Abstract
We described the effectiveness of functional filters for simulating dichromatic color-discrimination through Variantor (Universal (U), Protan (P), and Deutan (D) types) in processes of color universal design (CUD). Owing to the lack of real-time characteristics, possible misses in determining problems, and limited accuracy in printing objects, using the conventional technique is not sophisticated. In the conventional technique, software converts colors of digital photos under the model of dichromatic color-vision. Thus, we developed optical functional filters to simulate color difference of dichromats. In CUD evaluation, the use of color differences instead of modeled color appearances or color confusion lines provides the color design better accuracy and more freedom because the color difference includes the difference of luminance between target colors. We first developed Variantor U-type simulations of the smaller color differences between protanopes and deuteranopes for convenient use, and successively developed Variantor P- and D-types simulations of color differences on color confusion lines in each dichromatic. Moreover, these filters can function accurately in simulating the color difference of a non-white standard color. Although the low color discrimination area created by the filters may rotate from the direction of color confusion lines under some special illuminations, a suitable choice in the filters still enables accurate check of color discrimination. For practical use of the filters, we show the table of CIELAB color difference values between some of Munsell color chips.
