KR100275274B1 - Method for reducting volume of the mesh data - Google Patents

Abstract

PURPOSE: A mesh data amount reducing method is provided to reduce a mesh data amount by selecting a vertex, with one vertex skipped by a row/column unit with regard to a generated mesh. CONSTITUTION: Vertexes having the first index, which exists in the first column with regard to an initial generated mesh, is selected one by one using distance data(401). A loop is formed based on the selected vertex and a data amount is reduced(402). Vertexes having the second index, which exists in the first column with regard to the firstly updated mesh, is selected one by one using distance data(404). A loop is formed based on the selected vertex and a data amount is reduced(405). Vertexes having the first index, which exists in the second column with regard to the secondly updated mesh, is selected one by one using distance data(407). A loop is formed based on the selected vertex and a data amount is reduced(408). Vertexes having the second index, which exists in the second column with regard to the thirdly updated mesh, is selected one by one using distance data(410). A loop is formed based on the selected vertex and a data amount is reduced(411).

Description

How to reduce the amount of mesh data

The present invention relates to a method of generating a mesh by obtaining distance data, and more particularly, to a method of reducing a mesh data amount for reducing a data amount of a generated mesh.

In general, generating distance mesh by acquiring distance data is a technique mainly used in 3D modeling. However, since the amount of distance data acquired to generate the mesh is large, efforts are being made to reduce the amount of data for real time processing and overall cost reduction.

As part of this effort, a technique for reducing the amount of data of the mesh formed by the distance data has been proposed. The existing mesh generation process in which the technique of reducing the amount of mesh data is introduced is performed as shown in FIG. 1.

That is, in step 102, distance data of an object to be modeled is obtained by using a known method. In operation 104, the initial mesh is generated using the obtained distance data. Then, a data amount reduction process is performed on the mesh generated in step 106.

A data amount reduction process for the mesh made in step 106 is performed as shown in FIG. That is, in step 202, a vertex having the first index on the initial mesh is selected, and in step 204, a loop is formed from the peripheral surfaces existing around the selected vertex.

The flow proceeds to step 206 to check whether the formed loop is a complete loop. A complete loop here means one closed loop. Therefore, a complete loop does not form when centering on vertices existing at edges or outermost surfaces. As a result of the check in step 206, if the formed loop is a complete loop, the process proceeds to step 208 to detect the number of feature edges on the formed loop. If the number of detected back angles is '2', the process proceeds to step 212 through step 210 and cuts the loop using the detected back angles as a split line. In operation 214, the mesh reprocessing process is performed on the loop formed in operation 204. This remeshing process is also known as Re-Triangulation. This is because the mesh is generally formed in a triangular structure.

When the remesh generation process for the loop is completed, the process proceeds to step 218 through step 216. In step 218, data about the vertex and the mesh structure for the corresponding loop are updated using the remesh generation process result. In operation 220, it is checked whether a vertex to be selected next exists. As a result of the check, if there is a vertex to be selected next, the process proceeds to step 222 to select a next vertex, and returns to step 204 to repeat the above-described process.

On the other hand, as a result of checking the number of detected backside angles in the state determined as a complete loop, if the number of the backside angles is '0', it means that the corresponding loop can be expressed as one plane. Re-mesh generation process is performed so that the formed loop is formed in one surface. However, if the number of detected backside angles is not '2' or '0' when the loop is formed as a complete loop, the process proceeds to step 220 to check whether there is a vertex to be selected next. do. This means that the faces that exist in the loops that are formed remain intact.

In addition, as a result of checking in step 206, if the formed loop is not a complete loop, the process proceeds to step 226 to check whether the formed loop is an incomplete loop. As a result of the check, if it is not an incomplete loop, the reduction processing for the corresponding vertex is ignored and the process proceeds to step 220 and the processing is performed as described above. However, as a result of the check in step 226, if the formed loop is an incomplete loop, the process proceeds to step 228 to detect the number of backside angles of the corresponding loop. If the number of detected back angles is '1', the process proceeds to step 212 through step 230 and cuts the loop around the surface where the back angle exists. However, if the number of backside angles detected in step 228 is not 1, the process proceeds to step 224 and processes as described above.

When the data amount reduction process for the entire area of the initially generated mesh is completed (if it is determined that there is no vertex to be selected anymore), the mesh data amount reduction process is terminated, and the process proceeds to step 108 of FIG. 1. Then, the mesh updated by the processing is generated as the final mesh.

However, the above-described method simply selects and executes all vertices present on the mesh based on an index, and thus, an efficient method study for this is being continued.

The present invention has been made in accordance with the above-described trend, and provides a mesh data amount reduction method for reducing a mesh data amount by selecting a vertex while skipping a vertex in a column and / or row unit with respect to a generated mesh.

In order to provide the above objects, the mesh data amount reduction method according to the present invention is a device for generating a corresponding mesh using distance data obtained for an object, the method comprising: a first mesh for an initial mesh generated using distance data; A first reduction processing step of selecting vertices having a first predetermined index existing in a predetermined column one by one, and reducing a data amount while forming a loop based on the selected vertices; A second for selecting vertices having a second predetermined index existing in the first predetermined column one by one for the mesh updated primarily through the first reduction processing step, and reducing a data amount while forming a loop based on the selected vertices A reduction treatment step; A third for selecting vertices having a first predetermined index existing in the second predetermined column one by one for the mesh updated second through the second reduction processing step, and reducing a data amount while forming a loop based on the selected vertices A reduction treatment step; A fourth step of selecting vertices having a second predetermined index existing in the second predetermined column one by one for the mesh updated through the third reduction processing step, and reducing the amount of data while forming a loop based on the selected vertices; It is characterized in that it is carried out including a reduction treatment step.

1 is an operation flowchart for a general mesh generation process,

2 is a detailed flowchart of an existing method for reducing mesh data amount;

3 is a schematic block diagram of a system for performing a method according to the invention,

4 is a detailed flowchart of a mesh data amount reduction method according to the present invention.

<Description of the code | symbol about the principal part of drawing>

302: command authorization unit 304: model generation unit

306: processor 308: storage unit

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 is a block diagram of a system for performing a method of reducing a mesh data amount according to the present invention, wherein the command application unit 302 for applying a user command obtains distance data of an object to be modeled according to a conventional method. According to the present invention, a mesh is generated according to the user command applied through the distance data acquisition unit 304 and the command application unit 302 and the distance data acquired from the distance data acquisition unit 304. And a storage unit 308 controlled by the processor 306 to store information related to the mesh.

4 is a flowchart illustrating a method of reducing mesh data amount according to the present invention.

Next, an operation of the mesh data amount reduction method illustrated in FIG. 4 will be described with reference to FIGS. 3 and 2.

First, when modeling of a specific object is required through the command applier 302, and distance data about the object is obtained and transmitted from the distance data acquisition unit 304, the processor 306 performs the initial mesh as before. Generates and stores the generated initial mesh in the storage unit 308.

Processor 306 then performs a data amount reduction process on the generated initial mesh as shown in FIG.

That is, in step 401, the processor 306 processes to sequentially select vertices having even numbers of even indexes with respect to the initial mesh stored in the storage unit 308. Here, the index of the vertex is information set when forming a vertex list for generating a mesh. Therefore, the vertex initially selected in step 401 becomes a vertex having the first even index on the second column. When one vertex is selected as described above, the processor 306 proceeds to step 402 to perform a mesh data amount reduction process based on the index of the selected vertex.

At this time, the reduction processing performed in step 402 is performed in the same process as steps 204 through 218 and 226 through 230 of FIG. 2. That is, when one vertex is selected in step 401, the process proceeds to step 204 to form a loop based on the index of the selected vertex. The flow proceeds to step 206 to check whether the formed loop is a complete loop. As a result of the check, if the complete loop, the flow proceeds to step 208 to detect the number of feature edges present in the loop. If the detected number is '2', the process proceeds to step 212 through step 210 to set the detected back angle as a split line to perform a split process, and to proceed to step 214 to repeat the loop formed. Create a mesh. When re-mesh generation is completed, the process proceeds to step 218 through step 216, and updates the index and mesh structure information of the vertex for the corresponding loop stored in the storage unit 308, and then proceeds to step 403.

If the detected backside angle is 0 when the loop formed based on the index of the selected vertex is a complete loop, the process proceeds from step 210 to step 214 via step 224 and is processed as described above. As described above, when the index and the mesh structure information of the vertex for the corresponding loop are updated, the process proceeds to step 403.

If the loop formed based on the index of the selected vertex is not a complete loop, it is processed through steps 226 to 230 as described above with reference to FIG. 2, and the index and mesh structure information of the vertex for the corresponding loop is processed. If so, the flow proceeds to step 403.

In step 403, the processor 306 checks whether a selection has been made for a vertex having all even columns of even indexes on the entire mesh. As a result of the check, if there is an index of a vertex that is not yet selected, the process returns to step 401 and selects a vertex having an even index of even columns corresponding to the next sequence and repeats the above-described process. Here, the vertex of the even index corresponding to the next sequence is a vertex having the second even index on the second column when the vertex having the first even index on the second column is selected in step 401. However, if there are no vertices with even numbers on the second column, then the vertex with the first even index on column 4 is obtained.

When the vertex having the even index is the last of the last even column in step 401 and the mesh data amount reduction processing is performed based on the index of the selected vertex in step 401, the processor 306 determines the mesh in step 403. It is determined that a vertex having even indexes of all even columns present in the image is selected, and the process proceeds to step 404.

In operation 404, the processor 306 sequentially selects vertices having an even number of odd indexes, one by one, for the mesh updated to the storage unit 308 in a form in which the amount of data is reduced in the storage unit 308 through steps 401 to 403. FIG. Do it. Accordingly, the vertex first selected in step 404 becomes a vertex having the first odd index of two rows on the mesh that is primarily updated.

When one vertex is selected as described above, the processor 306 proceeds to step 405 and performs a mesh data amount reduction process by forming a corresponding loop as in step 402 based on the index of the selected vertex. When the mesh data amount reduction process based on the index of the selected vertex is completed, the processor 306 proceeds to step 406 and checks whether vertices having odd indexes of all even columns constituting the primary updated mesh are selected. .

If there is a check point that is not selected, the processor 306 returns to step 404 to select a vertex having an odd index of the next even numbered column. That is, in the case where the vertex previously selected in operation 404 is a vertex having the first odd index of the first even column existing on the first updated mesh, the currently selected vertex is the second of the first even column. To be a vertex with an odd index. However, if there are no vertices with more odd indexes in the first even column (for example 2), then vertices with the first odd indexes in the second even column (for example 4) Is selected. If a vertex having the last odd index of the last even column on the mesh that is selected in this order and primarily updated is selected, the processor 306 proceeds from step 406 to step 407.

In operation 407, the processor 306 selects vertices having even-numbered even indexes, one by one, for the meshes updated second through steps 404 to 406 and stored in the storage unit 308. In other words, vertices having an even index of odd columns constituting a mesh that is updated secondarily and stored on the storage unit 308 are sequentially selected.

When one vertex is selected in this manner, the processor 306 proceeds to step 408 to form a loop based on the indexes of the selected vertices as described in steps 402 and 403 to reduce the amount of mesh data. Do the processing. When the mesh data amount reduction process for the selected vertex is completed, the processor 306 proceeds to step 409 and checks whether all vertices having an even index of odd columns are selected on the second updated mesh.

In this case, if a vertex having the last even index of the last odd column is not selected in step 407, the processor 306 determines that there is a vertex that is not yet selected in step 409, and returns to step 407 to perform the next sequence Select a vertex. That is, when a vertex having the first even index of the first odd column (for example, column 1) is selected in step 407, the vertex having the second even index of the first odd column is selected. . In addition, when all vertices having even indexes of the first odd column are selected, the vertices having first even indexes of the second odd column are selected.

In this case, when a selection is made on a vertex having an even index of all odd columns existing in the secondary updated mesh, the processor 306 proceeds from step 409 to step 410.

In step 410, the processor processor 306 selects vertices having odd indexes of odd columns, one by one, for the meshes updated in steps 407 to 409 and stored in the storage unit 308. That is, vertices having an even index of odd columns, which are updated in a third order and constitute a mesh stored on the storage unit 308, are sequentially selected one by one.

In this manner, when one vertex is selected, the processor 306 proceeds to step 411 to form a loop based on the index of the selected vertex as in the above-described steps 402, 405, and 408. Reduce the mesh data amount. When the mesh data amount reduction process for the selected vertex is completed, the processor 306 proceeds to step 412 and checks whether all vertices having an odd index of odd columns are selected on the third updated mesh.

As a result of the check, if all vertices having an odd index of odd columns existing on the third updated mesh are not selected, the processor 306 returns to step 410 to select the next vertex. That is, in the case where a vertex having the first odd index of the first odd column is selected in the mesh in which the vertex previously selected in step 410 is updated in the third step, the vertex having the second odd index of the first odd column is selected.

If a vertex having an odd index of all odd columns existing in the third updated mesh is selected by the selection process, the processor 306 ends the mesh data amount reduction operation. Therefore, the storage unit 308 stores the mesh obtained by the mesh data amount reduction processing for four times.

In the embodiment shown in FIG. 4, first, the vertices having the even indexes of the even columns are selected and processed one by one, and then the vertices having the even indexes of the even columns are selected one by one and processed. The vertices are selected and processed one by one, and then the vertices having odd indexes of odd columns are selected and processed one by one, but the processing order may be changed. However, it may not be set in such a manner that it processes the vertices of even indexes of even columns, vertices of even indexes of odd columns, and processes vertices of even indexes of even columns. Therefore, the processing order for vertices with even indexes and vertices with odd indexes in odd-numbered dimensions may be changed, the processing order for vertices with even indexes and vertices with odd indexes in even-numbered dimensions may be changed, and odd trains The order of processing for the circle and even-order dimensions can be changed, but the order cannot be set to odd and even-index dimensions, regardless of the odd and even-order dimensions.

As described above, according to the present invention, when generating a mesh for an object using distance data, the mesh data is reduced by using vertices having even indexes and vertex conditions having odd indexes in even and odd column dimensions. By classifying the vertex selection conditions into four types and performing the mesh data amount reduction process, there is an effect of providing a new mesh data amount reduction method.

Claims (3)

In the apparatus for generating a corresponding mesh using the distance data obtained for the object, A first reduction processing step of selecting vertices each having a first predetermined index existing in a first predetermined column with respect to the initial mesh generated using the distance data, and reducing a data amount by forming a loop based on the selected vertices; Selecting vertices having a second predetermined index existing in the first predetermined column one by one for the mesh updated primarily through the first reduction processing step, and reducing the amount of data by forming a loop based on the selected vertices A second reduction treatment step; Selecting vertices having a first predetermined index existing in the second predetermined column one by one for the mesh updated second through the second reduction processing step, and reducing the amount of data while forming a loop based on the selected vertices A third reduction treatment step; Selecting vertices having a second predetermined index existing in the second predetermined column one by one with respect to the mesh updated through the third reduction processing step, and reducing a data amount by forming a loop based on the selected vertices And a fourth reduction processing step. The method of claim 1, wherein the mesh data amount reduction method sets the first predetermined column to an even column, the second predetermined column to an odd column, and the first predetermined index is one of an even index and an odd index. And the second predetermined index is operated by setting an index relative to the index set as the first predetermined index. The method of claim 1, wherein the mesh data amount reduction method sets the first predetermined column to an odd column, the second predetermined column to an even column, and the first predetermined index is one of an even index and an odd index. And the second predetermined index is operated by setting an index relative to the index set as the first predetermined index.

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