Fig. 11.

(a) The product of epidermal thickness and absorption coefficient as a function of wavelength estimated by the present model. An epidermal thickness $d_1$ of 70 µm and epidermal scattering coefficient ${\mu }_{s,1}^{\prime }$ of $1{\mathrm{mm}}^{-1}$ were assumed. (b) Melanin index ${\mathrm{MI}}_i$ predicted by a homogeneous model and the present two layer model.