Visualization of the human face skin moisturizing ability by spectroscopic imaging using two near-infrared bands

Abstract

The skin's ability to retain moisture, which is hereafter referred as skin moisturizing-ability, is one of the important factors in skin health. Skin defends the biological tissue from the outside influences, skin sebum and moisture especially play an important role in that protection. The sebum and moisture meters available on the market, however, need to contact with skin. As a non-contact method, near-infrared (NIR) spectroscopic imaging, using absorption of the OH stretching overtone, has recently been capable of detecting changes in skin hydration of the forearms. However, face skin hydration has not been measured, and the moisture-related sebum has not been paid attention to, even though the face is important from the cosmetic and medical point of view. This study, therefore, aims to measure and visualize the spatial distribution of moisturizing-ability of the face skin by NIR spectroscopic imaging. The NIR spectral imaging system consists of two interference filters (1060 nm and 1450 nm) mounted on a filter wheel and a NIR camera with indiumgallium arsenide array sensor. We measured human face skins with/without moisturizing lotion and found that the glabella and nose have strong moisturizing-ability because of sebaceous glands. It was also shown that the areas where moisturizing lotion was applied were successfully displayed by subtracting two absorbance images measured at different wavelength bands. This technique can be applied to the functional assessment of face skin moisturizer in medicine and cosmetics.