step S2:

In the embodiment of the disclosure, in order to obtain a terrain model with higher precision value, the thought of 'gradually refinement' can be adopted, a first terrain model with a non-grid structure is generated, and then the first terrain model is gradually divided into a plurality of grid surfaces, so that a target terrain model with higher precision value is obtained, and the target terrain model can clearly and accurately reflect the actual terrain state of a target terrain area.

It should be noted that, regarding the manner of dividing the first terrain model, the embodiment of the disclosure is not limited, and the adopted division manner may be different according to different types of the selected grid surface. For example, in the case where the first terrain model is selected to be divided into a plurality of quadrilateral mesh surfaces, the first terrain model may be divided in a quadtree recursive division manner, and the specific details of the division process will be described in the following embodiments, which will not be described in detail herein.

It should be further noted that, the embodiment of the present disclosure is not limited to a specific manner of generating the first terrain model, alternatively, the first terrain model may be directly generated according to the elevation data, or a second terrain model that may reflect an actual terrain state of the target terrain area and includes a plurality of grid surfaces may be generated according to the elevation data, and then the first terrain model is generated based on the second terrain model, where a specific manner of generating may be determined according to an actual requirement.

The following describes the execution of the steps in the method described above, taking as an example the generation of the first terrain model based on the second terrain model.

For step S3:

Alternatively, when generating the second terrain model including a plurality of grid surfaces according to the elevation data, the type of the grid surface to be used may be determined according to the actual terrain state of the target terrain area, for example, for the target terrain area with a relatively regular shape and a simple terrain condition, a quadrangle may be selected as the type of the grid surface when generating the corresponding second terrain model; for another example, for a target terrain area with a relatively complex actual terrain situation, when generating a corresponding second terrain model, a triangle may be selected as a mesh surface type, and a specific type of selection may be determined according to an actual requirement, which is not limited herein, and in the embodiment of the present disclosure, taking a quadrilateral as an example of a mesh surface type selected, fig. 2a is a second terrain model generated by using the quadrilateral mesh surface type, and a subsequent description will be described on the basis of the second terrain model.

Further, after the grid surface type is determined, the size of the grid surface may be determined based on the actual terrain state of the target terrain area, e.g., the more complex the actual terrain state of the target terrain area, the smaller the grid surface may be determined to represent richer terrain detail. Further alternatively, since in the actual scenario the actual terrain states of the different sub-areas in the target terrain area may be different, when setting the mesh surface size, the corresponding mesh surface may also be set to a different size according to the actual terrain state of each sub-area, so that the generated second terrain model is more relevant to the actual terrain state of the target terrain area.

It should be noted that the above-mentioned determination process for the type, number and size of the mesh surface for generating the second terrain model may be completed by commonly used three-dimensional modeling software, for example, but not limited to, three-dimensional modeling software such as Blender, maya, 3ds Max, etc., and the properties of the mesh surface are adjusted by adjusting various parameters in the three-dimensional modeling software.

Based on this, after determining the type, number and size of the mesh surfaces, height information of the mesh surfaces in space corresponding to each elevation data value may be determined according to the acquired elevation data, and then a second terrain model corresponding to the target terrain area may be generated using a model generation algorithm. Further, based on the size and the respective vertex coordinates of the second terrain model, a first terrain model having a non-mesh structure with the same size and vertex coordinates as the second terrain model can be generated. Optionally, when the first terrain model is generated, an initial terrain model with a non-grid structure can be constructed through three-dimensional modeling software and placed in a region corresponding to the second terrain model, and the size of the initial terrain model is adjusted to enable the boundary of the initial terrain model to coincide with the boundary of the second terrain model, so that the first terrain model matched with the size and each vertex coordinate of the second terrain model is obtained.

The embodiment of the present disclosure is not limited to the type of model generation algorithm, and any algorithm that can realize the generation of a terrain model is applicable to the embodiment of the present disclosure. Of course, after the second terrain model is generated, the second terrain model may be further optimized in terms of rendering efficiency, visual effect and the like, so that the balance of rendering efficiency and visual effect is achieved while the authenticity of the terrain condition is ensured, and the specific process is not described in detail herein.

In the embodiment of the disclosure, in order to make the finally generated target terrain model coincide with the actual terrain state of the target terrain area, a plurality of second areas may be determined in the second terrain model according to the actual terrain state of the target terrain area, and a plurality of first areas corresponding to the plurality of second areas respectively may be determined in the first terrain model according to the correspondence of the first terrain model and the second terrain model in spatial positions. The specific manner of determining the plurality of second regions in the second terrain model is not limited, and since the second terrain model is generated based on the elevation data of the target terrain region, the number, the size, the height information, the orientation and the slope of the grid surfaces of the plurality of grid surfaces included in the second terrain model reflect the actual terrain states of the different sub-regions in the target terrain region, the plurality of second regions can be determined from the second terrain model according to each grid surface attribute in the second terrain model. In this way, when the grid surface division operation is performed on the first terrain model, the specific grid surface division operation can be performed on the corresponding first area in the first terrain model according to the grid surface characteristics in each second area in the second terrain model, so as to obtain the target terrain model which is closer to the actual terrain state of the actual target terrain area.

For step S4:

In an embodiment of the disclosure, in order to perform a targeted mesh surface division operation on each first region in the first terrain model, a corresponding first depth value may be determined for each first region, where the first depth value is used to represent the number of times that the mesh surface in the corresponding first region is divided. As to the manner of determining the first depth value of each first region, the embodiment of the disclosure is not limited, alternatively, the second depth value of each second region in the second terrain model may be determined first, and the second depth value of each second region in the second terrain model may be used as the first depth value of the corresponding first region in the first terrain model. The method for determining the second depth value of each second area in the second terrain model is not limited, alternatively, the curvature value of each grid surface in the second terrain model may be determined first, and then the second depth values of the corresponding second areas may be determined according to the curvature values of the multiple grid surfaces in each second area in the second terrain model.

Alternatively, when determining the curvature value of each grid surface in the second terrain model, the spatial coordinates corresponding to the vertices of each grid surface may be obtained from the second terrain model, and based on this, the normal vector of each grid surface may be determined according to the spatial coordinates corresponding to the vertices of each grid surface. Further, for each grid surface, two principal curvature directions are determined based on the corresponding normal vector, curvature values are calculated in the two principal curvature directions respectively, and then the curvature value of the corresponding grid surface is determined according to the two curvature values. Alternatively, the curvature value of each mesh surface may be a gaussian curvature value or an average value of curvature values in two principal curvature directions, of course, not limited thereto.

Based on this, in the case of determining the curvature value of each mesh surface, the second depth value of the corresponding second region may be determined from the curvature values of the plurality of mesh surfaces in each second region in the second terrain model. In an alternative manner, the curvature values of the plurality of grid planes in each second area in the second terrain model may be input into a preset mapping function, and the depth values output by the preset mapping function for each grid plane are received, that is, the depth values output by the preset mapping function for each grid plane in the corresponding second area are received, and further, the second depth value of the corresponding second area in the second terrain model is determined according to the depth values of each grid plane in each second area. In another alternative, the curvature value of the corresponding second area may be determined according to the curvature values of the plurality of grid surfaces in each second area, for example, an average value of the curvature values of the plurality of grid surfaces in each second area may be used as the curvature value of the corresponding second area; further, the curvature value of each second region is input into a preset mapping function, and a second depth value output by the preset mapping function for the corresponding second region is received. FIG. 2b is an exemplary graph after depth values have been determined for each mesh surface in the second terrain model of FIG. 2a in the manner described above.

In the above example, the preset mapping function defines a mapping relationship between the curvature value and the depth value, and is used for determining and outputting a corresponding depth value according to the input curvature value, where the correspondence between the curvature value and the depth value may be determined according to experience or actual requirements, and is not limited herein. In the embodiment of the present disclosure, the specific function of the preset mapping function is not limited, and optionally, in order to unify the comparison criteria between the curvature values of different grid planes, the preset mapping function may normalize the input curvature value so as to fall within a predetermined numerical range, for example, the numerical range may be 0 to 1, which is not limited thereto.

Further optionally, the preset mapping function may further determine a topography state of a corresponding region according to the curvature values of the input multiple grid planes, so as to dynamically adjust the corresponding depth values according to topography states of different regions based on the preliminarily determined depth values, for example, increase the depth value corresponding to the region with the larger curvature value and decrease the depth value corresponding to the region with the smaller curvature value.

Further optionally, a mask object may be added to any one or more second regions in the second terrain model according to actual requirements, so as to optimize the second depth value of the corresponding second region by adjusting the attribute of the mask object. For example, any one of the second regions in the second terrain model may be selected in the three-dimensional modeling software and a desired mask object may be selected in the view to be added to the second region. Further, an edit control associated with the partitioning operation may be found in the property panel of the mask object and a parameter value corresponding to the desired number of partitions may be set to a second depth value for a second region affected by the mask object. Based on the above, after the second depth values of the plurality of second areas in the second terrain model are used as the first depth values of the corresponding first areas in the first terrain model, the second depth values can be used as the basis for carrying out grid surface division on the corresponding first areas, so that finer grid surface division operation is carried out on the grid surface in the corresponding first areas based on the first depth values of each first area.

Based on the above, in the case of obtaining the second depth value of each second region in the second terrain model, the second depth value of each second region may be used as the first depth value of the corresponding first region in the first terrain model, and may be used as a basis for dividing the grid surface of the corresponding first region. For example, any one first area in the first terrain model can be selected in the three-dimensional modeling software, an editing control related to grid surface dividing operation is found in a functional panel corresponding to the template attribute, and a parameter value corresponding to the expected dividing number is set as a first depth value of the corresponding first area.

In the above embodiment, the mask object is added to one or more second areas of the second terrain model, and the second depth value of the corresponding second area is further optimized, which is not limited to this in practical application. Alternatively, the second depth value of each second region in the second terrain model may be determined by the method in the foregoing embodiment, and then used as the first depth value of the corresponding first region in the first terrain model, and then a mask object is added to one or more first regions in the first terrain model, so as to optimize the corresponding first depth value. And further, grid surface division operation is carried out on the grid surfaces in the corresponding first areas according to the optimized first depth value of each first area, and the specific mode can be determined according to actual requirements.

In the above embodiment, the first region of the first terrain model and the second region of the second terrain model are described as examples, but the present invention is not limited to this in practical application. Because a region includes a plurality of grid planes, where depth values corresponding to the plurality of grid planes may be different, in practical application, each first region in the first terrain model and each second region in the second terrain model may also correspond to a plurality of depth values, which may be specifically determined according to practical requirements, and in order to facilitate explanation, this will not be described in detail.

For step S5:

Based on the above, in the case that the first depth value of each first region in the first terrain model is determined, the quadtree recursive partitioning operation may be performed on the corresponding first region according to the first depth value of each first region in the first terrain model until the depth values of the mesh planes partitioned in all the first regions match the first depth values of the corresponding first regions.

The procedure for performing the quadtree recursive partitioning operation on the first terrain model is described below.

Alternatively, the initial depth value of the first terrain model may be set to 0 before performing the quadtree recursive partitioning operation, indicating that the first terrain model is not partitioned; further, for any one of the first regions in the first terrain model, for convenience of description, the depth values of both the target region and the corresponding second region in the second terrain model are compared to determine whether to perform a quadtree recursive partitioning operation on the mesh surface within the target region; if the depth value of the target area is smaller than the second depth value of the second area corresponding to the target area in the second terrain model, performing a quadtree partitioning operation on the grid surface in the target area, otherwise stopping the partitioning operation on the target area; after the quadtree partitioning operation is executed for each time on the target area, adding 1 to the depth value of the newly partitioned grid surface in the target area on the basis of the depth value of the original grid surface until the depth value of the newly partitioned grid surface is matched with the first depth value of the target area, and stopping the partitioning operation on the target area.

And so on, the depth values of the grid surfaces obtained by dividing in all the first areas in the first terrain model are matched with the first depth values of the corresponding first areas, the dividing operation of the first terrain model is stopped, and the divided effect diagram can be seen in fig. 2c.

For step S6:

In the embodiment of the disclosure, grid smoothing operation may also be performed on the divided first terrain model to generate a target terrain model that is closer to the actual terrain state of the target terrain area. Optionally, grid smoothing operation can be performed on the divided first terrain model to obtain a third terrain model; performing Detail Level (LOD) division on the third terrain model according to different viewpoint positions to obtain a plurality Of target grid surfaces corresponding to different Detail levels; based on this, from the plurality of target mesh surfaces, a target terrain model corresponding to the target terrain area can be generated. Grid smoothing operation is carried out on the first terrain model, so that the T-Junction problem is solved, and the continuity and consistency of the surface morphology of the first terrain model are ensured; and the third model is subjected to detail level division operation, so that the sense of reality of the target terrain model is improved, and for an observer, the terrain state of the target terrain model seen from different viewpoint positions is the same as the actual terrain state of the target terrain area seen from the same viewpoint, and the visual effect is better.

Optionally, when grid smoothing is performed on the first terrain model, determining an area with a T-Junction problem in the first terrain model in three-dimensional modeling software, and determining whether a first vertex adjacent to a boundary closest to the area exists; if so, moving the middle point of the area to the first vertex, and if not, creating a second vertex at the middle point of the area to obtain a third terrain model with the structure shown in fig. 2 d; further, by performing curvature smoothing operation on each mesh surface, the T-shaped structure of the region is eliminated.

Optionally, when performing the detail level division operation on the third terrain model, defining the nearest viewpoint position as the highest detail level according to different viewpoint positions and identifying with LOD0, and generating a target grid surface corresponding to the LOD0 detail level; and so on, sequentially defining detail levels from the near to the far according to the viewpoint positions, and identifying and generating corresponding target grid surfaces by using LOD1, LOD2, LOD3 and the like to obtain a target terrain model with a structure shown in figure 2 e; the depth value corresponding to the target grid surface with higher detail level is larger, the dividing precision of the target grid surface with closer viewpoint position is higher, and the visual effect is met.

It should be noted that, the embodiment of the present disclosure is not limited to the specific manner of performing the detail level dividing operation, alternatively, the detail levels corresponding to different viewpoint positions may be manually set according to the distance between the camera and the target terrain area, or the different viewpoint positions may be input into a preset algorithm, and the corresponding detail levels are automatically determined by the preset algorithm, which is not limited to the specific type of the preset algorithm.

Further optionally, in order to further refine the accuracy of the grid surface division operation, a mask object may be added to any one or more first areas in the first terrain model according to actual requirements, and the depth value of the corresponding first area may be adjusted by adjusting the attribute of the mask object. For example, any one of the first regions in the first terrain model may be selected in the three-dimensional modeling software and a desired mask object may be selected in the view to be added to the first region. Further, an edit control associated with the partitioning operation may be found in an attribute panel of the mask object and a parameter value corresponding to a desired number of partitions may be set to a first depth value for a first region affected by the mask object.

For ease of understanding, the overall execution of the terrain model generation method provided by the embodiments of the present disclosure is described in overview below. In the above embodiments of the present disclosure, the second terrain model may be understood as an initial terrain model for determining an actual terrain state of the target terrain area, and the first terrain model may be understood as an intermediate terrain model in the process of generating the target terrain model.

In the embodiment of the disclosure, in order to generate the target terrain model which is closer to the actual terrain state of the target terrain area, after the elevation data of the target terrain area is acquired, the data density can be increased by performing oversampling processing on the elevation data of the target terrain area, the model precision is improved, and based on the data density, the initial terrain model of a grid structure is generated, so that the actual terrain state of the target terrain area can be primarily determined. Further, according to the attribute of each grid surface in the initial terrain model, the depth values corresponding to the grid surfaces in different areas in the initial terrain model can be determined, in order to improve the model precision, mask objects can be added to the different areas in the initial terrain model, parameter values corresponding to the dividing operation can be adjusted and increased, so that targeted optimization processing can be performed on the depth values of the different areas, and therefore, when the target terrain model is generated based on the initial terrain model, the grid surface dividing operation can be performed on the different areas in a targeted mode.

In the embodiment of the disclosure, based on the initial terrain model, an intermediate terrain model with a non-grid structure having the same size and the same vertex height as the intermediate terrain model can be generated, according to the corresponding relation between the initial terrain model and the intermediate terrain model in space position, the grid surface recursion division operation can be performed on each region corresponding to the intermediate terrain model according to the depth value of each region in the initial terrain model until the depth values of all regions in the intermediate terrain model are matched with the depth values of the corresponding regions in the initial terrain model, and the division operation is stopped. Further, the intermediate terrain model obtained in the process can be further optimized through grid surface smoothing processing, detail level division and other operations, and the quality and visual effect of the model are improved, so that a target terrain model which is closer to the actual terrain state of the target terrain area is obtained.

The overall flow of the above-described terrain model generation process will be briefly described with reference to the accompanying drawings.

FIG. 3 is a schematic diagram of another terrain model generation method according to an embodiment of the present disclosure, as shown in FIG. 3, in order to generate a target terrain model that matches an actual terrain state of a target terrain area, first, elevation data acquired according to the target terrain area needs to be acquired; furthermore, in order to improve the quality of the model, the obtained elevation data can be subjected to oversampling processing according to the expected precision value so as to increase the data density; based on this, an initial terrain model similar to the actual terrain state of the target terrain area can be generated as a base model for generating the target terrain model based on the elevation data subjected to the oversampling processing, wherein the initial terrain model includes a plurality of grid surfaces.

Based on this, by calculating the curvature value of each mesh surface and inputting the curvature value of each mesh surface into a preset mapping function, the depth value of each mesh surface can be determined as the number of divisions in which mesh surface division operation is performed in the subsequent generation of the target terrain model. Further, in order to further refine the dividing times of the grid surface dividing operation, corresponding mask objects can be added for different second areas in the initial terrain model, and the depth values of the different second areas are optimized by modifying the parameter values of the mask objects corresponding to the dividing operation, so that in the process of subsequently generating the target terrain model, the dividing operation of different degrees can be executed for different areas, and the model quality is improved.

As shown in fig. 3, in the case of generating the initial terrain model, an intermediate terrain model of a non-mesh structure having the same size and the same height information of each vertex may be generated according to the size of the initial terrain model and the height information of each vertex; further, based on the second depth value of each second region in the initial terrain model in the above process, the mesh surface dividing operation of the corresponding dividing number may be performed on the corresponding first region in the intermediate terrain model. In this example, in order to perform the mesh surface division operation for each first region in the intermediate terrain model, an initial value of 0 may be set for the depth value of each first region in the intermediate terrain model, and it is determined whether to further perform the mesh surface division operation by comparing with the second depth value of the corresponding second region in the initial terrain model; and adding 1 to the depth value of the corresponding first region every time the grid surface dividing operation is executed until the corresponding depth value is matched with the second depth value of the corresponding second region, ending the dividing operation of the corresponding first region, and the like until all the first regions in the first model are executed.

Further, as shown in fig. 3, for the intermediate terrain model after the above mesh surface division, the quality of the model can be improved through the processing such as the mesh surface smoothing operation and the detail level division operation, so as to obtain a target terrain model which is closer to the actual terrain state of the target terrain area.

It should be noted that this example is only one possible implementation, and is not limited to this in practical application. For example, after the curvature value of each grid surface is obtained by calculation, different areas in the initial terrain model can be determined according to the curvature value of each grid surface, and a preset mapping function is output to the curvature value of each area to obtain a depth value corresponding to each area; for another example, the process of optimizing depth values using mask objects may also be implemented in an intermediate terrain model. For detailed execution of each step in this example, reference may be made to the description of the corresponding portion in the above embodiment, and the detailed description is omitted here.

In the embodiment of the disclosure, the data density can be increased by performing the oversampling processing on the acquired elevation data, and the precision of the initial terrain model generated based on the elevation data is improved. Furthermore, the initial terrain model generated based on the elevation data is subjected to masking processing according to the actual terrain states of different areas in the target terrain area, and the number of grid faces in the different areas in the initial terrain model can be adjusted to reflect the actual terrain states of the different areas in the target terrain area. Based on the above, the depth values of the mesh surface recursion division operation performed on the different regions in the intermediate model may be determined, so that after the mesh surface recursion division operation is performed on the different regions according to the corresponding depth values, the target terrain model including a plurality of regions and having different mesh surface division degrees in the different regions is generated. The target terrain model generated by the method is higher in precision and is closer to the actual terrain state of different areas in the target terrain area. And before the target terrain model is generated, grid surface smoothing treatment, detail level division and other operations can be performed on the intermediate terrain model, so that the final generated target terrain model is more true in surface morphology and more in line with visual effect.

It is understood that the foregoing embodiments are merely examples, and modifications may be made to the foregoing embodiments in actual implementation, and those skilled in the art may understand that the modification methods of the foregoing embodiments without performing any inventive effort fall within the protection scope of the present disclosure, and are not repeated in the embodiments.

All the above optional solutions may be mutually referred to or combined to form an optional embodiment of the disclosure, which is not described herein in detail.

Based on the same inventive concept, the embodiments of the present disclosure further provide a terrain model generating device, and since the principle of the problem solved by the terrain model generating device is similar to that of the foregoing terrain model generating method, implementation of the terrain model generating device may refer to implementation of the foregoing terrain model generating method, and repeated parts are omitted.

Referring to fig. 4, fig. 4 is a block diagram of a terrain model generating apparatus according to an embodiment of the present disclosure. As shown in fig. 4, the terrain model generating apparatus 400 may include: an acquisition module 401, a generation module 402, a determination module 403, a first processing module 404 and a second processing module 405; wherein,

The acquisition module 401 is configured to acquire elevation data of a target terrain area;

The generating module 402 is configured to generate a first terrain model of a non-grid structure according to the elevation data;

the determining module 403 is configured to determine a plurality of first areas in the first terrain model according to an actual terrain state of the target terrain area; determining a first depth value of each first region, wherein the first depth value represents the number of times that the grid surface in the corresponding first region is divided according to a quadtree division mode;

The first processing module 404 is configured to perform a quadtree recursive partitioning operation on the corresponding first region according to each first depth value until the depth values of the mesh planes partitioned in all the first regions are matched with the first depth values of the corresponding first regions;

the second processing module 405 is configured to perform a mesh smoothing operation on the divided first terrain model, and generate a target terrain model corresponding to the target terrain area.

Optionally, the generating module 402 generates a first terrain model of the non-grid structure according to the elevation data, for: generating a second terrain model comprising a plurality of grid surfaces according to the elevation data; based on the dimensions and the vertex coordinates of the second terrain model, a first terrain model of a non-mesh structure having the same dimensions and vertex coordinates as the second terrain model is generated.

Optionally, the determining module 403 determines a plurality of first areas in the first terrain model according to the actual terrain state of the target terrain area for: determining a plurality of second areas in a second terrain model according to the actual terrain state of the target terrain area; and determining a plurality of first areas corresponding to the plurality of second areas in the first terrain model according to the corresponding relation of the first terrain model and the second terrain model in the space position.

Optionally, the determining module 403 determines a first depth value for each first region for: determining a curvature value of each grid surface in the second terrain model; determining a second depth value of the corresponding second region according to the curvature values of the grid surfaces in each second region; and taking the second depth value of each second area as the first depth value of the corresponding first area.

Optionally, the determining module 403 determines, according to curvature values of the plurality of grid planes in each second area, a second depth value of the corresponding second area, for: inputting curvature values of a plurality of grid planes in each second area into a preset mapping function, and receiving depth values output by the preset mapping function for each grid plane in the corresponding second area; and determining a second depth value of the corresponding second region according to the depth value of each grid surface in each second region.

Optionally, the determining module 403 determines, according to curvature values of the plurality of grid planes in each second area, a second depth value of the corresponding second area, for: determining curvature values of the corresponding second areas according to curvature values of the grid surfaces in each second area; and inputting the curvature value of each second region into a preset mapping function, and receiving a second depth value output by the preset mapping function for the corresponding second region.

Optionally, the second processing module 405 performs a mesh smoothing operation on the divided first terrain model, and generates a target terrain model corresponding to the target terrain area, for: performing grid smoothing operation on the divided first terrain model to obtain a third terrain model; performing detail level division on the third terrain model according to different viewpoint positions to obtain a plurality of target grid surfaces corresponding to different detail levels; a target terrain model corresponding to the target terrain area is generated based on the plurality of target mesh surfaces.

The terrain model generating device provided by the embodiment of the disclosure can initially reflect the actual terrain state of the target terrain area according to the initial terrain model generated by the elevation data corresponding to the target terrain area; further, according to actual terrain states of different areas in the target terrain area, curvature value calculation is carried out on each grid surface in the initial terrain model, depth values of grid surface recursion division operation on different areas in the intermediate terrain model can be determined, so that after grid surface recursion division operation is carried out on different areas according to corresponding depth values, the target terrain model which comprises a plurality of areas and is different in grid surface division degree in different areas is generated, and the target terrain model is higher in precision and is closer to the actual terrain states of different areas in the target terrain area. And before the target terrain model is generated, grid surface smoothing treatment, detail level division and other operations can be performed on the intermediate terrain model, so that the final generated target terrain model is more true in surface morphology and more in line with visual effect.

The embodiment of the disclosure further provides an electronic device, referring to fig. 5, and fig. 5 is a block diagram of the electronic device provided by the embodiment of the disclosure. As shown in fig. 5, the electronic device 500 may include a processor 501, a memory 502, and a program or an instruction stored in the memory 502 and capable of running on the processor 501, where the program or the instruction implements each process of the above-mentioned terrain model generating method embodiment when executed by the processor 501, and the same technical effects are achieved, and are not repeated herein.

It should be noted that, the electronic device in the embodiment of the present disclosure includes a mobile electronic device and a non-mobile electronic device.

The embodiments of the present disclosure further provide a computer readable storage medium, on which a computer program is stored, which when executed by a processor, implements the respective processes of the above-mentioned terrain model generation method embodiment, and can achieve the same technical effects, and in order to avoid repetition, a detailed description is omitted here.

The processor is a processor in the electronic device in the above embodiment. Readable storage media include computer readable storage media such as Read-Only Memory (ROM), random access Memory (Random Access Memory, RAM), magnetic or optical disks, and the like.

The present disclosure is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the disclosure. It will be understood that each flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

In this specification, each embodiment is described in a progressive manner, and identical and similar parts of each embodiment are all referred to each other, and each embodiment mainly describes differences from other embodiments. In particular, for the device embodiments, since they are substantially similar to the method embodiments, the description is relatively simple, and reference is made to the description of the method embodiments in part. In this document, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. The specific meaning of the terms in this disclosure will be understood by those of ordinary skill in the art as the case may be. It should be noted that, without conflict, the embodiments of the present disclosure and features of the embodiments may be combined with each other. The present disclosure is not limited to any single aspect, nor to any single embodiment, nor to any combination and/or permutation of these aspects and/or embodiments. Moreover, each aspect and/or embodiment of the disclosure may be used alone or in combination with one or more other aspects and/or embodiments.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present disclosure, and not for limiting the same; although the present disclosure has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the embodiments of the disclosure, and are intended to be included within the scope of the claims and specification of the present disclosure.

Claims (10)

1. A terrain model generation method, comprising:

Acquiring elevation data of a target terrain area;

Generating a first terrain model of a non-grid structure according to the elevation data;

Determining a plurality of first regions in the first terrain model according to the actual terrain state of the target terrain region;

Determining a first depth value of each first region, wherein the first depth value represents the number of times that the grid surface in the corresponding first region is divided according to a quadtree division mode;

Performing quadtree recursive partitioning operation on the corresponding first region according to each first depth value until the depth values of the grid planes obtained by partitioning in all the first regions are matched with the first depth values of the corresponding first regions;

and carrying out grid smoothing operation on the divided first terrain model to generate a target terrain model corresponding to the target terrain area.

2. The method of claim 1, wherein generating a first terrain model of a non-mesh structure from the elevation data comprises:

Generating a second terrain model comprising a plurality of grid surfaces according to the elevation data;

And generating a first terrain model of a non-grid structure with the same size and vertex coordinates as the second terrain model according to the size and the vertex coordinates of the second terrain model.

3. The method of claim 2, wherein determining a plurality of first regions in the first terrain model based on the actual terrain state of the target terrain region comprises:

determining a plurality of second regions in the second terrain model according to the actual terrain state of the target terrain region;

and determining a plurality of first areas corresponding to the plurality of second areas in the first terrain model according to the corresponding relation of the first terrain model and the second terrain model in the space position.

4. A method according to claim 3, wherein determining a first depth value for each first region comprises:

determining a curvature value of each grid surface in the second terrain model;

determining a second depth value of the corresponding second region according to the curvature values of the grid surfaces in each second region;

And taking the second depth value of each second region as the first depth value of the corresponding first region.

5. The method of claim 4, wherein determining a second depth value for each second region based on curvature values for a plurality of mesh surfaces within each second region comprises:

inputting curvature values of a plurality of grid planes in each second area into a preset mapping function, and receiving depth values output by the preset mapping function for each grid plane in the corresponding second area;

and determining a second depth value of the corresponding second region according to the depth value of each grid surface in each second region.

6. The method of claim 4, wherein determining a second depth value for each second region based on curvature values for a plurality of mesh surfaces within each second region comprises:

Determining curvature values of the corresponding second areas according to curvature values of the grid surfaces in each second area;

And inputting the curvature value of each second region into a preset mapping function, and receiving a second depth value output by the preset mapping function for the corresponding second region.

7. The method of any one of claims 1-6, wherein performing a mesh smoothing operation on the divided first terrain model to generate a target terrain model corresponding to the target terrain region comprises:

performing grid smoothing operation on the divided first terrain model to obtain a third terrain model;

Performing detail level division on the third terrain model according to different viewpoint positions to obtain a plurality of target grid surfaces corresponding to different detail levels;

and generating a target terrain model corresponding to the target terrain area based on the target grid surfaces.

8. A terrain model generation device, characterized by comprising:

the acquisition module is used for acquiring elevation data of the target terrain area;

the generation module is used for generating a first terrain model of a non-grid structure according to the elevation data;

A determining module for determining a plurality of first areas in the first terrain model according to the actual terrain state of the target terrain area; determining a first depth value of each first region, wherein the first depth value represents the number of times that the grid surface in the corresponding first region is divided according to a quadtree division mode;

The first processing module is used for executing the quadtree recursive partitioning operation on the corresponding first area according to each first depth value until the depth values of the grid surfaces obtained by partitioning in all the first partitioned areas are matched with the first depth values of the corresponding areas;

And the second processing module is used for carrying out grid smoothing operation on the divided first terrain model and generating a target terrain model corresponding to the target terrain area.

9. An electronic device, the electronic device comprising:

A memory for storing a computer program product;

a processor for executing a computer program product stored in said memory, which, when executed, implements the method of any of the preceding claims 1-7.

10. A computer readable storage medium, characterized in that the computer readable storage medium has stored thereon computer program instructions, which when executed, implement the method of any of the preceding claims 1-7.