JP3285142B2 - Embossed sheet, decorative sheet and method for producing line pattern, apparatus therefor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention expresses a glossy pattern called "shine" or "moku" of a natural wood grain on a decorative sheet of a building material having a wood grain pattern (hereinafter simply referred to as a decorative sheet). The present invention relates to a process for forming a concavo-convex pattern of a line pattern composed of a large number of wavy curves, and in particular, a method of forming a line pattern for performing such embossing, an apparatus therefor, and the like. The present invention relates to an embossed sheet and a decorative sheet in which a line pattern is embossed as an uneven pattern.

[0002]

2. Description of the Related Art A woodgrain pattern is the most popular motif used as a surface decoration of building materials such as wallpaper and flooring, and a surface decoration of furniture. When a decorative sheet having such a woodgrain pattern is created, a method is usually employed in which a natural wood surface is photographed with a camera or the like and the woodgrain pattern of the natural wood is used as it is. In recent years, computer-based image processing technology has become widespread in the printing field, so the grain pattern of a natural tree is captured as image data using a CCD camera or the like, and this image data must be processed using a computer. There is also widely used a method of performing image processing and performing printing based on the processed image data.

[0003] Recently, it has become difficult to obtain natural wood having a highly designed wood grain pattern, and it is possible to completely use a computer without using actual natural wood at all. Attempts have been made to create a wood grain pattern. For example, JP-A-8-22538
The publication discloses a method of defining a three-dimensional tree model in a three-dimensional space and cutting the three-dimensional tree model at a predetermined cutting plane to obtain a wood grain conduit cross-sectional pattern.

[0004] Generally, wood grain patterns found in natural trees are mainly composed of annual ring patterns, conduit groove patterns, illuminated patterns, and the like. The annual ring pattern is a dense and dense pattern of cell tissues formed according to the annual growth of a natural tree based on the temperature difference every year. The conduit groove pattern is a cross-sectional pattern obtained by cutting a fibrous conduit used as a passage for water and nutrients necessary for growing a natural tree, and usually has a somewhat distorted elliptical shape. On the other hand, the illuminated pattern is a glossy pattern generally called "illuminated" or "moku", and is a pattern generated based on light reflected from a material surface. On the surface of the natural wood, the orientation of the fibrous material differs from part to part, and the distribution of the orientation is observed as a shiny pattern. Since this is a pattern generated based on the reflection of light, different illuminated patterns appear depending on the incident direction of light from the light source and the observation direction by the observer even on the same material surface. That is, it can be said that the illuminated pattern is caused by anisotropic reflection from the fibrous material.

[0005] As described above, the illuminated pattern has a characteristic property that it changes depending on optical observation conditions. Therefore, in the case of an artificial building material in which a wood pattern is printed on a sheet of vinyl chloride or the like, It is difficult to express only by a normal printing layer. Therefore, embossing is applied to a decorative sheet printed with a wood grain pattern, or a laminated structure in which an embossed sheet is formed on a decorative sheet is adopted.
Techniques for expressing a shining pattern have been proposed. For example, Japanese Patent Application Laid-Open No. Hei 5-289302 discloses a method of expressing a shining pattern using a wood-like embossed sheet having a large number of linear grooves formed on the surface.
No. 948 discloses a technique for fusing the illuminated pattern on the wood-like embossed sheet with the annual ring pattern and the conduit groove pattern.

[0006]

The use of the wood-like textured embossed sheet using the linear grooves as described above makes it possible to express an illuminated pattern that changes according to the viewing direction. However, the conventionally proposed expression of the illuminated pattern by the parallel groove is merely a pseudo-expression, and cannot sufficiently reproduce the actual illuminated pattern obtained from the surface of the natural wood. For this reason, unnaturalness remains as compared with a natural illuminated pattern, resulting in an uncomfortable feeling for an observer.

Accordingly, the present invention provides a method of creating a line pattern capable of expressing a natural illuminated pattern closer to the surface of natural wood, an apparatus therefor, and such a line pattern embossed as an uneven pattern. It is an object to provide a processed embossed sheet and a decorative sheet.

[0008]

In order to achieve the above object, a line pattern forming method according to the present invention is a method for forming a line pattern for expressing a feeling of woodiness appearing on the surface of natural wood. At each point on a predetermined image forming surface, a fiber diving angle defining step of defining a fiber diving angle indicating the orientation of the fiber of the wood, and a given fiber diving angle is converted into a direction vector along the image forming surface. Defining a conversion formula to be converted, using this conversion formula, a direction vector generation step of converting the fiber dive angle defined at each point on the image forming surface into a direction vector, and A method for forming a line pattern that forms a line pattern along a vector, the method comprising: fluctuating the line pattern by applying a one-dimensional scalar field.

Further, the line pattern forming apparatus of the present invention comprises:
A line pattern creating apparatus for expressing a feeling of woodiness appearing on the surface of natural wood, comprising a vector field generating means for generating a three-dimensional vector field expressing the grain of natural wood, and a predetermined image forming surface, When the three-dimensional vector field is cut, the fiber diving angle is determined based on the orientation of the vector field at each point on the cut surface, and the fiber diving angle is defined at each point on the image forming surface. Calculating means for converting a given fiber dive angle defined at each point on the image forming surface into a direction vector based on a predetermined conversion formula for converting a given fiber dive angle into a direction vector along the image forming surface. And a direction vector calculating means for converting a line pattern having a predetermined width on the created image and arranged along the direction vector, and generating a binary image pattern composed of these line patterns. And a one-dimensional scalar field generating means for generating a one-dimensional scalar field, and a one-dimensional scalar field generated by the one-dimensional scalar field generating means acting on the line pattern. Pattern deformation means for causing the line pattern to fluctuate.

Further, the embossed sheet of the present invention is an embossed sheet in which a large number of line patterns for expressing a woody appearance appearing on the surface of natural wood are embossed into an uneven pattern. It has a directional component corresponding to the fiber dive angle indicating the orientation of the fiber of the wood, and is further characterized by being fluctuated by a one-dimensional scalar field.

Still further, the decorative sheet of the present invention is a decorative sheet in which a number of line patterns for expressing a woody appearance appearing on the surface of natural wood are embossed into a concavo-convex pattern on a sheet printed with a grain pattern. Wherein the parallel line pattern has a directional component corresponding to a fiber diving angle indicating the orientation of the fiber of the wood, and is further fluctuated by a one-dimensional scalar field.

[0012]

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

[1] Essence of shining pattern appearing on the surface of natural wood The main point of the present invention is to apply a natural shining pattern appearing on the surface of natural wood using an embossed sheet or by directly embossing. It is to reproduce artificially. Therefore, first, the essence of the shining pattern that appears on the surface of natural wood will be described.

As described above, a typical natural wood surface has an annual ring pattern, a conduit groove pattern, and an illuminated pattern. Here, the illumination pattern is a unique pattern that changes depending on the angle of the incident light and the observation direction, and is generally called “illumination” or “moku”. For example, when observing a timber board cut out of a natural tree from a certain direction, the shaded area in FIG. 1A appears to be whitish, and when the observation direction is slightly changed, the area shown in FIG. Other areas look whitish, like the shaded area. The reason why the illuminated pattern changes depending on the observation angle is that the orientation of the fibrous material differs from part to part on the surface of the natural wood. Various elements such as cells, conduits, and fibers are included in the interior of a natural tree in order to perform as a plant, and these elements are generally oriented in the direction of tree growth. Here, such an axial element along the growth direction of the tree is collectively referred to as fibrous material.

Thus, the orientation of the fibrous material of natural wood is
Although the whole is oriented in the growth direction of the tree, the orientation is often partially varied. Such an orientation is generally called “grain”, and is called by a name such as a wavy grain, a spiral grain, or a cross grain, depending on the orientation state. For example, assuming that the actual growth direction of the natural tree is the direction of the reference axis A, the fiber inside the natural tree as a whole extends in the direction along the reference axis A, but partially varies in its orientation. Has occurred. Such partial variation in orientation is recognized as a shining pattern on the material surface.

Here, a reference fiber bundle model as shown in FIG. 2 is considered so that the concept of “grain” can be visually grasped. The model shown here shows the orientation of axial elements such as conduits and fibers in a tree as a bundle of many elongated cylindrical fibers, and shows the direction of the flow of the fibrous material that makes up the tree. It is. Of course, actual natural wood is not composed of such a simple bundle of cylindrical fibers, but contains many elements such as cells, conduits, and fibers.
Here, a cylindrical fiber bundle model is used as a model showing the orientation of the axial elements of these many elements. Basically, as shown in FIG. 2, the orientation of the fiber bundle is along the reference axis A oriented in the growth direction, and all the individual fibers should be arranged parallel to the reference axis A. is there. That is, considering the positional relationship between a point of interest P on a certain fiber and an adjacent point Q on the same fiber, a vector from the point P to the point Q (hereinafter, referred to as a fiber direction vector) is It will be oriented. However, in trees growing in the natural world, there are many phenomena in which the orientation is partially different during the growth process, and such a variation in orientation appears as “grain”.

For example, as shown on the left side of FIG. 3, a direction perpendicular to the reference axis A is defined as B, and a component indicating the direction along the reference axis A is partially added with a component in the B direction. Fiber direction vector F1 → (from the restriction of electronic application,
In the specification of the present application, a vector symbol “→” which is originally added to the upper part of the code is defined to the right of the code). Then, each fiber has the fiber direction vector F
When the reference fiber bundle model shown in FIG. 2 is distorted so as to face in the direction along 1 →, a distorted fiber bundle model as shown on the right side of FIG. 3 is obtained. Points P and Q in the model of FIG.
Is displaced to points P ′ and Q ′ in the model of FIG. 3, and the vector from point P ′ to point Q ′ is the point P ′
(Or the fiber direction vector F at the position of the point P ′)
1 → Such a distorted fiber bundle model is a model including a grain generally called a wavy grain.

Further, as shown on the left side of FIG.
Is defined as a fiber direction vector F2 → which spirals around the circumference of the reference fiber bundle, and the reference fiber bundle model shown in FIG. 2 is distorted so that the individual fibers are directed along the fiber direction vector F2 →. Is obtained as shown on the right side of FIG. Points P and Q in the model of FIG. 2 are displaced to points P ′ and Q ′ in the model of FIG. 4, respectively, and a vector from point P ′ to point Q ′ is point P (or point P ′). Is the fiber direction vector F2 → at the position.
Such a distorted fiber bundle model is a model including a grain generally called spiral grain.

Next, the relationship between the orientation of the fibrous material and the illuminated pattern will be considered. Now, a reference fiber bundle model as shown in FIG. 2, that is, a model in which the fiber orientation is all along the reference axis A, is cut along a cutting plane J perpendicular to the reference axis A as shown in FIG. The specular reflected light intensity (glossiness) of the cut surface J will be compared between the case and the case where the cut surface J is cut along the cut surface J parallel to the reference axis A as shown in FIG. Generally, FIG.
As shown in FIG. 6, a cut surface that appears when a natural tree is cut along a cutting surface perpendicular to the growth direction of the tree (the direction of the reference axis A) is called a “kiguchi surface”, as shown in FIG. The cut surface that appears when a natural tree is cut along a cut surface parallel to the tree growth direction (the direction of the reference axis A) is called a “straight grain surface”. More precisely, the `` straight grain plane '' refers to a cut surface particularly when cut along a plane passing through the central axis, and when the cut plane is parallel to the growth direction, but deviated from the central axis, Although these are referred to as "grain faces," they are collectively referred to herein as "grain faces."

When cutting is performed by using a “wooden surface” as shown in FIG. 5, each fiber has an orientation such that it dives perpendicularly to the surface of the timber plate, and the irradiated light is applied to the timber plate. It is easily absorbed inside and hardly comes out. Therefore, the surface has a low specular reflectance, and has no glossiness. On the other hand, "Straight face" as shown in Fig. 6
When cutting is performed, the individual fibers have an orientation that lays horizontally on the timber board surface, and most of the irradiated light is reflected on the surface without penetrating into the interior of the timber board Will be. Therefore, the specular reflectance of the surface is high,
It becomes a glossy surface. It goes without saying that the glossiness seen by the observer is determined not only based on the specular reflectance of the surface but also based on the direction of the light source and the observation direction.

FIG. 7 is a diagram for explaining the relationship between the fiber orientation on the surface of the timber board and the specular reflectance. Now, timber board 1
In the figure, the fiber direction vector F →
It is assumed that the fibers F are arranged with an orientation as shown in FIG. At this time, the angle ξ between the cut surface J and the fiber F is called a fiber dive angle. "Kiguchi surface" shown in Fig. 5
In the case of cutting by the, the fiber diving angle ξ = 90 °, and in the case of the cutting by the “straight grain surface” shown in FIG.
Becomes

Here, a virtual light source 200 (surface light source) is assumed above the timber board 100, and the virtual light source 200
A light beam perpendicular to the surface (cut surface J) of the timber board 100 is radiated, and a simple case of observing diffuse reflection light and specular reflection light from this surface is considered. In this case, the intensity of the observed diffuse reflected light depends on the color component of the grain pattern on the surface of the timber board 100, and the image based on the diffuse reflected light is recognized as a so-called colored pattern. On the other hand, the intensity W (glossiness) of the observed specular reflected light
Depends on the fiber descent angle 、, and usually has a relationship as shown in the graph of FIG. More precisely, the specular reflected light intensity in each part is determined by both the light irradiation direction and the fiber descent angle ξ. That is, as shown in FIG. 7, if a ray direction vector L → and a fiber direction vector F → are defined as shown in FIG. 7 at a point P on the cut plane J, the mirror surface at the point P is determined by the intersection angle φ of both vectors. The reflected light intensity will be determined. In the case of the model in which the ray direction vector L → is perpendicular to the cutting plane J as in the above example,
The vector crossing angle φ = 90 ° −ξ, and as shown in the graph of FIG. 8, the intensity of the specular reflected light becomes maximum when φ = 90 ° and becomes minimum when φ = 0 °. In the case of cutting by the “cut surface” shown in FIG. 5, the fiber diving angle ξ = 90 °, so that the specular reflected light intensity W becomes small and the glossiness is reduced.
Conversely, in the case of cutting with the “straight grain surface” shown in FIG. 6, the fiber diving angle ξ = 0 °, so that the specular reflected light intensity W increases and the glossiness increases.

When the reference fiber bundle model as shown in FIG. 2 is cut in a plane, the magnitude of the glossiness of the entire cut surface depends on the cutting direction. Since it does not occur, a so-called shimmer pattern does not occur. The illuminated pattern is seen on the surface of the timber board cut from the actual natural wood because the actual natural wood contains a grain element as shown in FIG. 3 or FIG. In this way, when a tree containing a grain element is cut, a different fiber dive angle 得 is obtained for each part on the cut surface, and the shine pattern is determined based on the different fiber dive angle ξ for each part. Will appear. However, the change in fiber orientation based on the grain of natural wood is a gradual change with natural fluctuations. Become a loose thing with. In short, on natural wood,
There is a “unique flow of fibrous material” due to grain, and if the flow of fibrous material changes partially, the intensity of the specularly reflected light also changes as described above. That is, a so-called “shining pattern” appears.

[2] Approach to Illumination Pattern Reproduction According to the Present Invention As described above, the essence of the illumination pattern appearing on the surface of natural wood lies in the distribution of the fiber diving angle に based on the grain, and the fiber diving angle ξ Are almost the same at certain viewing conditions. Therefore, in order to reproduce the illuminated pattern of a natural tree with exactly the same principle, it is necessary to physically reproduce a fibrous structure having various fiber diving angles に on the surface of the sheet to be embossed. However, it is not realistic with current embossing technology to incorporate complex steps to reproduce such real fibrous structures into commercial building material manufacturing processes. At present, a commonly used method of manufacturing an embossing plate is a method called a direct etching method, and a two-step step structure of a concave portion and a convex portion is formed on the embossing plate created by this method. It is just done. If the direct etching method is repeated several times, a multi-stage structure can be obtained, but it is impossible to physically reproduce a fibrous structure having various fiber diving angles ξ.

The basic concept of the present invention is to replace the element of the fiber diving angle 現 れ る appearing on the surface of the actual natural wood with the direction of the parallel groove on the sheet to be embossed, thereby forming a large number of linear grooves. It is in expressing a shining pattern. In general, a pattern composed of many fine lines is called a line pattern. In the present invention, since this line pattern is formed as a line groove having an uneven structure on a sheet such as a decorative sheet. is there.

FIG. 9 is a perspective view showing the basic structure of the linear groove G formed on the sheet E. In this example, the width W1
Are formed at intervals of W2. The linear groove G has a depth D2 with respect to the entire thickness D1 of the sheet E.
Are formed, and a large number of linear grooves G are arranged substantially in parallel. Such a pattern formed by the linear groove G has a two-step structure of a concave portion having a width W1 and a convex portion having a width W2, and can be easily formed using a conventional general direct etching method. Can be configured.

It is known that the sheet E on which such linear grooves G are formed performs so-called anisotropic reflection, in which the intensity of reflected light obtained from the surface varies depending on the observation direction. FIG. 10A shows a cross section of the sheet E cut along a plane parallel to the line groove G, and FIG. 10B shows a cross section cut along a plane perpendicular to the line groove G. As shown in FIG. 10A, light incident from a direction parallel to the line groove G is reflected at the bottom surface of the line groove G and is directed in the direction along the line groove G as it is. And emitted as specularly reflected light. On the other hand, as shown in FIG. 10B, the light incident from the direction perpendicular to the linear groove G is reflected many times on the wall surface and the bottom surface of the linear groove G, and finally reflected. Emitted as diffusely reflected light in different directions. For this reason, when observed from a direction parallel to the line groove G, strong specular reflected light is obtained, but when observed from a direction perpendicular to the line groove G, the specular reflected light is weakened.

By utilizing such a property of the linear groove G, it is possible to express the illuminated pattern in a pseudo manner. For example, as shown in the plan view of FIG. 11, the linear groove G is formed over the entire surface of the sheet E, and the direction of the linear groove G in a certain partial area is changed. For example, the intensity of specular reflected light obtained from this partial area is different from the intensity of specular reflected light obtained from other partial areas, and a so-called illuminated pattern is observed.
At this time, whether the intensity of the specular reflected light is increased or decreased depends on the observation direction, as described above. Therefore, such an embossed sheet E is made of a transparent material, and as shown in FIG. 12, the embossed sheet E is laminated on a print sheet S on which a wood pattern is printed, such as a wallpaper or a floor material. By constructing building materials,
A wood grain pattern building material having a shining pattern can be obtained. Further, such a linear groove G may be directly embossed on a sheet on which a grain pattern is printed.

However, as described above, the technique itself for expressing the illuminated pattern by using the embossed sheet E having such a linear groove G as a building material is disclosed in Japanese Patent Laid-Open No. 5-28930.
No. 2 and JP-A-8-323948. However, in the conventional method, for example, a wavy line groove based on a sine wave is formed, or a plurality of closed regions are defined for convenience, and a line groove having a predetermined direction is defined for each closed region. Therefore, it was difficult to sufficiently reproduce the illuminated pattern having the natural texture seen on the surface of the actual natural wood.

A feature of the present invention is that, based on the essence of the illuminated pattern appearing on the surface of the natural wood described in [1], a similar illuminated pattern is pseudo-expressed by the parallel line grooves. .
The shining pattern appearing on the surface of the natural wood is based on the distribution of the fiber dive angle ξ, whereas the shining pattern appearing on the embossed sheet having the line groove is on the plane of the line groove. This is based on the distribution of directions (direction vectors). In the former, a region in which the fiber diving angle ほ ぼ is almost equal can be seen simultaneously glowing whitish in a certain state, whereas in the latter, a region in which the direction vector of the linear groove is almost equal is in a certain state. At the same time, you can see it glow whitish. Originally fiber dive angleξ
Is defined as the angle of intersection between the plane and the fiber vector F →, as shown in FIG. 7, whereas the direction vector of the parallel groove indicates the direction of the parallel groove on the plane. It is shown. Therefore, although the fiber divergence angle ξ and the direction vector of the linear groove are theoretically completely different physical quantities, both have the common feature that they both function as parameters governing the reflected light intensity during observation. . The present inventor paid attention to this common point, and linked the element of the fiber dip angle 現 れ る appearing on the surface of the actual natural wood to the element of the direction vector of the linear groove, thereby giving a shining pattern closer to the natural wood. I came up with the expression.

[3] Method of Creating Line Pattern According to the Present Invention Next, with reference to the flowchart of FIG. 13A, a basic procedure of a method of forming a line pattern capable of expressing a woody texture according to the present invention. Will be described. First, in step S10, a fiber dive angle is defined. That is, first, a predetermined image forming surface is defined, and at each point on the image forming surface, a fiber diving angle を indicating the orientation of the fiber of the wood is defined. The concept is shown in FIG. FIG. 13B shows a state in which an angle す between a fiber vector F → and the image forming surface J at a point P on the image forming surface J is defined as a fiber diving angle.
In step S10, a predetermined fiber diving angle ξ is defined for each point on the image forming surface J. However, in practice, as described in [4] later, since the final line pattern is constituted by individual pixels, a finite number of points are defined on the image forming surface J, and The fiber descent angle ξ may be defined for each point.

Hereinafter, a specific method for defining the fiber descent angle ξ will be described. A method considered by the present inventor to be the most preferred embodiment is to define a three-dimensional vector field in which the orientation with respect to a predetermined reference axis differs from part to part, cut this three-dimensional vector field at an image forming plane, and cut the plane. This is a method for defining the fiber descent angle based on the orientation of the vector field at each point above. For example, assuming that a distorted fiber bundle model expressing a wavy grain as shown in FIG. 14 is generated and this model is cut along a predetermined cutting plane J (in this example, a kiguchi face), as shown in FIG. The fiber vector F → can be obtained for an arbitrary point P on the cut surface J. Here, the fiber vector F → is a vector indicating the direction of the fiber located at the point P among the fibers constituting the distorted fiber bundle model shown in FIG. When such a fiber vector F → is obtained, an angle ξ formed by the cut surface J and the fiber vector F → is obtained, and this angle ξ is a fiber dive angle at the point P. Assuming that the cut surface J is an image forming surface, a predetermined fiber diving angle そ れ ぞ れ can be defined for each point on the image forming surface.

The distorted fiber bundle model shown in FIG. 14 is obtained by distorting the reference fiber bundle model shown in FIG. 2 along the fiber vector F1 → shown on the left side of FIG. The essence is nothing but a three-dimensional vector field. This three-dimensional vector field can be defined using a predetermined equation. For example, in the XYZ three-dimensional coordinate system, the position of each point constituting the reference fiber bundle model as shown in FIG. 2 is defined by coordinate values (x, y, z), and x ′ = x + α · sin (β · z) New coordinate values (x ′, y ′, z ′) are obtained based on a conversion formula (α and β are predetermined constants, random numbers or functions) of y ′ = y z ′ = z, and coordinate values ( If a point located at (x, y, z) is moved to a new coordinate value (x ', y', z '), a wave tree as shown in FIG. A logically distorted fiber bundle model is formed. Here, if two points P and Q arranged along the reference axis A in the model of FIG. 2 move to points P ′ and Q ′ respectively in the model of FIG. Can be defined, for example, as the direction of the vector field at point P '. In other words, a three-dimensional vector field corresponding to a wavy grain as shown in FIG. 3 can be defined by the above conversion equation. Similarly, a three-dimensional vector field corresponding to a spiral grain as shown in FIG. 4 is obtained by: x ′ = r · cos (θ ₀ + θ) y ′ = r where θ ₀ and β are predetermined constants, random numbers or functions. Sin (θ ₀ + θ) z ′ = z where r = (x2 + y2) 1/2 θ = β · z

After all, in the process of defining the fiber diving angle in step S10, a three-dimensional vector field is defined using the above-described coordinate conversion formula and the like, and a predetermined cutting plane J (image forming plane) is included in the three-dimensional vector field. Is defined, and for each position on the cutting plane J, the angle ξ formed by the vector and the cutting plane can be calculated. In other words, this method can be said to be a process of constructing a three-dimensional virtual tree model having a grain element in a computer, and calculating a fiber dive angle when this is cut at a virtual cutting plane.

Of course, instead of using a virtual tree model,
It is also possible to define the fiber dive angle using actual natural wood. That is, using a measurement system that can measure the intensity of the reflected light from each point on the surface of the natural wood, measure the reflected light intensity from each point when this natural wood is observed from various angles, Based on this measurement result, the fiber dive angle at each point on the natural wood surface is calculated by calculation. For example, as shown in FIG. 16, a natural wood T is prepared, a predetermined point P is observed from various directions such as observation directions O1, O2, O3,..., And the reflected light intensity in each case is obtained. [1]
As described above, since there is a predetermined correlation between the fiber diving angle ξ at the point P and the reflected light intensity in each observation direction, if the number of observation directions is increased to some extent, the reflected light in each observation direction can be increased. By analyzing the strength results, the point P
Can be determined with a certain degree of accuracy. As described above, it is also possible to define the fiber diving angle in step S10 by actually measuring the reflected light intensity on the surface of the natural wood.

However, this method of measuring the reflected light intensity of a natural tree to define the fiber dive angle requires a heavy work load at the stage of measuring the reflected light intensity, and analyzes the measurement results to determine the fiber dive angle. Since the computational burden for determining is also heavy, the above-described method of defining a three-dimensional vector field is more practical for commercial use for manufacturing building materials and the like.

After defining the fiber diving angle 各 for each point on the image forming surface in this way, subsequently, in step S20, a direction vector is generated for each point on the image forming surface. For that purpose, first, it is necessary to define a conversion formula for converting the given fiber diving angle ξ into a direction vector along the image forming surface J. The concept is shown in FIG. In this figure, the position of a point P on the image forming surface J is
Is defined as the direction vector V →. Here, this direction vector V → is represented by each θ formed by the reference line R defined on the image forming surface J, and the function of θ = f (ξ) is used as a conversion formula, and the fiber diving angle ξ Into an angle θ. By using such a conversion formula, all the fiber submergence angles 定義 defined in step S10 can be converted into angles θ, and a predetermined direction vector V → is defined at each point on the image forming surface. be able to.

FIG. 17 is a graph showing an example of a conversion formula for converting the fiber descent angle ξ into the angle θ. In this example, linear conversion is performed using a conversion formula of θ = 90 ° + ξ. That is, for the fiber descent angle ξ = −90 °, the angle θ =
0 °, the angle θ for the fiber dive angle ξ = 0 °
= 90 °, and for the fiber dive angle ξ = 90 °, the angle θ = 180 °. Of course, ξ and θ in the present invention
The conversion equation between is not limited to the conversion equation shown in the graph of FIG. 17, and any conversion equation may be used as long as a certain θ is determined for a predetermined ξ. However, in order to obtain a more effective illuminated pattern, it has been confirmed that it is preferable to use a conversion formula in which the angle θ monotonically increases or monotonically decreases with respect to an increase in the fiber descent angle ξ.

FIGS. 18 and 19 are diagrams showing a specific example of a process for converting the fiber descent angle に into the angle θ using the conversion formula shown in the graph of FIG. As shown in the perspective view of FIG. 18, predetermined points P1, P2, P on the cut surface J (image forming surface)
3 includes fiber vectors F1 →, F2 →, at each position.
As an angle formed by F3 → (vector of each point in the three-dimensional vector field) and the cut surface J, a fiber diving angle ξ1 =
60 °, ξ2 = 0 °, and ξ3 = -30 ° are defined. In this case, using the conversion formula of θ = 90 ° + ξ, as shown in the plan view of FIG.
Direction vector V1 included in cutting plane J (image forming plane)
→, V2 →, V3 → are defined. here,
When a reference line R is defined on one section of the cut surface J, angles formed by the direction vectors V1 →, V2 →, V3 → and the reference line R are θ1 = 150 °, θ2 = 90 °, θ3 = 60 °, respectively. .

In this specific example, the predetermined points P1, P2, P3
Although an example of the three points has been shown, in actuality, as described later in [4], a pixel array is defined at a predetermined resolution on the cutting plane J, and individual pixel positions, for example, the center position of each pixel are defined. Will be performed for a finite number of points corresponding to. Since the fiber descent angle ξ is in the range of −90 ° ≦ ξ ≦ 90 °, for example, as in this example, θ = 90 ° + ξ
When the conversion using the conversion formula is performed, the angle θ is 0 ° ≦ θ
≦ 180 °, and with reference to the reference line R shown in FIG. 19, the direction vector V → is divided into the right direction (when θ = 0 °) and the left direction (θ = 180 °) in the figure. Case)
, Including the critical direction of. The range of the direction to be taken by the direction vector V → can be controlled depending on the conversion formula to be defined. For example, if the conversion formula of θ = 90 ° + ξ / 2 is defined, the angle θ
Is in the range of 45 ° ≦ θ ≦ 135 °.

When the direction vector V → can be defined at each point (individual pixel position) on the cutting plane (image forming plane) J, a line pattern along each direction vector is formed in step S30. You. The concept is shown in FIG.
(D). This figure shows a state in which a line M is formed at the point P along the direction vector V →.

By the direction vector V → defined at each point on the image forming surface J, a two-dimensional vector field is formed on this surface. In the line pattern forming step of step S30, a process of forming a large number of lines along the two-dimensional vector field is performed. The specific processing procedure will be described in [4].

After the line pattern is formed in this manner, an embossed plate expressing the line pattern as a concavo-convex pattern is prepared, and a sheet made of a transparent material is embossed with the embossed plate to form an embossed sheet. What is necessary is just to create or to emboss directly on the decorative sheet which printed the wood grain pattern. In step S30,
If a line pattern is prepared as a binary image pattern, an embossing plate is created by a conventional general direct etching method based on the binary image pattern, and the wood-like texture embossing is performed using the embossing plate. Sheets can be mass-produced. FIG. 13E shows a side cross section of the embossed sheet thus formed.

By such a process, the embossed sheet E made of a transparent material is mass-produced.
Is laminated on a wood-grained printed sheet S as shown in FIG. 12 to form a building material, or if a decorative sheet on which a woodgrained pattern is printed is directly embossed, a natural wood-like natural wood surface is obtained. A building material with an illuminated pattern is obtained. That is,
When observed from a specific direction, a region in which the direction vectors of the embossed linear grooves are almost equal simultaneously glows whitish, and a glossy region is observed. This glossy area changes when the viewing direction is changed. In addition, since the direction vector of each linear groove is determined based on the fiber dive angle ξ, a natural shining pattern close to the surface of the natural wood is observed.

In the case where an artificial pattern generated by a computer is used as the woodgrain pattern printed on the print sheet S shown in FIG. 12, the woodgrain pattern on the print sheet S and the woody texture The line pattern on the embossed sheet E is preferably formed by computer image processing using the same three-dimensional vector field. For example, Japanese Patent Application Laid-Open No. H8-22538 discloses a three-dimensional tree model defined in a three-dimensional virtual space in a computer.
A method of artificially generating a grain pattern based on a two-dimensional pattern obtained on a cut surface when the three-dimensional tree model is cut at a predetermined cut surface is disclosed.
In the specification of Japanese Patent Application No. 8-168504, a three-dimensional tree model considering grain is defined by using a three-dimensional vector field, and the three-dimensional tree model considering the grain is cut. A technique for artificially generating a two-dimensional wood pattern including a grain element is disclosed. As described above, when the grain pattern on the print sheet S is artificially generated using the three-dimensional vector field, the line pattern on the embossed sheet E is also generated using the same three-dimensional vector field. It is preferably generated. As already mentioned,
Using a three-dimensional vector field, it is possible to add an element of distortion based on grain to a three-dimensional tree model. However, using the same three-dimensional vector field, a grain pattern on a print sheet S and an emboss sheet If the parallel line pattern on E is formed, the grain component included in the grain pattern on the print sheet S and the grain component included in the shimmer pattern on the embossed sheet E match. This is because, as a result, it is possible to express a natural wood-like texture as a whole, in which the illumination pattern and the grain pattern are synchronized.
The same applies to the case where embossing is directly performed on a decorative sheet on which a grain pattern is printed.

[4] Specific Procedure of Line Pattern Formation Process Here, a specific method of the line pattern formation step shown as step S30 in the flowchart of FIG. 13 will be described. FIG. 20 is a flowchart showing the specific procedure.
First, in step S31, the size of a created image for drawing a line pattern is set, and the pixel values of all the pixels of the created image are set to 0. Here, the width is w (hereinafter, referred to as x direction), and the height is h (hereinafter, referred to as y direction).
And This size may be the same size as the image forming surface described above, but may be a different size. However, since the position of the image forming surface and the position of the created image need to correspond one-to-one, when the sizes of the two are different, the sizes of the two are normalized to normalize the size of the two. What is necessary is just to take one correspondence. In the following, it is assumed that the position of the image forming surface and the position of the created image have a one-to-one correspondence.

As described above, a predetermined direction vector V → is defined for each point on the image forming surface.
The direction vector V (i, j) defined at the position (i, j) on the image forming surface can be associated with the pixel P (i, j) at an arbitrary position in the created image. As described above, in the method described here, it is sufficient to define a direction vector for each pixel on the image forming surface.
The fiber diving angle す べ き to be defined in step S10 of (a),
It is sufficient that the direction vector V → (angle θ) to be defined in step S20 is obtained only for the center point position of each pixel.

In the next step S32, on the first row of the pixel array, the positions of the representative pixels for forming the lines are defined, and a group of pixels arranged continuously near each representative pixel is formed. Processing for defining each pixel band is performed. At this time, the pixel value 1 is written to the representative pixel and the pixels in the pixel band. The number of representative pixels and the arrangement of the representative pixels in the first row are arbitrary, but a plurality of representative pixels may be defined at predetermined intervals.

FIG. 21 shows an example. FIG. 21 shows a state where representative pixels R11 and R12 are defined from among a number of pixels arranged in the first row of the created image. In the example of this figure, the pixel P (1, 7) in the seventh column is defined as the first representative pixel R11, and the pixels P (1, 17) and the pixels P (1, 27) appearing at a 10-pixel pitch are hereinafter described. , Pixel P (1,3
7) are defined as representative pixels R12, R13, R14,. Then, a pixel band is defined near each of the representative pixels. For example, FIG. 22 shows a state in which pixel bands H11, H12,... Composed of a total of five pixels including two pixels each adjacent to the left and right of each representative pixel are defined.
In this embodiment, the setting is made such that the pixel band is always constituted by a pixel group consisting of all five pixels centered on the representative pixel. Of course, as long as each pixel band is composed of a plurality of pixels arranged continuously, it may be composed of any number of pixels. For example, an individual pixel band may be constituted by all seven pixels, or an individual pixel band may be constituted by all eight pixels. Here, the pixels forming the pixel band are indicated by hatching inside, and particularly, the representative pixels are indicated by black circles at the center.

In the next step S33, a parameter y indicating the number of rows in the pixel array of the created image is set to an initial value of 1, and
Hereinafter, the processes of steps S34 and S35 are repeatedly executed. That is, in step S36, the parameter y =
Until it is determined that n-1 (where n is the total number of rows), the parameter y is updated one by one in step S37, and the processes in steps S34 and S35 are repeated.

In step S34, for each representative pixel on the y-th row, the pixel on the (y + 1) -th row located in the direction indicated by the direction vector defined at a point in each of the representative pixels is determined. Are defined as the representative pixels in the (y + 1) -th row, and a process of defining a pixel band composed of a group of pixels arranged continuously in the vicinity of the representative pixels in the (y + 1) -th row is executed. For example, when y = 1, as shown in FIG. 23, the representative pixels R11 and R1 in the first row
, The representative pixels R21, R2 in the second row
Are determined, and as shown in FIG. 24, pixel bands H21, H22,... In the second row are defined based on the representative pixels R21, R22 in the second row. The representative pixels R21 and R22 in the second row are, as shown in FIG.
The determination is made based on the direction vectors V11 →, V12 → defined for the representative pixels R11, R12 in the first row. Specifically, among the pixels in the second row, the pixel having the center point closest to the direction vector V11 → is the representative pixel R
The pixel having the center point closest to the direction vector V12 → is similarly selected as the representative pixel R22. Further, the pixel bands H21 and H22 in the second row are:
In this example, it is defined as a pixel band composed of a total of five pixels including two pixels adjacent to the left and right of each of the representative pixels R21 and R22. At this time, it is natural that the pixel value 1 is written to the defined representative pixel and the pixel of the pixel band.

As described above, when the representative pixel and the pixel band in the second row are defined in step S34, an adjustment process is performed in the following step S35. This adjustment processing will be described later. Subsequently, steps S36 and S37
Is updated to y = 2, and the process of step S34 is executed again. This time, the direction vector V2 defined for the representative pixels R21, R22,.
1 →, V22 →, the representative pixel R3 in the third row
, R32,... Are determined, and these representative pixels R31, R
32, the pixel bands H31, H32,.
Is defined. By repeating the above processing until y = n−1, for example, the lines M1 and M shown in FIG.
2,... Are formed. Eventually, the above-described repetitive processing is processing of extending individual lines to the lower side of the figure.

The feature of the line obtained in this way is that it has a flow along the direction vector defined for each pixel, and the flow indicated by the line is
This shows the flow of the direction vector defined in step S20.

In order to form a line expressing the flow of the direction vector with higher accuracy, it is preferable to connect the start point of the direction vector to the end point of the direction vector of the previous row. For example, as shown in FIG. 26, when a point Qa in the representative pixel Ra in the a-th row is set as a starting point and a direction vector Va → defined for this pixel is considered, the direction vector Va → and the The intersection Qb with the center line (indicated by a dashed line in the figure) is the end point of the direction vector Va →.
Then, based on the representative pixel Rb in the b-th row, the c-th
When obtaining the representative pixel Rc of the row, the direction vector Va
The end point of → is set as the start point of the direction vector Vb → defined for the representative pixel Rb. Then, an intersection Qc between the direction vector Vb → and the center line of the c-th row (indicated by a dashed line in the figure) may be set as the end point of the direction vector Vb →. Of course, a method in which the center point of each representative pixel is always set as the start point of the direction vector can be adopted. However, as shown in FIG.
The flow of the dimensional vector field can be expressed more faithfully as the flow of the line.

When a parallel line is formed by the method shown in the flowchart of FIG. 20A, the value of the angle θ defined in step S20 in the flowchart of FIG.
It is necessary to keep 0 ° ≦ θ ≦ 180 °. With this setting, the lines extend from the top to the bottom of the figure. If the representative pixel on the (i + 1) -th row cannot be determined based on the representative pixel on the i-th row (for example, when θ = 0 ° or θ = 180 °), the (i + 1) -th row
In the (+1) th row, neither the representative pixel nor the pixel band is defined, and the pixel band in the i-th row is set as the end of the line.

The method of defining a representative pixel at the center position of each pixel band has been described above. However, it is not always necessary to configure a pixel band so that the representative pixel is located at the center. Each pixel band can be constituted by a total of 5 pixels including 4 pixels. Alternatively, it is also possible to adopt a method in which one pixel band is defined by two representative pixels. For example, it is also possible to adopt a method in which the left end pixel and the right end pixel of one pixel band are each set as a representative pixel, and a portion sandwiched between both representative pixels is always set as a pixel band.

Next, the adjustment processing shown as step S35 in FIG. 20 will be described. The first purpose of this adjustment process is to generate a new line. For example, as shown in FIG. 27, when the two lines M1 and M2 are gradually extended downward in the figure, the lines M1 and M2
Is gradually increasing. In such a case, if left as it is, a large void region is generated between the two lines M1 and M2, which is not preferable. Therefore, it is preferable to perform an adjustment process for generating a new line M3 between the two lines M1 and M2 as shown in the figure. The second purpose of the adjustment processing in step S35 is as follows.
To terminate a line between a pair of lines approaching each other. For example, as shown in FIG. 28, when the three lines M1, M2, and M3 are gradually extended downward in the figure, the distance between the two lines M1 and M3 is gradually reduced. Let's say In such a case, if left unattended, the three lines M1, M2, and M3 come into contact with each other, which is not preferable. Therefore, as shown in the figure, an adjustment process for terminating the central line M2 is performed.

Specifically, in step S35, the following check is performed on the (i + 1) -th pixel band generated in step S34, and an adjustment process may be performed as necessary. First, it is checked whether or not there is a pair of pixel bands spaced apart from each other by a predetermined reference or more. Then, when such a pixel band exists, a new representative pixel is defined between the pair of pixel bands, and an adjustment process for generating a new pixel band based on the new representative pixel is performed. In the example shown in FIG. 27, the predetermined reference is d1, and d1
1 = 11 pixels, and a pair of pixel bands M
In the twelfth row where the interval between 1 and M2 is equal to or longer than d1, a new representative pixel RR and a new pixel band including the same are generated, and a new line M3 is generated. Also, it is checked whether there is a pixel band in which the distance between the pixel band adjacent to the left side of the self and the pixel band adjacent to the right side of the self approaches a predetermined reference or less. And
If such a pixel band exists, an adjustment process for extinguishing the pixel band and its representative pixel is performed. In the example shown in FIG. 28, d2 is set to 10 pixels with d2 as a predetermined reference, and a pixel band M1 adjacent to the left of the pixel band M2 and a pixel band M3 adjacent to the right of the pixel band M2 are set. The pixel band and its representative pixel RR disappear on the eleventh row in which the interval of d is equal to or less than d2.

Next, a one-dimensional scalar field is generated (step S38). This one-dimensional scalar field is used in the next step S3
In step 9, the shape of each line created by the processing up to step S37 is deformed, but the shape of each line is deformed for the following reason.

The 2 created by the processing up to step S37
Naturally, it is possible to form irregularities on the cylinder for the embossing plate by, for example, a general direct etching method based on the line pattern of the values, but the embossing plate formed in this way embosses the transparent sheet. When embossed sheets are created by processing, or when embossing is applied directly to a decorative sheet printed with a wood grain pattern, the grain of wood can be expressed more realistically than before, but the sharpness of the grain is sharp. It was too glaring, and it was difficult to obtain a mild wood texture with natural grain.

As a result of various considerations, the present inventor has found that the reason is that the direction vectors of the lines formed by the above-described processing are too finely aligned. It has been found that if the direction vector of the line pattern is fluctuated by deformation, the sharpness of the light can be alleviated, and a line pattern that can express the gentle woody texture of natural wood grain can be obtained. That is, matting is performed by deforming the line pattern.

A one-dimensional scalar field is used for this purpose, and the one-dimensional scalar field is deformed by acting on each line pattern. Any one-dimensional scalar field may be used, but it is for deforming the line pattern, and it is desirable that the deformation has a natural fluctuation. It is better to use a fractal field. In order to generate a one-dimensional fractal field, for example, a midpoint displacement method may be used.

The size of the one-dimensional scalar field can be set arbitrarily. Also, the range may be any, but here, for ease of understanding, [-1,1]
Is assumed to be normalized to the range

After the one-dimensional scalar field is prepared in this way, the one-dimensional scalar field is applied to each line pattern and deformed (step S39). First, extract the single line pattern M _i in the line pattern created, FIG. 2
As shown in FIG. 9, the position of this line pattern in the y direction and 1
The position of the dimensional scalar field is made to correspond one-to-one. For this purpose, the lengths of both may be normalized. The position indicated by p of the line M _i now corresponds to the position indicated by q of the one-dimensional scalar field, and the scalar value at this position is H (q).
If, for example, the position of the representative pixel and the pixel band at the position p of the line pattern is moved by [k · H (q)]. Here, [kH (q)] is kH
The maximum integer value not exceeding (q) is taken. As for the moving direction, if k · H (q) is a positive value, the moving direction is to the right in the drawing, that is, the direction in which the x coordinate value increases,
If it is a negative value, it may be moved in the left direction of the figure, that is, in the direction in which the x coordinate value decreases. Further, k is a coefficient, and an appropriate value can be used. When the value range of the one-dimensional scalar field is normalized to the range of [-1,1] as in this case, k is Since the maximum width of the movement amount of the representative pixel and the pixel band, that is, the magnitude of the deformation is determined, it is desirable that the value is set to a relatively small value. This is because if the value of k is increased, the line pattern will be greatly deformed, and such a line pattern may not be able to express a calm wood texture with natural grain. As described above, since the deformation of the line pattern is only required to have a slight fluctuation in the direction vector, the value of k may be a relatively small value.

[0065] Figure 30 is a diagram showing an example of deformation of the line pattern, the representative pixel and pixel band positions p of the line pattern M _i is at as indicated by oblique lines in FIG. 30 (a), [ k
· H (q)] = 3 and k · H (q) is a positive value, the representative pixel and the pixel band are three pixels in the right direction of the figure as shown in FIG. Will only be moved.

[0066] The above processing is performed for all the positions of the line pattern M _i, When transformation processing of the line pattern M _i is completed, the deformation in the same manner for the other line pattern. If the deformation processing is performed on all the line patterns formed by the processing up to step S37 in this way, a line pattern having a matting effect can be obtained, and the gentle woody texture of natural grain can be expressed. It has been confirmed that a line pattern that can be obtained is obtained. The degree of matting can be easily controlled by the one-dimensional scalar field generated in step S38 or the coefficient k.

The above-described calculation for deforming the line pattern is only an example, and the calculation for determining the movement amount of the representative pixel and the pixel band is performed by using a one-dimensional scalar field or the like to be generated. Can be determined appropriately according to Further, in the above description, the same coefficient k is used when deforming all line patterns, but it is also possible to use different coefficients when deforming each line pattern. For this purpose, for example, in step S39, the coefficients may be determined by the number of line patterns. Alternatively, step S3
In step 9, one-dimensional scalar fields are generated by the number of line patterns, and the line patterns and the one-dimensional scalar fields are made to correspond to each other. It may be.

After all the line patterns have been deformed in this way, the adjustment process is performed again (step S40).
This adjustment processing is the same as the adjustment processing in step S35. Here, the adjustment process is performed again because, as a result of deforming the line pattern, a large void area may be generated between adjacent lines, or the adjacent lines may come into contact with each other. It is. When the adjustment process is completed, the line pattern forming process is completed, and a line pattern having a matting effect is obtained.

[5] Apparatus for Producing Wood-like Embossed Sheet Lastly, the configuration of the apparatus for producing an embossed sheet for expressing woody texture according to the present invention will be described with reference to the block diagram of FIG. This apparatus comprises a vector field generating means 10, a fiber boring angle calculating means 20, a direction vector calculating means 30, a pattern generating means 40, a pattern deforming means 41, a one-dimensional scalar field generating means 42, a printing plate means 50, an embossing means 6.
0. Vector field generating means 10
Is a means having a function of generating a three-dimensional vector field expressing the grain of a natural tree, and has, for example, a function of generating a three-dimensional vector field corresponding to a distorted fiber bundle model as shown in FIG. . Specifically, any means capable of storing an equation for indicating the fiber vector F1 → shown in FIG. 3 may be used.

The fiber traversing angle calculating means 20 determines whether the vector field generating means 10
When cutting a two-dimensional vector field, a component that calculates the fiber dive angle based on the orientation of the vector field at each point on this cut plane and performs an operation to define the fiber dive angle at each point on the image forming surface It is. Specifically, a geometric operation is performed based on an equation indicating a three-dimensional vector field stored in the vector field generating means 10 and an equation indicating an image forming surface, and each point on the image forming surface is calculated. (For example, points corresponding to the center position of each pixel, etc., which are required in later calculations), are components for performing the process of obtaining the fiber dive angle 潜.

The direction vector calculating means 30 stores a predetermined conversion formula for converting the given fiber dive angle ξ into a direction vector along the image forming surface, and based on the conversion formula, converts Is performed to convert the fiber descent angle ξ defined at each point into a direction vector. Specifically, the direction vector is represented by an angle θ formed with a predetermined reference line R. For example, if a conversion formula of θ = 2 · ξ is prepared, the fiber descent angle に defined at each point on the image forming surface is converted into the angle θ based on this conversion formula.

The pattern generation means 40 generates the
A line having a predetermined width and arranged along the direction vector obtained by the direction vector calculating means 30 is defined, and an operation for generating a binary image pattern composed of these lines is performed. The specific method of this arithmetic processing is as already described in the section [4].

The pattern deforming means 41 is a component for deforming each line pattern generated by the pattern generating means 40 by applying the one-dimensional scalar field generated by the one-dimensional scalar field generating means 42 to the line pattern. The specific method is as described above in [4].

The one-dimensional scalar field generating means 42 is for generating a one-dimensional scalar field which is an operator for deforming the parallel line pattern by the pattern deforming means 41. It consists of things to generate.

Each of the components of the vector field generating means 10, the fiber dive angle calculating means 20, the direction vector calculating means 30, the pattern generating means 40, the pattern deforming means 41, and the one-dimensional scalar field generating means 42 is a computer. Finally, the computer outputs image data indicating a parallel line pattern which is a binary image.

The printing plate means 50 is a means for producing an embossed plate having a concavo-convex pattern based on the binary image pattern output from the pattern deforming means 41.
For example, if an embossing plate is to be created using a general direct etching method, the binary image pattern output from the pattern deforming means 41 is printed on a mask, and photomasks such as exposure, development, and etching are performed using the mask. By the system for performing the lithography process,
The printing plate means 50 can be constituted. If an embossing plate is formed by using the direct etching method, an embossed structure having a two-price difference structure in which a line portion forms a convex portion or a concave portion can be obtained. Embossing means 60
Is an apparatus for mass-producing an embossed sheet using the embossing plate thus created. Finally, an embossed sheet having a two-price difference structure in which a line portion forms a concave portion or a convex portion is obtained. Can be

The line formed on the embossed sheet has an appropriate dimensional value for exhibiting the optical characteristics described in the section [2], that is, the characteristics of presenting different glossiness depending on the viewing direction. It is necessary to have In the embodiment shown here, the following conditions are set. First, the binary image pattern output from the pattern generation means 40 is constituted by a set of square pixels each having a side of 10 μm, and
In the parallel line forming procedure shown in FIG. 20, one pixel band is constituted by a total of nine pixels centered on the representative pixel. As a result, the width of one line is 90 μm.
In step S32 in FIG. 20, the size of the gap between the individual pixel bands is also set to be 90 μm for nine pixels, and a line / space pattern including a 90 μm wide line and a 90 μm wide space is used. Basically, line formation is performed.

It should be noted that the embossing means 60 may directly emboss the decorative sheet on which the grain pattern is printed using an embossing plate.

Although the embodiment of the present invention has been described above, the present invention is not limited to this embodiment.
The present invention can be implemented in various other modes. In particular, the specific numerical values shown in the above-described embodiment are presented as examples, and the present invention is not limited to these numerical values. Further, in the above-described embodiment, the present invention has been described as a method for expressing a wooden texture. However, the present invention provides a pattern having a texture equivalent to a wooden texture, for example, a stone including a fluid flow element. It can also be applied to eye patterns and the like.

In the above description, a one-dimensional scalar field is formed and then deformed by applying a one-dimensional scalar field. However, a one-dimensional scalar field is generated in advance in step S31 in FIG. When defining a representative pixel at the stage of steps 32 and S34, it is also possible to apply a one-dimensional scalar field to deform. In this case, since the length of each line pattern is not determined, for example, the position in the y direction of the created image, that is, the position of each row and the position of the one-dimensional scalar field correspond one-to-one. After the position of the representative pixel is determined by the direction vector, the position of the representative pixel is moved by applying a one-dimensional scalar field, and a pixel band is defined for the moved representative pixel.

[0081]

As is clear from the above description, according to the present invention, the fiber passing angle indicating the flow of natural wood fibers is replaced by a direction vector and expressed as a parallel line.
Furthermore, since the line pattern is deformed by a one-dimensional scalar field to have fluctuations, it is possible to express a natural shining pattern close to the surface of natural wood.

[Brief description of the drawings]

FIG. 1 is a diagram showing a shining pattern seen on the surface of a general natural wood.

FIG. 2 is a perspective view showing a reference fiber bundle model in which all fiber bundles face the direction of a reference axis A.

FIG. 3 is a perspective view showing a distorted fiber bundle model in which the direction of the fiber bundle changes based on a wavy grain.

FIG. 4 is a perspective view showing a distorted fiber bundle model in which the direction of the fiber bundle changes based on spiral grain.

FIG. 5 is a perspective view showing a state where the reference fiber bundle model shown in FIG.

FIG. 6 is a perspective view showing a state where the reference fiber bundle model shown in FIG. 2 is cut along a straight-grained surface.

FIG. 7: Fiber direction vector F in a general timber board
FIG. 7 is a side sectional view showing a relationship between → and a ray direction vector L →.

FIG. 8: Vector intersection angle φ in a general timber board
6 is a graph showing a relationship between (fiber diving angle ξ) and the intensity of specular reflected light W.

FIG. 9 is a perspective view showing the structure of a linear groove G formed on the surface of the woody embossed sheet.

FIG. 10 is a cross-sectional view showing light reflection characteristics in the linear groove G shown in FIG.

FIG. 11 is a plan view showing a basic configuration of a woody embossed sheet E according to the present invention in which a linear groove is formed.

FIG. 12 shows a wooden embossed sheet E shown in FIG.
It is a perspective view which shows the state which comprises a building material by laminating on the printing sheet S which printed the woodgrain pattern.

FIG. 13 is a flowchart showing a basic procedure of a method of creating a line pattern capable of expressing a woody texture.

FIG. 14 is a perspective view showing an example of a method of defining a fiber descent angle ξ in step S10 in the flowchart of FIG.

15 is a perspective view showing a fiber diving angle ξ defined at a point P on an image forming surface J by the definition method shown in FIG.

FIG. 16 is a perspective view showing an example of another definition method of the fiber descent angle で in step S10 in the flowchart of FIG.

FIG. 17 is a graph showing an example of a 式 / θ conversion formula used when generating a direction vector in step S20 in the flowchart of FIG. 13;

FIG. 18: Step S10 in the flowchart of FIG.
FIG. 3 is a perspective view showing an example of a fiber diving angle ξ defined on an image forming surface J.

19 is a plan view showing a state in which the fiber diving angle 示 す shown in FIG. 18 is converted into an angle θ indicating a direction vector along the image forming surface J.

20 is a flowchart showing a detailed processing procedure in a line forming step of step S30 in the flowchart of FIG. 13;

FIG. 21 is a step S32 in the flowchart of FIG. 20;
FIG. 3 is a diagram showing representative pixels defined in the first row.

FIG. 22: Step S32 in the flowchart of FIG.
FIG. 3 is a diagram showing a pixel band defined in the first row.

FIG. 23 is a step S34 in the flowchart of FIG. 20;
FIG. 9 is a diagram showing representative pixels defined in the second row based on the representative pixels in the first row.

FIG. 24: Step S34 in the flowchart of FIG.
FIG. 9 is a diagram showing a pixel band defined in the second row based on the representative pixels in the first row.

FIG. 25 is a diagram showing a line created by the procedure shown in the flowchart of FIG. 20;

26 is a diagram showing a technique for executing the procedure shown in the flowchart of FIG. 20 with higher accuracy.

FIG. 27 is a diagram showing a state in which a new line M3 has been generated by the adjustment processing in step S35 in the flowchart of FIG. 20;

FIG. 28 is a diagram showing a state where the line M2 is terminated by the adjustment processing in step S35 in the flowchart of FIG. 20;

FIG. 29 is a diagram for explaining processing of deformation of a line pattern in step S39 in the flowchart of FIG. 20;

30 is a diagram illustrating an example of a case where a representative pixel and a pixel band are moved and deformed by the processing of deforming a line pattern in step S39 in the flowchart of FIG.

FIG. 31 is a block diagram showing a basic configuration of an apparatus for producing an embossed sheet having a wooden texture.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Vector field generation means 20 ... Fiber boring angle calculation means 30 ... Direction vector calculation means 40 ... Pattern generation means 41 ... Pattern deformation means 42 ... One-dimensional scalar field generation means 50 ... Plate means 60 ... Embossing means 100 ... Timber Plate 200: virtual light source A: reference axis E: embossed sheet F: fiber F →, F1 →, F2 →: fiber direction vector G: parallel groove H11, H12, H21, H22: pixel band J: cut plane (image Forming surface) L → light ray direction vector M, M1, M2, M3 ... line O1, O2, O3 ... observation direction P, Q ... fiber bundle model or point on image forming surface P ', Q' ... distorted fiber bundle Point on model P (i, j) ... Pixel on pixel array Qa, Qb, Qc ... End point of vector R ... Reference line R11, R12, R21, R22, RR ... Representative pixel Ra, Rb, Rc Representative pixel S: wood-grained print sheet T: natural wood V →: directional vector V11 →, V12 →: directional vector Va →, Vb →: directional vector V (i, j): pixel P (i, j) Direction vector W: Specular reflection light intensity (gloss) ξ: Fiber passing angle φ: Vector intersection angle θ: Angle between direction vector V → and reference line R

Continuation of front page (56) References JP-A-9-86028 (JP, A) JP-A-8-323948 (JP, A) JP-A-8-272851 (JP, A) JP-A-8-258393 (JP) JP-A-8-22538 (JP, A) JP-A-8-16772 (JP, A) JP-A-5-294100 (JP, A) JP-A-2-41574 (JP, A) 10-16375 (JP, A) JP-A-6-1100 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B41M 3/06 B44F 9/02 E04F 13/00 E04F 15 / 10 104 G06T 1/00

Claims (4)

(57) [Claims] 1. A method for creating a line pattern for expressing a woody appearance appearing on the surface of natural wood, comprising: a fiber diving angle indicating the orientation of wood fibers at each point on a predetermined image forming surface. Defining a fiber dive angle, and defining a conversion formula for converting a given fiber dive angle into a direction vector along the image forming surface, and using this conversion formula, each point on the image forming surface is defined. A direction vector generating step of converting each of the fiber diving angles defined in the above into a direction vector, and a line forming step of forming a line pattern along the direction vector on a created image. 5. The method of claim 1, further comprising the step of applying a one-dimensional scalar field to fluctuate the line pattern. 2. A line pattern creating apparatus for expressing a feeling of woody appearance on the surface of natural wood, comprising: a vector field generating means for generating a three-dimensional vector field expressing the grain of natural wood; When the three-dimensional vector field is cut by the image forming surface, the fiber diving angle is obtained based on the orientation of the vector field at each point on the cut surface, and the fiber diving angle is calculated at each point on the image forming surface. A fiber descent angle calculating means for defining, and a fiber descent defined at each point on the image forming surface based on a predetermined conversion formula for converting a given fiber dive angle into a direction vector along the image forming surface. A direction vector calculating means for converting each corner into a direction vector; defining a line having a predetermined width on the created image and arranged along the direction vector; Value drawing A line pattern creating apparatus comprising: a pattern generating means for generating a pattern; a one-dimensional scalar field generating means for generating a one-dimensional scalar field; and a one-dimensional scalar field generated by the one-dimensional scalar field generating means. A line pattern creating apparatus, comprising: pattern deforming means for causing the line pattern to fluctuate by acting on the pattern. 3. An embossed sheet in which a large number of line patterns for expressing a woody appearance appearing on the surface of natural wood are embossed into an uneven pattern, wherein the line pattern determines the orientation of wood fibers. An embossed sheet having a directional component corresponding to the indicated fiber diving angle, and further being fluctuated by a one-dimensional scalar field. 4. A decorative sheet in which a plurality of line patterns for expressing a woody appearance appearing on the surface of natural wood are embossed into a concavo-convex pattern on a sheet printed with a wood grain pattern, Has a directional component corresponding to a fiber diving angle indicating the orientation of wood fibers, and is further fluctuated by a one-dimensional scalar field.