Optics: measuring and testing – By shade or color
Reexamination Certificate
2002-02-28
2004-06-15
Font, Frank G. (Department: 2877)
Optics: measuring and testing
By shade or color
C356S425000
Reexamination Certificate
active
06750970
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a color library system for a color designer engaged in metallic-paint-color design capable of easily visually detecting an approximate color by quickly retrieving a metallic paint color to be changed depending on an observing angle by a computer and displaying a retrieved result on a display device (monitor) of the computer as a computer graphic of the metallic paint color.
2. Background and Prior Art of the Invention
A metallic paint color is frequently used which is obtained by adding a colored pigment, a scaly brilliant pigment (such as aluminum flake or pearl flake), and micro titanium dioxide using Rayleigh scattering to a binder in order to improve the design effect in the fields of paint and printing. The maximum feature of the coloring is to make a person feel various textures such as metallic feeling and pearl feeling because brightness, chroma, and hue are changed depending on an observing angle.
FIG. 1
shows the paint-film structure and the multi-angle gloss distribution of a general metallic color. By applying light from a direction of 45°, the light is directionally reflected by a brilliant pigment in a paint film. Therefore, there is a feature that the high-light side becomes bright and the shade side becomes dark. Moreover, an angle is generally shown by an open angle from specular reflected light (this is referred to as declination) by assuming the specular reflected light and 0°.
Because development of many new colors is requested from customers (automobile companies, general industrial companies, and construction companies) every year, pain makers prepare a plurality of paint colors matching images of the customers and continuously propose them. However, there is a problem that it is impossible to prepare a sufficient number of paint colors because it takes a lot of time to individually prepare new paint colors every time. Particularly in recent years, because improvement of the products power of automobiles is requested, the importance for the designing characteristic of an exterior color that is most remarkable by consumers is raised. For a designer of an automobile maker using the strategy for improving the products power of automobiles, a step of observing a plurality of colors approximate to image colors of the designer and selecting a better color has been important more and more.
Therefore, paint companies has respectively efficiently prepared a color desired by a customer by detecting a paint color having the color and texture matching the image desired by the customer out of a enormous number of stock colors prepared in the past and tuning the color and texture by using the paint color as a start color and using various color materials.
Moreover, the stock colors also have a role of efficiently handing down the experience, skill, and sense of a veteran color designer to a new color designer, which are properties of a paint company. Therefore, 500 or more new colors are registered every year.
However, when the number of stock colors exceeds 1,000, disadvantages occur that it takes a lot of time to find out a color matching the image of a customer only through visual observation, the work efficiency is deteriorated instead, and stock colors which are also the property of a paint company cannot be effectively used.
Therefore, Japanese Patent Application No. 167960/1987 discloses a method of storing a colorimetric value in a memory of a computer by using a colorimeter and retrieving an approximate color by using a color difference (JIS Z8730) as a parameter. However, though it is possible to achieve an object by computing the color difference between colorimetric values from one angle when using a solid color (color shown by only a pigment which excludes a flake brilliant pigment and whose color is not changed depending on an observing direction), it is impossible to achieve the object for a metallic color which is changed depending on an observing direction by the above method.
The present invention provides a system for quickly computing an approximate color of a metallic paint color which is changed depending on an observing angle and displaying the computed approximate color on a monitor as a computer graphic of the paint color, particularly displaying an approximate color of a metallic paint color preferred by a color designer.
The present invention mainly aims at a computer system to be used by a designer engaged in design of a paint of an exterior color for an automobile. However, when considering that metallic colors containing flake pigments are used for some railroad cars and building armors in recent years, the present invention can be effective means in fields of general industry and construction in future.
SUMMARY OF THE INVENTION
Main components of the present invention are described below. That is, the main components are composed of.
1. a procedure for storing stock colors of metallic colors as the digital information for colorimetric values, color classification codes, and computer graphic images of metallic paint colors by using a colorimeter;
2. an algorithm for quickly retrieving an approximate color of an optional metallic paint color in accordance with a prepared color classification code; and
3. an algorithm for computing an weighted color difference so as to match a visual approximate color in order to compute color differences from a high-light (bright color close to specular reflected light) of a metallic paint color up to a shade (dark color at the opposite side).
A specific treatment method is described below.
A method for measuring a metallic paint color generally uses a multi-angle colorimeter. Various types of colorimeters are marketed. Any colorimeter measures an object under an optical condition according to a general expression of −45°/×1, ×2, ×3, ×4, ×5, . . . , and ×n. In this case, −45° denotes the angle of incident light. However, the angle may be shown as 45° with no negative symbol. Symbol xi denotes a received angle. There are a colorimeter that continuously measures xi and a portable multi-angle colorimeter that discretely measures xi every 10° to 50°. Moreover, there are a colorimeter for measuring XYZ in accordance with the photoelectric tristimulus colorimetry and a colorimeter for measuring a spectral reflectance. Because a continuous-measuring colorimeter can measure an object every optional angle, it can measure from a high-light up to a shade in detail. However, the colorimeter is large and expensive and requires a lot of time for measurement and a lot of measured data. Therefore, it is not suitable for the present system. To obtain the number of measurements necessary and sufficient for the present system, a portable multi-angle spectrophotometer is suitable which can measure from the high-light side up to the shade side at five angles or more. It is recommended to use the method disclosed in Japanese Patent Laid-Open No. 10045/1998 in order to obtain a regression formula for estimating wide-range colors from high-light to shade.
Moreover, to obtain a computer graphic of a metallic paint color from the obtained regression formula, it is possible to use an already-publicly-known method. That is, the above computer graphic can be obtained by converting a reflectance estimated by the regression formula into tristimulus values XYZ in accordance with the expression specified in JIS Z8701 and then, into RGB of a monitor. It is possible to convert XYZ into RGB by using a determinant in accordance with values of XYZ obtained by measuring the spectral brightness of each of R, G, B, and WHITE of the monitor by a spectral-radiant luminance meter. Moreover, to more accurately perform the conversion from XYZ into RGB, it is necessary to obtain the function of luminescent brightness (this is referred to as &ggr; function) to input voltages of R, G, and B of the monitor for correction. To convert XYZ into RGB, it is allowed to directly measure the characteristic of a monitor to be dir
Font Frank G.
Kansai Paint Co. Ltd.
Punnoose Roy M.
Wenderoth Lind & Ponack LLP
LandOfFree
Method for quickly retrieving approximate color of metallic... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for quickly retrieving approximate color of metallic..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for quickly retrieving approximate color of metallic... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3360263