HAIR TREATMENT DEVICE HAVING A LIGHT-BASED HAIR DETECTOR

摘要

A hair treatment device is provided comprising a light-based detector (10) for detecting a hair (11) near a skin (12) surface. The light-based detector comprises a light source (13) for emitting optical radiation of at least a first wavelength and with an incident polarization towards the skin surface. A light sensor (14a, 14b) is provided for detecting light reflected at the skin surface. The light sensor (14a, 14b) is capable of separately detecting he reflected light with the incident polarization and with a different polarization and for providing a PP value representing the detected light with the incident polarization and a CP value representing the detected light with the different polarization. A processor (15) is operative to scale the CP value and the PP value to respective dynamic ranges, to determine a Minimum Intensity Projection (MIP) value by selecting the lowest value of the scaled CP value and the scaled PP value and to discriminate between the skin surface (12) and the hair (11) based on the minimum intensity projection.