JPH09204541A - Image synthesizing device and its method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the need for synthesizing previously a large image and also to reduce the necessary computational complexity by selecting the texture information that previously undergone the low pass processing when the texture aliasing is caused. SOLUTION: A texture information memory part 3 stores the texture data on the surface of an object set at a position corresponding to the range data and also the texture data obtained by applying the low pass processing to the texture data on the object surface and reducing every side don to 1/2. A texture selection part 5 selects the reduced texture data when the radius of a circle is far from a projection surface and the circle radius is smaller than 0.5 pixels on a projection surface when the position of a model is far from the projection surface and a ball distant from a center position by a unit vector is projecting on the projection surface. On the other hand, the part 5 select the non-reduced texture data when the circle radius is larger than 0.5 pixels on the projection surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for synthesizing images, for example, an image synthesizing device for synthesizing a two-dimensional image based on a three-dimensional structure of an object.

[0002]

2. Description of the Related Art A so-called three-dimensional computer graphics (CG) technique for synthesizing a two-dimensional image from a three-dimensional structure of an object using a computer is very important for data visualization in CAD / CAM and the like. It is a technology. Conventionally, in the technique of three-dimensional CG, the amount of calculation required for synthesizing a secondary image differs depending on the type of three-dimensional model information of one object, and is generally required for synthesizing a high-quality two-dimensional image. The amount of calculation tends to increase.

Specifically, there is aliasing that affects the image quality of CG. This is because when the change in the three-dimensional model and its texture information is large in one pixel on the projected screen, discontinuity occurs in the synthetic image even if the actual model is smooth and the image quality deteriorates. .

As a method for improving this, a method called anti-aliasing is famous. This is because when the pixels on the projection screen are set large in advance and, for example, CG of 512 × 512 pixels is combined, 1024 × 1024 or
512 × 5 by combining CG of 2048 × 2048 pixels and reducing this while performing low-pass processing
A CG of 12 pixels is obtained.

In such a case, the change in the three-dimensional model and its texture information in one pixel on the screen which is initially set large becomes small in inverse proportion to it, and the smoothness is maintained. ,
Since a blurred image similar to an actual image is obtained here, a high quality image with a high sense of reality can be obtained.

[0006]

However, this method requires a large amount of calculation processing and a large-scale computer and processing time in order to synthesize images of several times the area in advance. was there.

In view of the above problems, it is an object of the present invention to provide an image synthesizing apparatus that requires a small amount of calculation because it is not necessary to synthesize a large image in advance.

[0008]

According to a first aspect of the present invention for solving the above-mentioned problems, model information storage means for storing model information which is information about a model representing a three-dimensional structure of an object, and the object Texture information storage means for storing a plurality of texture information having different resolutions for all or part of the surface of the object, and a two-dimensional projection surface located at a predetermined position with respect to the model based on at least the model information. Polygon generating means for generating polygon information for generating a two-dimensional image on which the surface of the object is projected; texture selecting means for selecting texture information of any one resolution from the texture information storing means; Image composition for generating the two-dimensional image based on the polygon information and the texture information selected by the texture selecting means. An image synthesizing apparatus characterized by comprising a stage.

The image synthesizing apparatus further includes rendering information generating means for receiving information on at least the predetermined position and generating rendering information for the surface of the object determined based on at least the position of the projection plane. The predetermined position of the projection plane with respect to the model is determined based on the information regarding the predetermined position accepted by the rendering information generating means, and the polygon generating means includes the model information and the rendering information. Based on this, the polygon information may be generated.

The texture information storage means stores the texture information of the first resolution and the texture information of the second resolution for all or a part of the surface of the object, and the texture information storage means stores the texture information of the first resolution and the texture information of the second resolution. Is higher than the second resolution, the texture selecting means determines the position of a predetermined three-dimensional unit model based on the model information, arranges the three-dimensional unit model at that position, and the rendering information Based on that, the three-dimensional unit model is projected on the projection surface, and if the size of all or part of the three-dimensional unit model projected on the projection surface is larger than a predetermined value, then the first
The texture information of the resolution may be selected, and otherwise, the texture information of the second resolution may be selected.

Further, the texture information storage means stores texture information of a first resolution and texture information of a second resolution for all or a part of the surface of the object, and the texture information storage means stores the texture information of the first resolution. Is higher than the second resolution, and the texture selecting means back-projects a predetermined unit vector on the projection plane onto a polygon plane formed by the polygon information, and further back-projects the unit vector. If the size of the unit vector projected on the texture surface formed by the position information allocated together with the texture information is larger than a predetermined value, the texture information of the second resolution is set. Otherwise, the texture information of the first resolution may be selected.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of the image synthesizing apparatus and method according to the first embodiment of the present invention.
This will be described with reference to FIG. In FIG. 1, 1 is a model information storage unit, 2 is a rendering information generation unit, 3 is a texture information storage unit, 4 is an image composition unit, 5 is a texture selection unit, and 6 is a polygon generation unit.

Next, the operation of this embodiment will be described.

FIG. 2 is a diagram showing an example of data stored in each of the model information storage unit 1 and the texture information storage unit 3. The model information storage unit 1 in FIG.
As shown in FIG. 2A, the range data 11 is stored. The range data 11 is, as shown in FIG.
Model information of the object 10, which is X- of the cylindrical coordinate system 13.
It is the data of the radius r taken by Φ. The texture information storage unit 3 in FIG. 1 stores the texture data 12 of the surface of the object 10 at the position corresponding to the range data 11 as shown in FIG. 2B and the texture data 12 as shown in FIG. 2C. 12 is low-pass processed, and reduced texture data 12 ′ in which each side is reduced to ½ is stored.

FIG. 3 is a diagram showing an example of data regarding each of the rendering information generation unit 2, the composite image unit 4, the texture selection unit 5, and the polygon data generation unit 6 in the present embodiment. The rendering information generation unit 2 of FIG. 1 uses information other than the range data 11, which is model information of the object 10,
For example, the position, direction, or surrounding illumination information of the object 10 from the projection surface 15 is generated. Model 10a at this time
3B and 3C show the relationship between the center position O, the XYZ axes, and the three-dimensional position of the projection surface 15.

At this time, the texture selection unit 5 uses the model 1
If the position 0a is far from the projection surface 15 and the radius r of the circle 17 when the unit vector sphere 16 is projected from the center position O onto the projection surface 15 is 0.5 pixels or less on the projection surface 15, the reduced texture Select the data 12 '. The texture selection unit 5 selects the texture data 12 when the radius r on the projection surface 15 is larger than 0.5 pixel. Here, this unit vector corresponds to a substantially 1-pixel unit vector on the texture data 12.

As shown in FIG. 3 (a), the polygon data generator 6 converts the range data 11 which is model information into
Polygon 14 composed of each vertex shown on X-Φ
To generate the data.

Here, range data 1 which is model information
Information obtained from 1 is: polygon P: each vertex {p0, p1, p2} vertex pn (n = 0, 1, 2): {three-dimensional coordinate (X, Y, Z)}: {on texture information 12 The coordinates are (u, v)}. At this time, the three-dimensional coordinates (X,
From the Y, Z) information, the XY coordinates (x,
y) is calculated.

The image synthesizing section 4 carries out texture mapping based on the data of the polygon 14 and the texture data 12 or the reduced texture data 12 ', and FIG.
The composite image 18 as shown in (e) is composed.

As a result, when the model 10a is projected small on the projection surface 15, 2 on the texture data 12 surface with respect to changes in the horizontal and vertical unit vectors ix and iy on the projection surface 15. When a change in size of pixels or more occurs, the reduced texture data 12 ′ is selected, and the change on this surface is halved. Therefore, a smooth composite image 15 can be composed, and a high quality image can be obtained. To be

FIG. 4 is a block diagram of the image synthesizing apparatus and method according to the second embodiment of the present invention.
This will be described with reference to FIG. In FIG. 4, 1 is a model information storage unit, 2 is a rendering information generation unit, 3 is a texture information storage unit, 4 is an image composition unit, 5 is a texture selection unit, and 6 is a polygon generation unit.

Next, the operation of this embodiment will be described.

Similar to the first embodiment, the model information storage unit 1 of FIG. 4 stores range data 11 as shown in FIG. 2 (a). The range data 11 is shown in FIG.
As shown in (d), the model information of the object 10
It is the data of the radius r taken in X-Φ of the cylindrical coordinate system 13. As shown in FIG. 2B, the texture information storage unit 3 of FIG. 4 also has the object 10 at the position corresponding to the range data 11.
2 and the reduced texture data 12 ′ in which each side is reduced to ½ is stored as shown in FIG. 2C.

The rendering information generator 2 in FIG.
Generates information other than the range data 11, which is model information of the object 10, such as the position and direction of the object 10 from the projection surface 15, or surrounding illumination information.

FIG. 5 is a diagram showing an example of data regarding each of the composite image section 4, the texture selecting section 5 and the polygon data generating section 6 in the present embodiment. As shown in FIG. 5A, the polygon data generation unit 6 in FIG. 4 generates the data of the polygon 14 formed by the vertices on X-Φ from the range data 11 that is the model information.

Here, range data 1 which is model information
Information obtained from 1 is: polygon P: each vertex {p0, p1, p2} vertex pn (n = 0, 1, 2): {three-dimensional coordinate (X, Y, Z)}: {on texture information 12 The coordinates are (u, v)}. At this time, the XY coordinates (x, y) on the projection surface 15 are calculated from the information of the three-dimensional coordinates shown in FIG.
The relationship between the data of the polygon pieces 19 forming the model 10a and the three-dimensional position of the projection surface 15 at this time is shown in FIGS.

At this time, the texture selection unit 5 in FIG.
Are XY coordinates (x, x on the projection plane 15 shown in FIG.
Vectors ix 'and iy' are obtained by back-projecting the horizontal and vertical one-pixel unit vectors ix and iy in y) onto the polygon surface. Furthermore, the texture selection unit 5
Is the vector ix 'and iy' as shown in FIG.
Vectors ix "and iy" are obtained by projecting each of these on the surface of the texture data 12. Then, the texture selection unit 5 uses | ix ″ | and | i which are the magnitudes of these vectors.
If any of y ″ | has a size of 1.5 pixels or more on the surface of the texture data 12, the reduced texture data 12 ′ is selected; otherwise, the texture data 1
Select 2.

When texture mapping this polygon, the unit vectors ix and iy to the vector ix ″,
Since the relationship of iy "does not change, this selection is retained.

The image synthesizing unit 4 in FIG. 4 performs texture mapping based on the polygon data and texture data to synthesize a synthetic image 18 as shown in FIG. 5 (f).

As a result, when the unit vectors ix and iy in the horizontal direction and the vertical direction on the projection plane 15 change by a size of 1.5 pixels or more on the surface of the texture data 12, Since the reduced texture data 12 'is selected and the change on this surface is halved, the smooth composite image 18 can be composited and a high quality image can be obtained.

In the above embodiment, the reduced texture data 12 'is used, but instead, the texture data 1 whose resolution is halved by low-pass processing is used.
Texture data of the same size as 2 may be used.

In the above embodiment, the texture data of two layers having two resolutions is used, but the texture data of three layers or more may be used.

Further, in the above embodiment, each of the constituent elements of the image synthesizing apparatus is hardware-configured based on the block diagram shown in FIG. 1 or FIG. Without being limited thereto, some of the components of the image synthesizing apparatus of the present invention may be configured as software by a program that executes the process related to the operation described in the above embodiments and a computer on which the program is activated. Good. And at least that computer
A CPU that performs arithmetic processing and control by the program when loaded, a memory that is connected to the CPU through the internal bus and that is used for storage of the program and a work area, and data can be read and written. It is equipped with an auxiliary storage device.

[0035]

As is apparent from the above, according to the present invention, in the image synthesis by texture mapping, the area of the texture generated when the change of the texture information becomes large in one pixel on the screen to be projected. For this, by selecting the texture information that has been low-pass processed in advance when this occurs, there is an effect that a continuous image is obtained even in a synthetic image for an object whose actual model is smooth and the image quality is not deteriorated.

Further, unlike the conventional anti-aliasing method, since it is not necessary to synthesize a large image in advance, the amount of calculation required is small.

[Brief description of drawings]

FIG. 1 is a block diagram of an image composition device according to a first embodiment of the present invention.

FIG. 2 is a model information storage unit 1 and a texture information storage unit 3
FIG. 6 is a diagram showing an example regarding data stored in each of FIG.

FIG. 3 is a diagram showing an example of data regarding each of a rendering information generation unit 2, a composite image unit 4, a texture selection unit 5, and a polygon data generation unit 6 in the first embodiment.

FIG. 4 is a block diagram of an image processing apparatus according to a second embodiment of the present invention.

FIG. 5 is a diagram showing an example of data regarding each of a composite image unit 4, a texture selection unit 5, and a polygon data generation unit 6 in the second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Model information storage unit 2 ... Rendering information generation unit 3 ... Texture information storage unit 4 ... Image synthesis unit 5 ... Texture selection unit 6 ... Polygon generation unit 10 ... Object 10a ... Model 11 ... Range data 12 ... Texture data 12 '... Reduced texture data 13 ... Coordinate system 14 ... Polygon 15 ... Projection surface 16 ... Sphere 17 ... Circle 18 ... Synthetic image 19 ... Polygon piece

Claims (8)

[Claims] 1. A model information storage unit for storing model information, which is information about a model representing a three-dimensional structure of an object, and a plurality of texture information having different resolutions for all or part of the surface of the object. And a polygon information for generating a two-dimensional image in which the surface of the object is projected on a two-dimensional projection plane at a predetermined position with respect to the model, based on at least the model information. Based on the polygon information and the texture information selected by the texture selecting means, the polygon generating means for generating the texture information, the texture selecting means for selecting texture information of any one resolution from the texture information storing means, An image synthesizing device, comprising: an image synthesizing means for generating a two-dimensional image. 2. The image synthesizing apparatus further includes rendering information generating means for receiving information on at least the predetermined position and generating rendering information for the surface of the object determined based on at least the position of the projection plane. And a predetermined position of the projection plane with respect to the model is determined based on information about the predetermined position accepted by the rendering information generating unit, and the polygon generating unit includes the model information and the rendering information. The image synthesizing apparatus according to claim 1, wherein the polygon information is generated based on the polygon information. 3. The texture information storage means stores texture information of a first resolution and texture information of a second resolution for all or part of the surface of the object, and the first resolution. Is higher than the second resolution, and the texture selecting unit determines the position of a predetermined three-dimensional unit model based on the model information, arranges the three-dimensional unit model at that position, and sets the rendering information in the rendering information. Projecting the three-dimensional unit model on the projection plane based on
If the size of all or part of the three-dimensional unit model projected on the projection surface is larger than a predetermined value, the texture information of the first resolution is selected; otherwise, the texture information of the second resolution is selected. The image synthesizing apparatus according to claim 1, wherein texture information is selected. 4. The texture information storage means stores texture information of a first resolution and texture information of a second resolution for all or part of the surface of the object, and the first resolution. Is higher than the second resolution, and the texture selecting means back-projects a predetermined unit vector on the projection plane onto the polygon plane formed by the polygon information, and further back-projects the unit vector. If the size of the unit vector projected on the texture surface formed by the position information allocated together with the texture information is larger than a predetermined value, the texture information of the second resolution is set. 2. The texture information of the first resolution is selected otherwise, the texture information of the first resolution is selected.
Alternatively, the image synthesizing apparatus according to item 2. 5. Model information, which is information about a model representing a three-dimensional structure of an object, is stored, and a plurality of texture information having different resolutions is stored for all or part of the surface of the object, at least the model. Polygon information for generating a two-dimensional image in which the surface of the object is projected on a two-dimensional projection surface at a predetermined position with respect to the model is generated based on the information, An image synthesizing method characterized by selecting texture information of any one resolution and generating the two-dimensional image based on the polygon information and the texture information selected by the texture selecting means. 6. At least information about the predetermined position is received, and a predetermined position of the projection surface with respect to the model is determined based on the received information about the predetermined position, and based on at least the position of the projection surface. Generate rendering information for the surface of the object determined by, based on the model information and the rendering information,
6. The polygon information is generated, and the polygon information is generated.
The image synthesizing method as described above. 7. The plurality of pieces of texture information having different resolutions are texture information of a first resolution and texture information of a second resolution, the first resolution being higher than the second resolution, The texture information is selected by determining the position of a predetermined three-dimensional unit model based on the model information, arranging the three-dimensional unit model at that position, and projecting the three-dimensional unit model based on the rendering information. If the size of all or part of the three-dimensional unit model projected on the plane is larger than a predetermined value, then the first
3. The image synthesizing method according to claim 1, wherein the image synthesizing method is performed by selecting the texture information of the resolution of 1), and selecting the texture information of the second resolution otherwise. 8. The plurality of pieces of texture information having different resolutions are texture information of a first resolution and texture information of a second resolution, and the first resolution is higher than the second resolution, The texture information is selected by back-projecting a predetermined unit vector on the projection plane onto the polygon plane formed by the polygon information, and the back-projected unit vector is further assigned to the position information assigned together with the texture information. If the magnitude of the unit vector projected onto the texture surface formed by the above is larger than a predetermined value, the texture information of the second resolution is selected; otherwise, the first texture information is selected. 3. The image synthesizing method according to claim 1, wherein the image synthesizing method is performed by selecting texture information of the resolution.