A LIGHT-BASED SEBUM AND WATER LEVEL MEASUREMENT SYSTEM FOR SKIN

摘要

The invention provides a measurement system (110) for simultaneous light-based measurement of sebum and water levels in skin (160) using a suitable light source and at least three light intensity detectors to detect the intensity of light reflected (145) from the skin, i.e. a first detector (150) detecting a first light intensity in a first detection wavelength range, a second detector (250) detecting a second light intensity in a second detection wavelength range, and a third detector (350) detecting a third light intensity in a third detection wavelength range. The first, second and third detection wavelength ranges each have a maximum extension of 20 nm, wherein the first detection wavelength range comprises a wavelength for which an absorption coefficient for light of sebum is significantly higher than an absorption coefficient for light of water, the second detection wavelength range comprises a wavelength for which the absorption coefficient for light of sebum and the absorption coefficient for light of water are approximately equal, and the third detection wavelength range comprises a wavelength for which the absorption coefficient for light of water is significantly higher than the absorption coefficient for light of sebum. The measurement system (110) is further configured to determine a first parameter associated with a sebum level and a second parameter associated with a water level of the skin based on the first light intensity, the second light intensity and the third light intensity. By using an optical system for simultaneously measuring both the sebum and the water level in skin, said levels may be determined without or with minimum skin contact at approximately the same position in the skin. Additionally, the simultaneous measurement of water and sebum levels allows a more accurate and faster measurement compared to measurement systems known in the art.