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.