Precise Analysis of Spectral Reflectance Properties of Cosmetic Foundation

The present paper describes the detailed analysis of the spectral reflection properties of skin surface with make-up foundation, based on two approaches of a physical model using the Cook-Torrance model and a statistical approach using the PCA. First, we show how the surface-spectral reflectances changed with the observation conditions of light incidence and viewing, and also the material compositions. Second, the Cook-Torrance model is used for describing the complicated reflectance curves by a small number of parameters, and rendering images of 3D object surfaces. Third, the PCA method is presented the observed spectral reflectances analysis. The PCA shows that all skin surfaces have the property of the standard dichromatic reflection, so that the observed reflectances are represented by two components of the diffuse reflectance and a constant reflectance. The spectral estimation is then reduced to a simple computation using the diffuse reflectance, some principal components, and the weighting coefficients. Finally, the feasibility of the two methods is examined in experiments. The PCA method performs reliable spectral reflectance estimation for the skin surface from a global point of view, compared with the model-based method.