(a) 3D LC-OCT image of human skin in vivo , represented in slice view and (b) averaged intensity profile R (z ), showing mean linear regression fit of each skin layer (epidermis – red, dermis – blue) and a corresponding pairs of observables (\(\rho^{\text{epi}},\ µ_{\text{eff}}^{\text{epi}}\) and\(\rho^{\text{der}},\ µ_{\text{eff}}^{\text{der}}\)). Dermal layer parameter \(\rho^{\text{der}}\) deduced from the intercept with basal membrane (z = ~150 µm) and corrected from epidermal layer attenuation.