Method for determining three-dimensional model correspondence by using texture coordinate information
By determining positional and distance equality in texture coordinates, the method addresses the issue of duplicate 3D model identification, enhancing efficiency and reducing data redundancy.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- GAIA3D
- Filing Date
- 2025-12-19
- Publication Date
- 2026-07-02
AI Technical Summary
Existing methods for determining the identity of 3D models fail to accurately identify duplicates due to discrepancies in texture coordinates, even when the models have the same texture effects, leading to inefficiencies in network load and data redundancy.
A method that determines the identity of 3D models by checking positional and distance equality in the texture coordinate system, ensuring that the texture coordinates of corresponding vertices in two triangular meshes are identical.
Efficiently identifies identical 3D models by correcting and comparing texture coordinates, reducing data redundancy and network load by ensuring accurate duplicate removal.
Smart Images
Figure KR2025022306_02072026_PF_FP_ABST
Abstract
Description
Method for determining 3D model identity using texture coordinate information
[0001] The present invention relates to a method for determining the identity of a three-dimensional model using texture coordinate information, and more specifically, to a method for determining the identity of a three-dimensional model using positional identity and distance identity in a texture coordinate system of three-dimensional model data to be compared.
[0002] The background technology related to the present disclosure is provided herein, and these do not necessarily constitute known technology.
[0003] With the increasing number of services that allow viewing large volumes and multiple 3D models in a web browser, such as web-based digital twin services utilizing 3D spatial information, it is important to reduce network load by performing lightweighting when converting original 3D models into service data. One such method involves checking for redundancy among the service target data and efficiently constructing service data without duplication.
[0004] One method to check for redundancy in 3D models is to verify whether the 3D models being compared are identical. In 3D graphics, identical 3D models are defined as having the same geometric information, and if the models use textures, they must additionally have the same texture effects applied to be considered identical.
[0005] Therefore, to determine whether two 3D models being compared are identical, the following conditions need to be checked: i) that the number of triangles is the same for all triangles constituting the triangular mesh, which is the geometric information of the 3D models, and that the geometric coordinates of the three vertices constituting each triangle are all the same; ii) that the same texture file is used; and iii) that the texture coordinates used when attaching the texture file to the triangles are the same for all vertices of all triangles. However, there are cases where the check of the third condition above fails because the texture coordinates assigned to the vertices are different, even though the area where the texture file is attached is the same.
[0006] Therefore, in this situation, simply comparing texture coordinates to determine if they are the same is insufficient to identify them as identical models, making duplicate removal impossible; thus, it is necessary to correct and compare the texture coordinates to verify if they are identical.
[0007] [Prior Art Literature]
[0008] (Patent Document 1) Republic of Korea Published Patent 10-2024-0105756 (July 8, 2024)
[0009] One objective of the present invention is to provide a method for determining the identity of a 3D model using the positional identity and distance identity in the texture coordinate system of the 3D model data to be compared.
[0010] The method for determining the identity of a 3D model using texture coordinate information of the present invention comprises (a) the 11th triangular mesh (P1) of the 1st shape information (P1). 11 (b) a step of obtaining ); (b) the 21st triangular mesh (P of the 2nd shape information (P2) 21 Step of obtaining ); (c) the 11th triangular mesh (P 11 ) and the 21st triangular mesh (P 21 A step of determining the positional identity in the texture coordinate system of ); and (d) the 11th triangular mesh (P 11 ) and the 21st triangular mesh (P 21Includes a step of determining distance equality in the texture coordinate system of ).
[0011] The method for determining the identity of a 3D model using texture coordinate information according to the present invention can efficiently determine the identity of a 3D model by utilizing the positional identity and distance identity of the 3D model data in the texture coordinate system.
[0012] Figure 1 schematically shows the orthogonal coordinate system of a texture image.
[0013] Figure 2 briefly illustrates a method of applying a texture image to a triangular mesh.
[0014] Figure 3 conceptually illustrates how a graphics card understands a texture coordinate system.
[0015] Figure 4 shows an image taken from within a triangular area on a texture image and applied to a triangle of a triangular mesh.
[0016] Figure 5 schematically shows the triangles of a triangular mesh with different texture coordinates assigned to them.
[0017] FIG. 6 schematically illustrates a texture coordinate system for explaining a method for determining the identity of a three-dimensional model using texture coordinate information according to the present invention.
[0018] FIG. 7 shows a flowchart for performing a method for determining the identity of a three-dimensional model using texture coordinate information according to the present invention.
[0019] The national research and development projects that supported this invention are as follows.
[0020] Research project title (English): Implementation and Application of 3D Grid System for Advanced National Spatial Information
[0021] Research Project Title (Korean): Development of Technology for the Application and Utilization of 3D Grid Systems for the Advancement of National Geographic Information
[0022] Specialized Agency: Korea Agency for Infrastructure Technology Advancement
[0023] Project No.: RS-2025-02317649 (NTIS: 2610000447)
[0024] The present invention will be described in detail below with reference to the attached drawings.
[0025] Texture coordinates assigned to a vertex are a two-dimensional coordinate system indicating which part of the texture image corresponds to it, and are usually expressed as (u,v). This is a concept on the texture image plane that is different from actual geometric coordinates.
[0026] The image used as a texture is a rectangular area, and regardless of the number of horizontal and vertical pixels, the location of the image area is described using orthogonal coordinates where the bottom-left corner is (0.0,0.0) and the top-right corner is (1.0,1.0).
[0027] Figure 1 schematically shows the orthogonal coordinate system of a texture image.
[0028] For example, as shown in Fig. 1, the image coordinates are described in an orthogonal coordinate system where the bottom-left vertex is (0.0, 0.0) and the top-right vertex is (1.0, 1.0), regardless of the number of horizontal / vertical pixels of the texture image.
[0029] When attaching a texture image to a triangular mesh, the process is applied on a triangle-by-triangle basis. In other words, by combining the texture coordinates assigned to each of the three vertices of a triangle, a triangle on the texture image can be created; the method involves cropping the image of the triangular region on the texture image and attaching it to the corresponding triangle in the mesh. The geometric triangle and the triangle on the texture image do not need to be similar in shape. The graphics card scales the image to attach it.
[0030] Figure 2 briefly illustrates a method of applying a texture image to a triangular mesh.
[0031] Specifically, FIG. 2(A) shows a triangular mesh with texture coordinates assigned to the vertices of the triangle, FIG. 2(B) shows a triangular region in a texture image coordinate system composed of the corresponding texture coordinates of the triangular mesh, and FIG. 2(C) shows a state in which an image within the triangular region in the texture image is taken and applied to the triangle of the triangular mesh.
[0032] However, even though the area of the texture image is a rectangular area described by the four vertices (0.0, 0.0), (1.0, 0.0), (0.0, 1.0), (1.0, 1.0), it is allowed if the value of the u or v component of the texture coordinates assigned to the triangular mesh is less than 0.0 or greater than 1.0. This is a condition allowed for attaching the texture image as a repeating pattern.
[0033] When the same image appears repeatedly, the repeating pattern is the same but the number of repetitions differs; therefore, generating separate texture images for each case with different repetition counts results in inefficiency due to increased data capacity. Consequently, graphics cards support specifying how many times a texture image can be repeated using only texture coordinates.
[0034] Figure 3 conceptually illustrates how a graphics card understands a texture coordinate system.
[0035] As illustrated in Fig. 3, the graphics card understands the texture coordinate system as a grid pattern in which texture images appear repeatedly from -∞ to ∞ in both the u and v axis directions without overlapping or empty spaces.
[0036] Therefore, if a value less than 0.0 or greater than 1.0 is used as a coordinate, the image is cropped accordingly and the triangle is filled.
[0037] Figure 4 shows an image taken from within a triangular area on a texture image and applied to a triangle of a triangular mesh.
[0038] For example, as illustrated in FIG. 4, FIG. 4(A) shows texture coordinates assigned to a triangle of a triangular mesh, FIG. 4(B) shows a triangular region on a texture image composed of the texture coordinates, and FIG. 4(C) shows an image taken from within the triangular region on the texture image and applied to a triangle of a triangular mesh.
[0039] However, the problem is that there are cases where numbers smaller than 0.0 or larger than 1.0 are used even though they are not repeating patterns. 3D model production is mainly performed manually using model editing tools, and there are instances where coordinates are carried over when cutting and pasting to reuse texture images. In particular, there are cases where this is used artificially; for example, "Only numbers between 3.0 and 4.0 are used for texture coordinates of models generated in the AA project," or "Only numbers between 2.0 and 3.0 are used for texture coordinates when working with the BB team." In such cases, they are intentionally used depending on the work environment. Figure 5 schematically illustrates this situation.
[0040] Figure 5 schematically shows the triangles of a triangular mesh with different texture coordinates assigned to them.
[0041] As shown in Fig. 5, different texture coordinates are assigned to the triangles of the triangular mesh, but in fact, the same area image is taken from the texture image and applied.
[0042] Therefore, in this situation, simply comparing texture coordinates does not determine if they are the same model, making duplicate removal impossible; thus, the texture coordinates must be corrected and compared to verify if they are identical.
[0043] The present invention provides a method for determining the identity of a three-dimensional model using texture coordinate information.
[0044] The method for determining the identity of a 3D model using texture coordinate information of the present invention is a technique for determining whether the texture image regions described by the texture coordinates of the vertices of each triangle are actually the same texture image region when there are two triangular meshes to be compared that are geometrically congruent and use the same texture file, and since every triangle constituting one triangular mesh corresponds 1:1 with every triangle of the opposite triangular mesh to be compared.
[0045] There are two conditions for determining whether they are the same texture image region:
[0046] 1) Is the position the same in the texture image coordinate system?
[0047] 2) Are the distances of the vertices constituting a triangle in the texture coordinate system the same for corresponding triangles?
[0048] Accordingly, the method for determining the identity of a three-dimensional model using texture coordinate information of the present invention comprises: (a) the 11th triangular mesh (P1) of the first shape information (P1). 11 (b) a step of obtaining ); (b) the 21st triangular mesh (P of the 2nd shape information (P2) 21 Step of obtaining ); (c) the 11th triangular mesh (P 11 ) and the 21st triangular mesh (P 21 A step of determining the positional identity in the texture coordinate system of ); and (d) the 11th triangular mesh (P 11 ) and the 21st triangular mesh (P 21 Includes a step of determining distance equality in the texture coordinate system of ).
[0049] FIG. 6 schematically illustrates a texture coordinate system for explaining a method for determining the identity of a three-dimensional model using texture coordinate information according to the present invention.
[0050] A method for determining the identity of a three-dimensional model using texture coordinate information according to the present invention comprises, in step (a), the 11th triangular mesh (P1) of the first shape information (P1) to be compared. 11 ) obtain ), and in step (b), the 21st triangular mesh (P ) of the 2nd shape information (P2) 21 Acquires ).
[0051] In the subsequent step (c), the 11th triangular mesh (P 11 ) and the 21st triangular mesh (P 21 Determines the positional identity in the texture coordinate system of ).
[0052] In one embodiment, step (c) is, (c') the 11th triangular mesh (P 11 The decimal part of the texture coordinate system component of each vertex of ) and the corresponding 21st triangular mesh (P 21 It includes a step of determining the equality of the decimal part values of the texture coordinate system components of each vertex of ).
[0053] The fact that the positions in the texture coordinate system are identical means that the decimal values of the texture coordinate system components of each vertex of the triangular mesh are identical. This can be derived from the way the graphics card understands the texture coordinate system as a grid pattern in which texture images appear repeatedly from -∞ to ∞ in both the u and v axis directions, without overlapping or empty spaces, as explained earlier with reference to Figure 3.
[0054] Specifically, in one embodiment, step (c') is, (c'1) the 11th triangular mesh (P 11 The 11th coordinate value (u), which is the texture coordinate value of each vertex of ) 11 ,v 11 ; u 12 ,v 12 ; u 13 ,v 13 Step of obtaining ); (c'2) the 21st triangular mesh (P 21 The 21st coordinate value (u), which is the texture coordinate value of each vertex of ) 21 ,v 21 ; u22 ,v 22 ; u 23 ,v 23 A step of obtaining ); and (c'3) the 11th coordinate value (u 11 ,v 11 ; u 12 ,v 12 ; u 13 ,v 13 ) and the corresponding 21st coordinate value (u 21 ,v 21 ; u 22 ,v 22 ; u 23 ,v 23 It includes a step of determining the equality of the decimal part values of ).
[0055] That is, as shown in Equations 1-1 to 1-3 below, it is determined whether the decimal values of the u and v components are the same for each vertex of the triangle constituting each of the two triangular meshes being compared.
[0056] <Equation 1-1>
[0057] (u 11 Decimal value = u 21 decimal places) and (v 11 Decimal value = v 21 decimal places)
[0058] <Equation 1-2>
[0059] (u 12 Decimal value = u 22 decimal places) and (v 12 Decimal value = v 22 decimal places)
[0060] <Equation 1-3>
[0061] (u 13 Decimal value = u 23 decimal places) and (v 13 Decimal value = v 23 decimal places)
[0062] If equations 1-1 to 1-3 are satisfied, step (d) is performed next.
[0063] A method for determining the identity of a 3D model using texture coordinate information according to the present invention comprises, in step (d), the 11th triangular mesh (P 11 ) and the 21st triangular mesh (P 21 Determines the equality of distance in the texture coordinate system of ).
[0064] In one embodiment, step (d) is, (d') the 11th triangular mesh (P 11 The distance between the vertices of the 11th triangle constituting ) and the corresponding 21st triangular mesh (P 21 It includes a step of determining the equality of distances between the vertices of the 21st triangle constituting ).
[0065] Specifically, in one embodiment, step (d') is, (d'1) the 11th triangular mesh (P 11 The distance between the 11th and 12th vertices of the 11th triangle constituting ), and the 21st triangular mesh (P 21 A step of determining the equality of distances between the 21st vertex and the 22nd vertex of the 21st triangle constituting ); (d'2) the 11th triangular mesh (P 11 The distance between the 12th and 13th vertices of the 11th triangle constituting ), and the 21st triangular mesh (P 21 A step of determining the equality of distances between the 22nd and 23rd vertices of the 21st triangle constituting ); and (d'2) the 11th triangular mesh (P 11 The distance between the 13th vertex of the 11th triangle constituting ) and the 11th vertex, and the 21st triangular mesh (P 21 It includes a step of determining the equality of the distance between the 23rd vertex of the 21st triangle and the 21st vertex constituting the triangle.
[0066] That is, as shown in Equations 2-1 to 2-3 below, it is determined whether the distance between the vertices of the triangles constituting each of the two triangular meshes being compared is the same in the texture coordinate system.
[0067] <Equation 2-1>
[0068] (u 11 - u 12 ) = (u 21 - u 22 ) and (v 11 - v 12 ) = (v 21 - v 22 )
[0069] <Equation 2-2>
[0070] (u 12 - u 13 ) = (u 22 - u 23 ) and (v 12 - v 13 ) = (v 22 - v 23 )
[0071] <Equation 2-3>
[0072] (u 13 - u 11 ) = (u 23 - u 21 ) and (v 13 - v 11 ) = (v 23 - v 21 )
[0073] In this way, for each of the triangular meshes of the first shape information (P1) and the corresponding second shape information (P2), the positional identity and distance identity in the texture coordinate system are determined, and if identity is recognized, the two shape information is determined to be identical.
[0074] FIG. 7 shows a flowchart for performing a method for determining the identity of a three-dimensional model using texture coordinate information according to the present invention.
[0075] Various embodiments of the present invention are described below.
[0076] Example 1. (a) The 11th triangular mesh (P1) of the 1st shape information (P1) 11 (b) a step of obtaining ); (b) the 21st triangular mesh (P of the 2nd shape information (P2) 21 Step of obtaining ); (c) the 11th triangular mesh (P11 ) and the 21st triangular mesh (P 21 A step of determining the positional identity in the texture coordinate system of ); and (d) the 11th triangular mesh (P 11 ) and the 21st triangular mesh (P 21 A method for determining the identity of a 3D model using texture coordinate information, comprising the step of determining distance identity in a texture coordinate system of ).
[0077] Example 2. In Example 1, step (c) is, (c') the 11th triangular mesh (P 11 The decimal part of the texture coordinate system component of each vertex of ) and the corresponding 21st triangular mesh (P 21 A method for determining the identity of a 3D model using texture coordinate information, comprising the step of determining the identity of the decimal part values of the texture coordinate system components of each vertex of ).
[0078] Example 3. In Example 2, step (c') is, (c'1) the 11th triangular mesh (P 11 The 11th coordinate value (u), which is the texture coordinate value of each vertex of ) 11 ,v 11 ; u 12 ,v 12 ; u 13 ,v 13 Step of obtaining ); (c'2) the 21st triangular mesh (P 21 The 21st coordinate value (u), which is the texture coordinate value of each vertex of ) 21 ,v 21 ; u 22 ,v 22 ; u 23 ,v 23 A step of obtaining ); and (c'3) the 11th coordinate value (u 11 ,v 11 ; u 12 ,v 12 ; u 13 ,v 13 ) and the corresponding 21st coordinate value (u 21 ,v 21 ; u 22 ,v 22 ; u 23 ,v23 A method for determining the identity of a 3D model using texture coordinate information, comprising the step of determining the identity of decimal places of ).
[0079] Example 4. In Example 2, step (d) is, (d') the 11th triangular mesh (P 11 The distance between the vertices of the 11th triangle constituting ) and the corresponding 21st triangular mesh (P 21 A method for determining the identity of a 3D model using texture coordinate information, comprising the step of determining the equality of distances between the 21st triangle vertices constituting ).
[0080] Example 5. In Example 4, step (d') is, (d'1) the 11th triangular mesh (P 11 The distance between the 11th and 12th vertices of the 11th triangle constituting ), and the 21st triangular mesh (P 21 A step of determining the equality of distances between the 21st vertex and the 22nd vertex of the 21st triangle constituting ); (d'2) the 11th triangular mesh (P 11 The distance between the 12th and 13th vertices of the 11th triangle constituting ), and the 21st triangular mesh (P 21 A step of determining the equality of distances between the 22nd and 23rd vertices of the 21st triangle constituting ); and (d'2) the 11th triangular mesh (P 11 The distance between the 13th vertex of the 11th triangle constituting ) and the 11th vertex, and the 21st triangular mesh (P 21 A method for determining the identity of a 3D model using texture coordinate information, comprising the step of determining the equality of the distance between the 23rd vertex of the 21st triangle constituting the triangle and the 21st vertex.
Claims
1. (a) The 11th triangular mesh (P1) of the 1st shape information (P1) 11 Step of acquiring ); (b) The 21st triangular mesh (P2) of the 2nd shape information (P2) 21 Step of acquiring ); (c) The 11th triangular mesh (P 11 ) and the 21st triangular mesh (P 21 A step of determining positional identity in the texture coordinate system of ); and (d) The 11th triangular mesh (P 11 ) and the 21st triangular mesh (P 21 A step of determining distance equality in the texture coordinate system of ); Includes, Here, the texture coordinate system has texture coordinate values (u, v), and is a coordinate system formed by extending unit coordinates from -∞ to ∞ in both the u and v axis directions, with the texture coordinate values of the bottom-left vertex of the texture image being (0.0, 0.0) and the top-right vertex being (1.0, 1.0). In the texture coordinate system, texture images are assigned to unit coordinates and subsequently arranged in a grid pattern without overlapping or empty spaces, repeating from -∞ to ∞ in both the u and v axis directions, and Step (c) is (c') 11th triangular mesh (P 11 The decimal part of the texture coordinate system component of each vertex of ) and the corresponding 21st triangular mesh (P 21 A step of determining the equality of the decimal part values of the texture coordinate system components of each vertex of ); Includes, Step (d) (d') The 11th triangular mesh (P 11 The mutual distances between the three vertices of the 11th triangle constituting ) and the corresponding 21st triangular mesh (P 21 A step of determining the equality of distances between the three vertices of the 21st triangle constituting ); A method for determining the identity of a 3D model using texture coordinate information, including 2. In Claim 1, If the decimal places are the same in step (c') and the distances between vertices are the same in step (d'), then the 11th triangular mesh (P 11 The 11th triangle and 21st triangular mesh (P) constituting ) 21 A method for determining the identity of a 3D model using texture coordinate information, further comprising the step of determining that the texture images applied to each of the 21 triangles constituting the ) are identical.
3. In Claim 1, Step (c') is (c'1) The 11th triangular mesh (P 11 The 11th coordinate value (u), which is the texture coordinate value of each vertex of ) 11 ,v 11 ; u 12 ,v 12 ; u 13 ,v 13 Step of acquiring ); (c'2) 21st Triangular Mesh (P 21 The 21st coordinate value (u), which is the texture coordinate value of each vertex of ) 21 ,v 21 ; u 22 ,v 22 ; u 23 ,v 23 Step of acquiring ); and (c'3) 11th coordinate value(u 11 ,v 11 ; u 12 ,v 12 ; u 13 ,v 13 ) and the corresponding 21st coordinate value (u 21 ,v 21 ; u 22 ,v 22 ; u 23 ,v 23 A step of determining the equality of the decimal part values of ); A method for determining the identity of a 3D model using texture coordinate information, including 4. In Claim 1, Step (d') (d'1) The 11th triangular mesh (P 11 The distance between the 11th and 12th vertices of the 11th triangle constituting ), and the 21st triangular mesh (P 21 A step of determining the equality of distances between the 21st vertex and the 22nd vertex of the 21st triangle constituting ); (d'2) 11th triangular mesh (P 11 The distance between the 12th and 13th vertices of the 11th triangle constituting ), and the 21st triangular mesh (P 21 A step of determining the equality of distances between the 22nd and 23rd vertices of the 21st triangle constituting ); and (d'2) 11th triangular mesh (P 11 The distance between the 13th vertex of the 11th triangle constituting ) and the 11th vertex, and the 21st triangular mesh (P 21 A step of determining the equality of the distance between the 23rd vertex and the 21st vertex of the 21st triangle constituting ); A method for determining the identity of a 3D model using texture coordinate information, including