Color enhancement algorithm based on Daltonization and image fusion for improving the color visibility to color vision deficiencies and normal trichromats

Abstract

In recent years, helping individuals with color vision deficiency to distinguish confusing colors in digital images, which is called Daltonization, is a hot topic. However, a number of Daltonization methods have a color reduction problem that causes unnatural image colors for normal color vision observers and those with anomalous trichromatic color vision deficiencies. A color-enhancing algorithm is proposed to make up for the shortage in color naturalness. Based on the conclusion in previous studies that colors confused in the same type of color blindness are approximately straight lines (called confusion lines) on the u ′ v ′ chromaticity plane and all of the confusion lines intersect at the same point (called the confusion point), we propose a polar coordinate transformation based on intersection points of confusion lines, which can transform chromaticity information into perceptually sensitive and perceptually insensitive color blindness information. From the two color-blind sensitive information of the Daltonized image and the one color-blind insensitive information of the original image, the three-dimensional information can be combined to obtain an enhanced image. The enhanced image has a similar color appearance of the Daltonized image under the perspective of dichromats and has a more natural and colorful color appearance under the perspective of anomalous and normal trichromats. In addition, we propose a lightness modification to reduce lightness errors between the enhanced images and the Daltonized images. The quantitative evaluation shows that the method proposed is effective but sacrificing a small amount of color contrast of the Daltonized images.