KEYWORDS: Color vision, CIE 1931 color space, Optical engineering, Data conversion, Information science, Color imaging, Electronic imaging, Current controlled current source, Chromium, Eye
We usually recognize color by two kinds of processes. In the first, the color is recognized continually and a small difference in color is recognized. In the second, the color is recognized discretely. This process recognizes a similar color of a certain range as being in the same color category. The small difference in color is ignored. Recognition by using the color category is important for communication using color. It is known that a color vision defect confuses colors on the confusion locus of color. However, the color category of a color vision defect has not been thoroughly researched. If the color category of the color vision defect is clarified, it will become an important key for color universal design. In this research, we classified color stimuli into four categories to check the shape and the border of the color categories of varied color vision. The experimental result was as follows. The border of protanopia is the following three on the CIE 1931 (x, y) chromaticity diagram: y = -0.3068x + 0.4795, y = -0.1906x + 0.4021, y = -0.2624x + 0.3896. The border of deuteranopia is the following three on the CIE 1931 (x, y) chromaticity diagram: y = -0.7931x + 0.7036, y = -0.718x + 0.5966, y = -0.6667x + 0.5061.
KEYWORDS: Color vision, Light sources, Information visualization, Color difference, Analytical research, Visualization, Product engineering, Cognition, Information science, Visual communications
This report is af ollow-up to SPIE-IS+T / Vol. 7528 7528051-8, SPIE-IS+T / Vol. 7866 78660J-1-8 and SPIE-IS+T / Vol. 8292 829206-1-8.
Colors are used to communicate information in various situations, not just for design and apparel. However, visual information given only by color may be perceived differently by individuals with different color vision types. Human color vision is non-uniform and the variation in most cases is genetically linked to L-cones and M-cones. Therefore, color appearance is not the same for all color vision types. Color Universal Design is an easy-to-understand system that was created to convey color-coded information accurately to most people, taking color vision types into consideration. In the present research, we studied trichromat (C-type), prolan (P-type), and deutan (D-type) forms of color vision.
We here report the result of two experiments. The first was the validation of the confusion colors using the color chart on CIELAB uniform color space. We made an experimental color chart (total of color cells is 622, the color difference between color cells is 2.5) for fhis experiment, and subjects have P-type or D-type color vision. From the data we were able to determine "the limits with high probability of confusion" and "the limits with possible confusion"
around various basing points. The direction of the former matched with the theoretical confusion locus, but the range did not extend across the entire a* range. The latter formed a belt-like zone above and below the theoretical confusion locus. This way we re-analyzed a part of the theoretical confusion locus suggested by Pitt-Judd. The second was an experiment in color classification of the subjects with C-type, P-type, or D-type color vision. The color caps of fhe 100 Hue Test were classified into seven categories for each color vision type. The common and different points of color sensation were compared for each color vision type, and we were able to find a group of color caps fhat people with C-, P-, and D-types could all recognize as distinguishable color categories. The result could be used as the basis of a color scheme for future
Color Universal Design.
We report on the results of a study investigating the color perception characteristics of people with red-green color
confusion. We believe that this is an important step towards achieving Color Universal Design. In Japan, approximately
5% of men and 0.2% of women have red-green confusion. The percentage for men is higher in Europe and the United
States; up to 8% in some countries. Red-green confusion involves a perception of colors different from normal color
vision. Colors are used as a means of disseminating clear information to people; however, it may be difficult to convey
the correct information to people who have red-green confusion. Consequently, colors should be chosen that minimize
accidents and that promote more effective communication. In a previous survey, we investigated color categories
common to each color vision type, trichromat (C-type color vision), protan (P-type color vision) and deuteran (D-type
color vision). In the present study, first, we conducted experiments in order to verify a previous survey of C-type color
vision and P-type color vision. Next, we investigated color difference levels within "CIE 1976 L*a*b*" (the CIELAB
uniform color space), where neither C-type nor P-type color vision causes accidents under certain conditions (rain
maps/contour line levels and graph color legend levels). As a result, we propose a common chromaticity of colors that
the two color vision types are able to categorize by means of color names common to C-type color vision. We also offer
a proposal to explain perception characteristics of color differences with normal color vision and red-green confusion
using the CIELAB uniform color space. This report is a follow-up to SPIE-IS & T / Vol. 7528 7528051-8 and SPIE-IS
& T /vol. 7866 78660J-1-8.
The present study investigates the tendency of individuals to categorize colors. Humans recognize colors by categorizing
them using specific color names, such as red, blue, and yellow. When an individual with a certain type of color vision
observes an object, they categorize its color using a particular color name and assume that other people will perceive the
color in an identical manner. However, there are some variations in human color vision as a result of differences in
photoreceptors in the eye, including red and green confusion. Thus, another person with a different type of color vision
may categorize a color using a completely different name. To address this issue, we attempted to determine the
differences in the ranges of color that people with different types of color vision observe. This is an important step
towards achieving Color Universal Design, a visual communication method that is viewer-friendly irrespective of color
vision type. Herein, we report on a systematic comparison among individuals with trichromat (C-type), protan (P-type)
and deutan (D-type) color vision. This paper is a follow-up to SPIE-IS & T / Vol. 7528 752805-1.
The present study investigates the tendency of individuals to categorize colors. Humans recognize colors by categorizing
them with specific color names such as red, blue, and yellow. When an individual having a certain type of color vision
observes an object, they categorize its color using a particular color name and assume that other people will perceive the
color in an identical manner. However, there are many variations in human color vision caused by photoreceptor
differences in the eye, including red and green confusion. Thus, another person with a different type of color vision may
categorize the color using another name. To address this issue, we attempt to determine the differences in the ranges of
colors that people with different types of color vision categorize using particular color names. In the modern urban
environment, most visual information, including warning signs and notice boards, is coded by color. Finding the
common color categories among different types of color vision is an important step towards achieving Color Universal
Design, a visual communication method that is viewer-friendly irrespective of color vision type. Herein we report on a
systematic comparison between people with common (C-type) and deutan (D-type) color vision. Analysis of protan (P-type)
color vision will follow in a subsequent report.
Our projects are founded on the principles of Color Universal Design (CUD), the objective of which is to promote public
information systems, such as train maps, which feature colors recognizable to all color vision types1). In this paper, we
were looking for a red which would be clearly distinguishable protan-vision people who see some tone of red as a dark
color and consequently confuse it with black. These potentially kinds of red were represented on the Yokohama City
Subway map, which we were presented with. We at the CUD believe it is possible to establish color design which is
easily distinguishable to people of all color-vision types in order to facilitate excellent visual communication.
KEYWORDS: Color vision, Visual communications, Information science, Medicine, Product engineering, Genetics, Color imaging, Electronic imaging, Light sources and illumination, Prototyping
The objective of this project is to establish a practical application of the concept of Color Universal Design (CUD), the
design that is recognizable to all color vision types.
In our research, we looked for a clearly distinguishable combination of hues of four colors - black, red, green, and blue -
which are frequently used in these circumstances. Red-green confusion people do not confuse all kinds of red and all
kinds of green. By selecting particular hues for each color, the ability to distinguish between the four colors should be
greatly improved.
Our study thus concluded that, by carefully selecting hues within the range of each color category, it is possible to
establish color-combinations which are easily distinguishable to people of all color-vision types in order to facilitate
visual communication.
In this study, we measure the colors used in a Japanese Animations. The result can be seen on CIE-xy color spaces. It clearly shows that the color system is not a natural appearance system but an imagined and artistic appearance system. Color constancy of human vision can tell the difference in skin and hair colors between under moonlight and day light. Human brain generates a match to the memorized color of an object from daylight viewing conditions to the color of the object in different viewing conditions. For example, Japanese people always perceive the color of the Rising Sun in the Japanese flag as red even in a different viewing condition such as under moonlight. Color images captured by a camera cannot present those human perceptions. However, Japanese colorists in Animation succeeded in painting the effects of color constancy not only under moonlight but also added the memory matching colors. They aim to create a greater impact on viewer's perceptions by using the effect of the memory matching colors. In this paper, we propose the Imagined Japanese Animation Color System. This system in art is currently a subject of research in Japan. Its importance is that it could also provide an explanation on how human brain perceives the same color under different viewing conditions.
When we are viewing colored picture, what is the difference in our brain between a random Color dot picture and a digit figure pattern picture seen through its colored dots? We created 3 patterns that are a functional magnetic resonance imaging version of the Ishihara plate patterns to test multiple color-sensitive areas in human ventral occipitotemporal cortex. The results showed that area V4 is activated by the stimulus of reading shapes from its color dots in the Ishihara pseudoisochromatic plates but not by the stimulus of seeing a random color dot picture. We suggest that area V4 is activated not by color processing but by segregation.
KEYWORDS: Functional magnetic resonance imaging, Camouflage, Brain, Clouds, Colorimetry, Visualization, Magnetic resonance imaging, Color centers, Scanning probe microscopy, Color vision
Artists can imagine 2 kinds of coloured scenes with no recognizable objects. One is the abstract picture such as colour Mondrian, which includes geometric pattern: rectangles, circles and crosses. Another is the decorative texture such as Japanese traditional cloud pattern which is colour camouflage pattern and does not include geometric pattern. We created these 2 kinds of colour dot pattern stimuli composed of 4 iso-luminance colours and the same area and an achromatic version. These functional magnetic resonance imaging stimuli reveal multiple colour-sensitive areas in human ventral occipitotemporal cortex. The results showed that area V4 is highly activated by the stimulus of the abstract picture such as rectangle pattern and spiral but little activated by the stimulus of the decorative texture such as random colour dot picture and cloud pattern. We suggest V4 is activated by figures composed of colour dots with eye-like shape such as disks, crosses, gratings, spirals, and windmill-like figures, and V4 has low response to the camouflage figure in which colour dots do not include eye-like shapes.
Internet use by the people with disabilities and the elderly in Japan is still low, but growing. However, the majority of web contents written in Japanese, even government sites, have very low accessibility. This paper introduces the active measures being taken in Japan to improve such conditions; consideration of a web contents accessibility guideline tailored to the unique characteristics of the Japanese language, development of a system to evaluate accessibility and implementation of actual trials.
KEYWORDS: Color vision, Internet imaging, Visual communications, Digital color imaging, Reflectivity, Electronic imaging, Visualization, Electroluminescence, Colorimetry, Eye
Internet imaging is used as interactive visual communication. It is different form other electronic imaging fields because the imaging is transported from one client to many others. If you and I each had different color vision, we may see Internet Imaging differently. So what do you see in a digital color dot picture such as the Ishihara pseudoisochromatic plates? The ishihara pseudoisochromatic test is the most widely used screening test for red-green color deficiency. The full verison contains 38 plates. Plates 18-21 are hidden digit designs. For example, plate 20 has 45 hidden digit designs that cannot be seen by normal trichromats but can be distinguished by most color deficient observers. In this study, we present a new digital color pallette. This is the web accessibility palette where the same information on Internet imaging can be seen correctly by any color vision person. For this study, we have measured the Ishihara pseudoisochromatic test. We used the new Minolta 2D- colorimeter system, CL1040i that can define all pixels in a 4cm x 4cm square to take measurements. From the results, color groups of 8 to 10 colors in the Ishihara plates can be seen on isochromatic lines of CIE-xy color spaces. On each plate, the form of a number is composed of 4 colors and the background colors are composed of the remaining 5 colors. Normal trichromats, it is difficult to find the difference between the 4 color group which makes up the form of the number and the 5 color group of the background colors. We also found that for normal trichromats, colors like orange and red that are highly salient are included in the warm color group and are distinguished form the cool color group of blue, green and gray. Form the results of our analysis of the Ishihara pseudoisochromatic test we suggest the web accessibility palette consists of 4 colors.
In this study, 34 students and teachers form a college of fine arts selected suitable colors for their artistic work on CRT display. From the results, several fundamental colors selected by artists can be seen on CIE-xy color spaces. The result of our experiment clearly showed that the 34 subjects could be divided into three groups based on differences in the level of red light or green light in their color palette.
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