The invention relates to a measurement by means of atom interferometry, using a Raman source that is created by modulating a monochromatic laser source. The face of the subject is illuminated under different illumination conditions, and images of the subject are obtained for each different illumination condition. The upper body and base unit are connected with a tilting joint such that the upper body is tiltable relative to the base unit about a tilt axis that extends horizontally when the upright vacuum cleaner is in a position of use. This arrangement enables the ends of the filter mat to be welded together in a strong and long-lasting manner.