Improvement of lightness modification method based on Craik-O´Brien effect for dichromats

Dichromats is difficult to distinguish some color pairs. There is lightness modification method which considers the Craik-O´Brien effect. Although the method can obtain good results in many cases, there is a room for improvement. In this paper, a new lightness modification method which considers the Craik-O´Brien effect is proposed. In the proposed method, the lightness modification is mainly performed at parts which are difficult to distinguish for dichromats. The validity of the proposed method is shown by experiments using some images.