A dimensionality reduction expression method, terminal and readable storage medium for three-dimensional property rights

Abstract

The present invention discloses a dimensionality reduction representation method, terminal and readable storage medium of a three-dimensional property body, the method comprising: obtaining a three-dimensional property body model, converting the spatial topological structure of the three-dimensional property body model into a graph topological structure; traversing and storing the vertices of the graph topological structure along the edges of the graph topological structure; and restoring the three-dimensional property body model according to the positions and storage order of the vertices. The present invention pre-processes the spatial topological structure of the three-dimensional property body model, converts it into a three-dimensional graph topological structure, uses the data structure of the "graph model" to carry nonlinear topological hierarchical information, and realizes nonlinear interpretation of linear sequences, so that the topological information of the three-dimensional model can be effectively implied and stored through a one-dimensional point string sequence.

Description

Technical Field

[0001] The present invention relates to the field of three-dimensional model storage technology, and in particular to a dimensionality reduction representation method, a terminal and a readable storage medium for a three-dimensional property body. Background Art

[0002] In order to make better use of limited land space, existing technologies have entered the stage of multi-level three-dimensional utilization of land from horizontal expansion. With the continuous deepening of this three-dimensional development and utilization, inconsistent land ownership often occurs, resulting in the inability of the traditional two-dimensional cadastral management model to meet the needs of three-dimensional land application. Therefore, it is necessary to rebuild the concept of land in three-dimensional space, adopt a three-dimensional cadastral management method, and introduce a vertical dimension to solve the ownership issues brought about by the three-dimensional development of land. In cadastral management, land survey and demarcation is a crucial link, and the clarity of the boundaries is directly related to the personal interests of the right holder.

[0003] In the property certificate of traditional two-dimensional cadastral land, a plot map defining the scope of land use needs to be attached. The list of boundary points and the red line map of the land use are the key elements to establish clear boundaries of the use scope. The list of boundary points contains coding information and coordinate information. In addition to uniquely identifying the boundary points, the order of the coding also implies topological information, that is, the boundary points will form a ring after being linearly connected in sequence. This ring, combined with the coordinate information, is consistent with the scope of land use demarcated by the red line of the land use in the graphic element. Therefore, the one-dimensional boundary point sequence is interpreted in a linear manner, and the two-dimensional graphic information is well mapped to each other, which also ensures that the definition of the scope of the land in the property certificate is unique and clear.

[0004] However, in three-dimensional cadastral management, if we still interpret it in this one-dimensional linear way and define the three-dimensional space form in this way, it is not valid and the complete three-dimensional boundary space cannot be restored. The description of the property body in the existing technology in the three-dimensional cadastral property certificate is mainly expressed through three views, each view is expressed by a list of boundary points and a large amount of text description, and the model is displayed using a perspective view. However, this method not only cannot guarantee the accuracy and uniqueness of complex morphological recognition, but also still has problems such as overlapping annotations, difficulty in interpreting topological information, and redundant model storage. Summary of the invention

[0005] The purpose of the present invention is to provide a dimensionality reduction representation method, terminal and readable storage medium for three-dimensional property bodies, aiming to solve the problems that the existing dimensionality reduction representation methods for three-dimensional property bodies cannot guarantee the accuracy and uniqueness of complex morphological recognition, and still have problems such as overlapping annotations, difficulty in interpreting topological information and redundant model storage.

[0006] The technical solution adopted by the present invention to solve the technical problem is as follows:

[0007] The present invention provides a dimensionality reduction expression method for a three-dimensional property right body, the dimensionality reduction expression method for a three-dimensional property right body comprising:

[0008] Acquire a three-dimensional property body model, and convert the spatial topological structure of the three-dimensional property body model into a graph topological structure;

[0009] Traversing and storing the vertices of the graph topology structure along the edges of the graph topology structure;

[0010] The three-dimensional property body model is restored according to the positions and storage order of the vertices.

[0011] Furthermore, the converting of the spatial topological structure of the three-dimensional property entity model into a graph topological structure specifically includes:

[0012] Classifying the three-dimensional property body model according to the spatial topological structure of the three-dimensional property body model to obtain a classification result;

[0013] According to the classification result, the spatial topological structure of the three-dimensional property entity model is converted into a graph topological structure.

[0014] Further, the classification result includes basic types;

[0015] The step of converting the spatial topological structure of the three-dimensional property entity model into a graph topological structure according to the classification result specifically includes:

[0016] If the classification result is a basic type, converting the three-dimensional property body model into a graph topology structure that only retains non-vertical surfaces;

[0017] The method of restoring the three-dimensional property body model according to the positions and storage order of the vertices specifically includes:

[0018] If the classification result is a basic type, determining the coplanarity between all vertices to obtain coplanar vertices, and connecting the coplanar vertices in the order of storage to obtain a non-vertical surface;

[0019] Connecting the vertical adjacent points of the non-vertical surfaces restores the three-dimensional property body model.

[0020] Further, the classification result includes a coplanar type;

[0021] The step of converting the spatial topological structure of the three-dimensional property entity model into a graph topological structure according to the classification result specifically includes:

[0022] If the classification result is a coplanar type, converting the three-dimensional property body model into a graph topology structure that only retains non-vertical surfaces, and dividing the non-vertical surfaces into a plurality of non-vertical surface groups;

[0023] The traversing and storing the vertices of the graph topology structure along the edges of the graph topology structure specifically includes:

[0024] If the classification result is a coplanar type, traversing and storing the vertices of each non-vertical face group along the edge of the graph topology structure in sequence, and two adjacent non-vertical faces stored are not coplanar;

[0025] The method of restoring the three-dimensional property body model according to the positions and storage order of the vertices specifically includes:

[0026] If the classification result is a coplanar type, the coplanarity between all vertices is determined to obtain coplanar vertices, and the coplanar vertices are connected in the order of storage to obtain a non-vertical surface;

[0027] If two non-vertical faces are coplanar, determine whether all vertices of one of the non-vertical faces are within the boundary of the coplanar non-vertical face. If so, remove the non-vertical face.

[0028] Connecting the vertical adjacent points of the non-vertical surfaces restores the three-dimensional property body model.

[0029] Further, the classification result includes a common edge type;

[0030] The step of converting the spatial topological structure of the three-dimensional property entity model into a graph topological structure according to the classification result specifically includes:

[0031] If the classification result is a common edge type, converting the three-dimensional property body model into a graph topology structure that only retains non-vertical surfaces;

[0032] The traversing and storing the vertices of the graph topology structure along the edges of the graph topology structure specifically includes:

[0033] If the classification result is a common edge type, a non-vertical surface with only one connected surface is selected as the starting surface, and a vertex of the connecting edge between the starting surface and the connected non-vertical surface is selected as the starting point;

[0034] Starting from the starting point, traverse all non-vertical vertices along the edges of the graph topology structure in sequence and store them;

[0035] If the classification result is a co-edge type, the coplanarity between all vertices is determined to obtain coplanar vertices, and the coplanar vertices are connected in a storage order to obtain a non-vertical surface.

[0036] Further, the classification result includes irregular types;

[0037] The step of converting the spatial topological structure of the three-dimensional property entity model into a graph topological structure according to the classification result specifically includes:

[0038] If the classification result is an irregular type, the three-dimensional property body model is triangulated and converted into a graph topology structure;

[0039] The method of restoring the three-dimensional property body model according to the positions and storage order of the vertices specifically includes:

[0040] If the classification result is an irregular type, restoration is performed according to the positions and storage order of the vertices to obtain a semi-complete model;

[0041] Modifying the semi-complete model to obtain a triangular model;

[0042] The triangulated model is detriangulated to restore the three-dimensional property model.

[0043] Further, the irregular type includes a convex irregular type;

[0044] The converting the three-dimensional property body model into a graph topology structure by triangulation specifically includes:

[0045] If the classification result is a convex irregular type, generating a seed triangle on the surface of the three-dimensional property body model;

[0046] Repeating the spiral expansion of the generated triangles to generate new triangles until the triangulation of the three-dimensional property body model is completed;

[0047] The traversing and storing the vertices of the graph topology structure along the edges of the graph topology structure specifically includes:

[0048] If the classification result is a convex irregular type, then spirally traverse and store the vertices of the graph topology structure along the edge of the graph topology structure;

[0049] The restoration according to the positions and storage order of the vertices to obtain a semi-complete model specifically includes:

[0050] If the classification result is a convex irregular type, spirally expanding and restoring the model into multiple triangular faces according to the order in which the vertices are stored, thereby obtaining the semi-complete model;

[0051] The modifying of the semi-complete model to obtain a triangular model specifically includes:

[0052] If the classification result is a convex irregular type, all triangle edges belonging to only one triangle in the semi-complete model are obtained, and all triangle edges are connected to the last vertex;

[0053] The concave-convex relationship between each of the triangular faces and the adjacent triangular faces is calculated, and the triangular faces that are in a concave relationship with the adjacent triangular faces are repaired to have a convex relationship with the adjacent triangular faces to obtain the triangular model.

[0054] Furthermore, the irregular type includes a concave irregular type, and the triangulation of the three-dimensional property body model into a graph topology structure specifically includes:

[0055] If the classification result is a concave irregular type, an end point is selected for each face of the three-dimensional property body model;

[0056] Connect each of the end points to the remaining vertices of the face where the end point is located;

[0057] The traversing and storing the vertices of the graph topology structure along the edges of the graph topology structure specifically includes:

[0058] If the classification result is a concave irregular type, generating a seed triangle on the surface of the three-dimensional property body model;

[0059] The three vertices of the seed triangle are used as the first three vertices of the sequence to be traversed. Starting from the first vertex in the sequence to be traversed, all vertices of the face are traversed and stored in sequence. When each vertex is traversed, the number of adjacent vertices of the vertex is recorded, and all adjacent vertices of the vertex are traversed in sequence. When each vertex is traversed as an adjacent vertex for the first time, it is added to the sequence to be traversed;

[0060] The restoration according to the positions and storage order of the vertices to obtain a semi-complete model specifically includes:

[0061] If the classification result is a concave irregular type, the first three stored vertices are connected to restore the seed triangle;

[0062] Traverse each vertex according to the storage order of the vertices. When traversing each vertex, if the number of vertices connected to the vertex is not equal to the number of adjacent vertices of the vertex, then connect the vertices that are stored after the vertex and are not connected to the vertex in sequence until the number of vertices connected to the vertex is equal to the number of adjacent vertices of the vertex;

[0063] If the number of vertices connected to the vertex is equal to the number of adjacent vertices of the vertex, then connect the vertex to the previous and next vertices of the vertex;

[0064] The modifying of the semi-complete model to obtain a triangular model specifically includes:

[0065] If the classification result is a concave irregular type, a hole region is obtained, and all vertices in the hole region are obtained;

[0066] Loop through all vertices in the hole area until the hole area is repaired. When traversing each vertex, if the number of vertices connected to the vertex is equal to the number of adjacent vertices of the vertex, connect the vertex to the previous and next vertices of the vertex;

[0067] If the number of vertices connected to the vertex is not equal to the number of adjacent vertices of the vertex, skip the vertex.

[0068] In addition, to achieve the above-mentioned purpose, the present invention also provides a terminal, which includes: a memory, a processor, and a three-dimensional property right body dimensionality reduction representation program stored in the memory and executable on the processor, and when the three-dimensional property right body dimensionality reduction representation program is executed by the processor, it controls the terminal to implement the steps of the three-dimensional property right body dimensionality reduction representation method as described above.

[0069] In addition, to achieve the above-mentioned purpose, the present invention also provides a readable storage medium, which stores a three-dimensional property body dimensionality reduction representation program, and when the three-dimensional property body dimensionality reduction representation program is executed by a processor, the steps of the three-dimensional property body dimensionality reduction representation method as described above are implemented.

[0070] The present invention adopts the above technical solution to achieve the following effects:

[0071] The present invention pre-processes the spatial topological structure of the three-dimensional property model, converts it into a three-dimensional graph topological structure, uses the data structure of the "graph model" to carry nonlinear topological hierarchy information, and realizes nonlinear interpretation of linear sequences, so that the topological information of the three-dimensional model can be effectively implied and stored through a one-dimensional point string sequence, which not only realizes the efficient mapping of three-dimensional spatial data to one-dimensional linear storage space, but also ensures the ability to losslessly reconstruct the original three-dimensional model from one-dimensional information. This mapping method has a significant effect in solving data storage redundancy, and solves the problems of low model recognition and difficulty in interpreting topological information in the current expression method of the three-dimensional property model in the two-dimensional property certificate, and realizes a one-to-one mapping between the property model and the one-dimensional point string sequence in the three-dimensional space, ensuring that the definition of the land parcel scope in the property certificate is unique and clear. BRIEF DESCRIPTION OF THE DRAWINGS

[0072] Figure 1 It is a flowchart of the steps of a dimensionality reduction representation method of a three-dimensional property right body in a preferred embodiment of the present invention;

[0073] Figure 2 It is a technical flow chart of a dimensionality reduction representation method of a three-dimensional property right body in a preferred embodiment of the present invention;

[0074] Figure 3 It is a classification diagram of the rule property model in the preferred embodiment of the present invention;

[0075] Figure 4It is a classification diagram of the irregular property right model in the preferred embodiment of the present invention;

[0076] Figure 5 It is a schematic diagram of the basic type dimensionality reduction expression in a preferred embodiment of the present invention;

[0077] Figure 6 It is a schematic diagram of the coplanar type dimensionality reduction expression in a preferred embodiment of the present invention;

[0078] Figure 7 It is a schematic diagram of the dimension reduction expression of the common edge type in a preferred embodiment of the present invention;

[0079] Figure 8 Schematic diagram of convex irregular triangulation in a preferred embodiment of the present invention;

[0080] Fig. 9 Schematic diagram of triangulation of a concave irregular type in a preferred embodiment of the present invention;

[0081] Fig.10 It is a schematic diagram of vertex traversal storage of convex irregular type in a preferred embodiment of the present invention;

[0082] Fig.11 It is a schematic diagram of vertex traversal storage of concave irregular type in a preferred embodiment of the present invention;

[0083] Fig.12 It is a schematic diagram of a semi-model restoration of a convex irregular type in a preferred embodiment of the present invention;

[0084] Fig.13 It is a schematic diagram of a semi-model restoration of a concave irregular type in a preferred embodiment of the present invention;

[0085] Fig.14 It is a schematic diagram of repairing a convex irregular hole in a preferred embodiment of the present invention;

[0086] Fig.15 It is a schematic diagram of the repair of the concave-convex relationship of the convex irregular type in the preferred embodiment of the present invention;

[0087] Fig.16 It is a schematic diagram of repairing a concave irregular hole in a preferred embodiment of the present invention;

[0088] Fig.17 It is a schematic diagram of the operating environment of a preferred embodiment of the terminal of the present invention. DETAILED DESCRIPTION

[0089] In order to make the purpose, technical solution and advantages of the present invention clearer and more specific, the present invention is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0090] Embodiment 1

[0091] See also Figure 1 and Figure 2 Embodiment 1 of the present invention is a dimensionality reduction representation method for a three-dimensional property body, which includes performing dimensionality reduction representation on a three-dimensional property body model to obtain a one-dimensional representation of the three-dimensional property body, and performing dimensionality increase and restoration based on the one-dimensional representation to obtain a three-dimensional property body model.

[0092] The dimensionality reduction expression based on the model of the three-dimensional property right entity includes the following steps:

[0093] S1. Convert the spatial topological structure of the three-dimensional property entity model into a graph topological structure.

[0094] Specifically, after the three-dimensional property body model is acquired, the three-dimensional property body model is first classified according to the topological structure of the three-dimensional property body model.

[0095] Specifically, there are many types of property rights, including land parcels, real estate, infrastructure, etc. Among them, there are two common types, one is the real estate property unit (such as a house), and the other is airspace (land parcel).

[0096] But no matter which category, they are all geometrically expressed as regular bodies or irregular bodies. Most regular bodies are expressed as three-dimensional structures with vertical facades and horizontal top and bottom surfaces. For regular bodies, special dimensionality reduction storage and restoration methods corresponding to the regular bodies can be proposed, thereby reducing the computing resources for dimensionality reduction and restoration of regular bodies.

[0097] To do this, please refer to Figure 3 In this embodiment, the model that meets the characteristics is called a regular body, and according to the structural characteristics of the non-vertical surface, it is further subdivided into three categories: basic type, coplanar type and co-edge type. For irregular bodies that do not meet the characteristics, they are classified as irregular types.

[0098] Please refer to Figure 4 In this embodiment, according to the geometric features of the property model, the irregular types are divided into Figure 4 There are two types of models, the convex irregular type on the left and the concave irregular type on the right. The difference between convex and concave lies in whether there is an intersecting surface with an angle greater than 180 degrees between all adjacent faces of the model. If all adjacent faces are less than 180 degrees, it is called convex, otherwise it is called concave. For the concave and convex property body models, the difference between the dimensionality reduction expression methods proposed in the present invention lies in the different grid traversal methods. The convex type is mainly based on a line expansion idea to traverse and store the model, while the concave type is mainly expanded by faces. Different traversal methods correspond to different restoration and reconstruction paths.

[0099] Among them, the basic type mainly refers to the type in which the top and bottom surfaces are parallel to each other or the top surface is inclined, and the side is perpendicular to the bottom surface; it is suitable for some buildings or plots with particularly regular overall structures.

[0100] The coplanar type mainly refers to vertical surfaces. The top surface has concave and convex situations, and coplanar situations occur between different surfaces. The coplanar type is mainly divided into two situations: coplanar does not contain and coplanar does contain.

[0101] The common edge type refers to the type in which the vertical facades and top surfaces have some common edges with non-vertical surfaces, including some buildings with sloping roofs.

[0102] Since the linear analysis of a point set sequence can only be presented as a ring, and it is impossible to become a complete three-dimensional space body. Therefore, in order to present it as a body, the linear sequence can only be interpreted nonlinearly. The approach adopted in the present invention is to use the data structure of the "graph model" to carry this nonlinear topological hierarchical information. Therefore, based on relevant theories such as graph theory and topology, the spatial topological structure of the property body model is preprocessed and converted into a three-dimensional graph structure.

[0103] Based on this, in this embodiment, after the classification is completed, the spatial topological structure of the three-dimensional property body model is converted into a graph topological structure according to the classification of the three-dimensional property body model using a method corresponding to the classification.

[0104] For details, please refer to Figure 5 ,For the three-dimensional property body model classified as the basic type, it is converted into a ,graph topology structure with the non-vertical surface as the core, that is, the non-vertical surface of the ,three-dimensional property body model is retained and other structures are removed.

[0105] Please refer to Figure 6 For the three-dimensional property model classified as a coplanar type, the dimensionality reduction process is also to convert it into a graph topology structure dominated by non-vertical surfaces. In this graph topology structure, the non-vertical surfaces are divided into multiple non-vertical surface groups. The non-vertical surfaces include multiple vertices. If any vertex has a corresponding vertical adjacent point, the non-vertical surface where the vertical adjacent point is located and the non-vertical surface, the two non-vertical surfaces constitute a non-vertical surface group.

[0106] Please refer to Figure 7 , for the three-dimensional property body model classified as the common edge type, it is relatively complicated. In this embodiment, we mainly discuss one of the common types, that is, the three-dimensional property body model in which the same group of non-vertical faces with common edges can meet the "one-stroke drawing" requirement. Its dimensionality reduction process is also to convert it into a graph topology structure dominated by non-vertical faces.

[0107] The dimensionality reduction expression of rule models has been applied to most property models and has wide applicability, but it is not sufficient to handle all scenario property models. In order to systematically realize the dimensionality reduction storage of property models, research on complex irregular models of non-vertical facades is equally important.

[0108] Specifically, different from the dimensionality reduction expression method of regular bodies, for irregular types, the present invention starts from the perspective of mesh traversal and restoration, and refers to relevant theoretical ideas such as data compression and mesh repair in computer graphics. For three-dimensional property body models classified as irregular bodies, it is first necessary to triangulate the polygonal structure of the property body model to obtain a graph topology structure formed by a combination of multiple triangles. According to the two types of convex and concave property body models, the present invention proposes corresponding graph topology transformation and vertex traversal methods, respectively, which further expands the dimensionality reduction expression method of the property body model.

[0109] Please refer to Figure 8 The convex model is mainly based on the idea of ​​regional expansion for triangulation, which gradually expands outward from a seed triangle to finally realize the triangulation of the entire polyhedron model. Specifically, after the convex triangulation generates the seed triangle, a right-angled side of the seed triangle is used as the starting side. In this embodiment, the side connected by vertices 1 and 3 is used as the starting side, vertex 3 is used as the starting point, and vertex 1 is used as the end point. Then, according to the plane where the seed triangle is located, the adjacent vertex of the end point in the current face is first obtained, the starting point and the adjacent point are connected, and it is determined whether the adjacent point has been traversed.

[0110] If it has been traversed, the adjacent point within the surface of the adjacent point is obtained and recorded as the starting point, and the end point remains unchanged. In this embodiment, vertex No. 1 is taken as the center and the adjacent points around it are traversed in turn. When vertex No. 2 is traversed, since vertex No. 2 has been traversed, at this time, the adjacent point within the surface that has not been traversed of vertex No. 2 is selected as the starting point, and vertex No. 2 is the end point. The edge connected by the starting point and the end point is used as the next traversal edge. Repeat the above steps to realize the triangulation of the entire model starting from the seed triangle.

[0111] Please refer to Fig. 9 , the triangulation method of the concave model mainly divides a single polygonal face, and obtains the adjacent points before and after the current vertex to form a triangular face. The concave triangulation is shown as follows. A central vertex is selected for each face of the three-dimensional property body; all vertices of the face where the central vertex is located are connected to the central vertex to triangulate the three-dimensional property body model. For example, the edge connected by vertices V1 and V2 is selected as the input edge, and the polygon is traversed clockwise, traversing the point V1, connecting V2 and V3 to form a triangular face, and removing V1 from the list to be traversed; constructing a face for the point V2, connecting the two points V3 and V4, removing V2 from the sequence, repeating the iteration, and triangulating the entire polygon.

[0112] S2. Traverse and store the vertices of the graph topology structure.

[0113] For details, please refer to Figure 5 ,For the three-dimensional property body model classified as the basic type, all vertices within the acquired non-vertical surface are traversed counterclockwise to implement one-dimensional storage of vertex information.

[0114] Please refer to Figure 6 For the three-dimensional property body model classified as coplanar type, when traversing the vertices of the graph topology structure, the traversal order is limited compared to the basic type. First, all vertices in a non-vertical face group are obtained, and then the subsequent information is traversed. When storing vertices, it is also necessary to ensure that the adjacent non-vertical faces between adjacent non-vertical face groups are not coplanar. The latter non-vertical face in the first non-vertical face group must be guaranteed not to be coplanar with the previous non-vertical face in the second non-vertical face group. Otherwise, the traversal order of the faces in the group needs to be changed until the conditions are met.

[0115] Please refer to Figure 7 , for the three-dimensional property model classified as the co-edge type, determine whether there are non-vertical faces co-edge in the model. If there are multiple faces co-edge, it is necessary to obtain the correct starting point. First, select a non-vertical face with a single co-edge as the starting traversal face (single co-edge means that the current non-vertical face only has one edge co-edge with the adjacent non-vertical face), obtain the two endpoints of the co-edge, start with one of the endpoints of the co-edge, first obtain the adjacent point where the endpoint is located in the starting face, then find the vertical adjacent point of the adjacent point, and determine whether the vertical adjacent point has been traversed. If not, select the adjacent point of the current endpoint as the starting point, traverse to obtain all vertices of the co-edge non-vertical face group, and store the point string information in order (the starting point is the last one), and then start with the vertical adjacent point that has not been traversed by the starting point, and traverse the new non-vertical face to achieve the traversal of the co-edge non-vertical faces in the same group. Loop through and store the remaining vertex information.

[0116] For the three-dimensional property body model of irregular classification, the triangular mesh obtained after triangulation is traversed, and its vertex information is stored in a one-dimensional linear manner. The process mainly refers to some methods in data compression. The compression method is not directly used because the traversal results of data compression basically store vertices repeatedly, and the unique storage and restoration of vertices cannot be achieved. This is contrary to the premise of unique storage of boundary points in the boundary point list of this article. On this basis, the idea of ​​partial triangle traversal is integrated, and a triangular mesh traversal method suitable for property body dimensionality reduction is proposed.

[0117] For details, please refer to Fig.10The convex model is based on the spiral expansion method of the edge. Any triangular face in the triangular mesh is used as the seed triangle, and its edge is selected as the starting edge. The traversal of the next edge depends on the current starting edge. The nearest untraversed vertex in the adjacent face on the right side of the current starting edge is obtained, thereby forming new traversed edges and vertices to achieve dimensionality reduction storage of the model. Select the triangle formed by e1, e2 and e1 as the starting seed triangle, with the initial edge being e1. Traverse counterclockwise. The acquisition of edge e4 depends on e3. Take vertex 3 as the starting point and vertex 1 as the end point. Get the right adjacent face of edge e3. Determine whether the in-face adjacent vertex 4 of the end point vertex 1 has been traversed. If not, store the adjacent vertex 4 in the linear sequence. At the same time, replace the starting vertex with vertex 4, and the end point remains unchanged as vertex 1. The edge connecting vertex 1 and vertex 4 is the starting edge of the next traversal. Repeat the above steps. If the in-face adjacent vertex has been traversed, replace the end point with the adjacent point. Similarly, get the right adjacent face of the new traversed edge. Get the in-face adjacent point of the end point. Repeat the above steps until the untraversed adjacent vertex is obtained and stored in the vertex sequence. Repeat the above iterative traversal steps until all vertices in the entire model are encoded and stored.

[0118] Please refer to Fig.11 , the dimensionality reduction storage method for concave models is different from the edge-based spiral expansion idea of ​​convex models, and requires additional recording of point adjacency information. It mainly uses faces as research units, and also uses a regional expansion idea to traverse complete information. The triangle formed by vertices 1, 2, and 3 is used as the starting triangle and marked. The edge formed by vertex 1 and vertex 2 is used as the starting edge. All adjacent triangles of vertex 2 are obtained counterclockwise, and the newly obtained vertices that have not been traversed are marked. The adjacent vertices corresponding to vertex 2 are vertices 4, 5, 6, and 7, and the number of adjacent points of vertex 2 is recorded. According to the traversal order, after traversing vertex 7, the next vertex to be traversed counterclockwise is vertex 3. This vertex has been traversed, so it is skipped and no longer recorded repeatedly. When the traversed vertex is obtained, it means that the current vertex traversal is completed. Then, starting from the edge formed by vertex 2 and vertex 3, the traversal is repeated until all the triangles and vertices of the entire model are traversed, thereby obtaining complete one-dimensional point string information and realizing one-dimensional storage of the three-dimensional model.

[0119] It can be seen that this embodiment proposes a corresponding dimensionality reduction storage method for the three types of basic type, coplanar type, and coedge type in regular body models based on the idea of ​​graph traversal. For the two types of concave and convex models divided in irregular models, this embodiment combines the existing triangular mesh traversal method to propose an edge-based spiral traversal method and a face-based region expansion method, which also achieves dimensionality reduction expression of irregular body models.

[0120] According to the one-dimensional representation, a dimensional reduction is performed to obtain a three-dimensional property right model, which specifically includes the following steps:

[0121] S3. Restore the three-dimensional property model according to the order of the vertices.

[0122] Dimensionality reduction expression is not only required to realize the traversal storage of the three-dimensional model, but also to restore the three-dimensional model losslessly based on the one-dimensional information. The present invention reversely analyzes various types of dimensionality reduction methods in step S1 to obtain corresponding restoration methods.

[0123] Among them, the restoration of regular bodies is centered on non-vertical surfaces and is repaired in combination with the structural features of vertical facades. The irregular model is based on triangular meshes. It is difficult to achieve direct restoration in a single step during the restoration process. The initially restored model has problems such as holes and erroneous surfaces. Therefore, the idea of ​​mesh repair is introduced to achieve lossless restoration of the three-dimensional model.

[0124] Specifically, different methods are used to restore three-dimensional property bodies of different categories.

[0125] Please refer to Figure 5 For three-dimensional property models classified as basic types, the restoration process is mainly based on the spatial relationship of the vertices to determine whether the subsequent vertices are coplanar with the plane determined by the current initial three vertices, so as to obtain all the vertices in a plane to restore the non-vertical surface; the restoration principle of the vertical surface is based on the characteristics of the vertical facade of the model, and the vertices on the same vertical surface are connected. Specifically, the z-axis can be set up along the vertical direction, and the x-axis and y-axis can be set up along the horizontal direction respectively, and the vertices with equal x and y values ​​and different z values ​​can be connected to restore the vertical surface.

[0126] Please refer to Figure 6 For the three-dimensional property body model classified as the coplanar type, the restoration process has an additional judgment on the intersecting surfaces compared to the basic type, and the obtained intersecting surfaces are eliminated. For the annular surface in the original model, it is regarded as two inner and outer non-vertical surfaces in the dimensionality reduction stage, so the inner surface needs to be deleted in the restoration stage. In this embodiment, the judgment of the intersecting surfaces first determines the coplanarity between the non-vertical surfaces. For the non-vertical surfaces in the same plane, it is determined whether all the point sets of one surface are contained in the boundary of the other surface to determine their spatial relationship. The restoration of the vertical surface is also based on the structural characteristics of the vertical facade.

[0127] Please refer to Figure 7, For the three-dimensional property body model classified as the co-edge type, the restoration process is also mainly to restore the co-edge non-vertical faces, and how to distinguish co-edge non-vertical faces from ordinary non-vertical faces. Traverse the point string, select the first three vertices (A, B, C) to determine a plane, determine whether the plane is a non-vertical face, if so, determine whether the next vertex belongs to the current plane, and traverse in a loop to determine all the vertices of a non-vertical face; if not, move back one position and reselect three vertices (B, C, D). When traversing the next non-vertical face, there are certain restrictions on the selection of the starting point. Instead of starting the traversal from the subsequent vertices, it is necessary to go back two positions. For example, after determining the non-vertical face ABCD, the starting point of the next face is not E, but C, and CDE is selected as the starting plane. Repeat the traversal to generate all non-vertical faces. Because the traversal order of non-vertical faces in the dimensionality reduction process is not generated counterclockwise, the normal direction of the face needs to be adjusted during the restoration process. Then complete the restoration of the vertical face.

[0128] Please refer to Fig.12 For the three-dimensional property model classified as irregular type, first, it is necessary to obtain the initial semi-complete model. The restoration of the convex model is mainly based on the convexity judgment of the face. First, all vertices are connected at once to obtain the initial structure of the model, and then all adjacent triangular faces of the current traversal vertex are reconstructed in the order of spiral traversal. For an edge, it is necessary to meet the two-manifold condition, that is, each edge is referenced by two and only two triangular faces. According to this condition, for the current traversal edge, it is necessary to obtain the third vertex to construct the triangular face, and the third vertex has two sources. It may be the next vertex that has not been traversed in the sequence list or the next vertex of the current traversal vertex. It must be one of the two. The selection of the vertex is judged according to the normal relationship between each adjacent face of the convex model. The triangular face formed by the traversal edge and the two vertices is judged by the concave and convex face with the previous triangular face respectively. According to the relationship between the normal vectors, it is judged whether the normal angle between the new triangular face and the original triangular face is a convex angle relationship. If it is a convex angle, it proves that the current vertex is the third vertex of the next triangular face. After all adjacent faces of the currently traversed vertex are constructed, the next sequential vertex is traversed and the iteration is repeated until all triangular faces that can be initially restored are reconstructed.

[0129] Please refer to Fig.13, since concave models may have both concave and convex surfaces, the position of the third vertex cannot be determined by the concaveness of the surface, so it is not suitable for the traversal restoration method of convex meshes. Its restoration method mainly relies on the number of adjacent points of the vertex obtained in the traversal stage. Specifically, first, according to the obtained boundary point list information, the vertices are connected in sequence to obtain the preliminary structure of the model. The first three vertices restore the initial triangular surface, and the number of adjacent points that have been restored for the current vertex is determined. Then, according to the difference between its total number of adjacent points and its value, the number of adjacent points that have not been restored is obtained. The corresponding vertices are selected from the point string sequence in order to construct all the adjacent triangular surfaces of the vertex. During the restoration process, all the adjacent points of a vertex may have been traversed. At this time, the two vertices before and after in the one-dimensional sequence are connected to construct the triangular surface. The connection principle corresponds to the triangulation method.

[0130] After the initial restoration of the model is completed, the obtained model may have problems such as concave and convex surface errors and holes, which need to be repaired. The specific repair method is mainly based on a mesh repair idea, and the triangular mesh model after the repair is de-triangulated to achieve lossless restoration of the original model.

[0131] Please refer to Fig.14 and Fig.15 For convex models to be repaired, the main repair points are the presence of erroneous concave surfaces and holes around the last vertex in the traversal order. To solve these problems, first process the hole area, please refer to Fig.14 , without considering the concavity of the surface, repair the hole area to obtain a complete closed model. According to the traversal order, there are holes around the last vertex. Traverse the outer edge of the entire area, obtain all edges that are only used once, and connect them to the last vertex respectively, without considering the concavity of the surface, to fill the hole area. After the holes are repaired, a complete closed model is obtained. At this time, there may be multiple erroneous concave surfaces. To repair this problem, you first need to obtain the erroneous surfaces. To traverse the triangular surfaces of the entire closed model, please refer to Fig.15 , based on the result of surface normal vector calculation, the concave-convex relationship between the surface and the adjacent surfaces is judged, the common edges between the incorrect adjacent surfaces are deleted, the topological relationship is reorganized, and the concave surface repair is realized.

[0132] Please refer to Fig.16,According to the initial model obtained by the concave model restoration method, there may be incomplete topological relationships, that is, areas with hole defects, and repairs are performed to address this problem. Specifically, first, all the hole areas in the model are obtained based on the reference relationship of the edges, and all the vertices in them are extracted in order. According to the vertex relationship currently connected to the vertex and the total number of adjacent points, the repair rule of the current vertex is determined. If the difference is 0, the front and back adjacent points of the current vertex are connected to reconstruct the triangle surface, otherwise the current vertex is skipped and the loop is traversed until the area is completely repaired, so as to achieve the repair of the concave model and obtain a complete model triangle mesh.

[0133] The model obtained after the steps of hole repair and error face restoration is a triangular mesh, which needs to be detriangulated to restore the original polygonal structure of the property model. The idea of ​​detriangulation is mainly based on the parallel relationship between faces. First, all adjacent faces that are coplanar with any triangular face are obtained. According to the coplanar relationship between faces, the external boundary lines are retained, and the external boundaries of all adjacent faces are extracted as the edges of the original polygon. All internal connection lines are further deleted to achieve detriangulation of triangular faces. The same treatment is performed on all triangular faces to complete the dimensionality reduction expression and lossless reconstruction of the model.

[0134] Embodiment 2

[0135] See also Fig.17 Based on the above method, the present invention also provides a terminal, which includes: a memory 10, a processor 20, and a three-dimensional property right body dimensionality reduction representation program stored in the memory 10 and executable on the processor 20. When the three-dimensional property right body dimensionality reduction representation program is executed by the processor 20, the terminal is controlled to implement the steps of the three-dimensional property right body dimensionality reduction representation method described above.

[0136] In some embodiments, the memory 10 may be an internal storage unit of the terminal, such as a hard disk or memory of the terminal. In other embodiments, the memory 10 may also be an external storage device of the terminal, such as a plug-in hard disk, a smart memory card (SmartMediaCard, SMC), a secure digital (SecureDigital, SD) card, a flash card (FlashCard), etc. equipped on the terminal. Furthermore, the memory 10 may also include both an internal storage unit of the terminal and an external storage device. The memory 10 is used to store application software and various types of data installed in the terminal, such as the program code of the installation terminal. The memory 10 may also be used to temporarily store data that has been output or is to be output. In one embodiment, a three-dimensional property body dimensionality reduction expression program is stored on the memory 10, and the three-dimensional property body dimensionality reduction expression program can be executed by the processor 20, thereby realizing the three-dimensional property body dimensionality reduction expression method in the present application.

[0137] In some embodiments, the processor 20 may be a central processing unit (CPU), a microprocessor or other data processing chip, used to run the program code or process data stored in the memory 10, such as executing the three-dimensional property body dimensionality reduction representation method.

[0138] Embodiment 3

[0139] This embodiment provides a storage medium, wherein the readable storage medium stores a three-dimensional property right body dimensionality reduction expression program, and when the three-dimensional property right body dimensionality reduction expression program is executed by a processor, the steps of the three-dimensional property right body dimensionality reduction expression method described above are implemented.

[0140] In summary, the present invention pre-processes the spatial topological structure of the three-dimensional property model, converts it into a three-dimensional graph topological structure, uses the data structure of the "graph model" to carry nonlinear topological hierarchical information, and realizes nonlinear interpretation of linear sequences, so that the topological information of the three-dimensional model can be effectively implied and stored through a one-dimensional point string sequence, which not only realizes the efficient mapping of three-dimensional spatial data to one-dimensional linear storage space, but also ensures the ability to losslessly reconstruct the original three-dimensional model from one-dimensional information. This mapping method has a significant effect in solving data storage redundancy, and solves the problems of low model recognition and difficulty in interpreting topological information in the current expression method of three-dimensional property model in two-dimensional property certificates, and realizes a one-to-one mapping between the property model and the one-dimensional point string sequence in three-dimensional space, ensuring that the definition of the land scope in the property certificate is unique and clear.

[0141] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or terminal including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or terminal. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or terminal including the element.

[0142] Of course, those skilled in the art can understand that all or part of the processes in the above-mentioned embodiments can be implemented by instructing related hardware (such as a processor, a controller, etc.) through a computer program, and the program can be stored in a computer-readable storage medium, and the program can include the processes of the above-mentioned method embodiments when executed. The storage medium can be a memory, a disk, an optical disk, etc.

[0143] It should be understood that the application of the present invention is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A dimensionality reduction representation method for a three-dimensional property right entity, characterized in that: The three-dimensional property right body dimension reduction expression method includes: Acquire a three-dimensional property body model, and convert the spatial topological structure of the three-dimensional property body model into a graph topological structure; Traversing and storing the vertices of the graph topology structure along the edges of the graph topology structure; Restoring the three-dimensional property body model according to the positions and storage order of the vertices; The converting the spatial topological structure of the three-dimensional property entity model into a graph topological structure specifically includes: Classifying the three-dimensional property body model according to the spatial topological structure of the three-dimensional property body model to obtain a classification result; According to the classification result, converting the spatial topological structure of the three-dimensional property entity model into a graph topological structure; The classification results include irregular types; The step of converting the spatial topological structure of the three-dimensional property entity model into a graph topological structure according to the classification result specifically includes: If the classification result is an irregular type, the three-dimensional property body model is triangulated and converted into a graph topology structure; The method of restoring the three-dimensional property body model according to the positions and storage order of the vertices specifically includes: If the classification result is an irregular type, restoration is performed according to the positions and storage order of the vertices to obtain a semi-complete model; Modifying the semi-complete model to obtain a triangular model; Detriangulating the triangular model to restore the three-dimensional property body model; The irregular type includes a convex irregular type; The converting the three-dimensional property body model into a graph topology structure by triangulation specifically includes: If the classification result is a convex irregular type, generating a seed triangle on the surface of the three-dimensional property body model; Repeating the spiral expansion of the generated triangles to generate new triangles until the triangulation of the three-dimensional property body model is completed; The traversing and storing the vertices of the graph topology structure along the edges of the graph topology structure specifically includes: If the classification result is a convex irregular type, then spirally traverse and store the vertices of the graph topology structure along the edge of the graph topology structure; The restoration according to the positions and storage order of the vertices to obtain a semi-complete model specifically includes: If the classification result is a convex irregular type, spirally expanding and restoring the model into multiple triangular faces according to the order in which the vertices are stored, thereby obtaining the semi-complete model; The modifying of the semi-complete model to obtain a triangular model specifically includes: If the classification result is a convex irregular type, all triangle edges belonging to only one triangle in the semi-complete model are obtained, and all triangle edges are connected to the last vertex; The concave-convex relationship between each of the triangular faces and the adjacent triangular faces is calculated, and the triangular faces that are in a concave relationship with the adjacent triangular faces are repaired to have a convex relationship with the adjacent triangular faces to obtain the triangular model.

2. A dimensionality reduction representation method for a three-dimensional property right according to claim 1, characterized in that: The classification results include basic types; The step of converting the spatial topological structure of the three-dimensional property entity model into a graph topological structure according to the classification result specifically includes: If the classification result is a basic type, converting the three-dimensional property body model into a graph topology structure that only retains non-vertical surfaces; The method of restoring the three-dimensional property body model according to the positions and storage order of the vertices specifically includes: If the classification result is a basic type, determining the coplanarity between all vertices to obtain coplanar vertices, and connecting the coplanar vertices in the order of storage to obtain a non-vertical surface; Connecting the vertical adjacent points of the non-vertical surfaces restores the three-dimensional property body model.

3. A dimensionality reduction representation method for a three-dimensional property right according to claim 1, characterized in that: The classification results include coplanar types; The step of converting the spatial topological structure of the three-dimensional property entity model into a graph topological structure according to the classification result specifically includes: If the classification result is a coplanar type, converting the three-dimensional property body model into a graph topology structure that only retains non-vertical surfaces, and dividing the non-vertical surfaces into a plurality of non-vertical surface groups; The traversing and storing the vertices of the graph topology structure along the edges of the graph topology structure specifically includes: If the classification result is a coplanar type, traversing and storing the vertices of each non-vertical face group along the edge of the graph topology structure in sequence, and two adjacent non-vertical faces stored are not coplanar; The method of restoring the three-dimensional property body model according to the positions and storage order of the vertices specifically includes: If the classification result is a coplanar type, the coplanarity between all vertices is determined to obtain coplanar vertices, and the coplanar vertices are connected in the order of storage to obtain a non-vertical surface; If two non-vertical faces are coplanar, determine whether all vertices of one of the non-vertical faces are within the boundary of the coplanar non-vertical face. If so, remove the non-vertical face. Connecting the vertical adjacent points of the non-vertical surfaces restores the three-dimensional property body model.

4. A dimensionality reduction representation method for a three-dimensional property right according to claim 1, characterized in that: The classification result includes a common edge type; The step of converting the spatial topological structure of the three-dimensional property entity model into a graph topological structure according to the classification result specifically includes: If the classification result is a common edge type, converting the three-dimensional property body model into a graph topology structure that only retains non-vertical surfaces; The traversing and storing the vertices of the graph topology structure along the edges of the graph topology structure specifically includes: If the classification result is a common edge type, a non-vertical surface with only one connected surface is selected as the starting surface, and a vertex of the connecting edge between the starting surface and the connected non-vertical surface is selected as the starting point; Starting from the starting point, traverse all non-vertical vertices along the edges of the graph topology structure in sequence and store them; The method of restoring the three-dimensional property body model according to the positions and storage order of the vertices specifically includes: If the classification result is a co-edge type, the coplanarity between all vertices is determined to obtain coplanar vertices, and the coplanar vertices are connected in the order of storage to obtain a non-vertical surface; Connecting the vertical adjacent points of the non-vertical surfaces restores the three-dimensional property body model.

5. A dimensionality reduction representation method for a three-dimensional property right according to claim 1, characterized in that: The irregular type includes a concave irregular type, and the triangulation of the three-dimensional property body model into a graph topology structure specifically includes: If the classification result is a concave irregular type, an end point is selected for each face of the three-dimensional property body model; Connect each of the end points to the remaining vertices of the face where the end point is located; The traversing and storing the vertices of the graph topology structure along the edges of the graph topology structure specifically includes: If the classification result is a concave irregular type, generating a seed triangle on the surface of the three-dimensional property body model; The three vertices of the seed triangle are used as the first three vertices of the sequence to be traversed. Starting from the first vertex in the sequence to be traversed, all vertices of the face are traversed and stored in sequence. When each vertex is traversed, the number of adjacent vertices of the vertex is recorded, and all adjacent vertices of the vertex are traversed in sequence. When each vertex is traversed as an adjacent vertex for the first time, it is added to the sequence to be traversed; The restoration according to the positions and storage order of the vertices to obtain a semi-complete model specifically includes: If the classification result is a concave irregular type, the first three stored vertices are connected to restore the seed triangle; Traverse each vertex according to the storage order of the vertices. When traversing each vertex, if the number of vertices connected to the vertex is not equal to the number of adjacent vertices of the vertex, then connect the vertices that are stored after the vertex and are not connected to the vertex in sequence until the number of vertices connected to the vertex is equal to the number of adjacent vertices of the vertex; If the number of vertices connected to the vertex is equal to the number of adjacent vertices of the vertex, then connect the vertex to the previous and next vertices of the vertex; The modifying of the semi-complete model to obtain a triangular model specifically includes: If the classification result is a concave irregular type, a hole region is obtained, and all vertices in the hole region are obtained; Loop through all vertices in the hole area until the hole area is repaired. When traversing each vertex, if the number of vertices connected to the vertex is equal to the number of adjacent vertices of the vertex, connect the vertex to the previous and next vertices of the vertex; If the number of vertices connected to the vertex is not equal to the number of adjacent vertices of the vertex, skip the vertex.

6. A terminal, characterized in that: The terminal includes: a memory, a processor, and a three-dimensional property right body dimensionality reduction expression program stored in the memory and executable on the processor. When the three-dimensional property right body dimensionality reduction expression program is executed by the processor, the terminal is controlled to implement the steps of the three-dimensional property right body dimensionality reduction expression method as described in any one of claims 1 to 5.

7. A readable storage medium, characterized in that: The readable storage medium stores a three-dimensional property right body dimensionality reduction expression program, and when the three-dimensional property right body dimensionality reduction expression program is executed by a processor, the steps of the three-dimensional property right body dimensionality reduction expression method according to any one of claims 1 to 5 are implemented.

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