APPARATUS AND METHOD FOR DETERMINING A SKIN PARAMETER VALUE

According to an aspect, there is provided a method for determining a value of a skin parameter for skin of a subject. The method comprises receiving (510) a first sensor signal that is output by a first light sensor that is arranged to receive light emitted by a first light source after interaction of the emitted light with the skin. The first sensor signal is output while the first light source operates according to a first duty cycle to intermittently emit the light, and the emitted light has a first central wavelength. The method also comprises receiving (520) a first modulation reference signal that is related to the first duty cycle; integrating (530) a first function output signal, resulting from a function of the first sensor signal and the first modulation reference signal, to determine a first integrated value; determining (540) a first number of cycles of the emitted light that are required for the first integrated value to exceed a first threshold value; and determining (550) the value of the skin parameter based on the determined first number of cycles.