JP2006277555A - Method, apparatus and program for generating granular metallic paint color image - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method, an apparatus and a program that generate a metallic paint color image of a metallic paint color presenting color texture, shading and granularity which is shareable among customers in paint color design, does not require a large capacity memory and a fast CPU in image creation and enables efficient paint color development. <P>SOLUTION: The granular metallic paint color image generation method includes the steps of measuring the color of a plate painted a metallic paint color at a plurality of reflection angles to acquire multangular spectral reflectances consisting of a plurality of spectral reflectances, generating a metallic paint color image as a digital image from the multangular spectral reflectances, calculating a lightness from the multangular spectral reflectances to decide a lightness index corresponding to the lightness, and generating a composite image from the metallic paint color image and a micro texture image as a digital image corresponding to a predetermined granularity index. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for generating a computer graphic image, and in particular, a computer graphic image representing the color texture and shadow feeling of a metallic paint color and a microtexture image representing a grain feeling are combined to form a metallic paint color having a grain feeling. The present invention relates to a method for generating a computer graphic image.

  With regard to industrial products in recent years, especially automobiles, it has become an era when more and more product power is required. One of this product strength is appearance quality. In order to improve the appearance quality, a metallic coating color in which a coloring pigment and a scale-like glitter pigment (aluminum flake, pearl flake) or fine particle titanium oxide using Rayleigh scattering is mixed may be applied. Here, the metallic paint color means a paint color in which the color texture such as brightness, saturation, and hue changes depending on the viewing angle, and a texture such as a metallic feeling or a silky feeling is felt.

  In a conventional automobile company, a paint color design applied to an automobile outer plate color is performed as follows. First, a car company designer creates an image in line with the concept of the vehicle model to be applied. An image image is an image created by appropriately selecting and combining photos and pictures from fabrics, cosmetic bottles, shells, natural shaped objects, and magazines. Then, based on this image, he spoke to a color-matching designer at a paint company and spoke about the desired color texture, and asked him to develop a paint color.

  On the other hand, with the progress of computer-related technology in recent years, it is expected to improve the accuracy of paint colors and speed up development by improving the performance and digitization of color measuring devices and display devices. The Therefore, automobile companies and paint companies are planning to use a computer to design paint colors in the development of new designs for automotive exterior panel colors. Computers that can be applied in various situations in paint color development are used. A paint color design support tool is being developed.

  In general, when a designer or engineer of an automobile company designs a new design on a display device using a computer, it is rare to create a new color from nothing. In general, it is common to modify the color in the desired direction based on the existing paint color.

  For example, Patent Document 1 below displays a computer graphic image of a metallic paint color on a screen based on a plurality of spectral reflectances having different light receiving angles (hereinafter referred to as “multi-angle spectral reflectance”), and the spectral reflectance. A method and apparatus for changing the color texture of a computer-graphic image with a metallic paint color by modifying the above is disclosed.

  Here, the design of the metallic paint color has not only a color texture but also a grain feeling, and a microtexture that affects the grain feeling is an important factor. For example, a glaring silver metallic coating color with an aluminum flake pigment having a large particle diameter in the coating film gives a “metal feeling with a profound feeling”. On the other hand, a “silky feeling” is felt in the silver metallic coating color containing an aluminum flake pigment having a small particle diameter.

  In this specification, the color texture of the metallic paint color is the overall color change when the surface is observed with the metallic paint color separated by 1 m or more, and the hue, saturation, and brightness from the highlight part to the shade part are measured. Expressed by change. On the other hand, the particle feeling of the metallic paint color is felt when the surface is observed within 1 m of the metallic paint color, and is a micro-texture on the metallic coating film generated by the size of the glitter pigment incorporated. To express.

  In the field of computer graphics, texture mapping for pasting texture has been developed for a long time in order to give a material feeling to a computer graphic image representing a three-dimensional shape.

  For example, Patent Document 2 below discloses a method for obtaining a changed three-dimensional image when data of a two-dimensional image is changed in a three-dimensional simulation in which a two-dimensional image is mapped to three-dimensional shape data to confirm a three-dimensional shape. Is disclosed. In this method, when data of a two-dimensional image is corrected or changed to create a new two-dimensional image, each point of the two-dimensional image corrected or changed with reference to the position correspondence data of the conversion table is referred to. In this method, the position on the projection surface is obtained, and the color of each point of the two-dimensional image is obtained from the color change data.

  The method disclosed in Patent Document 2 applies a method called bump mapping, which is a method of imparting a material feeling to a computer graphic image. Bump mapping is a method of using fluctuation data with respect to a normal, called a bump map, at the same time when rendering (texture mapping) is performed. As a result, it is possible to easily create an image that looks as if there are irregularities from a flat image.

  Japanese Patent Application Laid-Open No. H10-228707 discloses a device for pasting a plurality of texture images on the surface of a three-dimensional model as a texture mapping / texture mosaic processing device.

The method disclosed in Patent Document 3 also applies a method called bump mapping, as in Patent Document 2.
JP 2004-258854 A JP-A-6-231274 JP 2000-339499 A

  However, in the above-mentioned paint color design at an automobile company, the paint color design depends on the experience and expressiveness of the individual, and the color between the designer of the automobile company who is often the color orderer and the toning designer of the paint company. There may be a difference in the recognition of the texture, and there is a problem that a paint color that does not match the order is created.

  In order to solve this problem, a paint color design using a computer has been studied. However, with the method disclosed in Patent Document 1, there is a problem that the particle feeling of metallic paint color cannot be expressed on a display device. is there. This is because the metallic graphic computer graphic image is created based on the color texture which is the color information measured by the spectrocolorimeter, and the microscopic particle feeling is not measured.

  Further, the method disclosed in Patent Document 2 requires a high load calculation called ray tracing in order to express a microscopic particle feeling, so that the calculation speed is slow, and a large-capacity memory and a high-speed CPU are required. There is a problem. Further, even if the particle feeling can be displayed as virtual digital data, there is a problem that the data (parameters) used for the display cannot be used for the paint color design.

  Further, the method disclosed in Patent Document 3 can provide a more realistic computer graphic image by simultaneously mapping a plurality of texture images. There is a problem that racing calculation is required, the calculation speed is slow, and a large-capacity memory and CPU are required. Similarly, even if a computer graphic image having a particle feeling can be displayed, there is a problem that data (parameters) used for display cannot be used for paint color design.

  Therefore, at present, the target particle sensation is verbally stated and a paint color development is requested, and the problem of inefficiency of paint color development has not been solved.

  Therefore, an object of the present invention is to be used in common with customers in paint color design, and does not require a large-capacity memory or a high-speed CPU for image creation, and improves paint color development efficiency. Another object of the present invention is to provide a method, apparatus, and program for generating a metallic paint color image having a metallic paint color texture, shading feeling, and grain feeling.

  In the method (1) for generating a metallic paint color image having a particle feeling according to the present invention, a metallic paint plate is measured at a plurality of reflection angles to obtain a multi-angle spectral reflectance composed of a plurality of spectral reflectances. A step of generating a metallic paint color image that is a digital image using the multi-angle spectral reflectance, and calculating a lightness using the multi-angle spectral reflectance, and determining a lightness index corresponding to the lightness And a step of generating a composite image using the metallic paint color image and a microtexture image which is a digital image corresponding to a predetermined particle sensation index.

  Further, the method (2) for generating a metallic paint color image having a particle feeling according to the present invention is the method (1) for generating a metallic paint color image having a particle feeling as described above, wherein the microtexture image includes the lightness index and The metallic paint color corresponding to the particle sensation index is a digital image obtained by imaging a color chart painted on the surface.

  In addition, the method (3) for generating a metallic paint color image having a particle feeling according to the present invention is the method for generating a metallic paint color image having a particle feeling (1) or (2). A value is obtained by multiplying the corresponding pixel value of the metallic paint color image by a transmittance p greater than 0 and less than 1, and by multiplying the corresponding pixel value of the microtexture image by (1-p). It is characterized by being obtained by adding the obtained value.

  Further, the method (4) for generating a metallic paint color image having a particle feeling according to the present invention is the lightness of the color chart in the method (2) or (3) for generating a metallic paint color image having a particle feeling. The index is 3 or more and 7 or less, and the particle feeling index of the color chart is 3 or more and 7 or less.

  Further, the method (5) for generating a metallic paint color image having a particle feeling according to the present invention is the color chart according to any one of the methods (2) to (4) for generating a metallic paint color image having a particle feeling described above. However, it is characterized by being obtained by painting a paint obtained by blending a black pigment and a luster pigment.

  Further, the method (6) for generating a metallic paint color image having a particle feeling according to the present invention is the method (5) for generating a metallic paint color image having a particle feeling as described above, wherein the glitter pigment is a scaly aluminum flake. It is a white pearl pigment in which a pigment or scaly substrate is coated with titanium oxide, and has an average particle diameter in the range of 5 μm to 40 μm.

  Further, the method (7) for generating a metallic paint color image having a particle feeling according to the present invention is the microtexture according to any one of the methods (2) to (6) for generating a metallic paint color image having a particle feeling described above. The brightness of the image is a measurement value obtained by measuring the color chart in the range of 15 degrees or more and 25 degrees or less from the specular reflection light of incident light of 45 degrees, and the brightness of the metallic paint color image is the coating plate The calculated value is calculated in the range of 15 degrees or more and 25 degrees or less using the spectral reflectance.

  Further, the method (8) for generating a metallic paint color image having a particle feeling according to the present invention is the method (7) for generating a metallic paint color image having a particle feeling described above, wherein the lightness of the microtexture image is 10 The value is in the range of 200 or less.

  In addition, the method (9) for generating a metallic paint color image having a particle feeling according to the present invention is the microtexture according to any one of the methods (3) to (8) for generating a metallic paint color image having a particle feeling. An image is obtained by imaging the color chart with a declination angle of 15 degrees to 25 degrees with respect to incident light of 0 degrees and a magnification of 5 times to 50 times.

  In addition, the method (10) for generating a metallic paint color image having a particle feeling according to the present invention is the spectral reflection according to any one of the above methods (1) to (9) for generating a metallic paint color image having a particle feeling. The rate is obtained by the regression equation and the regression coefficient using the measured values of the spectral reflectance obtained by measuring the specular reflection light of 45 degrees from five angles in the range of 10 degrees or more and 110 degrees or less from the regular reflection light of 45 degrees. It is characterized by having a spectral reflectance at an angle.

  Further, the method (11) for generating a metallic paint color image having a particle feeling according to the present invention is the method (1) for generating a metallic paint color image having a particle feeling as described above, wherein the composite image is the metallic paint color image. And the microtexture image having an approximate lightness.

  Further, the method (12) for generating a metallic paint color image having a particle feeling according to the present invention is the above-described method (3) for generating a metallic paint color image having a particle feeling, wherein the range of the transmittance p is 0.9. It is characterized by ≦ p ≦ 0.98.

  In addition, a metallic paint color image generating device having a particle feeling according to the present invention includes an image input device that captures a color chart and obtains a microtexture image that is a digital image, and a plurality of reflective plates that are coated with a metallic paint color. A spectral colorimeter that measures colors at an angle and obtains a multi-angle spectral reflectance composed of a plurality of spectral reflectances, and generates a metallic paint color image that is a digital image using the multi-angle spectral reflectances. Lightness is calculated using the angular spectral reflectance, a lightness index corresponding to the lightness is determined, and a composite image using the metallic paint color image and a microtexture image which is a digital image corresponding to a predetermined particle sensitivity index And an arithmetic unit for generating

  In addition, the program according to the present invention measures the color of a metallic paint plate at a plurality of reflection angles and generates a multi-angle spectral reflectance comprising a plurality of spectral reflectances on a metallic paint color image generating device having a particle feeling. A function to acquire, a function to generate a metallic paint color image that is a digital image using the multi-angle spectral reflectance, and a brightness index using the multi-angle spectral reflectance, and a brightness index corresponding to the brightness is calculated. A function of determining and a function of generating a composite image using the metallic paint color image and a microtexture image that is a digital image corresponding to a predetermined particle sensation index are realized.

  A computer-readable recording medium according to the present invention is characterized by recording the above program.

  According to the present invention, it is possible to generate a metallic image having a metallic texture, shading, and particle feeling.

  Further, according to the present invention, a metallic image having a particle feeling can be commonly used in the paint color design, so that the color texture recognition does not differ among the persons in charge, and the paint color as ordered is created. be able to.

  Further, according to the present invention, the toning operator uses the particle sensitivity index and the brightness index numerical data (parameters) used for the synthesis of the metallic image having a particle feeling, and the pigment blending at the time of creating the corresponding color chart Toning work can be performed based on the data, and the efficiency of paint color development can be improved.

  In addition, according to the present invention, in order to give a texture to a three-dimensional computer graphic image, compared with the conventional texture mapping in which a texture is pasted, the calculation load is heavy and is not accompanied by a two-dimensional calculation. By using the calculation of the dimensional pixel value, it is possible to reduce the load of the calculation amount.

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

  FIG. 1 is a block diagram showing a schematic configuration of a metallic paint color image generating apparatus according to the present embodiment. The metallic paint color image generation apparatus according to the embodiment includes an arithmetic device (101), a display device (102), a spectrocolorimeter (103), and an image input device (104). The arithmetic unit (101) includes a CPU (111) that performs predetermined arithmetic operations described later, a memory (112) used for a work area, an I / F unit (113) that inputs and outputs data to and from external devices, A bus (114) for transmitting data between the respective units, a recording unit (115) used for recording operation results, and an operation unit (116) for receiving instructions from the outside are provided. A display device (102) for displaying image data and a program execution screen, a spectrocolorimeter (103) for measuring the color of the metallic paint plate (105), and an image input device (104) for imaging the color chart (106) ) Are connected to the arithmetic unit (101) via the I / F unit (113). Further, the image data calculated by the CPU (111), the colorimetric measurement values of the multi-angle spectral reflectance, and the microtexture image obtained by the imaging are in the form of electronic data in the I / F section ( 113) and stored in the recording unit (115).

  The outline of the operation of the metallic paint color image generating apparatus according to the embodiment will be described as follows. First, a particle sample color chart collection composed of a plurality of color charts (106) having different stages is created in advance, and a microtexture image of the color chart (106) imaged using the image input device (104) is recorded on the recording unit. (115), and a microtexture image database is constructed. Next, a multi-angle spectral reflectance value obtained by measuring the metallic paint plate (105) using the spectrocolorimeter (103) is acquired, and a metallic image is created using this. Next, a microtexture image corresponding to the brightness index that approximates the brightness of the metallic image and the specified particle feeling index is searched from the microtexture image database. Finally, the microtexture image and the metallic image are combined, and the obtained metallic paint color image is output to the display device (102). Thereby, a metallic paint color image is displayed.

  FIG. 2 is a process diagram for explaining a method for generating a microtextured paint color image using the metallic paint color image generating apparatus according to the present embodiment. Hereinafter, it demonstrates in detail based on process drawing shown in FIG.

  In the following description, the CPU (111) uses the memory (112) as a work area, temporarily stores necessary data (setting values, intermediate data during processing, etc.), and calculates it in the recording unit (115). Record long-term data such as results as appropriate. Further, an input from the operation unit (116) is accepted as necessary for processing.

  The first step S201 is a step of creating a particle sample color chart collection composed of a plurality of color charts (106) having different stages in advance. In this step S201, this metallic paint color image generating apparatus is not used.

  The particle color sample color chart collection is a paint toning method in which a plurality of color charts (106), which are paint color samples created with a paint color having a plurality of levels of particle feeling, are arranged step by step for each level of brightness. This is a sample collection. Usually, it is preferable that the grain feel is 3 or more and 7 or less and the brightness is 3 or more and 7 or less. Since the color chart (106) can be created by a known method (for example, the methods described in JP-A-2004-53260 and JP-A-2004-93522), the description is omitted here.

  First, a plurality of color charts (106) painted in metallic paint colors having different particle feelings and brightness are created. The particle feeling in the metallic paint color can be adjusted by the size of the particle size of the bright pigment such as aluminum flake pigment or white pearl to be blended.

  When the particle feeling is made into three stages, the particle diameter of the bright pigment to be blended is, for example, three stages of fine (less than 10 μm), medium (less than 10 μm and less than 20 μm) and coarse (more than 20 μm). In the case of 5 stages, it should be fine (less than 10 μm), slightly fine (less than 10 to 15 μm), medium (15 to less than 20 μm), slightly rough (20 to less than 25 μm), and rough (more than 25 μm). Usually, the average particle system is in the range of 5 μm to 40 μm.

  The brightness can be adjusted by changing the ratio of the black pigment and the luster pigment to be blended. The lightness includes the lightness of the highlight portion and the lightness of the shade portion depending on the measurement angle, but it is preferable to use the lightness of the highlight portion. That is, the brightness measured at a measurement angle in the range of 15 degrees or more and 25 degrees or less from the specularly reflected light of incident light of 45 degrees is used. Here, the declination means an angle with the regular reflection light of the incident light as a reference line (0 degree). L * 25 described in the present specification means lightness measured at a measurement angle of 25 degrees with a declination from specularly reflected light of incident light of 45 degrees. The brightness L * 25 of the highlight portion of the color chart (106) is determined by directly measuring using the spectrocolorimeter (103).

  When the lightness is set at three levels, it is set at three levels: dark (L * 25 is less than 20), medium (L * 25 is 20 or more and less than 70), and light (L * 25 is 70 or more). In the case of five stages, deep color (L * 25 is less than 20), medium color (L * 25 is 20 or more and less than 40), medium color (L * 25 is 40 or more and less than 60), medium light color (L * 25 is 60 or more and less than 80) and pale (L * 25 is 80 or more). Usually, the brightness is a value in the range of 10 to 200.

  As described above, 9 to 49 color charts (106) are created for each of 9 to 49 stages, in which the grain feeling is changed to 3 to 7 stages and the brightness of the highlight portion is changed to 3 to 7 stages. A particle swatch color chart with 9 to 49 sections is created.

  The second step S202 is a step of creating a microtexture image database in advance.

  First, a predetermined number (9 to 49) of color charts (106) of the particle sample color chart collection obtained in step S201 are image input devices (one for each division divided by the stage of particle feeling and brightness). 104).

  The imaging condition is usually 15 degrees or more and 25 degrees with respect to the incident angle (the same direction as the incident light) or 0 degree incident light in accordance with the measurement angle of the brightness L * 25 of the highlight portion described above. The imaging angle is in the following range. Under these conditions, an image in which the glitter pigment particles are shining can be taken. There is no particular limitation as long as the glittering pigment is oriented in the coating film and is capable of capturing an image shining by receiving illumination light during imaging.

  The imaging magnification is 5 to 50 times, more preferably 30 to 40 times. When the imaging magnification is set to 1, the same image as that of visual observation can be obtained. However, in that case, it is impossible to perceive the feeling of particles due to the bright pigment blended in the metallic paint color. Even if they are synthesized, the particle feeling cannot be perceived. Therefore, it is preferable to take an image at 5 times or more and 50 times or less.

  Next, the captured microtexture image is stored in the recording unit (115) for each microtexture image, and a database is created. The electronic data of the microtexture image captured by the image input device (104) is stored in the recording unit (115) via the I / F unit (113). At the time of storage, in order to enable searching of the database by the CPU (111), a particle sensation index indicating particle sensation and a brightness index indicating lightness are assigned as character data for each microtexture image. For example, a particle sensation index and a brightness index may be used for the file name of the electronic data of the microtexture image.

  8-bit gray is used for the color depth of the microtexture image. This is because the color tone of the image is not affected when it is combined with a metallic image described later. The color chart (106) is an achromatic color because it is obtained by painting a bright pigment such as an aluminum flake pigment or white pearl and a paint containing only a black pigment. Since the color chart is achromatic, it is created as a gray image in the form of electronic data.

  Finally, the CPU (111) receives input of brightness, brightness index, particle feeling, and particle feeling index via the operation unit (116), and a table as shown in Table 1 using these input data. The created table is stored in the recording unit (115) as electronic data.

The created table is used to specify the grain feeling of the microtexture image used for synthesis and to determine the brightness index, which will be described later in step S205.

  The third step S203 is a step of measuring the color of the metallic paint plate.

  First, a coated plate (105) created in the same manner as the color chart (106) created in step S201 and coated with a metallic color having a desired color texture is set in the spectrocolorimeter (103). Next, the CPU (111) measures the color of the metallic paint plate (105) using the spectrocolorimeter (103). The CPU (111) acquires the electronic data of the multi-angle spectral reflectance obtained by the measurement via the I / F unit (113) and stores it in the recording unit (115). The multi-angle spectral reflectance is divided into the spectral reflectance of the highlight portion and the spectral reflectance of the shade portion depending on the light receiving angle. As the measurement angle of the spectral reflectance of the highlight portion, it is preferable to adopt a range of 15 degrees or more and 25 degrees or less from the standards of ASTM and ISO.

  The fourth step S204 is a step of creating a metallic image. The multi-angle spectral reflectance data obtained in step S203 is calculated to obtain the RGB value of the metallic image. Subsequent to this step, the processing performed by the CPU (111) will be described unless otherwise specified.

  Here, an example program used after this process will be described. 3 to 6 are flowcharts of an example showing the functional module configuration of the program used in the metallic paint color image generating apparatus according to the present embodiment and each functional module. The program shown as an example in FIG. 3 functions by combining four functional modules of a metallic image creation module (A), a microtexture image reading module (B), an image composition module (C), and an image display module (D). To do. The program is recorded in the recording unit (115) in advance, and the CPU (111) can perform a predetermined process. That is, the CPU (111) performs processing by sharing the memory (112) according to the procedure of the schematic flowcharts of the functional modules (A) to (D) shown as an example in FIGS.

  First, according to the flowchart shown in FIG. 4 (function of the functional module (A)), multi-angle spectral reflectance data obtained by color measurement in step S203 is calculated. The multi-angle spectral reflectance data is read from the recording unit (115) (S41), and it is determined whether or not the measurement angle of the data is in increments of 1 degree (S42). If the data measurement angle is in increments of 1 degree, the multi-angle spectral reflectance data measured as it is is converted into RGB values (S44 and S45). The conversion procedure is as follows. First, using the method described in JIS Z8701, the measured multi-angle spectral reflectance is converted into chromaticity coordinates XYZ of the XYZ color system (S44). Next, an RGB value of the metallic image is obtained using an expression for converting from chromaticity coordinates XYZ to RGB defined by the CIE (International Commission on Illumination) (S45). The RGB values of the obtained metallic image are stored in the recording unit (115) (S46).

  On the other hand, if the measurement angle of the data is not in increments of 1 degree, the data is interpolated by calculation using the predictive regression equation according to the flowchart shown in FIG. 4 (function of the function module (A)) before conversion to RGB values. To do. First, in a known method (for example, Japanese Patent Laid-Open No. 10-10045), a spectral reflectance at an arbitrary angle is calculated in advance from a regression equation of reflectivity at five angles, and an angle from a highlight portion to a shade portion using a prediction regression equation. Is calculated (S43). The measurement angle of 5 angles is preferably in the range of 10 degrees or more and 110 degrees or less in declination from the regular reflection light with respect to the incident light of 45 degrees. Next, the RGB values of the metallic image are calculated and stored in the recording unit according to the above-described steps (S44, S45, and S46) using the spectral reflectance obtained by this calculation in increments of 1 degree. .

  The fifth step S205 is a step of reading a microtexture image. The brightness index and particle feeling index to be given are determined, the microtexture image database created in the recording unit (115) is searched, and the microtexture image corresponding to the search condition is read.

  First, according to the flowchart shown in FIG. 5 (function of the function module (B)), the data of the multi-angle spectral reflectance of the metallic paint color measured in step S203 is read from the recording unit (115) (S51), and the multi-angle spectral reflection is performed. Among the rates, the lightness L * 25 of the metallic paint color is obtained by calculation from the spectral reflectance of the highlight portion (S52 and S53). The calculation procedure is as follows. First, using the method described in JIS Z8701, the multi-angle spectral reflectance is converted to chromaticity coordinates XYZ of the XYZ color system (S52). Next, the lightness L * 25 is calculated using an expression defined in JIS Z8729 (S53), and the lightness corresponding to the lightness L * 25 obtained with reference to Table 1 recorded in the recording unit (115). The index value is determined (S54).

  For the particle sensation index, for example, the CPU (111) receives an input of a predetermined value via the operation unit (116) (S55). For example, a desired particle sensation index that the operator wants to add to the metallic image is determined with reference to Table 1 and input from the operation unit (116).

  The CPU (111) searches the microtexture image database created in the recording unit (115) in step S202 using the determined particle sensation index and lightness index as search conditions (S56). The retrieved microtexture image is a microtexture image that has a particle feeling that the operator wants to give and approximates the brightness L * 25 of the metallic paint color and the brightness of the highlight portion.

  The determined particle feeling index and lightness index data (parameters) are used for paint color design to be described later.

  The sixth step S206 is a step of synthesizing the microtexture image with the metallic image.

  Here, it is desirable for the metallic image that the color texture of the metallic coating color does not change even if the microtexture image is synthesized. Therefore, the brightness L * 25 of the highlight portion of the metallic image (calculated value from the multi-angle spectral reflectance which is a measured value) and the brightness L * 25 of the highlight portion of the microtexture image (direct measurement by the spectrocolorimeter) The value) is preferably approximate. By approximating the lightness L * 25 of the highlight portion, the change in the color texture of the metallic paint color can be minimized.

  Hereinafter, the synthesis procedure will be described by taking as an example a case where each image data is stored as an RGB value for each pixel. When the image data is stored in another format, it is necessary to convert the image data into RGB values before synthesizing the image.

  First, according to the flowchart shown in FIG. 6 (function of the function module (C)), the RGB value of the microtexture image and the RGB value of the metallic image corresponding to the search condition are read from the recording unit (115) into the memory (113) ( S61 and S62). Next, image composition of the RGB value of the metallic image and the RGB value of the microtexture image is performed (S63). The calculation procedure of image composition is as follows. Assuming that the metallic image is A, the microtexture image is B, and the post-synthesis particle-feeling metallic image is C, the CPU (111) obtains the RGB value for each pixel of the image C by calculating with the following formula. Can do.

R (C) = pR (A) + (1-p) R (B)
G (C) = pG (A) + (1-p) G (B)
B (C) = pB (A) + (1-p) B (B)
here,
R (C), G (C), and B (C) are the R data, G data, and B data of image C, respectively.
R (A), G (A), and B (A) are R data, G data, and B data of image A, respectively.
R (B), G (B), and B (B) mean R data, G data, and B data of the image B, respectively.

  p is the transmittance of the microtexture image and is a value in the range of 0 <p <1. The range is preferably 0.90 ≦ p ≦ 0.98, and more preferably 0.94 ≦ p ≦ 0.96. If the transmittance p is small, the contribution of the microtexture image becomes too large, and the color texture in the synthesized image becomes inconspicuous. On the other hand, if the transmittance p is large, the contribution of the microtexture image becomes too small, and the particle feeling in the composited particle feeling imparted metallic image becomes inconspicuous. A preferable numerical value of the transmittance may be determined as a numerical value in which these problems are unlikely to occur based on the results of investigation with various metallic paint colors.

  The seventh step S207 is a step of displaying the particle-feel imparting metallic image obtained by the calculation on the display device (102). According to the flowchart shown in FIG. 6 (function of the function module (D)), the display device (102) displays the RGB value of the particle-feel imparting metallic image created in step S206, which exists on the memory (112) of the arithmetic device (101). (S64).

  The displayed particle feeling imparted metallic image is an image that allows the operator to perceive the color texture, shadow feeling, and particle feeling of the metallic paint color. A comprehensive judgment of the color texture, shading feeling, and grain feeling is the design of the metallic paint color. By observing the displayed particle-feel imparting metallic image, a designer or engineer of an automobile company who performs paint color design can evaluate the design of the metal paint color. On the other hand, paint company designers and engineers create metallic paint colors based on the color texture and particle feeling information of the displayed metallic image with particle feeling, and provide customers (automotive company designers and engineers). Can be proposed.

  Although the present embodiment has been described above, according to another embodiment, the multi-angle spectral reflectance measured in step S203, the microtexture image and microtexture image database created in step S202, and created in step S206. By storing intermediate data to be created in each process such as a particle-feel imparting metallic image in the recording unit (115) in the electronic data format in advance, it is possible to freely combine these electronic data. .

  For example, if the particle feeling of the obtained particle feeling imparted metallic image is different from the desired one, the microtexture image search condition is changed in step S205 to specify a different particle feeling, and the particle feeling imparting metallic image. Can be newly synthesized. If you want to change the color texture or shading of the metallic paint color, it is calculated from the multi-angle spectral reflectance of different metallic paint colors stored in the recording unit (115) instead of the metallic image created in step S204. It is possible to synthesize the metallic image and the microtexture image. Further, if the RGB values of the particle sensation imparting metallic image created in step S206 are stored in the recording unit (115), by performing step S207, the particle sensation impartation is performed without repeating steps S204 to S206. The metallic image can be displayed on the display device (102).

  Furthermore, according to other embodiments, the present invention can be implemented on a remote host. The external computing device (121) shown in FIG. 1 has the same function as the computing device (101) and is connected to the recording unit (115) via the wide area network (107). The external display device (122) has the same function as the display device (102) and is connected to the external arithmetic device (121). The recording unit (115) is accessible from an external computing device (121) via the wide area network (115).

  Thereby, not only the stand-alone implementation described in the present embodiment but also the remote host (121) can be implemented by freely combining these electronic data. For example, a designer of a paint company first stores the necessary electronic data in the recording unit (115) in advance. Next, a designer of an automobile company uses electronic data stored in an external computing device (121), an external display device (122), and a recording unit (115) that is accessible via a wide area network. It becomes possible to carry out design work freely at an automobile company.

  In addition, each device and electronic data used in the present embodiment is not limited to the description.

  As the arithmetic unit (101) and the external arithmetic unit (121), a personal computer can be used instead of an expensive three-dimensional graphic creation computer.

  The display device (102) and the external display device (122) are preferably display devices capable of expressing 32,768 colors or more. This is because if the display capability is 32,768 colors or more, a natural image can be seen visually even if the number of colors of the displayed image is reduced. In particular, a display device that can express about 16.77 million colors, which is generally referred to as full color, is preferable because of its excellent ability to display color changes.

  The spectrocolorimeter (103) is not particularly limited, but is a GCMS (manufactured by Murakami Color Research Co., Ltd.) or a portable spectrophotometer: MA68II that can change the incident angle and the light receiving angle by 1 degree. (US x-rite) is used. MA68II measures the color at five angles of 15, 25, 45, 75, and 110 degrees with the incident angle being 45 degrees and the light receiving angle being a declination angle from the specularly reflected light. This is preferable because it is possible.

  As the image input device (104), an image scanner, a digital microscope, a digital camera, an electron microscope, or the like can be used.

  Full color can be used for the number of colors of the microtexture image. When the surface of the metallic paint color in which the bright pigment that expresses the interference color is blended is observed at a high magnification, it is possible to perceive that different interference colors are generated for each part on the surface of the bright pigment. Therefore, by setting the number of colors to full color, not only the particle feeling but also the expression of the interference color by the glitter pigment can be expressed by a particle feeling imparted metallic image obtained by synthesizing the microtexture image and the metallic image. it can.

  The image format of the microtexture image is preferably a raster image such as TIFF, BMP, JPEG, GIF, and PNG that are widely used in general. In addition, when the microtexture image is a gray image, it is only necessary to be able to read the average value of the RGB values, so image formats such as PICT, EPS (extended postscript), SVG, and PDF that are vector images can also be used. .

  When the size of the microtexture image and the metallic image to be synthesized are equal, these images can be synthesized by calculation as they are. In the case where the sizes of these images are different, the size of the microtexture image can be adjusted to the size of the metallic image and then synthesized.

  When using a microtexture image with a large particle feeling, such as an observer observing the color chart (106) from a close distance, for image synthesis, the microtexture image and the metallic image are enlarged in advance. Further, it is possible to cut out an image of a certain area and synthesize the cut out images to obtain a particle-feeling metallic image.

  Hereinafter, the features of the present invention will be described more clearly by describing examples.

(1) Creation of particle sample color chart collection In accordance with step S201, a particle sample color chart collection comprising 30 color charts having a total of 30 stages of brightness index 5 stages and particle sensitivity index 6 stages shown in Table 1 It was created.

  The brightness was set to the following five levels (L10, L30, L50, L70, L90 in the dark order). This numerical value is a value of L * 25, and is the brightness at a measurement angle of 25 degrees measured with a spectrocolorimeter (Minolta, CM512m3). The brightness was adjusted by the amount of black pigment blended in the paint.

  The grain feeling was classified into the following 6 stages (1 = very fine, 2 = fine, 3 = slightly fine, 4 = slightly rough, 5 = rough, 6 = very rough). The particle feeling was adjusted by the particle diameter of the aluminum flake pigment or white pearl pigment blended in the paint.

  In addition, the sample names of the created color charts were L10-X, L30-X, L50-X, L70-X, and L90-X, corresponding to the brightness index and the particle index. L is a lightness index, for example, L10 means that L * 25 is approximately 10. X is a particle feeling index, which is a number from 1 to 6, and the larger the number, the larger the particle feeling.

(2) Creation of Microtexture Image Database According to step S202, the color chart prepared in (1) was imaged using a CCD camera. Each color chart was picked up with a reflection image magnification of 25, and an 8-bit gray image of 512 horizontal pixels × 512 vertical pixels was obtained. For example, in a microtexture image having a lightness index L90 and a particle sensitivity index 6, a region of 256 pixels wide by 400 pixels long near the center of the obtained image is associated with the sample name of the color chart. 6 and stored as a JPEG image in the recording unit. FIG. 7 shows a microtexture image obtained by classifying the obtained color chart for each stage. Further, the data shown in Table 1 was input to the arithmetic unit using the operation unit, and stored in the recording unit together with the obtained microtexture image.

(3) Implementation of Design Work First, according to step S203, a metallic paint plate containing 15 PWC (Pigment Weight Concentration) of an aluminum flake pigment having a medium particle size (average particle size of 14 μm) was prepared. The coated plate was measured with a spectrocolorimeter (manufactured by X-Rite, USA, MA68II) to obtain multi-angle spectral reflectance data. Using the obtained multi-angle spectral reflectance data, calculation was performed according to step S204, and a metallic image A of horizontal 128 pixels × vertical 200 pixels shown in FIG. 8 was obtained.

  Next, according to step S205, L * 25, which is the brightness of the highlight portion (25 degrees with respect to specular reflection light) of the metallic paint color, is calculated using a program, and the brightness index is displayed on the screen. 25 = 110 and brightness index = L90 were displayed on the screen. In order to input the particle feeling index, output the contents of Table 1 on the screen, imagine the particle feeling of the actual automobile outer plate, and program the particle feeling index "6 (very coarse)" that seems to be preferable. I input it.

  From a microtexture image database constructed in the recording unit using a program, an image L90-6. jpg was searched and image data was read. Since the size of the image in the database is 256 pixels × 400 pixels, the image was reduced to 1/2 within the program to obtain a microtexture image B shown in FIG.

  Next, the metallic image A and the microtexture image B were synthesized using a program according to step S206, and a particle-feel imparting metallic image C shown in FIG. 8 was obtained. Since the image format is not RGB, the image format of the microtexture image B was converted from JPEG to RGB before synthesis. The RGB values at arbitrary pixels of the particle-feel imparting metallic image C were obtained by the following formulas, and the image synthesis operation was performed.

R data of C image = 0.94 × (R data of A image) + (1.0−0.94) × (R data of B image)
G data of C image = 0.94 × (G data of A image) + (1.0−0.94) × (G data of B image)
B data of C image = 0.94 × (B data of A image) + (1.0−0.94) × (B data of B image)

  Finally, the particle-feel imparting metallic image C obtained according to step S207 is output and evaluated on a screen, and it is determined that the particle feeling is almost suitable for the image, and the image data of the obtained metallic image C is stored in the recording unit. Saved and finished the design work.

(4) Toning work Toning work is performed on the basis of information on the obtained particle feeling imparting metallic image, lightness index, and particle feeling index. First, the program is started, and the particle-feel imparting metallic image created in step S206 of (3) and stored in the recording unit is displayed on the screen in the procedure of step S207. Next, in order to realize the color texture, shading feeling and particle feeling of the particle feeling imparted metallic image displayed on the screen by actually using the paint, the color chart corresponding to L90-6 of the particle feeling sample color chart collection is used. Toning was performed based on the formulation data. The type of medium-sized aluminum flakes used at first was changed, and a paint in which 8PWC was added to 8PWC for medium-sized aluminum flakes and 8PWC for medium-sized aluminum flakes was created. After confirming that it had the same particle feeling, color texture, and shading feeling as the particle-feel imparting metallic image displayed on the screen, the toning work was completed.

  As described above, by carrying out the present invention according to the procedure described in the present embodiment, it was possible to generate a metallic image having a particle feeling that can be commonly used in paint color design. In addition, using the numerical data used for the synthesis of the metallic image having the grain feeling, it was possible to perform the toning work based on the pigment blending data at the time of creating the corresponding color chart. As a result, there is no difference in recognition among the persons in charge, and the paint color development can be performed efficiently.

It is a block diagram which shows schematic structure of the metallic paint color image generation apparatus which concerns on this Embodiment. It is process drawing explaining the production | generation method of the micro texture paint color image using the metallic paint color image generation apparatus which concerns on this Embodiment. It is a flowchart of an example which shows the functional module structure of the program used in the metallic paint color image generation apparatus which concerns on this Embodiment. 5 is a flowchart illustrating an example of a functional module A. 3 is a flowchart illustrating an example of a functional module B. 4 is a flowchart illustrating an example of a functional module C. It is a figure which shows the microtexture image which classified the color chart which concerns on a present Example for every step. It is a figure which shows the metallic image A, the microtexture image B, and the particle-feel imparting metallic image C which concern on a present Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Arithmetic apparatus 102 Display apparatus 103 Spectral colorimeter 104 Image input apparatus 105 Metallic paint plate 106 Color chart 107 Wide area network 111 CPU
112 memory 113 I / F unit 114 bus 115 recording unit 116 operation unit 121 external computing device 122 external display device

Claims (15)

Measuring a metallic paint plate at a plurality of reflection angles, obtaining a multi-angle spectral reflectance comprising a plurality of spectral reflectances; and
Generating a metallic paint color image that is a digital image using the multi-angle spectral reflectance;
Calculating brightness using the multi-angle spectral reflectance and determining a brightness index corresponding to the brightness;
Generating a composite image using the metallic paint color image and a microtexture image, which is a digital image corresponding to a predetermined particle sensitivity index, and generating a metallic paint color image having a particle feeling .   2. The particle according to claim 1, wherein the microtexture image is a digital image obtained by imaging a color chart in which a metallic coating color corresponding to the lightness index and the particle sensitivity index is coated on a surface. Of generating a metallic paint color image having a feeling.   Each pixel value of the composite image is obtained by multiplying a corresponding pixel value of the metallic paint color image by a transmittance p larger than 0 and smaller than 1, and a corresponding pixel value of the microtexture image by (1− 3. The method for generating a metallic paint color image having a particle feeling according to claim 1, wherein the method is obtained by adding a value obtained by multiplying by p).   The particle feeling according to claim 2 or 3, wherein the lightness index of the color chart is 3 or more and 7 or less, and the particle feeling index of the color chart is 3 or more and 7 or less. A method for generating a metallic paint color image.   5. The metallic paint color having a particle feeling according to claim 2, wherein the color chart is obtained by applying a paint obtained by blending a black pigment and a glitter pigment. Image generation method.   6. The bright pigment is a scaly aluminum flake pigment or a white pearl pigment obtained by coating a scaly substrate with titanium oxide, and has an average particle diameter in a range of 5 μm to 40 μm. A method for generating a metallic paint color image having a particle feeling described in 1.   The lightness of the microtexture image is a measurement value obtained by measuring the color chart in a range of 15 degrees or more and 25 degrees or less in declination from the regular reflection light of 45 degrees incident light, and the lightness of the metallic paint color image is The metallic coating having a particle feeling according to any one of claims 2 to 6, wherein the metallic coating has a calculated value calculated in a range of 15 degrees or more and 25 degrees or less using the spectral reflectance of the coating plate. Color image generation method.   The method of generating a metallic paint color image having a particle feeling according to claim 7, wherein the brightness of the microtexture image is a value in a range of 10 to 200.   The micro-texture image is obtained by imaging the color chart at a declination angle range of 15 to 25 degrees and a magnification of 5 to 50 times with respect to incident light of 0 degrees. Item 9. A method for generating a metallic paint color image having a particle feeling according to any one of Items 3 to 8.   Using the spectral reflectance measured values obtained by measuring the spectral reflectance at five angles in the range of 10 degrees to 110 degrees with a declination from the regular reflected light of 45 degrees incident light, a regression equation and a regression 10. The method for generating a metallic paint color image having a particle feeling according to claim 1, wherein the spectral reflectance is an angle obtained by a coefficient.   The composite image according to claim 1, wherein the composite image is obtained using the lightness of the metallic paint color image and the micro texture image having an approximate lightness. Method.   4. The method for generating a metallic paint color image having a particle feeling according to claim 3, wherein the range of the transmittance p is 0.9 ≦ p ≦ 0.98. An image input device that captures a color chart and obtains a microtexture image that is a digital image;
A spectrocolorimeter that measures the color of a metallic paint plate at a plurality of reflection angles and obtains a multi-angle spectral reflectance composed of a plurality of spectral reflectances;
A metallic paint color image that is a digital image is generated using the multi-angle spectral reflectance, a brightness is calculated using the multi-angle spectral reflectance, a brightness index corresponding to the brightness is determined, and the metallic paint color An apparatus for generating a metallic paint color image having particle feeling, comprising: an arithmetic unit that generates a composite image using an image and a microtexture image that is a digital image corresponding to a predetermined particle feeling index. In a device for generating a metallic paint color image having a particle feeling,
A function of measuring a metallic paint plate at a plurality of reflection angles and obtaining a multi-angle spectral reflectance composed of a plurality of spectral reflectances;
A function of generating a metallic paint color image which is a digital image using the multi-angle spectral reflectance;
A function of calculating brightness using the multi-angle spectral reflectance, and determining a brightness index corresponding to the brightness;
A program for realizing a function of generating a composite image using the metallic paint color image and a microtexture image which is a digital image corresponding to a predetermined particle feeling index.   The computer-readable recording medium which recorded the program of Claim 14.