JP2015041224A - Texture creation device, texture creation method, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image processing method for periodically arranging a plurality of elements to create a realistic texture of fabric at a low cost.SOLUTION: An image processing apparatus 1 receives the input of a plurality of textons having different shapes (S101), receives the input of arrangement intervals different for each of the textons (S102), and creates pattern images in which predetermined textons are arranged (S103). When the image processing apparatus 1 creates the pattern images for all the input textons (YES in S104), then combines the created pattern images to create texture (S105), and displays the texture on a monitor (S106).

Description

  The present invention relates to an image processing apparatus or the like that automatically generates a texture.

In recent years, high quality AR (Augmented
Many engineers are demanding realistic CG (Computer Graphics) for the proposal of commercial products. However, the production of realistic CG has problems such as a long modeling period and a great expense for technical development.

  For example, Patent Document 1 describes a method for generating an element arrangement pattern based on comparison with a sample pattern or the like.

JP 2009-59368 A

  The technique described in Patent Document 1 has a problem that it takes time and effort to generate a pattern because single elements are arranged one by one.

  In order to develop high-quality AR merchandise in a short period of time, the present inventors focused on the fact that humans feel realistic rather than realism, and focused on textile fabrics that are easily subject to AR merchandise. I tried to make CG. As a result, it became clear that the texture contributed to the real taste of the fabric surface. Here, the texture is a pseudo expression of the pattern on the surface of the object using visual contrast.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to periodically arrange a plurality of element images to generate a realistic fabric texture at low cost. It is to provide a processing method and the like.

A first invention for achieving the above-described object is a texture generation device that periodically arranges element images to generate a texture of a fabric, and inputs two or more types of the element images having different shapes. An input means, a first image generation means for generating a first image by periodically arranging the element images in two dimensions, and a first image generated for each of the element images are combined to form a first image. And a second image generating means for generating two images, wherein the cycle for generating the first image is different for each element image.
According to the first invention, a realistic fabric texture can be generated only by defining an element image and a period.

In addition, it is preferable that the pixel value of the contour portion of the element image is calculated by a radial basis function.
As a result, it is possible to approximate the frequency domain when the gray scale image of the actual fabric is Fourier transformed, and a more realistic fabric texture can be generated.

In addition, it is desirable that the first image generation means arranges about 20% of the size of the element image with a non-periodic shift, thereby adjusting the frequency domain when the generated texture is Fourier transformed. This makes it possible to generate a more realistic fabric texture.

In addition, each time the element image is arranged, the first image generation unit preferably adds or subtracts the pixel value corresponding to the element image to the pixel value before the element image is arranged.
Thereby, a realistic texture of the fabric can be easily generated.

  The image processing means preferably further includes an output means for outputting the second image.

A second invention is a texture generation method for generating a texture of a fabric by arranging element images periodically, an input step of inputting two or more types of the element images having different shapes, and the element image A first image generation step of periodically arranging in two dimensions to generate a first image and a second image to generate a second image by combining the first images generated for each of the required images An image generation step, wherein the period for generating the first image is different for each element image.
According to the second aspect of the invention, a realistic fabric texture can be generated simply by defining elements and periods.

A third invention is a program for causing a computer to function as a texture generating device that periodically arranges element images and generates a texture of a fabric. The computer includes two or more types of the different shapes. Input means for inputting an element image, first image generating means for generating a first image by periodically arranging the element images in two dimensions, and synthesizing the first image generated for each element image Then, the program is made to function as second image generation means for generating a second image, and the cycle for generating the first image is different for each element image.
According to the third invention, a realistic fabric texture can be generated only by defining elements and periods.

  According to the present invention, a realistic fabric texture can be generated at low cost by periodically arranging a plurality of element images.

It is a figure which shows the structural example of the hardware of the image processing apparatus which concerns on embodiment of this invention. It is a figure which shows an example of the grayscale image of an actual textile fabric. It is a flowchart which shows the flow of a texture production | generation process. It is an image which shows the texton A which is an example of a texton. It is an image which shows Texton B which is an example of a texton. It is a figure explaining arrangement | positioning of a texton. It is an image which shows an example of the texture produced | generated by arrange | positioning a convex-shaped texton. It is an image which shows an example of the texture produced | generated by arrange | positioning a concave-shaped texton.

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

<Embodiment of the present invention>
FIG. 1 is a diagram illustrating a hardware configuration example of an image processing apparatus 1 according to an embodiment of the present invention. Note that the hardware configuration in FIG. 1 is an example, and various configurations can be adopted depending on applications and purposes.

  As shown in FIG. 2, the computer of the image processing apparatus 1 includes, for example, a control unit 11, a storage unit 12, a media input / output unit 13, a communication control unit 14, an input unit 15, a display unit 16, and a peripheral device I / F unit. 17 etc. are connected via the bus 18.

The control unit 11 is a CPU (Central
A processing unit (ROM), a read only memory (ROM), a random access memory (RAM), and the like.
The CPU calls and executes a program stored in the storage unit 12, ROM, storage medium, or the like in a work memory area on the RAM, drives and controls each device connected via the bus 18, and the image processing apparatus 1 The texture generation process to be performed is realized. The ROM is a non-volatile memory and permanently holds a computer boot program, a program such as BIOS, data, and the like. The RAM is a volatile memory, and temporarily holds a loaded program, data, and the like, and includes a work area used by the control unit 11 to perform each process.

The storage unit 12 is an HDD (Hard
Disk drive), the program executed by the control unit 11, data necessary for program execution, OS (Operating)
System) etc. are stored. These program codes are read by the control unit 11 as necessary, transferred to the RAM, and read and executed by the CPU.

The media input / output unit 13 is a media input / output device such as a CD drive, a DVD drive, an MO drive, and a floppy (registered trademark) disk drive, and inputs / outputs data such as images.
The communication control unit 14 includes a communication control device, a communication port, and the like, and is a communication interface that mediates communication between the image processing apparatus 1 and a network (not shown). Perform communication control.

  The input unit 15 performs data input and includes, for example, a keyboard, a pointing device such as a mouse, and an input device such as a numeric keypad. The input data is output to the control unit 11.

  The display unit 16 includes, for example, a display device such as a CRT monitor and a liquid crystal panel, and a logic circuit (such as a video card) for executing display processing in cooperation with the display device, and is input under the control of the control unit 11. The displayed display information is displayed on the display device.

  Note that the texture generation processing according to the embodiment of the present invention does not require complicated parameter adjustment, and the algorithm is simple, so that it can be executed by a GPU (Graphics Processing Unit) mounted on a video card or the like. .

The peripheral device I / F (interface) 17 unit is a port for connecting a peripheral device to the computer, and the computer transmits / receives data to / from the peripheral device via the peripheral device I / F unit 17. The peripheral device I / F unit 17 is configured by USB, IEEE 1394, RS-232C, or the like, and usually includes a plurality of peripheral devices I / F. The connection form with the peripheral device may be wired or wireless.
The bus 18 is a path that mediates transmission / reception of control signals, data signals, and the like between the devices.

  FIG. 2 is an image obtained by converting an image of an actual fabric selected at random into a gray scale using an intermediate threshold method. The present invention performs a perceptual experiment using a texture generated by blurring a grayscale image of an actual fabric, and frequency analysis of an image obtained by Fourier transforming the grayscale image of an actual fabric, etc. It was invented based on the knowledge obtained by them.

Next, the texture generation process will be described with reference to FIGS.
The texture generation process according to the present invention is a process of inputting a plurality of realistic fabric element images (hereinafter referred to as textons), arranging them at different periods for each texton, and generating a realistic fabric texture. is there.

  FIG. 3 is a flowchart showing the flow of texture generation processing. Note that the texture generation processing according to the present embodiment is executed by the control unit 11 of the image processing apparatus 1, but may be executed by the display unit 16 instead of the control unit 11.

  The control unit 11 of the image processing apparatus 1 receives input of a plurality of textons having different shapes from the input unit 15 or the like (step S101). In the present embodiment, a texton having a convex shape (shifted from light to dark from the center to the periphery) as illustrated in FIGS. 4 and 5 is input.

4 and 5 show examples of two types of textons having different shapes.
FIG. 4 is a circular element image with a blurred outline, and is hereinafter referred to as Texton A. Texton A is an image generated by applying a radial basis function to 1 pixel (center pixel) with a pixel value of 0 so that the pixel value gradually increases toward the periphery of the center pixel. , 11 pixels × 11 pixels. Here, it is assumed that the pixel value 0 represents white and the maximum pixel value 127 represents black.

  FIG. 5 is a long element image with a blurred outline, and is hereinafter referred to as Texton B. This is an image generated by applying a radial basis function to three pixels with a pixel value of 0 and an inclination angle of 45 ° with respect to the horizontal axis, and is composed of 11 pixels × 11 pixels. Note that when generating the texton A and the texton B, a general Gaussian function is used as the radial basis function, but other functions may be used.

  Note that “different in shape” means that, as in textons A and B, in the pixel having a pixel value of 0, the blurring degree of the outline, the inclination angle with respect to the horizontal axis, the length, and the like are different.

  The control unit 11 of the image processing apparatus 1 receives an input of a predetermined arrangement interval for arranging a predetermined texton from the input unit 15 or the like (step S102), and generates a pattern image (step S103). The arrangement interval is a pixel interval (dx) in the X-axis direction and a pixel interval (dy) in the Y-axis direction between the central pixels when the texton is arranged. The arrangement interval can be appropriately set by the user.

With reference to FIG. 6, generation of the pattern image of Texton A will be described.
FIG. 6A shows an example of an arrangement interval with respect to the X axis and the Y axis when the texton A is arranged. As shown in FIG. 6A, the pattern pixels are generated by arranging the center pixels of Texton A at intervals of 3 pixels in the X-axis direction and 5 pixels in the Y-axis direction.

FIG. 6B is a diagram for explaining a method of arranging the texton A with an X-axis arrangement interval of 3 pixels and a Y-axis arrangement interval of 5 pixels. The center pixel of blob C ₁ representing texton A is placed at (x, y) = (6, 6). Subsequently, the central pixel of the blob C ₂ indicating the texton A is arranged at (x, y) = (10, 6) so that the pixel interval in the X axis direction with the central pixel of the blob C ₁ is 3 pixels. To do. Subsequently, the central pixel of the blob C ₃ indicating the texton A is arranged at (x, y) = (6, 12) so that the pixel interval in the Y-axis direction with the central pixel of the blob C ₁ is 5 pixels. To do.

  Furthermore, each time a blob is placed, in addition to a predetermined placement interval, a non-periodic fluctuation is given on the X-axis or Y-axis by about 1 pixel (about 20% of the size of the blob) to determine the placement position. To do.

The pixel value R at an arbitrary position (x, y) of the arranged image is
Indicated by Here, T is the pixel value of (x, y) of the image before arrangement, and S is the pixel value of (x, y) of the blob defined as texton A. Note that the pixel value after addition does not exceed the maximum pixel value (for example, 255 if the pixel value range is 0 to 255). Every time one blob is arranged, the pixel value after the arrangement is calculated using Expression (1).

  As described above, the image processing apparatus 1 determines the position where the blob defined as the texton A is arranged by giving a non-periodic fluctuation to the designated pixel area in addition to the predetermined arrangement interval, Each time a blob is arranged, a pixel value is calculated, and a pattern image composed of texton A is generated.

  When the pattern images for all the textons input in step S101 have been generated (YES in step S104), the control unit 11 of the image processing apparatus 1 proceeds to step S105. If not generated (NO in step S104), the control unit 11 returns to step S102. In addition, the arrangement | positioning space | interval input in step S102 is set so that it may differ for every texton.

  The control unit 11 of the image processing apparatus 1 combines all the pattern images generated in step S103 to generate a texture (step S105). Combining means adding or subtracting pixel values at corresponding positions (x, y) between pattern images.

  The control unit 11 of the image processing apparatus 1 outputs the generated texture to the display unit 16 (step S106) and ends the process.

  FIG. 7 shows an example of a texture generated using the texton A and the texton B shown in FIGS. The image shown in FIG. 7 is a pattern image of Texton A in which the arrangement interval of the X axis is 3 pixels and the arrangement interval of the Y axis is 5 pixels, the arrangement interval of the X axis is 7 pixels, and the arrangement interval of the Y axis is 5 pixels. This is generated by synthesizing the pattern image of Texton B arranged in pixels.

  The output texture was displayed on the display unit 16 (monitor) of the image processing apparatus 1, and a sensory experiment was performed with five subjects. The display size of one pixel is 0.2 mm, and the distance from the monitor to the viewpoint is about several tens of centimeters. As a result, all the subjects perceived the image shown in FIG. 7 as a realistic fabric.

  FIG. 8 shows an example of a texture generated by inputting a texton having a plurality of different concave shapes (shifting from dark to bright from the center to the periphery) in step S101.

Here, in step S103, the pixel value is calculated using Expression (1), but instead of Expression (1), Expression (2)
May be used. Here, R is the pixel value of (x, y) of the image after arrangement, T is the pixel value of (x, y) of the image before arrangement, and S is (x, y of the blob defined as texton y) pixel value. Note that the pixel value after subtraction does not fall below the minimum pixel value (for example, 0 if the pixel value range is 0 to 255). Every time one blob is arranged, the pixel value after the arrangement is calculated using Expression (2).

  According to the present embodiment, by arranging a plurality of element images periodically, a realistic fabric texture can be easily generated at low cost.

  The preferred embodiments of the image processing apparatus 1 and the like according to the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to such examples. It will be apparent to those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea disclosed in the present application, and these naturally belong to the technical scope of the present invention. Understood.

DESCRIPTION OF SYMBOLS 1 ......... Image processing apparatus 11 ......... Control part 12 ......... Storage part 13 ......... Media input / output part 14 ......... Communication control part 15 ......... Input part 16 ......... Display part 17 ......... Peripheral equipment I / F section

Claims (7)

A texture generation device that periodically arranges element images to generate a texture of a fabric,
Input means for inputting two or more types of element images having different shapes;
First image generating means for periodically arranging the element images in two dimensions to generate a first image;
Second image generation means for generating a second image by combining the first images generated for each of the element images;
Comprising
The texture generation device, wherein the cycle for generating the first image is different for each element image. The texture generation device according to claim 1, wherein the pixel value of the contour portion of the element image is calculated by a radial basis function. The first image generating means includes
The texture generation device according to claim 1 or 2, wherein about 20 percent of the size of the element image is shifted aperiodically. The first image generating means includes
4. The method according to claim 1, wherein each time the element image is arranged, the corresponding pixel value of the element image is added to or subtracted from the pixel value before the element image is arranged. The texture generating apparatus according to crab. The texture generation device further includes:
The texture generating apparatus according to claim 1, further comprising an output unit that outputs the second image. A texture generation method for periodically arranging element images to generate a texture of a fabric,
An input step of inputting two or more types of element images having different shapes;
A first image generation step of periodically arranging the element images in two dimensions to generate a first image;
A second image generation step of generating a second image by combining the first images generated for each of the required images;
Including
The texture generation method, wherein the cycle for generating the first image is different for each element image. A program for causing a computer to function as a texture generating device that periodically arranges element images and generates a texture of a fabric,
The computer,
Input means for inputting two or more types of element images having different shapes;
First image generation means for periodically arranging the element images in two dimensions to generate a first image;
Second image generation means for generating a second image by combining the first images generated for each of the element images;
Function as
The program for generating the first image is different for each element image.