The present invention relates to a system and method for determining at least one vital sign of a subject. To improve the ambient light robustness, said system comprises an illumination unit (2) configured to illuminate a skin region of the subject, said illumination unit comprising a first radiation source (20) and a second radiation source (21), which are configured to emit differently modulated electromagnetic radiation in two or more wavelength channels and/or in two or more polarization channels, a detection unit (4) configured to detect electromagnetic radiation reflected from the skin region of the subject and to generate detection signals, a processing unit (11) configured to demodulate the detection signals corresponding to the modulation applied by the illumination unit to obtain demodulated detection signals, and a vital signs determination unit (5) configured to determine, per wavelength or polarization channel, a statistical measure from said demodulated detection signals and to extract a vital sign from said statistical measures.
