Morphological Color Processing Based on Distances. Application to Color Denoising and Enhancement by Centre and Contrast Operators

The extension of mathematical morphology operators to multi-valued functions, and in particular to color images, is neither direct nor general. In this paper is proposed a generalisation of distance-based and lexicographical-based approaches, allowing the extension of morphological operators to color images for any color representation (e.g. RGB, LSH and L*a*b*) and for any metric distance to a reference color. The performance of these morphological color operators is illustrated by means of two applications: color denoising by the centre operator and color enhancement by the contrast mapping.