1113 ディザ近似手法を用いた色の組み合わせを制限しないカラーユニバーサルデザイン : 可変ディザ近似および最適ディザサイズ導出手法(OS9-1 ヒューマンインタフェース・ユーザビリティ1)

Abstract

The previous dithering method for color universal design, lightness contrast dithering approximation, has problems that it changes all of the background of pictures and it is difficult for color vision handicapped person to perceive the detail drawing patterns of pictures in a particular dither size. Therefore in this study, methods of variable dithering and optimal size derivation are proposed. The hypotheses are that using variable dithering method, which decreases the lightness contrast as the distance from the edge of drawing patterns increases, the appearance of pictures for the person with normal color vision is changed less than previous dithering method and also color vision handicapped person can perceive the drawing patterns, and optimal dither size is derived from the shape of the drawing patterns. Color patterns with three lightness contrasts and three dither sizes generated by variable dithering method are evaluated about appearance for normal color vision and visibility for the color vision handicapped. Also, patterns with seven dither sizes including the sample generated by optimal dither size derivation method are evaluated about visibility for the color vision handicapped. The results confirmed the hypothesis about variable dithering method. On the other hand, the results also showed that the sample generated by optimal dither size method does not have optimal visibility. In this study, it is hypothesized that optimal dither size is derived from only the shape of the drawing patterns, but other parameters, for example lightness contrast, should be taken into account.