JP3618234B2 - 3D model compression method and 3D model image generation method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a technique for generating a three-dimensional model used in image generation using three-dimensional computer graphics such as a video game machine or industrial CAD, and in particular, compresses a predetermined three-dimensional model. Thus, the present invention relates to a three-dimensional model compression method for generating a three-dimensional model with a small amount of data and little image degradation caused by the data amount reduction.
[0002]
[Prior art]
Conventionally, three-dimensional computer graphics techniques for generating an image using three-dimensional shape data of an object have been actively studied. In recent years, even relatively inexpensive devices for home use such as video game machines and personal computers, image generation using 3D computer graphics technology has been actively performed, which is very important industrially. One of the technologies.
[0003]
Image generation by three-dimensional computer graphics includes modeling for generating a three-dimensional model composed of information on the three-dimensional shape and color of an object, and rendering for generating an image of the object using the three-dimensional model. Can be roughly divided into two steps.
[0004]
As one method for describing a three-dimensional model generated by modeling, a polygon model in which the three-dimensional shape of the surface of an object is approximated by a collection of a plurality of polygons is widely used. Further, as one rendering method using a polygon model, a method in which a plurality of polygons are sequentially projected onto an arbitrary two-dimensional plane and an object image is drawn as a collection of polygons is widely used.
[0005]
In image generation using such a polygon model, it is possible to generate an image that more accurately reflects an object having fine irregularities or a smooth curved surface by using more polygons. Therefore, the cost for recording and transmitting the three-dimensional model increases. Conversely, if the number of polygons is reduced, the amount of data decreases, but the generated image tends to be a rough and highly deteriorated image.
[0006]
Therefore, as a field of modeling technology in recent years, a detailed polygon model using a large number of polygons obtained with a three-dimensional measuring instrument capable of precisely measuring the three-dimensional coordinate value of the surface of an object is input. A three-dimensional model compression technique for generating an efficient three-dimensional model by compressing this and generating a small amount of data and less deterioration of an image accompanying a reduction in the amount of data has been actively studied.
[0007]
As an example of the above-described conventional three-dimensional model compression technique, for example, “Huges Hoppe, et al:“ Mesh Optimization ”, SIGGRAPH 93 Conference Processings,
pp. 19-26, August 1993 ".
[0008]
In an example of these three-dimensional model compression methods, the amount of data is reduced by approximating and reconstructing a plurality of polygons in a detailed polygon model with fewer polygons. The approximation reconstruction method first defines a function for quantifying the approximation error between the polygon model before approximation and the polygon model after approximation, and for all vertices of the polygon in the polygon model before approximation, An approximation error increment is calculated when one vertex is reduced and approximated with fewer polygons. Then, the vertex having the smallest increase in approximation error is selected and reduced, and the polygon model is approximately reconstructed. Further, by approximating the polygon model by reducing one vertex until a predetermined condition is reached, a polygon model with a small number of vertices and polygons is generated.
[0009]
At this time, the number of vertices and polygons are reduced by approximate reconstruction, that is, the amount of data is reduced. Therefore, as a result, it can be said that the compression method generates an efficient three-dimensional model.
[0010]
[Problems to be solved by the invention]
However, in the conventional modeling technique described above, all the vertices of the polygon model are evaluated using the same recent error function, but the outline (boundary between the object and the background or foreground) and Even if the error increment due to the approximation error is the same between the part and the part other than the outline, the outline part is often more prominent in the image degradation. Therefore, there is a problem that the efficiency is not always good.
[0011]
Such a problem that the deterioration of the contoured portion on the generated image is conspicuous is that Hoppe et al. Described above “View-Dependent Definition of Progressive Meshes” (SIGGRAPH 97 Conference Processings, pp. ) Point out. In order to cope with this, Hoppe et al. Describe a method in which a detailed three-dimensional model and a rough model are described hierarchically and stored, and a detailed three-dimensional model is selected and used as a contour portion when generating an image. is suggesting. However, this method does not focus on the compression of the three-dimensional model, and has a problem that the amount of data increases although there is little deterioration in the image quality of the contour portion.
[0012]
In view of the above problems, an object of the present invention is to provide a three-dimensional model compression method for generating an efficient three-dimensional model that has a small amount of data and little image deterioration due to data amount reduction.
[0013]
[Means for Solving the Problems]
The three-dimensional model compression method and the three-dimensional model image generation method of the present invention may be able to assume in advance a part that is likely to become an outline at the time of image generation depending on the shape of the target object or the target three-dimensional model, Further, the three-dimensional model is described by combining the information corresponding to the contour with the three-dimensional model.
[0014]
According to the present invention, by describing the shape of the boundary portion of the divided partial shape data as newly generated region data, the boundary portion of the partial shape data when the partial shape data is approximately reconstructed, that is, the image It is possible to realize a compression method that can reduce deterioration in image quality of a portion that may become an outline at the time of generation and generate a three-dimensional model with a small amount of data.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
The three-dimensional model compression method according to claim 1 is a method for compressing a three-dimensional model including three-dimensional shape data and texture composed of a plurality of polygons, wherein the shape data is converted into a plurality of partial shape data. A shape data dividing process for dividing the plurality of partial shape data, a region data generating process for generating region data indicating which region the plurality of divided partial shape data correspond to on the texture, and a plurality of the partial shape data. A partial shape data reconstruction process for generating compressed partial shape data approximated by a small number of polygons, Retained in region data Partial shape day Of The shape of the end face, Stored in compressed partial shape data Approximate partial shape data Shape The three-dimensional model is described by dividing it into two types of shapes.
[0016]
The three-dimensional model compression method according to claim 2 is a method for compressing a three-dimensional model including three-dimensional shape data and textures composed of a plurality of polygons, wherein the shape data is converted into a plurality of partial shape data. A shape data dividing process for dividing the plurality of partial shape data, a region data generating process for generating region data indicating which region the plurality of divided partial shape data correspond to on the texture, and a plurality of the partial shape data. Approximate with few polygons Generated compressed partial shape data A partial shape data reconstruction process, Retained in region data Partial shape day Of The shape of the end face, Stored in compressed partial shape data Approximate partial shape data Shape The three-dimensional model is described in two types of shapes: Said A hierarchical encoding process that encodes a texture in a hierarchical manner for each area of the area data; And territory It is characterized by combining two types of data with area data and compressing them into one data.
[0017]
The three-dimensional model compression method according to claim 3 is a method for compressing a three-dimensional model including three-dimensional shape data and textures composed of a plurality of polygons, wherein the shape data is converted into a plurality of partial shape data. A shape data dividing process for dividing the plurality of partial shape data, a region data generating process for generating region data indicating which region the plurality of divided partial shape data correspond to on the texture, and a plurality of the partial shape data. Approximate with few polygons Generated compressed partial shape data A partial shape data reconstruction process, Retained in region data Partial shape day Of The shape of the end face, Stored in compressed partial shape data Approximate partial shape data Shape The three-dimensional model is described by dividing the shape data into two types of shapes, and the shape data dividing process is configured such that the shape data is converted into a plurality of partial shape data based on the distance between vertices of a plurality of polygons constituting the shape data. It is characterized by dividing into two.
[0018]
The 3D model image generation method according to claim 4 is a method of generating an image from a 3D model including 3D shape data and texture, wherein the hierarchically encoded texture data is input and decoded. A plurality of textures, a decoding process for outputting a plurality of mask data indicating an effective region of pixels of the plurality of textures, the plurality of textures, the plurality of mask data, and a plurality of shape data are input, A mapping process in which image generation processing is performed by texture mapping using a plurality of mask data as masks, and the shape of each contour included in the hierarchically encoded texture data and the shape included in the shape data are 2 An image reflecting one shape is generated.
[0019]
6. The three-dimensional model compression apparatus according to claim 5, wherein the three-dimensional model compression apparatus includes a plurality of polygonal three-dimensional shape data and a three-dimensional model including a texture, the shape data being a plurality of partial shape data. Shape data dividing means for dividing the divided partial shape data, region data generating means for generating region data indicating which region the divided partial shape data corresponds to on the texture, and a number of the partial shape data Approximate with few polygons Generated compressed partial shape data And partial shape data reconstructing means.
[0020]
The three-dimensional model compression apparatus according to claim 6, An apparatus for compressing a three-dimensional model including three-dimensional shape data and texture composed of a plurality of polygons, the shape data dividing means for dividing the shape data into a plurality of partial shape data, and the division Region data generating means for generating region data indicating which region on the texture corresponds to a plurality of partial shape data, and a partial shape for approximating and reconstructing the partial shape data with a smaller number of polygons Data reconstruction means; Hierarchical encoding means for hierarchically encoding a texture for each area of the area data is provided.
[0021]
The three-dimensional model compressing apparatus according to claim 7 is the three-dimensional model compression apparatus according to claim 5 or 6, wherein the shape data dividing means converts the shape data into a plurality of parts based on distances between vertices of a plurality of polygons constituting the shape data. It is characterized by being divided into shape data.
[0022]
The three-dimensional model image generation device according to claim 8 is a device that generates an image from a three-dimensional model including three-dimensional shape data and texture, and inputs and decodes hierarchically encoded texture data. A plurality of textures, decoding means for outputting a plurality of mask data indicating effective regions of pixels of the plurality of textures, the plurality of textures, the plurality of mask data, and a plurality of shape data, And mapping means for performing image generation processing by texture mapping using a plurality of mask data as a mask.
[0023]
The recording medium according to claim 9 is written with software necessary to execute the three-dimensional model compression method according to any one of claims 1 to 3 or the three-dimensional model image generation method according to claim 4. It is characterized by that.
[0024]
Hereinafter, the three-dimensional model compression method of the present invention will be described based on specific embodiments.
(Embodiment 1)
FIG. 1 is a schematic diagram of a processing procedure of a three-dimensional model compression method according to (Embodiment 1) of the present invention.
[0025]
In FIG. 1, reference numeral 110 denotes shape data describing a three-dimensional shape of an object using a polygon model, and 111 denotes a texture of the object. The two constitute a three-dimensional model of the object. In this (Embodiment 1), the texture 111 is an image obtained by capturing an object from a certain angle, and the shape data 110 is obtained by measuring a three-dimensional coordinate value on the object surface corresponding to each pixel of the texture 111. Suppose that the obtained point is a vertex and the adjacent vertices are connected. Both the shape data 110 and the texture 111 are stored in the storage unit 103 in advance. Reference numeral 100 denotes shape data dividing means for dividing the shape data 110 to generate a plurality of partial shape data 112a and 112b. Reference numeral 101 denotes partial shape data reconstruction means. By approximating a plurality of polygons in the partial shape data 112a and 112b with polygons having a smaller number, compressed partial shape data 113a and 113b having a small amount of data are obtained. It is generated and stored in the storage means 103. Reference numeral 102 denotes area data generation means, which generates area data 114 indicating where each area of the partial shape data 112 a and 112 b corresponds on the texture 111 and stores it in the storage means 103.
[0026]
The processing operation of the three-dimensional model compression method configured as described above will be described.
FIG. 2 shows an example of a description method of a three-dimensional model composed of shape data 110 and texture 111. In this example, the shape data 110 is composed of n triangles including a total of m vertices, and the i-th triangle P (i) is a point referenced by three vertices (Vi1, Vi2, Vi3). The j-th vertex V (j) is a vertex and indicates that it is composed of the three-dimensional coordinate value (xi, yi, zi) and the coordinate (ui, vi) of the corresponding point on the texture 111. In addition, the texture 111 indicates a wu × wv two-dimensional array of RGB color system pixels.
[0027]
First, it is assumed that the processing of each means in the three-dimensional model compression method of the (Embodiment 1) is realized by software of a computer, and the shape data 110 and the texture 111 to be processed or processed are processed. The designation shall be made by the user. When the processing is started, the shape data dividing unit 100 reads the shape data 110 from the storage unit 103 and generates a plurality of partial shape data 112a and 112b.
[0028]
Processing in the shape data dividing unit 100 will be described with reference to FIGS.
FIG. 3 is a diagram of processing in the shape data dividing means. FIG. 3A is an enlarged view of a part of the shape data 110 in FIG. 1, and corresponds to the example of the shape data in FIG.
[0029]
The shape data dividing unit 100 compares the distance between the vertices constituting the triangle with a threshold value T1 given in advance for all triangles P (i) in the shape data 110 (FIG. 3A). The triangle that is larger than the threshold is deleted from the shape data 110 (FIG. 3B).
[0030]
Next, the shape data from which some of the triangles are deleted is scanned for whether or not there is a triangle in contact with the triangle P (i), and divided into groups of a plurality of adjacent triangles. 3 (c) partial shape data is generated.
[0031]
In the example of FIG. 1, it is shown that two partial shape data 112a and 112b are generated by this shape data division processing.
Next, processing in the area data generation unit 102 will be described with reference to FIGS. 1, 4, and 5.
[0032]
The area data 114 is information indicating whether each pixel of the texture 111 that is a two-dimensional array of wu × wv pixels belongs to which of the partial shape data 112a and 112b. The region data 114 can be expressed by a wu × wv two-dimensional array having data of the number of bits necessary for the above. In this (Embodiment 1), since the number of partial shape data is two, the number of bits of element data may be one.
[0033]
FIG. 4 is an example in which the partial shape data a (112a) and the partial shape data b (112b) divided into two by the shape data dividing means 100 are expressed in the same format as in FIG. The two partial shape data and the texture 111 are associated by (ua, va) (ub, vb) constituting the vertex data of the partial shape data. This is shown as an example of the area data 114 in FIG.
[0034]
In this (Embodiment 1), since it is assumed that each pixel of the texture 111 and each vertex of the shape model 110 have a one-to-one correspondence, the processing procedure in the region data generation unit 102 is 2 Horn Partial shape data All the vertices Va (j) and Vb (j) are sequentially scanned, and 1-bit value meaning “region a” is added to the region data of coordinates (uaj, vaj) corresponding to the vertex Va (j). Is recorded, and a 1-bit value indicating “region b” is recorded in the region data of the coordinates (ubj, vbj) corresponding to the vertex Vb (j) (FIG. 5B).
[0035]
Finally, processing in the partial shape data reconstruction unit 101 will be described with reference to FIGS. 1 and 6.
The partial shape data reconstruction unit 101 generates compressed partial shape data 113a and 113b with a small amount of data by approximating and reconstructing a plurality of polygons in the partial shape data 112a and 112b with fewer polygons. , Processing to be stored in the storage means 103 is performed.
[0036]
The processing procedure in the partial shape data reconstruction means is as follows:
Focusing on one vertex and assuming two large approximate triangles approximating the area surrounded by its eight adjacent vertices (step 1)
When the two approximate triangles include vertices other than the partial shape data, the three-dimensional coordinate values of the vertices are newly calculated (Step 2).
An approximation error between the approximate triangle and the partial shape data is calculated by a function given in advance, and it is determined whether or not the approximation error exceeds a threshold value T2 given in advance (step 3);
If the approximation error is less than or equal to the threshold value, the partial shape data is reconstructed with the two large approximate triangles assumed in (Step 1) (Step 4).
The compressed partial shape data is generated by repeating the four steps (step 1) to (step 4) for all the vertices in the partial shape data.
[0037]
The above steps will be described with reference to FIG. When attention is paid to the vertex ve, the region surrounded by the eight vertices va, vb, vc, vd, vf, vg, vh, vi adjacent to ve and including the triangles pa, pb, pc, pd, pe, pf Assume that two larger triangles pg and ph are approximate triangles (step 1). At this time, since the vertex vi of the approximate triangle is not included in the original partial shape data, the three-dimensional coordinates of the vertices vc, ve, vf, vg, and vh of the partial shape data in the region of the approximate triangle ph. Using the values (x, y, z), a new three-dimensional coordinate value of vi ′ is obtained by extrapolation (step 2). Next, an approximation error between the approximate triangles pg and ph and the triangles pa to pf in the partial shape data is obtained and compared with a threshold value T2. Here, the approximation error is the distance between each vertex va, vb, vc, vd, ve, vf, vg, vh and the approximate triangle pg, ph included in the partial shape data. It is assumed that the threshold value is equal to or less than T2 (step 3). If at least one approximation error in step 3 exceeds the threshold value, the approximate reconstruction process is not performed. Conversely, if all of the approximation errors are equal to or less than the threshold value, triangles pa, pb, pc in the partial shape model are used. , Pd, pe, pf are replaced with pg, ph to perform approximate reconstruction of the partial shape model (step 4).
[0038]
Here, in the above-described (Step 4), if approximate reconstruction processing is performed, it can be seen that the data amount of a large amount of partial shape data can be reduced to 2/6 for the number of triangles and 5/8 for the number of vertices. .
[0039]
Further, the above four steps are performed on all the vertices of the partial shape data, thereby generating the compressed partial shape data 113 a and 113 b and storing them in the storage means 103.
[0040]
FIG. 7 is an example of a compressed three-dimensional model generated by the three-dimensional model compression method of the (Embodiment 1) and stored in the storage unit 103. Compared with the input three-dimensional model in FIG. 2, the texture 111 remains the same, and the shape data 110 is placed in the area data 114 and the compressed partial shape data 113a and 113b. Instead I can see that
[0041]
As described above, according to the three-dimensional model compression method of the first embodiment, the data amount of the compressed partial shape data 113a and 113b can be reduced with respect to the data amount of the shape model 110. In particular, the amount of data can be significantly reduced by the processing of the shape data reconstruction means 101.
[0042]
In addition, the area data 114 is newly added. In this (Embodiment 1), the area data is 1 bit per pixel, whereas one vertex data of the shape data is many. Since there are tens of bits or more in some cases, an increase in the amount of data due to the addition of area data can be offset by reducing one vertex to several tens of vertices.
[0043]
From the above, it can be said that the three-dimensional model compression method of (Embodiment 1) can generate a three-dimensional model with a smaller amount of data.
Furthermore, in order to clarify the effect of the region data 114, a case will be described in which image generation is performed using the three-dimensional model generated by the three-dimensional model compression method in (Embodiment 1).
[0044]
FIG. 8 is a schematic diagram of a processing procedure of a method for generating an image by a three-dimensional computer graphic using a three-dimensional model newly generated by the three-dimensional model compression method in (Embodiment 1).
[0045]
The mask data generation unit 104 reads the area data 114 from the storage unit 103 and generates mask data a and b (115a and 115b). The mask data is a two-dimensional array of wu × wv that is the same as the texture 111, and the mask data a (115a) is “1” in the area corresponding to the partial shape data area a and “0” in the other parts. In the data b (115b), it is assumed that the area corresponding to the partial shape data area b is “1” and the other parts are “0”.
[0046]
The texture mapping means 105 outputs two sets of data, a set of the texture 111, mask data a (115a), and compressed partial shape data 113a, and a set of the texture 111, mask data b (115b), and compressed partial shape data 113b. The composite image 116 is generated by using this. At this time, rendering is performed by texture mapping (texture mapping with alpha) in which only the texture of the pixel whose mask data is “1” is mapped as an image, and a composite image 116 is generated. The composite image 116 thus obtained reflects the two shapes of the shape of the area data 114, that is, the shape of the end face of the partial shape data 112 and the three-dimensional shape of the compressed partial shape data 113. It has become a thing.
[0047]
The technology of texture mapping with alpha is also disclosed in “David F. Rogers:“ Practical computer graphics ”(English title“ Procedural elements for computer graphics ”), supervised by Fujio Yamaguchi, published by Nikkan Kogyo Shimbun, etc. This technique is generally known as a general technique of three-dimensional computer graphics, and detailed description thereof is omitted here.
[0048]
Here, in the process of the three-dimensional model compression method of the (Embodiment 1), the shape data is reduced mainly by the processing of the partial shape data reconstruction means. It can be considered that the deterioration almost occurs in the processing by the partial shape data reconstruction means.
[0049]
On the other hand, the area data retains the shape of the end face of the partial shape data before performing the approximate reconstruction process by the partial shape data reconstruction means, that is, before the generated image is deteriorated due to the shape data reduction. In particular, the area data can express a shape corresponding to one pixel of texture in a very small amount of data compared to the shape data, as can be expressed by 1 bit in this (Embodiment 1). Therefore, it can be said that it is suitable for describing the shape of the contour portion where the deterioration of the image is conspicuous.
[0050]
Therefore, if the portion that is likely to become the contour portion at the time of image generation can be matched with the end face of the partial shape data, the detailed shape of the contour portion can be described with a small amount of data by the region data, As a result, it is possible to reduce image degradation due to the reduction of shape data to a small amount of data.
[0051]
As an example in which there is a high possibility that the portion corresponding to the end face of the partial shape data becomes a contour portion at the time of image generation, a plurality of objects (dolls and backgrounds) measured by three-dimensional measurement as in the example of FIG. ) Including shape data and shape data having sharp edges. Such shape data is separated by the shape data dividing means of this (Embodiment 1) when the distance between the vertices of the triangle is larger than the threshold (FIGS. 3A and 3B). There is a high possibility that the data is divided into partial shape data having a boundary portion between a plurality of objects and an acute edge portion as an end face. Furthermore, it can be said that the boundary of an object or an acute edge is generally highly likely to be an outline at the time of image generation even when conditions such as the viewpoint at the time of image formation change. From the above, especially in the case of the above-described shape, the 3D model compression method according to (Embodiment 1) compresses a 3D model with little deterioration of the contour portion during image generation and a small amount of data. It can be said that this is a generation method.
[0052]
As described above, according to (Embodiment 1), the shape data dividing unit 100 that divides the shape data into a plurality of partial shape data, and in which region the divided plurality of partial shape data are on the texture. Fewer area data generation means 102 for generating area data indicating whether it corresponds, and partial shape data reconstruction means 101 for approximating and reconstructing the partial shape data with a plurality of polygons having a smaller number of parts It is possible to generate a three-dimensional model with a small amount of data and little deterioration in image quality. In particular, it is possible to efficiently compress a three-dimensional model into shape data having an open end face.
[0053]
1 is implemented by executing a software program on a computer. The software program includes a shape data dividing process for dividing shape data into a plurality of partial shape data, and a region for generating region data indicating which region the plurality of divided partial shape data corresponds to on the texture It describes the data generation process and the partial shape data reconstruction process that approximates and reconstructs the partial shape data with a plurality of polygons having a smaller number, and the computer executes the shape data division process to split the shape data Means 100 is realized, and the region data generation means 102 is realized by the computer executing the region data generation process, and the partial shape data reconstruction means 101 is realized by the computer executing the partial shape data reconstruction process. Is done.
[0054]
Similarly, the processing of FIG. 8 is also realized by executing the software program on a computer, and the mask data generating means 104 and the texture mapping means 105 are realized by executing the processes of the software program.
[0055]
Such a software program for the processing of FIG. 1 or FIG. 8 can be written on a recording medium and distributed to the market. The same applies to the following embodiments.
[0056]
(Embodiment 2)
FIG. 9 is a schematic diagram of the processing procedure of the three-dimensional model compression method in (Embodiment 2) of the present invention.
[0057]
The difference from FIG. 1 is that the hierarchical encoding means 106 is provided and that the texture 111 and the region data 114 are encoded and stored in the storage means 103 by the hierarchical encoding means. The processing in the means is the same processing as in (Embodiment 1) of the present invention.
[0058]
The processing in the hierarchical encoding means 106 is input with the texture 111 and the region data 114 as input, and the texture 111 is divided into two regions corresponding to the region data 114, and encoding is performed by paying attention only to images in each region. To generate a compressed texture 117 with a small amount of data and store it in the storage means 103.
[0059]
For a method of hierarchical encoding / decoding of such an image and a detailed configuration of an apparatus for realizing the method, Japanese Patent Laid-Open No. 8-116543 and a research report by Eito et al. “The Journal of the Institute of Image Information and Media Studies, Vol. 51, No. 12, pp. 1966-1973, 1997”, etc., and detailed description of the processing procedure is omitted here.
[0060]
In the above-described (Embodiment 2) of the present invention, data having completely different properties such as texture and region data generated from three-dimensional shape data are combined and compressed by hierarchical encoding, so that data is more compressed than when compressed individually. Since the compression method with a small amount is realized, it can be said that the method is highly novel and effective.
[0061]
Hierarchical coding technology has recently been attracting attention as a technology that can increase coding efficiency by separating and coding each of different objects in a single image. However, it is difficult to automatically separate a plurality of objects in the image using only the image, and conventionally, processing such as separating the image manually has been performed. On the other hand, (Embodiment 2) of the present invention has three-dimensional shape data in addition to the image (texture) of the object, and generates region data using this, It is a novelty and highly effective method in that automatic hierarchization of images is realized.
[0062]
As described above, according to this (Embodiment 2), by providing hierarchical encoding means for encoding texture and region data, the amount of data is smaller than that of (Embodiment 1) of the present invention. A dimensional model can be generated.
[0063]
(Embodiment 3)
FIG. 10 is a schematic diagram of a processing procedure of the three-dimensional model image generation method according to (Embodiment 3) of the present invention.
[0064]
8 differs from FIG. 8 in that a decoding unit 107 is provided instead of the mask data generation unit 104, and that the texture data 111a and 111b and the mask data 115a and 115b are hierarchically encoded in advance by the decoding unit 107. The compressed texture 117 is generated by decoding. The processing in the texture mapping unit 105 is similar to the image generation method in FIG.
[0065]
In the processing in the decoding unit 107, the decoding process is performed with the compressed texture 117 stored in the storage unit 103 as hierarchically encoded in advance. Here, since the hierarchically encoded data includes information indicating the region of the image to be encoded, this region information is generated and output as the mask data 115 and the texture 111 that is the image is also output. Is decoded and output.
[0066]
As described above, according to this (Embodiment 3), by using hierarchical coding as a method of compressing texture, not only the effect of texture compression is obtained, but also the image included in hierarchical coding is By using region information as mask information at the time of texture mapping, an image was generated using a rough shape model with a small amount of data, similar to the effects of (Embodiment 1) and (Embodiment 2) of the present invention. Even in this case, since an image including shape information included in the mask information can be generated, there is an effect that it is possible to generate an image with less data deterioration with a small amount of data.
[0067]
【The invention's effect】
As described above, according to the present invention, as a method of compressing a three-dimensional model including three-dimensional shape data and textures composed of a plurality of polygons, an end face when shape data is separated into a plurality of partial shape data is used. It is possible to generate a three-dimensional model with a smaller amount of data and less image quality degradation by describing the shape and the rough shape that approximates the partial shape data separately. is there.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of a processing procedure of a three-dimensional model compression method according to (Embodiment 1) of the present invention.
FIG. 2 is a diagram showing an example of shape data and texture in the embodiment
FIG. 3 is an explanatory diagram of a processing procedure in a shape data dividing unit in the same embodiment
4 is a diagram showing an example of partial shape data and texture in the embodiment; FIG.
FIG. 5 is an explanatory diagram of a processing procedure in the area data generation unit in the embodiment
FIG. 6 is an explanatory diagram of a processing procedure in the partial shape data reconstruction unit in the embodiment;
FIG. 7 is a diagram showing an example of a three-dimensional model generated by the compression method according to the embodiment
FIG. 8 is a schematic diagram of an image generation processing procedure using a three-dimensional model compressed by the compression method according to the embodiment;
FIG. 9 is a schematic diagram of a processing procedure of a three-dimensional model compression method according to (Embodiment 2) of the present invention.
FIG. 10 is a schematic diagram of a processing procedure of a three-dimensional model image generation method according to (Embodiment 3) of the present invention.
[Explanation of symbols]
100 Shape data dividing means
101 Partial shape data reconstruction means
102 Area data generation means
103 storage means
110 Shape data
111 texture
112 Partial shape data
113 Compressed partial shape data
114 area data

Claims (10)

A method of compressing a three-dimensional model including three-dimensional shape data and textures composed of a plurality of polygons,
A shape data dividing process for dividing the shape data into a plurality of partial shape data;
A region data generation step of generating region data indicating which region the plurality of divided partial shape data corresponds to on the texture;
The partial shape data and a partial shape data reconstruction process of generating the compressed partial shape data approximated in a more small number of the plurality of polygons, and the shape of the end face of the partial shape data stored in the region data , 3-dimensional model compression method that describes a three-dimensional model divided into two kinds of shapes of the compressed partial shape data part held in the shape data shape approximating the. A method of compressing a three-dimensional model including three-dimensional shape data and textures composed of a plurality of polygons,
A shape data dividing process for dividing the shape data into a plurality of partial shape data;
A region data generation step of generating region data indicating which region the plurality of divided partial shape data corresponds to on the texture;
A partial shape data reconstruction process for generating compressed partial shape data approximating the partial shape data with a plurality of polygons having a smaller number, and the shape of the end face of the partial shape data held in the region data ; with describing a three-dimensional model divided into two kinds of shapes of the compressed partial shape data part held in the shape data shape approximating the encoding hierarchized the texture for each area of the region data hierarchical encoding process includes a three-dimensional model compression method of compressing a combination of two kinds of data between the texture and the realm data into one data. A method of compressing a three-dimensional model including three-dimensional shape data and textures composed of a plurality of polygons,
A shape data dividing process for dividing the shape data into a plurality of partial shape data;
A region data generation step of generating region data indicating which region the plurality of divided partial shape data corresponds to on the texture;
The partial shape data and a partial shape data reconstruction process of generating the compressed partial shape data approximated in a more small number of the plurality of polygons, and the shape of the end face of the partial shape data stored in the region data , as well as describing a three-dimensional model divided into two kinds of shapes of the compressed partial shape data part held in the shape data shape approximating the said shape data dividing process, a plurality of constituting the shape data multi A three-dimensional model compression method for dividing shape data into a plurality of partial shape data on the basis of the distance between vertexes of a square. A method for generating an image from a three-dimensional model including three-dimensional shape data and texture,
A decoding process in which hierarchically encoded texture data is input and decoded to output a plurality of textures and a plurality of mask data indicating regions in which pixels of the plurality of textures are valid;
A hierarchically encoded texture comprising: a mapping process of inputting the plurality of textures, the plurality of mask data, and a plurality of shape data, and performing image generation processing by texture mapping using the plurality of mask data as a mask A three-dimensional model image generation method for generating an image reflecting two shapes of a contour shape of each layer included in data and a shape included in shape data. An apparatus for compressing a three-dimensional model including three-dimensional shape data and textures composed of a plurality of polygons,
Shape data dividing means for dividing the shape data into a plurality of partial shape data;
Area data generating means for generating area data indicating which area the plurality of divided partial shape data correspond to on the texture;
A three-dimensional model compression apparatus comprising partial shape data reconstruction means for generating compressed partial shape data approximating the partial shape data with a plurality of polygons having a smaller number. An apparatus for compressing a three-dimensional model including three-dimensional shape data and textures composed of a plurality of polygons,
Shape data dividing means for dividing the shape data into a plurality of partial shape data;
Area data generating means for generating area data indicating which area the plurality of divided partial shape data correspond to on the texture;
Partial shape data reconstruction means for approximately reconstructing the partial shape data with a plurality of polygons having a smaller number;
A three-dimensional model compression apparatus comprising hierarchical encoding means for hierarchically encoding a texture for each area of the area data. The three-dimensional model compression apparatus according to claim 5 or 6, wherein the shape data dividing means divides the shape data into a plurality of partial shape data based on a distance between vertices of a plurality of polygons constituting the shape data. An apparatus for generating an image from a three-dimensional model including three-dimensional shape data and texture,
Decoding means for inputting hierarchically textured texture data, decoding and outputting a plurality of textures, and a plurality of mask data indicating regions where pixels of the plurality of textures are valid;
A three-dimensional model image generation apparatus comprising mapping means for inputting the plurality of textures, the plurality of mask data, and a plurality of shape data and performing image generation processing by texture mapping using the plurality of mask data as a mask. A recording medium in which software necessary for executing the three-dimensional model compression method according to claim 1 or the three-dimensional model image generation method according to claim 4 is written. An apparatus for compressing a three-dimensional model including three-dimensional shape data and textures composed of a plurality of polygons,
Shape data dividing means for dividing the shape data into a plurality of partial shape data;
Area data generating means for generating area data indicating which area the plurality of divided partial shape data correspond to on the texture;
Partial shape data reconstruction means for generating compressed partial shape data approximating the partial shape data with a plurality of polygons having a smaller number;
An image composition device comprising image composition means for composing an image using the compressed partial shape data and the region data.

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