Method and device for decrypting DEM file and machine readable storage medium

Abstract

The invention discloses a method and device for performing decryption processing on a DEM file and a machine readable storage medium. The method comprises the following steps: receiving a DEM file to be processed; the received DEM file is converted into a Mesh file; carrying out the following processing on the Mesh file: reducing the resolution and smoothing the fuzzy terrain; wherein the resolution reduction is carried out on the basis of an area reduction modifier of the Blender three-dimensional modeling, and the fuzzy terrain smoothing is carried out on the basis of a smoothing modifier of the Blender three-dimensional modeling. Therefore, the security of decrypting the DEM file is improved.

Description

Technical Field

[0001] The present application relates to the technical field of decryption processing, and more specifically, to a method and device for decrypting a DEM file and a machine-readable storage medium. Background Art

[0002] Digital Elevation Model (DEM) stores terrain elevation data in the form of a regular grid, with each grid cell corresponding to a geographic coordinate and an elevation value. Elevation values ​​are usually in meters or feet, indicating the height of a point on the ground relative to sea level. Common data formats include GeoTIFF, ASCII, and ESRI Grid. DEM is widely used in geographic information systems (GIS), remote sensing, environmental science, and engineering surveying. It can be used for terrain analysis, hydrological analysis, flood simulation, soil erosion research, and urban planning.

[0003] With the widespread use of DEM in various fields, it is crucial to protect the security of its data. Since the elevation information and terrain features in DEM data may involve national security and sensitive information, when publicly publishing or transmitting these data, all or part of the spatial location, accuracy, attribute content and their interrelationships contained in the DEM file must be kept confidential, and the confidentiality results need to be irreversible to ensure the security and confidentiality of the information. At present, ArcGIS, QGIS, ENVI and other software are generally used to decrypt DEM files, with a single algorithm and low 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, the present application proposes a method and device for decrypting DEM files and a machine-readable storage medium, which can improve the security of decrypting DEM files.

[0006] In a first aspect, an embodiment of the present application provides a method for decrypting a DEM file based on Blender three-dimensional modeling, the method comprising: receiving a DEM file to be processed; converting the received DEM file into a Mesh file; performing the following processing on the Mesh file: reducing the resolution, and smoothing the blurred terrain; wherein the resolution reduction is performed based on a face reduction modifier of the Blender three-dimensional modeling, and the smoothing of the blurred terrain is performed based on a smoothing modifier of the Blender three-dimensional modeling.

[0007] Optionally, the method further comprises: adding noise to the Mesh file, wherein the adding noise is performed based on a displacement modifier of the Blender three-dimensional modeling.

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

[0009] Optionally, the method further comprises: performing data thinning processing on the Mesh file, wherein the data thinning is performed based on a mesh re-division modifier of the Blender three-dimensional modeling.

[0010] Optionally, the method further comprises: performing spatial transformation processing on the Mesh file, wherein the spatial transformation is performed based on the Blender three-dimensional modeling tool.

[0011] Optionally, the method further comprises: performing area shielding processing on the Mesh file, wherein the area shielding is performed based on a selection tool of the Blender three-dimensional modeling.

[0012] Optionally, after processing the Mesh file, the method further comprises: rendering a file obtained by processing the Mesh file using an Eevee real-time rendering engine based on the Blender three-dimensional modeling.

[0013] In a second aspect, an embodiment of the present application also provides a device for decrypting DEM files based on Blender three-dimensional modeling, the device comprising: a receiving module for receiving the DEM file to be processed; a conversion module for converting the received DEM file into a Mesh file; a processing module for performing the following processing on the Mesh file: reducing the resolution and smoothing the blurred terrain; wherein the resolution reduction is performed based on the face reduction modifier of the Blender three-dimensional modeling, and the smoothing of the blurred terrain is performed based on the smoothing modifier of the Blender three-dimensional modeling.

[0014] Optionally, the processing module is further used to: perform a noise-adding process on the Mesh file, wherein the noise-adding is performed based on a displacement modifier of the Blender three-dimensional modeling.

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

[0016] Optionally, the processing module is further used to: perform data thinning on the Mesh file, wherein the data thinning is performed based on a mesh re-division modifier of the Blender three-dimensional modeling.

[0017] Optionally, the processing module is further used to: perform spatial transformation processing on the Mesh file, wherein the spatial transformation is performed based on the Blender three-dimensional modeling tool.

[0018] Optionally, the processing module is further used to: perform area shielding processing on the Mesh file, wherein the area shielding is performed based on a selection tool of the Blender three-dimensional modeling.

[0019] Optionally, the device further includes: a rendering module, for rendering a file obtained by processing the Mesh file using an Eevee real-time rendering engine based on the Blender three-dimensional modeling after processing the Mesh file.

[0020] In a third aspect, an embodiment of the present application further provides a machine-readable storage medium, on which instructions are stored, and when the instructions are executed by a processor, the processor is configured to execute the steps according to the above method.

[0021] According to the technical solution of the present application, the DEM file is declassified based on Blender 3D modeling, the DEM file to be processed is converted into a Mesh file, and the obtained Mesh file is subjected to operations of reducing the resolution and smoothing the blurred terrain, wherein the resolution is reduced by a face reduction modifier based on Blender 3D modeling, and the blurred terrain is smoothed by a smooth modifier based on Blender 3D modeling. The face reduction modifier includes a Collapse algorithm, an Un-Subdivide algorithm, and a Planar algorithm. The smoothing modifier includes a Laplace smoothing algorithm. Data downsampling is achieved based on the Collapse algorithm, the Un-Subdivide algorithm, and the Planar algorithm. The terrain details are blurred based on the Laplace smoothing algorithm. In this way, a variety of algorithms are used when declassifying the DEM file. The combination of a variety of algorithms can greatly enhance the irreversibility of the declassification process, thereby ensuring data security. In this way, the security of declassifying the DEM file is improved.

[0022] Other features and advantages of the present application will be described in detail in the subsequent detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings constituting a part of the present application are used to provide a further understanding of the present application, and the schematic implementation modes and descriptions of the present application are used to explain the present application. In the accompanying drawings:

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

[0025] Figure 2 It is a structural block diagram of a device for decrypting DEM files based on Blender three-dimensional modeling according to a preferred embodiment of the present application. DETAILED DESCRIPTION

[0026] The technical solution of the present application will be described in detail below with reference to the accompanying drawings and in combination with the implementation modes.

[0027] In a first aspect, an embodiment of the present application provides a method for decrypting a DEM file based on Blender three-dimensional modeling.

[0028] Figure 1 The flowchart of the method for decrypting DEM files based on Blender 3D modeling according to the preferred embodiment of the present application is as follows. Figure 1 As shown, the method includes the following contents.

[0029] In step S10, a DEM file to be processed is received. Specifically, the DEM file is received based on Blender 3D modeling. The user imports the DEM file to be processed into Blender 3D modeling, and Blender 3D modeling receives the DEM file to be processed. 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, and Blender 3D modeling converts the received DEM file into a DEM file. For example, the selection of the DEM file and the "Convert to Mesh" command are received, and the running instruction is executed to convert the received DEM file into a DEM file.

[0031] Convert the DEM file into a Mesh file, and then process the DEM file with higher geometric accuracy.

[0032] In computer graphics and 3D modeling, "Mesh" is a basic structure used to represent three-dimensional objects. The basic components of Mesh are vertices, edges, and faces. Among them, 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. An edge defines the relationship between vertices and how they are connected. A face is a planar area surrounded by three or more edges, usually a triangle or quadrilateral. A face defines the surface of an object and can be used to calculate lighting and texture mapping.

[0033] In step S12, the converted Mesh file is subjected to the following operations: reducing the resolution and smoothing the blurred terrain. The resolution is reduced by using the Decimate modifier of Blender 3D modeling, and the blurred terrain is smoothed by using the Smooth modifier of Blender 3D modeling.

[0034] Specifically, a Decimate modifier and a Smooth modifier are added in Blender 3D modeling, and the Mesh file is processed based on the added Decimate modifier and Smooth modifier. For example, an instruction to add the Decimate modifier and the Smooth modifier is received on the interactive interface of Blender 3D modeling, the Decimate modifier and the Smooth modifier are added, and then the processing is performed.

[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 reduce 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 accuracy of the data to be processed.

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

[0039] 0 < Ratio < 1: The mesh is simplified according to the ratio. For example, Ratio = 0.5 means reducing the number of faces of the mesh to 50% of the original number of faces. Ratio = 0.1 means reducing 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 the implementation mode of the present application, the Mesh file is processed using the Decimate modifier to simplify the terrain features and reduce the level of detail of the DEM by reducing the number of vertices and faces. The Mesh file is processed using the Decimate modifier, which can be applied to delete information such as the location, length, width and height of bridges and tunnels, and simplify the details of transportation networks such as roads and railways, so that the original elevation data is no longer so detailed, but the overall terrain contour is still maintained. It should be noted that in the implementation mode of the present application, there is no restriction on the scenario of using the Decimate modifier to process the Mesh file.

[0042] Use the Smooth modifier to smooth the Mesh file. The Smooth modifier includes a Laplace smoothing algorithm based on vertex positions, which mainly achieves a smoothing effect based on the Laplace smoothing algorithm based on vertex positions. Specifically, by iteratively moving vertices multiple times, the position of each vertex is made closer to the center position of its neighboring vertices.

[0043] In the implementation of the present application, the degree of smoothing of the Mesh file can be controlled. Specifically, the parameter Factor is set on the interactive interface of the Smooth modifier to control the intensity of smoothing. The parameter Factor ranges from 0 to 1. The higher the value of the parameter Factor, the more obvious the smoothing effect.

[0044] In addition, in the implementation of the present application, the value of the parameter Factor can be adjusted in real time so that the smoothing effect can achieve a satisfactory result. Specifically, after the Mesh file is processed, it is rendered to preview the effect, and the value of the parameter Factor is adjusted according to the preview effect until a satisfactory effect is achieved.

[0045] In the implementation mode of the present application, the value of the parameter Repeat can be set on the interactive interface of the Smooth modifier to control the number of iterations. Through multiple iterations, the vertex V gradually moves to the average position of the adjacent vertices, making the mesh smoother as a whole.

[0046] In addition, in the implementation of the present application, the value of the parameter Repeat can be adjusted in real time so that the iterative effect can achieve a satisfactory result. Specifically, after the Mesh file is processed, it is rendered to preview the effect, and the value of the parameter Repeat is adjusted according to the preview effect until a satisfactory effect is achieved.

[0047] In the implementation mode of the present application, the Smooth modifier is used to process the Mesh file, smooth the elevation data, reduce the sharpness of terrain changes, and blur the sensitive areas. The use of the Smooth modifier to process the Mesh file can be applied to delete the geographical location and elevation of the commanding heights such as the highest point of the map, the main peaks, etc. It can also be used to blur the detailed geographical location and distribution characteristics of the settlements and the geographical location and distribution characteristics of the national defense projects. It should be noted that in the implementation mode of the present application, there is no restriction on the scenario of using the Smooth modifier to process the Mesh file.

[0048] Optionally, in the implementation mode of the present application, before the Mesh file is subsequently processed, the mesh can be subdivided using the Subdivide command, and the mesh can be subdivided multiple times 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 the implementation manner of the present application, the method may further include the following contents: adding noise to the Mesh file based on Blender 3D modeling, wherein the adding noise is performed based on the displacement modifier of Blender 3D modeling. In this way, the irreversibility of the decryption process can be further enhanced, and the security of the decryption process of the DEM file can be further improved.

[0050] Specifically, in the implementation of the present application, a displacement modifier (Displace modifier) ​​is added in Blender 3D modeling, and the Mesh file is processed based on the added Displace modifier. For example, an instruction to add the Displace modifier is received on the interactive interface of Blender 3D modeling, the Displace modifier is added, and then the processing is performed.

[0051] Optionally, in an embodiment of the present application, the process of adding noise to the Mesh file may include the following contents.

[0052] Add a clamp node to the shader editor based on the displacement modifier. Specifically, add a shader editor (Shader Editor) to the interactive interface of the Displace modifier. Specifically, receive an add instruction to the Shader Editor and add the Shader Editor. Display the interactive interface of the Shader Editor. Add a clamp node to the interactive interface of the Shader Editor, receive an add instruction to the clamp node, and add the clamp node. The clamp node can control the noise deviation.

[0053] Adding a noise node based on the shader editor, wherein the noise node includes at least one of the following: a texture coordinate node, a mapping node, a noise texture node, a Voronoi Texture node, a Musgrave Texture node, a Wave Texture node, a Math node, a Mix RGB node, and a ColorRamp node. Specifically, adding a noise node is added on the interactive interface of the Shader Editor, for example, receiving an instruction to add a noise node, and adding the noise node.

[0054] The Mesh file is processed based on the clamp node and the add noise node to add noise. Specifically, noise is generated based on the clamp node and the add noise node, and the generated noise is added to the Mesh file. For example, the generated noise is added to the Mesh file based on the displacement node (Displacement node) or the attribute noise node (Attribute Noise node) of Blender 3D modeling.

[0055] Optionally, in an embodiment of the present application, when adding noise nodes including a Texture Coordinate node, a Mapping node, and a Noise Texture node, in the Shader Editor, add a Texture Coordinate node and a Mapping node, and connect them to a Noise Texture node. Generate a basic noise pattern suitable for creating random and natural textures. Apply the generated noise pattern to the Mesh file through the Displacement node or the Attribute Noise node to add noise to the Mesh file.

[0056] In the implementation manner of the present application, the Voronoi Texture node, the Musgrave Texture node, and the WaveTexture node can all create procedural textures. Among them, the Voronoi Texture node generates a Voronoi pattern using a procedural texture algorithm to create a noise effect similar to a cell structure. The Musgrave Texture node generates Musgrave noise using a procedural texture algorithm to simulate complex natural terrain and textures. The Wave Texture node generates a ripple pattern to create a periodic noise effect. In the implementation manner of the present application, the procedural texture generation algorithm based on the Voronoi diagram and / or the Musgrave diagram adds random noise to the data, which can disrupt the details of the original terrain data.

[0057] In addition, you can use the Mapping node to adjust texture coordinates for translation, rotation, and scaling of texture patterns. You can use the Math node to generate random noise using algorithms such as hash functions. You can use the Mix RGB node to mix two textures or colors to create complex texture effects. You can use the ColorRamp node to map the grayscale value of a texture to a color ramp to adjust and control the output of the texture.

[0058] Texture Coordinate node, Mapping node, Noise Texture node, Voronoi Texture node, Musgrave Texture, Wave Texture node, Mix RGB node, ColorRamp node can be used alone to add noise to Mesh files. On this basis, in conjunction with the Clamp node, the deviation of the generated terrain can be controlled to ensure that the terrain height is within a reasonable range. Multiple nodes can also be used in combination to superimpose noise at multiple levels to multiply the irreversibility of the results. Math nodes can also be used to perform mathematical operations, combine and adjust texture values ​​to generate fake data that is similar to real terrain but not real terrain, thereby protecting the privacy of the original data.

[0059] In the implementation manner of the present application, performing mathematical operations in conjunction with the Math node may include the following. Through the Add operation of the Math node, multiple layers of noise values ​​are added to generate a new noise pattern. Through the Multiply operation of the Math node, multiple layers of noise values ​​are multiplied to generate a new noise pattern, wherein the multiplication operation can enhance the impact of high-frequency noise. Through the Minimum operation of the Math node, the minimum value of each pixel in the multi-layer noise pattern is taken to generate a new noise pattern, wherein the minimum operation can be used to generate a concave effect. In the above manner, the irreversibility of the decryption results can be greatly increased.

[0060] In the implementation mode of the present application, the Mesh file is processed by adding noise, introducing randomness in the DEM data, and masking specific terrain features. This can be used to protect sensitive information and create virtual terrain. It can be used to delete the reservoir capacity and dam height, river width, water depth and other attributes, and 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 the implementation manner of the present application, the method may further include the following contents: Data thinning is performed on the Mesh file, wherein the data thinning is performed based on a mesh re-division modifier (Remesh modifier) ​​of Blender 3D modeling.

[0062] Specifically, a Remesh modifier is added based on the interactive interface of Blender 3D modeling. For example, an instruction to add the Remesh modifier is received on the interactive interface of Blender 3D modeling, and the Remesh modifier is added to perform data thinning on the Mesh file. To use the Remesh modifier for data thinning, the input Mesh file needs to be converted into a voxel grid file. Voxels are small cubes in three-dimensional space, and each voxel represents a fixed position in space. A new grid structure is generated based on the voxel grid. Each voxel corresponds to a new vertex or face. The Remesh modifier applies the Laplacian Smoothing algorithm through the Smooth mode to generate a smooth surface. The Laplacian Smoothing algorithm is simple and efficient, and is suitable for real-time processing and large-scale mesh smoothing.

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

[0064] In the implementation mode of the present application, the Mesh file is processed for data thinning to reduce the density of the DEM data so that the detail information is cut but the overall terrain shape is retained. This can be applied to reducing the details of the terrain landscape, deleting river width, water depth, flow rate and other attributes. It can also be used to reduce the detailed information of residential areas and retain only the necessary geographical features.

[0065] Optionally, in the embodiments of the present application, the method may further include the following contents.

[0066] The Mesh file is processed by spatial transformation, wherein the spatial transformation is performed based on a modeling tool (Modeling tool) of Blender three-dimensional modeling.

[0067] Specifically, in an embodiment of the present application, a Modeling tool is added based on the interactive interface of Blender 3D modeling. For example, an instruction to add a Modeling tool is received in the interactive interface of Blender 3D modeling, and the Modeling tool is added, so that the Mesh file is processed based on the Modeling tool.

[0068] Use the Modeling tool to perform geometric operations on points, lines, and surfaces in the Mesh file, including translation, rotation, and scaling. These operations can be combined with Blender's numerical input function to accurately control the amplitude and range of the operation, and can change the position and shape of the data in three-dimensional space without changing its internal geometric structure.

[0069] The spatial position of the DEM can be changed by performing spatial transformation on the Mesh file. The spatial transformation technology can change the position and direction of the DEM in space through translation, rotation and scaling operations, making it difficult to directly compare it with the real terrain, thereby further enhancing the irreversibility of the decryption process and further improving the security of the decryption of the DEM file.

[0070] Optionally, in the embodiments of the present application, the method may further include the following contents.

[0071] The Mesh file is processed by regional shielding, wherein the regional shielding is performed based on the selection tool of Blender 3D modeling, wherein the regional shielding includes the selection of sensitive areas to be shielded and the shielding of sensitive areas.

[0072] Specifically, a selection tool is added based on the interactive interface of Blender 3D modeling. For example, an instruction to add a selection tool is received in the interactive interface of Blender 3D modeling, and the selection tool is added, and processing is performed based on the selection tool. Among them, the selection tools include Box Select, Circle Select, etc. Use the selection tool to select the sensitive area to be shielded. Determine the vertices of the sensitive area. For example, the user may select the vertices of the sensitive area on the interactive interface of the selection tool; or, the coordinates of the vertices of the sensitive area may be input on the interactive interface of the selection tool, thereby determining the sensitive area based on the selection tool.

[0073] Shield the sensitive area, that is, mask it. Set the elevation values ​​of the vertices in the sensitive area to fixed values ​​or delete these vertices. Alternatively, use materials and textures for shielding. For example, enter the EditMode of the selection tool, select the face of the sensitive area; assign a new material different from the material of the sensitive area to the selected face, set the material and texture to make the sensitive area transparent or invisible. Alternatively, use effect textures such as color, ground, and green plants to shield the sensitive area.

[0074] The regional shielding of Mesh files makes sensitive areas shielded or disappear in DEM data, protects specific geographic information, and further enhances the irreversibility of declassification and the security of declassification of DEM files. It can be applied to the geographical location and distribution characteristics of national defense projects, as well as the geographical location of transportation hubs and residential areas.

[0075] In the implementation mode of the present application, a variety of methods are combined for processing, and the terrain can be processed by combining the selection and shielding methods. Zoning processing allows the decryption scheme to be flexibly customized according to specific needs. According to the characteristics and sensitivity of different regions, appropriate decryption methods and parameters can be selected to achieve refined processing. In this way, the security and practicality of data can be ensured while meeting different application requirements.

[0076] In addition, you can also use Geometry Nodes to perform attribute randomization and mixing. For example, Geometry Nodes such as Attribute Randomize, Attribute Mix, and AttributeSample Texture can perform mixed operations, thereby providing a more complex and flexible geometry processing method, which can achieve a high-precision desensitization effect.

[0077] Specifically, Geometry Nodes are added to the interactive interface based on Blender 3D modeling. For example, an instruction to add Geometry Nodes is received in the interactive interface of Blender 3D modeling, Geometry Nodes are added, and processing is performed based on Geometry Nodes. At least one of Attribute Randomize, Attribute Mix, and Attribute Sample Texture is added to the interactive interface of Geometry Nodes, and Mesh files are processed based on the added nodes. Specifically, the Mesh file is connected to the added node, and the Mesh file is processed.

[0078] Geometry Nodes is a procedural modeling tool in Blender 3D modeling. It allows users to build logical relationships of geometric operations and attribute modifications by connecting nodes through a node-based operation interface. The 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, Curve, and observe the effects in real time. Geometry Nodes is non-destructive, which means that geometry can be modified in real time without affecting the integrity of the original model. Using this tool in DEM data decryption can enhance the irreversibility of data while maintaining the geometric characteristics of the data by performing highly random and mixed operations on geometric vertices, faces, normals, textures and other attributes. This method not only improves the security of data, but also ensures the high quality of decrypted data and the feasibility of practical applications.

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

[0080] Attribute Randomize, this node can randomize the geometric attributes of the model (such as vertex position, normal, color, etc.) through parameters such as Attribute, Data Type, Operation, Replace, Add, Multiply, Min, and Max, disrupting the original attribute distribution. This is very effective in ensuring the unpredictability of data and the desensitization effect. In the desensitization process, by randomizing the position or color of vertices, the terrain details can be blurred, ensuring that the terrain data is difficult to restore after being modified.

[0081] Attribute Mix, this node allows you to mix two attributes, such as linear interpolation or other forms of mixing two vertex attributes or two textures. By combining different weights, you can generate geometric modifications with multiple effects. The Attribute Mix node provides a variety of operations including: Clamp, Mix, Multiply Add, Tangent, etc. Mix the vertex position attributes (Position) of the geometry, randomize or disturb the vertices through Mix (linear interpolation) or other operations, thereby changing the appearance of the geometry. Mix the normal attribute (Normal), randomize or disturb the normal direction of the surface, blurring the details of the original surface. Mix the color attribute (Color), blur or change the surface texture by mixing the original color with the randomly generated color value, so that it cannot show the original details. Mix the height attribute (Height), change the fineness of the terrain by randomizing or weighted mixing the Z axis (height value) of the vertex, and ensure that the original terrain data cannot be restored.

[0082] Attribute Sample Texture, this node can map the attributes of the texture (such as color, brightness, etc.) to the attributes of the geometry. By sampling different parts of the texture, the user can dynamically modify the vertex or face information of the geometry. In the desensitization process, the Voronoi Texture node, Musgrave Texture node, Wave Texture node, etc. can be used to interfere with the vertices or faces of the geometry to generate irregular terrain data. This method can produce highly random and unpredictable changes and enhance the security of the data.

[0083] Optionally, in the embodiments of the present application, the method may further include the following contents.

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

[0085] Declassification of terrain data is performed. In the process of adjusting various parameters such as smoothness, noise intensity, simplification ratio, etc., the changes in the model can be observed in real time using Blender's Eevee real-time rendering engine. Changes in the model can be viewed in real time, avoiding the tedious process of repeatedly exporting and importing data in traditional methods. Real-time rendering can intuitively monitor changes in terrain details to ensure that important terrain features are retained while hiding sensitive information. If the processing is excessive or insufficient, the parameters (for example, the various parameters described in the above embodiment) can be immediately fine-tuned for optimization. When using masks and selection tools to refine specific areas, real-time rendering can clearly show the processing effects of different areas to ensure that the results meet expectations.

[0086] The real-time rendering and interactive adjustment functions of this method significantly reduce the time and effort of trial and error. You can judge whether the current operation is appropriate without waiting for a long time for the rendering results. In addition, real-time rendering can also help to flexibly customize the decryption plan according to the needs of different application scenarios, accurately handle sensitive areas, and ensure that the decryption effect meets security standards.

[0087] In the implementation mode of the present application, after the decryption of the DEM data, ensuring that the results of these data can be exported smoothly is a key link in realizing the continuous use of data in different platforms and tools. Blender supports the import and export of multiple data formats including OBJ, FBX, STL, PLY, and GLTF. These formats cover multiple professional fields such as 3D modeling, animation production, geographic information system (GIS) analysis, and 3D printing, meeting diverse data processing needs. Among them, OBJ and FBX are commonly used for 3D modeling, STL is commonly used for 3D printing, PLY format is commonly used for point cloud data, and GLTF format is commonly used for Web display. Blender's multi-format support capability enables it to be seamlessly integrated with various GIS software and 3D tools, greatly facilitating the transmission and processing of data between different platforms.

[0088] In summary, the implementation method of the present application provides a method for decrypting DEM files based on Blender 3D modeling and rendering software, aiming to ensure data security while maintaining the application value of the data, improving the quality of results, and improving processing efficiency.

[0089] First, the technical solution provided in the implementation mode of the present application adopts multiple algorithms, such as Laplacian smoothing to blur terrain details, Linear Interpolation Subdivision, Collapse algorithm, Un-Subdivide algorithm to achieve data downsampling, and programmatic texture generation algorithm based on Voronoi diagram and Musgrave diagram to add random noise to the data to disrupt the details of the original terrain data. Through the combination of these algorithms, the irreversibility of the decryption process can be greatly enhanced compared to using a single algorithm, thereby ensuring data security.

[0090] Secondly, the technical solution provided by the implementation method of this application not only focuses on data security, but also makes full use of Blender's geometric precision control tools and flexible parameter adjustment functions. Through node-based modeling and rendering tools, it can combine smoothing, downsampling, random noise injection and other methods to comprehensively process data. On this basis, using masking and selection tools, the terrain can be partitioned and refined to ensure that while reducing the data resolution and accuracy, the terrain features and important ground object information can still be retained, thereby ensuring the availability of the data after declassification, making the data both safe and able to meet the actual application needs of terrain analysis, hydrological analysis, flood simulation, etc.

[0091] Thirdly, in terms of improving the quality of the results, the technical solution provided by the implementation method of this application uses Blender's real-time preview function to make the operation process more intuitive and flexible. Users can adjust parameters and preview the effects at any time during the operation. At the same time, Blender has high-quality rendering capabilities, which can generate accurate terrain visualization results, thereby helping to identify and process sensitive data. Through Blender's built-in 3D visualization rendering engine, users can intuitively view the adjusted DEM data to ensure that the declassified data meets the usage requirements.

[0092] In addition, in terms of improving processing efficiency, Blender does not need to rely on additional plug-ins to perform automatic data decryption. Advanced automated processing can be performed using tools such as Geometry Nodes built into the software, and Python scripts can also be written for automated processing. The adoption of automated processing procedures has significantly improved processing efficiency and made large-scale data processing more convenient, thereby greatly improving the convenience and overall efficiency of DEM file decryption. On this basis, the technical solution provided by the implementation method of this application allows users to flexibly customize the decryption process according to specific needs, including detail levels, processing areas, and noise parameters. In the visual interface, users can interactively adjust the decryption parameters, view the effects in real time, and make modifications to meet various refined data processing needs.

[0093] Finally, Blender supports the import and export of multiple data formats, including OBJ, FBX, STL, etc., enabling it to be seamlessly integrated with other GIS software and tools. Through this data conversion capability, users can easily transfer and process DEM data between different platforms, improving the flexibility and efficiency of the workflow.

[0094] In a second aspect, an embodiment of the present application also provides a device for decrypting DEM files based on Blender three-dimensional modeling.

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

[0096] The receiving module 1 is used to receive the DEM file to be processed. The conversion module 2 is used to convert the received DEM file into a Mesh file. The processing module 3 is used to perform the following processing on the Mesh file: reducing the resolution and smoothing the fuzzy terrain; wherein the resolution reduction is performed based on the face reduction modifier of Blender 3D modeling, and the fuzzy terrain smoothing is performed based on the smoothing modifier of Blender 3D modeling.

[0097] Optionally, the processing module is further used for: adding noise to the Mesh file, wherein the adding of noise is performed based on a displacement modifier of Blender three-dimensional modeling.

[0098] Optionally, the processing of adding noise to the Mesh file includes: adding a clamp node based on a shading editor of a displacement modifier; adding an add noise node based on the shading editor, wherein the add noise node includes at least one of the following: a texture coordinate node, a mapping node, a noise texture node, a Thiessen polygon texture node, a Mahalanobis fractal texture node, a ripple texture node, a math node, a mixed RGB node, a color gradient node; and processing the Mesh file based on the clamp node and the add noise node to add noise.

[0099] Optionally, the processing module is further used to: perform data thinning on the Mesh file, wherein the data thinning is performed based on a mesh re-division modifier of Blender three-dimensional modeling.

[0100] Optionally, the processing module is further used to: perform spatial transformation processing on the Mesh file, wherein the spatial transformation is performed based on a modeling tool such as Blender three-dimensional modeling.

[0101] Optionally, the processing module is further used to: perform region shielding processing on the Mesh file, wherein the region shielding is performed based on a selection tool of Blender three-dimensional modeling.

[0102] Optionally, the device further comprises: a rendering module, which is used to render a file obtained by processing the Mesh file using an Eevee real-time rendering engine based on Blender three-dimensional modeling after processing the Mesh file.

[0103] The specific working principle and benefits of the device for decrypting DEM files based on Blender three-dimensional modeling provided in the embodiment of the present application are similar to the specific working principle and benefits of the method for decrypting DEM files based on Blender three-dimensional modeling provided in the embodiment of the present application, and will not be repeated here.

[0104] In a third aspect, an embodiment of the present application further provides a machine-readable storage medium, on which instructions are stored, and when the instructions are executed by a processor, the processor is configured to execute the steps of the method described in the above embodiment.

[0105] The preferred embodiments of the present application are described in detail above; however, the present application is not limited to the specific details in the above embodiments. Within the technical concept of the present application, a variety of simple modifications can be made to the technical solution of the present application, and these simple modifications all fall within the protection scope of the present 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 manner without contradiction. In order to avoid unnecessary repetition, this application will not further describe various possible combinations.

[0107] In addition, the various implementation modes of the present application may be arbitrarily combined, and as long as they do not violate the concept of the present application, they should also be regarded as the contents disclosed in the present 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: reducing the resolution and smoothing the blurred terrain; The resolution reduction is performed based on a face reduction modifier of the Blender 3D modeling, and the smoothing of the blurred terrain is performed based on a smoothing modifier of the Blender 3D modeling.

2. The method according to claim 1, characterized in that The method further includes: The Mesh file is processed by adding noise, wherein the adding noise is performed based on the displacement modifier of the Blender three-dimensional modeling.

3. The method according to claim 2, characterized in that The process of adding noise to the Mesh file includes: Add a clamp node to the shader editor based on the displacement modifier; Adding an add noise node based on the shading editor, wherein the add noise node includes at least one of the following: a texture coordinate node, a mapping node, a noise texture node, a Thiessen polygon texture node, a Mahalanobis fractal texture node, a ripple texture node, a math node, a blend RGB node, and a color gradient node; and The Mesh file is processed based on the clamp node and the add noise node to add noise.

4. The method according to claim 1, characterized in that: The method further includes: The Mesh file is subjected to data thinning, wherein the data thinning is performed based on a mesh re-division modifier of the Blender three-dimensional modeling.

5. The method according to claim 1, characterized in that The method further includes: The Mesh file is processed by spatial transformation, wherein the spatial transformation is performed based on the Blender three-dimensional modeling tool.

6. The method according to claim 1, characterized in that The method further includes: The Mesh file is subjected to a region shielding process, wherein the region shielding is performed based on a selection tool of the Blender three-dimensional modeling.

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

8. A device for decrypting DEM files based on Blender three-dimensional modeling, characterized in that: The device includes: A receiving module is used to receive the DEM file to be processed; A conversion module, used for converting the received DEM file into a Mesh file; A processing module, used to perform the following processing on the Mesh file: reducing the resolution and smoothing the blurred terrain; The resolution reduction is performed based on a face reduction modifier of the Blender 3D modeling, and the smoothing of the blurred terrain is performed based on a smoothing modifier of the Blender 3D modeling.

9. The device according to claim 8, characterized in that The processing module is also used for: The Mesh file is processed by adding noise, wherein the adding noise is performed based on the displacement modifier of the Blender three-dimensional modeling.

10. The device according to claim 9, characterized in that The process of adding noise to the Mesh file includes: Add a clamp node to the shader editor based on the displacement modifier; Adding an add noise node based on the shading editor, wherein the add noise node includes at least one of the following: a texture coordinate node, a mapping node, a noise texture node, a Thiessen polygon texture node, a Mahalanobis fractal texture node, a ripple texture node, a math node, a blend RGB node, and a color gradient node; and The Mesh file is processed based on the clamp node and the add noise node to add noise.

11. The device according to claim 8, 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 a mesh re-division modifier of the Blender three-dimensional modeling.

12. The device according to claim 8, characterized in that The processing module is also used for: The Mesh file is processed by spatial transformation, wherein the spatial transformation is performed based on the Blender three-dimensional modeling tool.

13. The device according to claim 8, characterized in that The processing module is also used for: The Mesh file is subjected to a region shielding process, wherein the region shielding is performed based on a selection tool of the Blender three-dimensional modeling.

14. The device according to claim 8, characterized in that The device also includes: A rendering module is used to render the file obtained by processing the Mesh file using the Eevee real-time rendering engine based on the Blender three-dimensional modeling after processing the Mesh file.

15. A machine-readable storage medium, characterized in that: The machine-readable storage medium stores instructions, which, when executed by a processor, cause the processor to be configured to perform the steps of the method according to any one of claims 1 to 7.

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