Abstract: This paper defines a new measure of color difference, mapping chromatism, aiming to solve color clustering problems. The measure satisfies three conditions of distance axiom. Based on the measure lower bounded by <em<L</em<<sub<2</sub< distance between one inspected image and the reference image, a new surface inspection of color clustering is proposed. The inspection extracts dominant colors using radius weighted method in CIE 1976 <em<L<sup<*</sup<a<sup<*</sup<b</em< space and clusters the dominant colors to realize surface inspection by minimized distance principle based on mapping chromatism. Experiments performed auto inspection to RMB bills and tiles of surface quality and obtained good results consistent with HVS.