Method and device for decrypting DEM files and machine-readable storage medium

Abstract

This application discloses a method, apparatus, and machine-readable storage medium for decrypting DEM files. The method includes: receiving a DEM file to be processed; converting the received DEM file into a Mesh file; and performing the following processing on the Mesh file: reducing resolution and smoothing blurred terrain; wherein the reduction in resolution is performed based on a polygon reduction modifier of the Blender 3D model, and the smoothing of blurred terrain is performed based on a smoothing modifier of the Blender 3D model. This improves the security of decrypting DEM files.

Description

Technical Field

[0001] This application relates to the field of decryption processing technology, and more specifically, to a method, apparatus, and machine-readable storage medium for decrypting DEM files. Background Technology

[0002] A Digital Elevation Model (DEM) stores topographic elevation data in a regular grid format, with each grid cell corresponding to a geographic coordinate and elevation value. Elevation values ​​are typically expressed in meters or feet, representing the height of a point on the ground relative to sea level. Common data formats include GeoTIFF, ASCII, and ESRI Grid. DEMs are widely used in Geographic Information Systems (GIS), remote sensing, environmental science, and engineering surveying, and can be used for topographic analysis, hydrological analysis, flood simulation, soil erosion studies, and urban planning.

[0003] With the widespread use of Data Models (DEMs) across various fields, protecting their data security has become crucial. Because the elevation information and topographic features within DEM data may involve national security and sensitive information, when publicly releasing or transmitting this data, all or part of the spatial location, accuracy, attribute content, and interrelationships contained in the DEM file must be kept confidential. Furthermore, the confidentiality measures must be irreversible to ensure information security and confidentiality. Currently, declassification of DEM files generally uses software such as ArcGIS, QGIS, and ENVI, but these algorithms are simplistic and lack sufficient security.

[0004] Therefore, how to improve the security of decryption processing of DEM files has become a technical problem that needs to be solved in this field. Summary of the Invention

[0005] In view of this, this application proposes a method, apparatus, and machine-readable storage medium for decrypting DEM files, which can improve the security of decrypting DEM files.

[0006] In a first aspect, embodiments of this application provide a method for decrypting DEM files based on Blender 3D modeling. The method includes: receiving a DEM file to be processed; converting the received DEM file into a Mesh file; and performing the following processing on the Mesh file: reducing resolution and smoothing blurred terrain; wherein the reduction in resolution is performed based on the Blender 3D modeling's polygon reduction modifier, and the smoothing of blurred terrain is performed based on the Blender 3D modeling's smoothing modifier.

[0007] Optionally, the method further includes: adding noise to the Mesh file, wherein the noise is added based on the displacement modifier of the Blender 3D model.

[0008] Optionally, the process of adding noise to the Mesh file includes: adding a clamping node based on the shading editor of the displacement modifier; adding a noise-adding node based on the shading editor, wherein the noise-adding node includes at least one of the following: texture coordinate node, mapping node, noise texture node, Thiessen polygon texture node, Mahalanobis fractal texture node, ripple texture node, mathematical node, blended RGB node, color gradient node; and processing the Mesh file based on the clamping node and the noise-adding node to add noise.

[0009] Optionally, the method further includes: performing data thinning on the Mesh file, wherein the data thinning is performed based on the mesh re-division modifier of the Blender 3D model.

[0010] Optionally, the method further includes: performing a spatial transformation on the Mesh file, wherein the spatial transformation is performed using the Blender 3D modeling tool.

[0011] Optionally, the method further includes: performing region masking on the Mesh file, wherein the region masking is performed based on the selection tool of the Blender 3D modeling.

[0012] Optionally, after processing the Mesh file, the method further includes: rendering the file obtained after processing the Mesh file based on the Eevee real-time rendering engine of the Blender 3D model.

[0013] Secondly, embodiments of this application also provide an apparatus for decrypting DEM files based on Blender 3D modeling. The apparatus includes: a receiving module for receiving a DEM file to be processed; a conversion module for converting the received DEM file into a Mesh file; and a processing module for performing the following processing on the Mesh file: reducing resolution and smoothing blurred terrain; wherein the reduction in resolution is performed based on the polygon reduction modifier of the Blender 3D modeling, and the smoothing of blurred terrain is performed based on the smoothing modifier of the Blender 3D modeling.

[0014] Optionally, the processing module is further configured to: add noise to the Mesh file, wherein the noise addition is performed based on the displacement modifier of the Blender 3D model.

[0015] Optionally, the process of adding noise to the Mesh file includes: adding a clamping node based on the shading editor of the displacement modifier; adding a noise-adding node based on the shading editor, wherein the noise-adding node includes at least one of the following: texture coordinate node, mapping node, noise texture node, Thiessen polygon texture node, Mahalanobis fractal texture node, ripple texture node, mathematical node, blended RGB node, color gradient node; and processing the Mesh file based on the clamping node and the noise-adding node to add noise.

[0016] Optionally, the processing module is further configured to: perform data thinning on the Mesh file, wherein the data thinning is performed based on the mesh re-division modifier of the Blender 3D model.

[0017] Optionally, the processing module is further configured to: perform spatial transformation processing on the Mesh file, wherein the spatial transformation is performed based on the Blender 3D modeling tool.

[0018] Optionally, the processing module is further configured to: perform region masking on the Mesh file, wherein the region masking is performed based on the selection tool of the Blender 3D modeling.

[0019] Optionally, the device further includes a rendering module, used to render the file obtained after processing the Mesh file based on the Eevee real-time rendering engine of the Blender 3D modeling after processing the Mesh file.

[0020] Thirdly, embodiments of this application also provide a machine-readable storage medium storing instructions that, when executed by a processor, configure the processor to perform the steps according to the method described above.

[0021] According to the technical solution of this application, DEM files are de-encrypted based on Blender 3D modeling. The DEM file to be processed is converted into a Mesh file, and the resulting Mesh file is subjected to resolution reduction and terrain smoothing / blurring operations. The resolution reduction is performed using the polygon reduction modifier based on Blender 3D modeling, and the terrain smoothing / blurring is performed using the smoothing modifier based on Blender 3D modeling. The polygon reduction modifier includes the Collapse algorithm, the Un-Subdivide algorithm, and the Planar algorithm, and the smoothing modifier includes the Laplacian smoothing algorithm. Data downsampling is achieved based on the Collapse algorithm, the Un-Subdivide algorithm, and the Planar algorithm, and terrain details are blurred based on the Laplacian smoothing algorithm. In this way, multiple algorithms are used in the de-encryption process of DEM files. The combination of multiple algorithms can greatly enhance the irreversibility of the de-encryption process, thereby ensuring data security. Thus, the security of de-encryption processing of DEM files is improved.

[0022] Other features and advantages of this application will be described in detail in the following detailed description section. Attached Figure Description

[0023] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application, and the illustrative embodiments and descriptions thereof are used to explain this application. In the drawings:

[0024] Figure 1 A flowchart illustrating a preferred embodiment of a method for decrypting DEM files based on Blender 3D modeling according to this application; and

[0025] Figure 2 This is a structural block diagram of an apparatus for decrypting DEM files based on Blender 3D modeling according to a preferred embodiment of this application. Detailed Implementation

[0026] The technical solution of this application will now be described in detail with reference to the accompanying drawings and embodiments.

[0027] In one aspect, embodiments of this application provide a method for decrypting DEM files based on Blender 3D modeling.

[0028] Figure 1 This is a flowchart illustrating a method for decrypting DEM files based on Blender 3D modeling according to a preferred embodiment of this application. Figure 1 As shown, the method includes the following.

[0029] In step S10, the DEM file to be processed is received. Specifically, this is done using Blender 3D modeling. The user imports the DEM file to be processed into Blender 3D modeling, and Blender 3D modeling receives the DEM file. For example, the DEM file can be in GeoTIFF format.

[0030] In step S11, the received DEM file is converted into a Mesh file. Specifically, the conversion is performed based on Blender 3D modeling. Specifically, the user selects the received DEM file and the "Convert to Mesh" command, and then runs the Blender 3D modeling program to convert the received DEM file into a Mesh file. For example, upon receiving the selection of a DEM file and the "Convert to Mesh" command, the program executes the command to convert the received DEM file into a Mesh file.

[0031] Converting a DEM file to a Mesh file allows for subsequent geometric precision processing of the DEM file.

[0032] In computer graphics and 3D modeling, a "mesh" is a fundamental structure used to represent three-dimensional objects. The basic components of a mesh are vertices, edges, and faces. A vertex is a point in three-dimensional space, representing a basic unit of an object. Each vertex is determined by its position (coordinates) in three-dimensional space. An edge is a line segment connecting two vertices. Edges define the relationships and connections between vertices. A face is a planar region enclosed by three or more edges, typically a triangle or quadrilateral. Faces define the surface of an object and can be used to calculate lighting and texture mapping.

[0033] In step S12, the following operations are performed on the converted Mesh file: resolution reduction and terrain smoothing. Resolution reduction is performed using the Decimate modifier based on Blender 3D modeling, and terrain smoothing is performed using the Smooth modifier based on Blender 3D modeling.

[0034] Specifically, in Blender 3D modeling, Decimal and Smooth modifiers are added, and the Mesh file is processed based on these added modifiers. For example, the Blender 3D modeling interface receives instructions to add Decimal and Smooth modifiers, which are then added and processed.

[0035] In the embodiments of the present application, the Decimate modifier is used to reduce the resolution to simplify terrain features.

[0036] The Decimate modifier includes three algorithms: the Collapse algorithm, the Un-Subdivide algorithm, and the Planar algorithm. Among them, the Collapse algorithm (merging ratio algorithm) reduces the number of vertices and faces by merging the edges in the mesh; the Un-Subdivide algorithm (undo subdivision algorithm) is used to reverse the subdivision of the mesh and reduces the number of faces by undoing the subdivision operation, which is applicable to meshes that have been previously subdivided; the Planar algorithm (plane algorithm) reduces the number of faces by merging the faces on the same plane and is applicable to geometries with a large number of coplanar surfaces.

[0037] Optionally, in the embodiments of the present application, the simplification degree of the mesh in the Mesh file can be controlled. Specifically, the simplification degree of the mesh in the Mesh file is controlled by setting the Ratio parameter on the interactive interface of the Decimate modifier. In the embodiments of the present application, the setting of the Ratio parameter can be determined according to the precision of the data to be processed.

[0038] The control range of the Ratio parameter is from 0 to 1. Ratio = 1 means to maintain the subdivision degree of the original mesh, that is, no simplification is performed. Ratio = 0 means to simplify the mesh to the limit and retain as few faces as possible, which usually causes the mesh to degenerate into a single face (or a few most basic faces).

[0039] 0 < Ratio < 1: The mesh is simplified according to the ratio. For example, Ratio = 0.5 means to reduce the number of faces of the mesh to 50% of the original number of faces. Ratio = 0.1 means to reduce the number of faces of the mesh to 10% of the original number of faces.

[0040] In addition, in the embodiments of the present application, the Ratio parameter can be adjusted in real time, so that the simplification degree of the mesh can be flexibly controlled, thereby reducing the complexity of the mesh while retaining the overall shape. Specifically, in the embodiments of the present application, after processing the Mesh file, rendering is performed to preview the simplification effect, and the Ratio parameter is adjusted according to the previewed simplification effect until a satisfactory result is achieved.

[0041] In this embodiment, the Decimal modifier is used to process the mesh file, simplifying terrain features and reducing the level of detail in the DEM by reducing the number of vertices and faces. Using the Decimal modifier to process the mesh file is applicable to removing information such as the location, length, width, and height of bridges and tunnels, as well as simplifying the details of transportation networks such as roads and railways. This makes the original elevation data less detailed, but still maintains the overall terrain outline. It should be noted that this embodiment does not limit the scenarios in which the Decimal modifier is used to process the mesh file.

[0042] Use the Smooth modifier to smooth the mesh file. The Smooth modifier includes a Laplacian smoothing algorithm based on vertex positions to achieve the smoothing effect. Specifically, it iteratively moves the vertices, bringing each vertex closer to the center of its neighboring vertices.

[0043] In this embodiment, the degree of smoothing applied to the mesh file can be controlled. Specifically, the Factor parameter is set on the interactive interface of the Smooth modifier to control the smoothing intensity. The Factor parameter ranges from 0 to 1. The higher the value of the Factor parameter, the more pronounced the smoothing effect.

[0044] Furthermore, in this embodiment, the value of the Factor parameter can be adjusted in real time to achieve a satisfactory smoothing effect. Specifically, after processing the Mesh file, it is rendered to preview the effect, and the value of the Factor parameter is adjusted based on the preview until a satisfactory result is achieved.

[0045] In this embodiment, the value of the Repeat parameter can be set on the interactive interface of the Smooth modifier to control the number of iterations. Through multiple iterations, vertex V gradually moves towards the average position of neighboring vertices, making the overall mesh smoother.

[0046] Furthermore, in this embodiment, the value of the Repeat parameter can be adjusted in real time to achieve satisfactory iteration results. Specifically, after processing the Mesh file, it is rendered to preview the effect, and the value of the Repeat parameter is adjusted based on the preview until a satisfactory result is achieved.

[0047] In this embodiment, the Smooth modifier is used to process the Mesh file, smoothing elevation data, reducing the sharpness of terrain changes, and blurring sensitive areas. Using the Smooth modifier to process the Mesh file can be applied to deleting the geographical location and elevation of topographic features, the highest point on the map, major peaks, and other commanding heights. It can also be used to blur the detailed geographical location and distribution characteristics of settlements and defense projects. It should be noted that this embodiment does not limit the scenarios in which the Smooth modifier is used to process the Mesh file.

[0048] Optionally, in this embodiment, the mesh can be subdivided using the Subdivide command before further processing of the mesh file, and can be subdivided multiple times as needed according to the size of the DEM file. The subdivision of the mesh using the Subdivide command is based on a linear interpolation subdivision algorithm.

[0049] Optionally, in embodiments of this application, the method may further include the following: adding noise to the Mesh file based on Blender 3D modeling, wherein the noise addition is performed using a displacement modifier based on Blender 3D modeling. This further enhances the irreversibility of the decryption process and improves the security of decrypting DEM files.

[0050] Specifically, in this embodiment, a Displace modifier is added to the Blender 3D model, and the Mesh file is processed based on the added Displace modifier. For example, a Displace modifier addition command is received on the Blender 3D model's interactive interface, the Displace modifier is added, and then processing is performed.

[0051] Optionally, in embodiments of this application, adding noise to a Mesh file may include the following:

[0052] Add a clamp node to the shader editor based on the displacement modifier. Specifically, add a shader editor to the Displace modifier's interface. Specifically, receive the command to add a shader editor and add it. Display the shader editor's interface. Add a clamp node to the shader editor's interface, receive the command to add a clamp node, and add the clamp node. The clamp node can control the noise deviation.

[0053] Adding noise nodes is based on the Shader Editor. These noise nodes include at least one of the following: Texture Coordinate node, Mapping node, NoiseTexture node, Voronoi Texture node, Musgrave Texture node, Wave Texture node, Math node, Mix RGB node, and ColorRamp node. Specifically, noise nodes are added through the Shader Editor's interactive interface; for example, by receiving an instruction to add a noise node and then adding it.

[0054] The mesh file is processed using clamping nodes and noise-adding nodes to add noise. Specifically, noise is generated based on clamping nodes and noise-adding nodes, and the generated noise is added to the mesh file. For example, noise generated based on Blender 3D modeling displacement nodes or attribute noise nodes is added to the mesh file.

[0055] Optionally, in this embodiment, when adding noise nodes including Texture Coordinate, Mapping, and Noise Texture nodes, a TextureCoordinate node and a Mapping node are added in the Shader Editor, and they are connected to a Noise Texture node. A basic noise pattern is generated, suitable for creating random and natural textures. The generated noise pattern is applied to the Mesh file through a Displacement node or an Attribute Noise node to add noise to the Mesh file.

[0056] In this embodiment, the Voronoi Texture node, Musgrave Texture node, and WaveTexture node can all create procedural textures. Specifically, the Voronoi Texture node generates Voronoi patterns using a procedural texture algorithm to create a cellular-structure-like noise effect. The Musgrave Texture node generates Musgrave noise using a procedural texture algorithm to simulate complex natural terrain and textures. The Wave Texture node generates ripple patterns to create periodic noise effects. In this embodiment, the procedural texture generation algorithm based on Voronoi and / or Musgrave maps adds random noise to the data, which can disrupt the details of the original terrain data.

[0057] In addition, the Mapping node can be used to adjust texture coordinates for translating, rotating, and scaling texture patterns. The Math node can be used to generate random noise using algorithms such as hash functions. The Mix RGB node can be used to blend two textures or colors to create complex texture effects. The ColorRamp node can be used to map the grayscale values ​​of a texture to color gradients for adjusting and controlling texture output.

[0058] The Texture Coordinate node, Mapping node, Noise Texture node, Voronoi Texture node, Musgrave Texture, Wave Texture node, Mix RGB node, and ColorRamp node can be used individually to add noise to mesh files. Combined with clamping nodes, they can control the deviation of the generated terrain, ensuring the terrain height is within a reasonable range. Multiple nodes can also be used in combination to layer noise, significantly increasing the irreversibility of the result. They can also be used with the Math node to perform mathematical operations, combining and adjusting texture values ​​to generate fake data that resembles real terrain but is not, protecting the privacy of the original data.

[0059] In this embodiment, performing mathematical operations with the Math node can include the following: The Add operation of the Math node adds multiple noise values ​​to generate a new noise pattern. The Multiply operation of the Math node multiplies multiple noise values ​​to generate a new noise pattern; the multiplication operation can enhance the effect of high-frequency noise. The Minimum operation of the Math node takes the minimum value of each pixel in the multiple noise patterns to generate a new noise pattern; the minimum value operation can be used to generate a concave effect. Through the above methods, the irreversibility of the de-encryption results can be significantly increased.

[0060] In this application, the Mesh file is processed by adding noise, which introduces randomness into the DEM data and masks specific terrain features. This can be used to protect sensitive information and create virtual terrain, to delete attributes such as reservoir capacity and dam height, river width, and water depth, and to disrupt the geographical location and distribution characteristics of transportation hubs. It can also be used to disrupt the geographical location of national defense projects and military facilities.

[0061] Optionally, in embodiments of this application, the method may further include the following: performing data thinning on the Mesh file, wherein the data thinning is performed using a Blender 3D modeling-based mesh remesh modifier (Remesh modifier).

[0062] Specifically, a Remesh modifier is added to the Blender 3D modeling interface. For example, the interface receives a command to add a Remesh modifier, which is then added to thin the mesh file. Using the Remesh modifier for data thinning requires converting the input mesh file into a voxel grid file. A voxel is a small cube in 3D space, and each voxel represents a fixed position in space. A new mesh structure is generated based on the voxel grid. Each voxel corresponds to a new vertex or face. The Remesh modifier uses the Laplacian Smoothing algorithm in Smooth mode to generate a smooth surface. The Laplacian Smoothing algorithm is simple and efficient, suitable for real-time processing and large-scale mesh smoothing.

[0063] Data thinning of Mesh files can further enhance the irreversibility of decryption and improve the security of decryption of DEM files.

[0064] In this application embodiment, the Mesh file is subjected to data thinning to reduce the density of DEM data, thereby reducing detailed information while preserving the overall terrain shape. This method can be used to reduce the details of terrain landscapes, delete attributes such as river width, water depth, and flow velocity, and can also be used to reduce the detailed information of settlements, retaining only the necessary geographical features.

[0065] Optionally, in embodiments of this application, the method may further include the following:

[0066] Spatial transformation is performed on the Mesh file, which is done using the Modeling tool based on Blender 3D modeling.

[0067] Specifically, in the embodiments of this application, a Modeling tool is added to the interactive interface of Blender 3D modeling. For example, the Modeling tool is added by receiving an instruction to add the Modeling tool in the interactive interface of Blender 3D modeling, thereby processing the Mesh file based on the Modeling tool.

[0068] Modeling tools allow for geometric operations on points, lines, and surfaces in a mesh file, including translation, rotation, and scaling. These operations, combined with Blender's numerical input capabilities, allow for precise control over the magnitude and range of the manipulation, enabling changes to the position and shape of data in 3D space without altering its underlying geometry.

[0069] By performing spatial transformation on the mesh file, the spatial position of the DEM can be changed. Spatial transformation technology, through translation, rotation, and scaling operations, can change the position and orientation of the DEM in space, making it difficult to directly compare with the real terrain. This further enhances the irreversibility of the declassification process and improves the security of declassifying DEM files.

[0070] Optionally, in embodiments of this application, the method may further include the following:

[0071] The mesh file undergoes region masking, which is performed using Blender's 3D modeling selection tools. Region masking includes selecting the sensitive areas to be masked and masking those sensitive areas.

[0072] Specifically, selection tools are added to the Blender 3D modeling interface. For example, the interface receives a command to add a selection tool, which is then added and processed accordingly. These selection tools include Box Select and Circle Select. The user then uses these tools to select sensitive areas that need to be masked. The vertices of these sensitive areas are then determined. For instance, the user can select the vertices of the sensitive area directly on the selection tool's interface; or, the user can input the coordinates of the vertices on the interface to determine the sensitive area.

[0073] To mask sensitive areas, you can either set a fixed elevation value for the vertices in the sensitive area or delete those vertices. Alternatively, you can use materials and textures for masking. For example, enter EditMode using the selection tool, select the faces of the sensitive area, assign a new material (different from the material of the sensitive area) to the selected faces, and set the material and texture to make the sensitive area transparent or invisible. Alternatively, you can use color, ground, or vegetation effects textures to mask the sensitive area.

[0074] By masking areas in Mesh files, sensitive areas are hidden or disappear from DEM data, protecting specific geographic information. This further enhances the irreversibility of declassification and improves the security of DEM file declassification. It can be applied to processing the geographical location and distribution characteristics of defense projects, as well as the geographical locations of transportation hubs and residential areas.

[0075] In this application's implementation, multiple processing methods are combined, employing both selection and masking techniques to partition the terrain. Partitioning allows for flexible customization of declassification schemes based on specific needs. Appropriate declassification methods and parameters can be selected according to the characteristics and sensitivity of different areas, achieving refined processing. This ensures data security and usability while meeting diverse application requirements.

[0076] Furthermore, attribute randomization and blending can be performed through geometry nodes. For example, attribute randomization, attribute mixing, and attribute sample texture can be used to perform blending operations, thereby providing more complex and flexible geometric processing methods and achieving high-precision desensitization effects.

[0077] Specifically, Geometry Nodes are added to the Blender 3D modeling interface. For example, the interface receives a command to add Geometry Nodes, which are then added, and processing is performed based on these Geometry Nodes. At least one of Attribute Randomize, Attribute Mix, and Attribute Sample Texture is added to the Geometry Nodes interface. Based on the added nodes, the Mesh file is processed. Specifically, the Mesh file is connected to the added nodes, and the Mesh file is then processed.

[0078] Geometry Nodes is a procedural modeling tool in Blender 3D modeling. Through a node-based interface, it allows users to construct logical relationships for geometric operations and attribute modifications by connecting nodes. This tool supports real-time modification of geometry while maintaining the integrity of the original model. Users can dynamically adjust parameters such as scalar, vector, color, texture, range, and curve, and observe the effects in real time. Geometry Nodes is non-destructive, meaning that geometry can be modified in real time without affecting the integrity of the original model. In DEM data de-identification, this tool enhances data irreversibility by performing highly randomized and mixed operations on geometric vertices, faces, normals, and textures, while preserving the geometric characteristics of the data. This method not only improves data security but also ensures the high quality of the de-identified data and its feasibility for practical applications.

[0079] During the decryption process of DEM data, the following nodes of Geometry Nodes can be used: AttributeRandomize, Attribute Mix, and Attribute Sample Texture.

[0080] The Attribute Randomize node randomizes the model's geometric attributes (such as vertex positions, normals, and colors) using parameters like Attribute, Data Type, Operation, Replace, Add, Multiply, Min, and Max, thus disrupting the original attribute distribution. This is highly effective in ensuring data unpredictability and desensitization. During the desensitization process, randomizing vertex positions or colors can blur terrain details, ensuring that terrain data is difficult to restore after modification.

[0081] The Attribute Mix node allows for the blending of two attributes, such as linear interpolation or other forms of blending between two vertex attributes or two textures. By combining different weights, geometric modifications with multiple effects can be generated. The Attribute Mix node provides various operations including Clamp, Mix (linear interpolation), Multiply Add, and Tangent. Blending the vertex position attribute (Position) of a geometry, through Mix (linear interpolation) or other operations, randomizes or perturbs the vertices, thereby changing the appearance of the geometry. Blending the normal attribute (Normal) randomizes or perturbs the normal direction of the surface, blurring the details of the original surface. Blending the color attribute (Color) blurs or alters the surface texture by mixing the original color with randomly generated color values, making it impossible to display the original details. Blending the height attribute (Height) changes the refinement of the terrain by randomizing or weighting the Z-axis (height value) of the vertices, ensuring that the original terrain data cannot be restored.

[0082] The Attribute Sample Texture node maps texture attributes (such as color and brightness) to geometric attributes. By sampling different parts of the texture, users can dynamically modify the vertex or face information of the geometry. In desensitization processing, nodes such as Voronoi Texture, Musgrave Texture, and Wave Texture can be used to perturb the vertices or faces of the geometry, thereby generating irregular terrain data. This method can produce highly random and unpredictable variations and enhance data security.

[0083] Optionally, in embodiments of this application, the method may further include the following:

[0084] The Eevee real-time rendering engine, based on Blender 3D modeling, renders the file obtained after processing the Mesh file.

[0085] During terrain data de-encryption, various parameters such as smoothness, noise intensity, and simplification ratio are adjusted. Blender's Eevee real-time rendering engine allows for real-time observation of model changes, avoiding the tedious process of repeatedly exporting and importing data in traditional methods. Real-time rendering provides intuitive monitoring of terrain detail changes, ensuring that important terrain features are preserved while sensitive information is hidden. If processing is over- or under-processed, parameters (e.g., the various parameters described in the above embodiments) can be fine-tuned immediately for optimization. When using masking and selection tools to refine specific areas, real-time rendering clearly displays the processing effects in different areas, ensuring the results meet expectations.

[0086] This method's real-time rendering and interactive adjustment features significantly reduce trial-and-error time and effort, allowing users to determine the appropriateness of their current operation without having to wait for long rendering results. Furthermore, real-time rendering enables flexible customization of declassification solutions based on the needs of different application scenarios, accurately handling sensitive areas and ensuring that the declassification effect meets security standards.

[0087] In this embodiment, ensuring the successful export of DEM data after declassification is crucial for its continued utilization across different platforms and tools. Blender supports importing and exporting various data formats, including OBJ, FBX, STL, PLY, and GLTF. These formats cover multiple professional fields such as 3D modeling, animation, Geographic Information System (GIS) analysis, and 3D printing, meeting diverse data processing needs. OBJ and FBX are commonly used for 3D modeling, STL for 3D printing, PLY for point cloud data, and GLTF for web-based display. Blender's multi-format support enables seamless integration with various GIS software and 3D tools, greatly facilitating data transmission and processing across different platforms.

[0088] In summary, the embodiments of this application provide a method for decrypting DEM files based on Blender 3D modeling and rendering software, which aims to ensure data security while maintaining the application value of the data, improving the quality of the results, and increasing processing efficiency.

[0089] First, the technical solution provided in this application employs multiple algorithms, such as Laplacian smoothing to blur terrain details, linear interpolation subdivision, collapse, and un-subdivide algorithms to downsampling data, and procedural texture generation algorithms based on Voronoi and Musgrave maps to add random noise to perturb the details of the original terrain data. By combining these algorithms, the irreversibility of the declassification process is greatly enhanced compared to using a single algorithm, thereby ensuring data security.

[0090] Secondly, the technical solution provided in this application not only emphasizes data security but also fully utilizes Blender's geometric precision control tools and flexible parameter adjustment functions. Through node-based modeling and rendering tools, it can comprehensively process data by combining various methods such as smoothing, downsampling, and random noise injection. Furthermore, by using masking and selection tools, terrain can be partitioned and refined, ensuring that while reducing data resolution and accuracy, terrain features and important ground information are still preserved. This guarantees the usability of the declassified data, making the data both secure and able to meet the practical application needs of terrain analysis, hydrological analysis, flood simulation, and other applications.

[0091] Furthermore, regarding improving the quality of the results, the technical solution provided in this application utilizes Blender's real-time preview function, making the operation process more intuitive and flexible. Users can adjust parameters and preview the effects at any time during the operation. Simultaneously, leveraging Blender's high-quality rendering capabilities, accurate terrain visualization results can be generated, thereby aiding in the identification and processing of sensitive data. Through Blender's built-in 3D visualization rendering engine, users can intuitively view the adjusted DEM data, ensuring that the declassified data meets usage requirements.

[0092] Furthermore, in terms of improving processing efficiency, Blender can perform automated data decryption without relying on additional plugins. Advanced automation can be achieved using built-in tools such as Geometry Nodes, and Python scripts can also be written for automation. The adoption of automated processing significantly improves processing efficiency, making large-scale data processing more convenient and greatly enhancing the ease and overall efficiency of DEM file decryption. Based on this, the technical solution provided in this application allows users to flexibly customize the decryption process according to specific needs, including level of detail, processing area, and noise parameters. In the visual interface, users can interactively adjust decryption parameters, view the effects in real time, and make modifications to meet various refined data processing needs.

[0093] Finally, Blender supports importing and exporting various data formats, including OBJ, FBX, and STL, enabling seamless integration with other GIS software and tools. This data conversion capability allows users to easily transfer and process DEM data across different platforms, improving workflow flexibility and efficiency.

[0094] Secondly, embodiments of this application also provide an apparatus for decrypting DEM files based on Blender 3D modeling.

[0095] Figure 2 This is a structural block diagram of an apparatus for decrypting DEM files based on Blender 3D modeling, according to a preferred embodiment of this application. Figure 2 As shown, the device includes a receiving module 1, a conversion module 2, and a processing module 3.

[0096] Receiving module 1 receives the DEM file to be processed. Conversion module 2 converts the received DEM file into a Mesh file. Processing module 3 performs the following processing on the Mesh file: reducing resolution and smoothing blurred terrain; wherein, reducing resolution is performed using the polygon reduction modifier based on Blender 3D modeling, and smoothing blurred terrain is performed using the smoothing modifier based on Blender 3D modeling.

[0097] Optionally, the processing module is also used to: add noise to the Mesh file, wherein the noise is added by a displacement modifier based on Blender 3D modeling.

[0098] Optionally, adding noise to the Mesh file includes: adding clamping nodes based on the shading editor using the displacement modifier; adding noise-adding nodes based on the shading editor, wherein the noise-adding nodes include at least one of the following: texture coordinate nodes, mapping nodes, noise texture nodes, Thiessen polygon texture nodes, Mahalanobis fractal texture nodes, ripple texture nodes, mathematical nodes, blended RGB nodes, and color gradient nodes; and processing the Mesh file based on clamping nodes and noise-adding nodes to add noise.

[0099] Optionally, the processing module is also used to: perform data thinning on the Mesh file, wherein the data thinning is performed using a mesh re-division modifier based on Blender 3D modeling.

[0100] Optionally, the processing module is also used to: perform spatial transformation processing on the Mesh file, wherein the spatial transformation is performed using a Blender 3D modeling tool.

[0101] Optionally, the processing module is also used to: perform region masking on the Mesh file, wherein the region masking is performed based on the selection tool of Blender 3D modeling.

[0102] Optionally, the device further includes a rendering module for rendering the processed Mesh file using the Eevee real-time rendering engine based on Blender 3D modeling, after processing the Mesh file.

[0103] The working principle and benefits of the apparatus for decrypting DEM files based on Blender 3D modeling provided in this application are similar to those of the method for decrypting DEM files based on Blender 3D modeling provided in this application, and will not be repeated here.

[0104] Thirdly, embodiments of this application also provide a machine-readable storage medium storing instructions that, when executed by a processor, cause the processor to perform the steps of the method described in the above embodiments.

[0105] The preferred embodiments of this application have been described in detail above. However, this application is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this application, various simple modifications can be made to the technical solution of this application, and these simple modifications all fall within the protection scope of this application.

[0106] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable way without contradiction. In order to avoid unnecessary repetition, this application will not describe the various possible combinations separately.

[0107] Furthermore, various different implementations of this application can be combined in any way, as long as they do not violate the spirit of this application, they should also be regarded as the content disclosed in this application.

Claims

1. A method for decrypting DEM files based on Blender 3D modeling, characterized in that, The method includes: Receive the DEM file to be processed; Convert the received DEM file into a Mesh file; The Mesh file is processed as follows: resolution is reduced, and terrain is smoothed and blurred; The resolution reduction is performed using the polygon reduction modifier based on the Blender 3D model, and the smoothing of the blurred terrain is performed using the smoothing modifier based on the Blender 3D model. The Mesh file is subjected to noise addition, wherein the noise addition is performed based on the displacement modifier of the Blender 3D model; The process of adding noise to the Mesh file includes: Add clamp nodes to the shader editor based on the displacement modifier; Based on the shading editor, noise-adding nodes are added, wherein the noise-adding nodes include at least one of the following: texture coordinate nodes, mapping nodes, noise texture nodes, Thiessen polygon texture nodes, Mahalanobis fractal texture nodes, ripple texture nodes, mathematical nodes, blended RGB nodes, and color gradient nodes; and The Mesh file is processed based on the clamping node and the noise-adding node to add noise; The process of adding noise to the Mesh file, based on the clamping node and the noise-adding node, includes: The Mesh file is processed based on the texture coordinate node, the mapping node, the noise texture node, the Thiessen polygon texture node, the Mahalanobis fractal texture node, the ripple texture node, the mathematical node, the mixed RGB node, and the color gradient node to obtain multi-layer noise values. Mathematical operations are performed on the multi-layer noise values ​​based on the Math node, and noise is added in conjunction with the clamping node.

2. The method according to claim 1, characterized in that, The method also includes: The Mesh file is subjected to data thinning, wherein the data thinning is performed based on the mesh re-division modifier of the Blender 3D model.

3. The method according to claim 1, characterized in that, The method also includes: The Mesh file undergoes a spatial transformation, wherein the spatial transformation is performed using the Blender 3D modeling tool.

4. The method according to claim 1, characterized in that, The method also includes: The Mesh file is subjected to region masking, wherein the region masking is performed based on the selection tool of the Blender 3D modeling.

5. The method according to claim 1, characterized in that, After processing the Mesh file, the method further includes: The file obtained by rendering the Mesh file using the Eevee real-time rendering engine based on the Blender 3D modeling.

6. A device for decrypting DEM files based on Blender 3D modeling, characterized in that, The device includes: The receiving module is used to receive the DEM file to be processed; The conversion module is used to convert the received DEM file into a Mesh file; The processing module is used to perform the following processing on the Mesh file: reduce resolution and smooth blurred terrain; The resolution reduction is performed using the polygon reduction modifier based on the Blender 3D model, and the smoothing of the blurred terrain is performed using the smoothing modifier based on the Blender 3D model. The processing module is further configured to: add noise to the Mesh file, wherein the noise addition is performed based on the displacement modifier of the Blender 3D model; The process of adding noise to the Mesh file includes: Add clamp nodes to the shader editor based on the displacement modifier; Based on the shading editor, noise-adding nodes are added, wherein the noise-adding nodes include at least one of the following: texture coordinate nodes, mapping nodes, noise texture nodes, Thiessen polygon texture nodes, Mahalanobis fractal texture nodes, ripple texture nodes, mathematical nodes, blended RGB nodes, and color gradient nodes; and The Mesh file is processed based on the clamping node and the noise-adding node to add noise; The process of adding noise to the Mesh file, based on the clamping node and the noise-adding node, includes: The Mesh file is processed based on the texture coordinate node, the mapping node, the noise texture node, the Thiessen polygon texture node, the Mahalanobis fractal texture node, the ripple texture node, the mathematical node, the mixed RGB node, and the color gradient node to obtain multi-layer noise values. Mathematical operations are performed on the multi-layer noise values ​​based on the Math node, and noise is added in conjunction with the clamping node.

7. The apparatus according to claim 6, characterized in that, The processing module is also used for: The Mesh file is subjected to data thinning, wherein the data thinning is performed based on the mesh re-division modifier of the Blender 3D model.

8. The apparatus according to claim 6, characterized in that, The processing module is also used for: The Mesh file undergoes a spatial transformation, wherein the spatial transformation is performed using the Blender 3D modeling tool.

9. The apparatus according to claim 6, characterized in that, The processing module is also used for: The Mesh file is subjected to region masking, wherein the region masking is performed based on the selection tool of the Blender 3D modeling.

10. The apparatus according to claim 6, characterized in that, The device also includes: The rendering module is used to render the file obtained after processing the Mesh file based on the Eevee real-time rendering engine of the Blender 3D modeling.

11. A machine-readable storage medium, characterized in that, The machine-readable storage medium stores instructions that, when executed by a processor, cause the processor to perform the steps of the method according to any one of claims 1 to 5.

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