Fig. 3

Commission Internationale d’Eclairage (CIE) L*a*b* color. Color is expressed as 3 numerical values, L* for lightness and a* and b* for the green-red and blue-yellow color components, respectively. The system was designed to be perceptually uniform with respect to human color vision. The space itself is a 3-dimensional real-number space; therefore, any color variation can be expressed in L*a*b* coordinates