Measurement of Optical Properties of Human Skin

In order to predict the skin colors, we need to analyze the reflection spectra of the skins. For the diffuse reflection, it is essential to know the skin optical properties that describe the propagation of light in the skin. We measure the absorption coefficient μ_a, scattering coefficient μ_s, scattering phase function p(θ) and refractive index n of human skins in this study. We attempt to build a measurement system which can accurately measure the optical properties of the skin samples with a size of as small as 5 mm and a thickness of as thin as 50 micrometer in the visible wavelength range with the wavelength step of 50 nm. Then we measured the optical properties of stratum corneum obtained from a cultured model of human epidermis and those of epidermis obtained from human skin. The effect of the exposure of epidermis to sunlight on the optical properties is discussed.