Functional spectral filter for optical simulation of dichromats in color discrimination

Abstract

We are gradually recognizing the importance of Color Universal Design in which confusing color combinations for color deficient people should be avoided in documents and signs, while the design is still comfortable for people with normal color vision. However, it is not so easy to avoid those confusing colors perfectly because it is difficult to describe them only by words like a manual. A special kind of software or some color combination charts are currently used for this purpose. Thus, we proposed the functional spectral filter with which users in normal color vision can easily find the confusing color combinations for dichromats. Spectral transmittance of the filter was designed as that the amount of color differences for a normal observer with the filter should be close to the one for color dichromats. This designing process of the filter was formulated as an optimization problem of minimizing a discrepancy in color differences between them. The filter was realized by vacuum deposition technology. Evaluation results for Ishihara plates, Panel D-15 test and color discrimination ellipse (Cambridge Color Test) indicated that color normal observers with the filter are reasonably similar to dichromats in color discrimination property as expected from the filter design.

Footnotes

 This work was basically supported by the Regional New Consortium Projects from the Ministry of Economy, Trade and Industry of Japan (17C4020) and the Graduate School Sophistication Special Promotion Support by the Promotion and Mutual Aid Corporation for Private Schools of Japan to K. Shinomori.