A method is provided for operating a position detection arrangement. An optical unit is also provided for a position detection arrangement. A position detection arrangement is also provided for a head position of a driver. An optical unit includes at least one light source providing backlight directed to the driver and a mask device for blocking the light of the at least one light source when being arranged in an optical path between the at least one light source and the driver's head position. A manipulator device is provided for accomplishing a relative movement between the at least one light source and a blocking member of the mask device. A computing unit is coupled to the optical unit for capturing a distance between at least one of (a) two or more dedicated light-source positions, and (b) two or more dedicated blocking member positions, and/or for calculating a position of the driver's head based on an angle between the positions and the driver's head position.
