JP3985879B2 - Anisotropic reflection simulation method and simulation apparatus - Google Patents

Description

[0001]
[Industrial application fields]
In the present invention, a pattern (hereinafter referred to as a line pattern) composed of a large number of curves or straight lines (hereinafter collectively referred to as a line pattern) is embossed and referred to as “shine”. The present invention relates to a method and an apparatus for simulating how the shine changes in a sheet that can express a glossy pattern.
[0002]
[Prior art]
In decorative sheets used for the surface decoration of wallpaper and flooring materials and furniture, the line pattern can be embossed directly on the decorative sheet to express a glossy pattern called shimmer. Alternatively, an embossed sheet is created by embossing a line pattern on a transparent sheet, and the embossed sheet is applied to a decorative sheet on which a pattern such as a wood grain pattern is printed to form a laminated structure.
[0003]
In this way, the principle that shine can be expressed by embossing the line pattern is as follows.
FIG. 8 is a perspective view of a sheet E on which a multi-line pattern is embossed to form a multi-line groove G. In this example, a large number of multi-line grooves G having a width W1 are formed at intervals of W2. Yes. With respect to the total thickness D1 of the sheet E, the line groove G forms a groove with a depth D2, and a large number of line grooves G are arranged substantially in parallel. Such a pattern composed of the multi-row grooves G has a two-step step structure of a concave portion having a width W1 and a convex portion having a width W2.
[0004]
It is known that the intensity of the reflected light obtained from the surface of the sheet E on which such a linear groove G is formed varies depending on the position. That is, anisotropic reflection is performed. When the line of sight of such a sheet E is continuously changed, a portion that strongly reflects, that is, a portion that has high brightness and shines brightly changes. This is called shimmering movement.
[0005]
[Problems to be solved by the invention]
As described above, in a sheet embossed with a line pattern, the shine can be expressed by anisotropic reflection based on the uneven structure of the emboss, and the shine moves when the line-of-sight direction is changed. In particular, the movement of the shimmer when moving in the line of sight is a very important matter, for example, in a decorative sheet printed with a wood grain pattern. Therefore, the designer is finished in designing the line pattern. However, it is very difficult to predict what kind of shimmer movement the designed line pattern will actually cause, and the embossed version will be based on the actually created line pattern. It was impossible to understand unless the sheet was prepared, embossed on the embossed plate, and observed.
[0006]
Therefore, if the embossed plate is created based on the created line pattern and the sheet is embossed with the embossed plate, if the shimmer movement as intended by the designer cannot be realized, The current situation is that patterns have been modified and new line patterns have been designed.
[0007]
However, it would be wasteful and time consuming if the embossing of the line pattern created in this way was not actually embossed. Met.
[0008]
Therefore, the present invention provides an anisotropic reflection simulation method that can easily confirm and evaluate what kind of shimmer movement occurs in the created line pattern without actually performing embossing, and The object is to provide a simulation apparatus.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, an anisotropic reflection simulation method according to the present invention is an anisotropic reflection simulation method for simulating the movement of light appearing on a sheet obtained by endlessly processing a line pattern of a line image. And defining the relationship between the angle θ between the direction vector of the line and the imaginary ray direction and the luminance, obtaining the pixel position on the line image corresponding to each display pixel of the display, and The angle φp of the direction vector at the pixel position on the image is obtained, the angle θ is obtained from the angle φp and the angle φl of the virtual light direction set at that time, and the luminance at the time of θ is obtained. The processing for obtaining and displaying from the relationship between the defined angle θ and luminance is performed while sequentially changing the angle φl of the virtual light beam direction.
[0010]
The anisotropic reflection simulation apparatus according to the present invention is an anisotropic reflection simulation apparatus for simulating movement of shine appearing on a sheet obtained by endlessly processing a line pattern of a line image. Means for defining the relationship between the angle θ between the direction vector and the virtual ray direction and the luminance, and the pixel position on the line image corresponding to each display pixel of the display, and the pixel position on the line image Is obtained from the angle φp of the direction vector and the angle φl of the imaginary ray direction set at that time, and the luminance at the time of θ is defined as the angle defined above. and means for performing a process of obtaining and displaying from the relationship between θ and luminance while sequentially changing the angle φl of the virtual ray direction.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments will be described with reference to the drawings.
First, an embodiment of the anisotropic reflection simulation method according to the present invention will be described.
FIG. 1 is a flowchart for explaining the flow of processing in this embodiment.
[0012]
First, a line image on which a line pattern is drawn is captured (step S1). The line pattern may be created by any method. For example, a method disclosed in Japanese Patent Laid-Open Nos. 5-289302 and 8-323948 may be used. Since the line pattern is for embossing, it is natural that it is a binary image.
[0013]
If this line image is output by a printer or the like, the line image can be read by a scanner. If there is digital data of the generated line pattern, the digital data is read. You just have to take it in. Here, as shown in FIG. 2A, the size of the captured line image in the x direction (horizontal direction in the figure) is wo, and the size in the y direction (vertical direction in the figure) is ho. . In this line image, each line is drawn vertically in the y direction as indicated by M in the figure.
[0014]
Next, a first memory is prepared (step S2). The size of the first memory is set to the same size as the screen area of the display for displaying the simulation result. Here, the size of the first memory is assumed to be wd pixels in the x direction and hd pixels in the y direction, as shown in FIG. Accordingly, the simulation result described below is displayed in the wd × hd area of the display.
[0015]
Now, what we are trying to simulate here is what kind of shimmering movement will occur in the line image, so when changing the line-of-sight direction or the direction of illumination to see the line image, sometimes It is necessary to determine which part of the line image has high luminance and which part has low luminance, and display the light and dark state of the line image. For that purpose, it is necessary to obtain the luminance value at each position of the line image at that time, changing the line-of-sight direction or the direction of illumination, and display it on the display with the brightness corresponding to the obtained luminance value. There is.
[0016]
However, the size of the display screen of the display is usually about several hundred pixels both vertically and horizontally, and is about several hundreds of pixels at most, whereas the size of the line image is about several tens of thousands of pixels for both wo and ho. Therefore, even if the luminances at all positions of the line image are obtained, it is impossible to display all of them. Of course, if an area of wd × hd is taken at an arbitrary position in the line image and the luminance values at all positions in the area are obtained and displayed, the light / dark state by the line pattern in the area is displayed. Although it is possible to do this, the purpose here is to make it possible to check macroscopically how the shimmer moves in the entire line image. The object cannot be achieved even if the bright and dark state of the illumination of only the wd × hd area is displayed.
[0017]
Therefore, here, first, the pixels of the line image corresponding to each pixel of the first memory are determined, and the luminance value is obtained for the pixels of the line image corresponding to each pixel of the first memory.
[0018]
By the way, when a sheet embossed with a line pattern of a line image is illuminated from a certain angle and viewed from a certain line of sight, what part becomes brighter and what part becomes Whether or not the brightness is lowered has not been completely clarified theoretically, but it has been clarified that the parts having the same direction vector of the lines shine simultaneously with the same brightness. The method of defining the direction vector is arbitrary, but here it is assumed to be a downward tangential direction at each position of the line. Now, as shown in FIG. 3, two parallel lines M arranged in the x direction with exactly the same shape. ₁ , M ₂ Considering the line M ₁ P ₁₁ , P ₁₂ , P ₁₃ , P ₁₄ The direction vector at the position of is indicated by an arrow in the figure, and similarly, the line M ₂ P _{twenty one} , P _{twenty two} , P _{twenty three} , P _{twenty four} It is assumed that the direction vector at the position is as shown by the arrow in the figure. Here, M Line M ₁ P ₁₁ , P ₁₂ , P ₁₃ , P ₁₄ Y-coordinate value of each line M ₂ P _{twenty one} , P _{twenty two} , P _{twenty three} , P _{twenty four} Is the same as the y-coordinate value. And M Line M ₁ P ₁₂ Direction vector at the position of P and P ₁₄ It is assumed that the direction vectors at the positions are both directly below, that is, in the y-axis direction.
[0019]
In a sheet embossed with such a multi-line pattern, the line M is aside from the brightness value when illuminated from a certain direction and viewed from a certain direction. ₁ Position P ₁₁ And M Line M ₂ Position P _{twenty one} Is the same direction vector, so it shines at the same brightness at the same time. ₁ P ₁₂ , P ₁₄ , And M ₂ P _{twenty two} , P _{twenty four} Since the directional vector has the same direction vector, it simultaneously shines with the same luminance. Similarly, line M ₁ P ₁₃ And M Line M ₂ P _{twenty three} Since the direction vector has the same direction vector, it shines at the same brightness at the same time.
[0020]
As described above, in order to obtain the luminance value for the pixels of the line image corresponding to each pixel of the first memory, the direction vector at the pixel position of the line image must be obtained. It is known that the angle is not a problem and only the angle is a problem. Therefore, in order to obtain the luminance value for the pixels of the line image corresponding to each pixel of the first memory, it is first necessary to obtain the angle of the direction vector at the pixel position of the line image. This is the process of step S3.
[0021]
Hereinafter, the process of step S3 will be described in detail with reference to the flowchart of FIG.
First, initial setting of the pixels of the first memory is performed (step S31). Here, assuming that the pixel position of the first memory is represented by (ix, iy), first, ix = 1 and iy = 1. This pixel position is the pixel position of the upper left corner of the display area of the display that displays the result of this simulation.
[0022]
Next, the position (xo, yo) of the pixel on the line image corresponding to the pixel at the position (ix, iy) in the first memory is determined (step S32). here
xo = ix · (wo / wd) (1)
yo = ii / (ho / hd) (2)
Thus, the pixels of the first memory and the pixels of the line image are associated with each other. Accordingly, in this case, the pixel position on the line image corresponding to the pixel at the position (1, 1) in the first memory is (wo / wd, ho / hd).
[0023]
Next, in step S33, the angle φp of the direction vector in the pixel at the position (xo, yo) in the line image is obtained, and the value of the obtained angle φp is written in the position (1, 1) of the first memory.
[0024]
The angle of the direction vector can be obtained as follows, for example. For example, if the pixel on the line image corresponding to the pixel at the position (1, 1) in the first memory is at the position indicated by p in FIG. The case of obtaining the angle of the direction vector at the position p will be described as an example. Attention is paid to a range of n × n pixels centered on the position indicated by p. An example is shown in FIG. FIG. 5 shows an example in which n = 11. In FIG. 5, a rectangle indicated by white is a pixel having a pixel value of 0 or 1, and a hatched rectangle is a pixel having a pixel value of 1 or 0. When the sheet is actually embossed, either one of the pixels having the pixel value of 0 or the pixel having the pixel value of 1 is formed to form a recess in the sheet. The pixel indicated by p may be any.
[0025]
Then, in the range, the pixels at both ends of the uppermost pixel band of the region having the same pixel value as p are q ₁ , Q ₂ As these pixels q ₁ , Q ₂ Let q be the midpoint of. Therefore, in the case shown in FIG. 5, the coordinates of the pixel q on the line image are (xo-2, yo-5). Similarly, in the range, the pixels at both ends of the lowermost pixel band of the region having the same pixel value as p are defined as r. ₁ , R ₂ These pixels r ₁ , R ₂ Let r be the midpoint of. In the case of FIG. 5, r is at the position of the boundary between pixels, but the coordinate value can be defined for such a position. Therefore, in the case shown in FIG. 5, the coordinates of the pixel r on the line image are (xo + 2.5, yo + 5). Next, a straight line connecting the position of q and the position of r is taken, and the angle formed by this straight line and the y-axis is defined as an angle φp of the direction vector at the pixel position indicated by p. Here, the angle φp is assumed to be counterclockwise from the y-axis as shown in FIG. Since the equation of the straight line connecting the position of q and the position of r is uniquely determined, it is obvious that the angle φp formed by this straight line and the y axis can be calculated.
[0026]
Thus, the angle φp of the direction vector at the pixel position on the line image corresponding to the pixel at the position (1, 1) in the first memory is obtained. Write to position 1).
[0027]
Next, ix is updated by +1 (step S34). In step S35, it is determined whether or not ix is greater than wd. If the value of ix updated in step S34 is greater than wd, the process proceeds to step S36. If not, the process returns to step S32, and a process for obtaining the pixel position on the line image corresponding to the (2,1) pixel position of the first memory is performed. According to (1) and (2), the pixels on the line image corresponding to the (2,1) pixel of the first memory are (2 · wo / wd, ho / hd). Therefore, the pixel positions on the line image corresponding to the pixels adjacent in the x direction on the first memory are separated by wo / wd in the x direction on the line image.
[0028]
Next, the angle φp of the direction vector at the pixel position (2 · wo / wd, ho / hd) on the line image is obtained by the method described above, and the obtained angle φp is (2,1) in the first memory. ) Is written at the position (step S33).
[0029]
When the above processing is performed while updating ix by +1 in step S34, the angle φp of the direction vector at the pixel position on the line image corresponding to all the pixels in the first row of the first memory is obtained, If ix = wd + 1 is satisfied in step S34, the determination process in step S35 is yes, so iy is updated by +1 in step S36, and ix = 1 is set, and the processes in steps S32 to S36 satisfy iy> hd. Repeat until. As a result, the angle φp of the direction vector at the pixel position on the line image corresponding to all the pixels of the first memory is obtained, and the angle φp is written to each pixel position of the first memory. According to (1) and (2), the pixel position on the line image corresponding to the pixel adjacent in the y direction on the first memory is only ho / hd on the line image in the y direction. I will leave.
[0030]
When the process of step S3 in FIG. 1 is completed as described above, the relationship between the angle θ and the luminance is then defined (step S4). The relationship between the angle θ and the luminance can be arbitrarily determined as shown in FIGS. 6A, 6B, and 6C, for example. In any case, the value range may be defined to be 0 or more and symmetric with respect to θ = 0. Such a relationship between the angle θ and the luminance can be given by a mathematical expression or can be configured by a look-up table (LUT).
[0031]
Here, the relationship between luminance I and angle θ
I = A ・ cos ⁿ θ (where I ≧ 0) (3)
It is defined as Here, A is a coefficient. The relationship between the angle θ and the luminance I is determined in this way. In the sheet embossed with a line pattern, the maximum luminance is obtained when the direction vector of the line forms a right angle with the direction vector of the light beam. The brightness decreases as the distance from the state increases. If the angle between the direction vector of the line and the direction vector of the ray is θ, the brightness is cos. ⁿ This is because it is considered to be proportional to θ. Thus, the angle θ represents the angle formed by the direction vector of the line and the direction vector of the light ray.
[0032]
Next, in order to simulate the movement of the shimmer in the sheet embossed with the line pattern of the line image, an initial value of the angle φl in the direction of the virtual light beam that illuminates the embossed sheet is set. (Step S5). Here, φl = 0 °.
[0033]
Next, a display memory is prepared (step S6). The size of the display memory is the same as the size of the first memory. Therefore, in this case, the size of the display memory is wd (x direction) × hd (y direction). As a result, there is a one-to-one correspondence between the pixels of the first memory and the pixels of the display memory.
[0034]
Next, the luminance value of each pixel in the display memory is obtained (step S7). This processing may be performed as follows, for example. First, paying attention to one pixel of the first memory, the angle φp written in the pixel position is read out. And
θ = φp−φl (4)
The angle θ is obtained as follows. Next, the luminance value at the angle θ is obtained from the relationship between the angle θ and the luminance defined in step S4. Therefore, when the luminance value is obtained in step S7 immediately after the angle φl is set to 0 ° in step S5, the luminance value is obtained as θ = φp. Then, the obtained luminance value is written in the corresponding pixel position in the display memory. By this processing, the luminance value is written in all the pixel positions of the display memory.
[0035]
After the luminance values are obtained and stored in this way for all the pixel positions in the display memory, the contents of the display memory are then displayed in a predetermined display area of the display with the luminance corresponding to the luminance value ( Step S8). As a result, a light / dark state is displayed in the predetermined display area of the display. This is initially performed in step S5 on the sheet on which the line pattern of the line image is embossed. This corresponds to a bright and dark state observed when illumination is applied from a set virtual light direction, that is, a state of illumination.
[0036]
Next, it is determined whether or not the process is finished (step S9). This termination condition can be determined as appropriate. For example, a menu for ending the simulation is displayed in an area outside a predetermined display area for displaying the result of the simulation, and when the end is instructed by the menu, the process of the simulation is ended. It may be. Alternatively, the simulation is sequentially performed while updating the angle of the virtual ray direction in step S10, and the simulation processing is automatically terminated when the simulation for the angle θ = 360 ° is completed. May be.
[0037]
If the termination condition is satisfied in step S9, the simulation process is terminated. If not, the virtual ray direction angle φl is updated by Δφ in step S10, and steps S7 and S8 are performed. Perform the process. This Δφ can be arbitrarily determined. In this way, changing the angle φl of the imaginary ray direction relatively means that the angle of the ray direction when the line pattern of the line image is applied to the embossed sheet is kept constant and the line of sight is kept constant. Is the same as changing the angle of the light beam, and is the same as rotating the embossed sheet while keeping the angle and line of sight in the light beam direction constant.
[0038]
If the above processing is repeated until it is determined to be “yes” in step S9, the predetermined display area of the display is in a light and dark state as the virtual light direction angle φl is updated in step S10. The state of changing sequentially will be displayed as an animation. This is nothing but the state of movement of the light that appears on the sheet embossed with the line pattern of the line image.
[0039]
As described above, according to this anisotropic reflection simulation method, it is possible to simulate the movement of the shimmer that appears when embossing using the created line pattern image. Thus, the created line pattern can be evaluated without actually performing an embossing process by making an embossed plate from the line pattern.
[0040]
In the above embodiment, the two memories having the same size, the first memory and the display memory, are used. However, the same operation can be performed by using only the display memory. In that case, it is necessary to define the relationship between the angle θ and the luminance in step S4 in FIG. 1 in advance. Then, the pixel position on the line image corresponding to each pixel of the display memory is obtained, the angle φp of the direction vector at the pixel position on the line image is obtained, and the angle φp and the angle φp set at that time are set. Θ is obtained from the angle φl of the virtual light beam direction, and the luminance at the time of θ is obtained from the relationship between the angle θ and the luminance, and written to the corresponding pixel position of the display memory, and is written into the display. The process of displaying in the display area may be repeated until the end condition is satisfied while sequentially changing the angle φl of the virtual light direction.
[0041]
The embodiment of the anisotropic reflection simulation method according to the present invention has been described above. Next, an embodiment of a simulation apparatus for performing the above-described simulation will be described with reference to FIG.
[0042]
This simulation apparatus includes a line image input means 1, a setting means 2, a memory means 3, a line angle calculation means 4, a luminance calculation means 5, and a display means 6. The line image input means 1 is a means for capturing a line image on which a line pattern for performing the simulation is drawn, such as a scanner for reading the line pattern from an original on which the line pattern is drawn, and the like. It is comprised with the apparatus for taking in a line pattern from the apparatus of this as digital data.
[0043]
The setting means 2 is used to set various parameters for performing the simulation. The setting means 2 is used for setting illumination conditions, specifically, setting the definition of the relationship between the angle θ and the brightness, or for the first memory and display. For setting the memory size, setting Δφ which is a parameter used when updating the angle of the virtual ray direction in step S10 in FIG. 1, setting the end condition used in the determination process in step S9, etc. It is. The setting means 2 can be configured with a keyboard or the like.
In the memory means 3, areas of a first memory and a display memory are set.
[0044]
The line angle calculation means 4 obtains the pixel position on the line image corresponding to each pixel of the first memory set in the memory means 3, and performs the process of step S3 in FIG. The direction vector angle φp at the pixel position on the line image corresponding to each of the pixels is obtained, and the obtained angle φp is written into the corresponding pixel position in the first memory.
[0045]
The luminance calculation means 5 obtains an angle θ from the written angle φp and the virtual ray direction angle φl at that time for each pixel position in the first memory, and further, the angle defined by the setting means 2 The process of obtaining the brightness from the relationship between θ and the brightness, and the process of writing the obtained brightness value to the corresponding pixel position in the display memory while satisfying the end condition while updating the angle φl of the virtual ray direction It is executed repeatedly until
[0046]
The display unit 6 displays the luminance value written by the luminance calculation unit 5 in the display memory of the memory unit 3 in a predetermined display area with luminance according to the luminance value.
[0047]
Each component of the setting unit 2, the memory unit 3, the line angle calculation unit 4, the luminance calculation unit 5 and the display unit 6 is a component constructed using a computer. By this computer, the state of movement of the light appearing on the sheet obtained by endlessly processing the line pattern of the line image is simulated.
[0048]
According to the above configuration, when a line image is input, a predetermined parameter is set by the setting unit 2 and the memory unit 3, the line angle calculation unit 4 and the luminance calculation unit 5 are activated, the display unit is displayed. In the predetermined display area 6, a state in which the state of light and darkness changes sequentially is displayed in an animated manner.
[0049]
The above operation is the case where two memories, the first memory and the display memory, are set in the memory means 3, but only the display memory may be set in the memory means 3. In that case, the line angle calculation means 4 obtains the pixel position on the line image corresponding to each pixel of the display memory set in the memory means 3, and performs the process of step S3 in FIG. Then, the angle φp of the direction vector at the pixel position on the line image corresponding to each pixel of the display memory is obtained, and the obtained angle φp is passed to the luminance calculating means. The angle θ is obtained from the angle φp passed from 4 and the angle φ1 of the virtual light direction at that time, and the luminance is further obtained from the relationship between the angle θ and the luminance defined by the setting means 2. Then, the process of writing the calculated luminance value to the corresponding pixel position in the display memory may be performed repeatedly while the imaginary ray direction angle φl is updated and the end condition is satisfied.
[0050]
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and it will be apparent to those skilled in the art that various modifications are possible.
[Brief description of the drawings]
FIG. 1 is a flowchart showing an embodiment of a simulation method for anisotropic reflection according to the present invention.
FIG. 2 is a diagram for explaining a line image and a first memory.
FIG. 3 is a diagram for explaining a relationship between a shimmer appearing in a sheet obtained by endlessly processing a line pattern and a direction vector at each position of the line.
FIG. 4 is a flowchart for explaining details of processing in step S3 of FIG. 1;
FIG. 5 is a flowchart for explaining details of processing in step S33 of FIG. 4;
6 is a diagram illustrating an example of a relationship between an angle θ defined in step S4 of FIG. 1 and luminance. FIG.
FIG. 7 is a diagram showing an embodiment of a simulation apparatus for anisotropic reflection according to the present invention.
FIG. 8 is a perspective view showing a structure of a line groove G formed on the surface of a sheet on which a line pattern is endlessly processed.
[Explanation of symbols]
1 ... Line image input means
2 Setting means
3. Memory means
4 ... Line angle calculation means
5. Luminance calculation means
6. Display means

Claims (2)

A method of simulating anisotropic reflection for simulating the movement of shine appearing on a sheet obtained by endlessly processing a line pattern of a line image,
Define the relationship between the angle θ between the direction vector of the line and the imaginary ray direction and the luminance, and determine the pixel position on the line image corresponding to each display pixel of the display, and the pixel on the line image The angle φp of the direction vector at the position is obtained, the angle θ is obtained from the angle φp and the angle φl of the virtual ray direction set at that time, and the luminance at the time of θ is defined as above. A method for simulating anisotropic reflection, characterized in that the processing for obtaining and displaying from the relationship between the angle θ and the luminance is performed while sequentially changing the angle φl of the virtual ray direction. An anisotropic reflection simulation device for simulating the movement of shine that appears on a sheet obtained by endlessly processing a line pattern of a line image,
Means for defining the relationship between the angle θ between the direction vector of the line and the virtual ray direction and the luminance;
The pixel position on the line image corresponding to each display pixel of the display is obtained, the angle φp of the direction vector at the pixel position on the line image is obtained, the angle φp, and the virtual set at that time The angle θ is obtained from the angle φ1 of the light ray direction, and the brightness at that θ is obtained from the relationship between the defined angle θ and the luminance, and the process of displaying the angle φl of the virtual light direction is sequentially performed. An anisotropic reflection simulation apparatus comprising: means for performing while changing.

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