Abstract: An occupant monitoring system for a vehicle comprises: a first light source to generate first infrared (IR) light illuminating at least part of the body of an occupant of a vehicle, wherein the first light source is time modulated with a duty cycle; an IR reflective surface to reflect second IR light reflected from the body of the occupant; and a first IR camera to receive at least part of the second IR light reflected by the IR reflective surface, wherein the first IR camera is time modulated with the duty cycle of the first light source.