Authors:
André R. S. Marçal
1
;
2
Affiliations:
1
Departamento de Matemática, Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre s/n, 4169-007, Porto, Portugal
;
2
INESC TEC, Porto, Portugal
Keyword(s):
Color Distance, Color Perception, Color Normalisation, Dunn Index.
Abstract:
This paper presents normalised color distances based on widely used metrics in the RGB and L*a*b* color models, and an adjusted City Block distance for the HSV model. Three experiments were carried out, focusing on color perception, the identification of the actual range of the various normalised color distances, and their ability of compare and match images which have a predominant color perceived by a human observer. For this task, a spatially tolerant color distance is proposed. The image comparison experiment uses subsets of 6 images, out of 15 square tile images, with a total of 270 test cases considered. A modified Dunn index is proposed for the evaluation. L*a*b* based distances were found to be better adjusted to the human color perception. Color distances based on L*a*b* model were also more effective for image comparison, with spatially tolerant color distances having slightly better performance than using a direct image pixel pairing.