As specified before for digital color images every pixel is
described by more than one value, usually 3 values. Each of
these values has a special meaning according to the color space
used for representation. In digital image processing a color
space can be defined as a color model used for the numerical
description of colors. A color model is an abstract
mathematical concept whose role is to describe how the colors
can be represented as a vector of 3 or more components.