Development of a color graphic icon for image color content and color shift

Cauwerts, Coralie [UCL] Jost, Sophie [ENTPE]

This work develops a color graphic icon providing descriptive information about the color content of a complex (real) scene. The icon aims both at representing color content and at informing on color shifts (in hue and chroma) due to illuminant and/or glazing changes. Such a graphic presents an interest (van der Burgt et al., CRA, 2010), color icon (Davis and Ohno, Optical Engineering, 2010), color vector graphic (IES, TM-30-15, 2015) and was adapted for real scenes. This adaptation raised questions about color appearance models for complex environments, color spaces and their division. The resulting color graphic icon is a projection of the color content of images (original and distorted) in PT plane of IPT color space, after application of iCAM06 algorithm aiming at predicting visual appearance of such complex scenes (Kuang et al., VCIP, 2007). For communication and interpretation, the PT plane was divided in six principal bins, corresponding to orange, yellow, green, blue, purple and red. Color attributes were averaged for these bins. Last, to inform on scene’s color repartition, a circular histogram complements the projection in the PT plan.