A device may include a display system including at least one of a mirror and a video system including a camera and a screen configured to return to a user positioned in front of the camera, an image acquired by the camera. The device may also include: a first polarizing system configured to polarize in a first direction light emitted by a light source; a second polarizing system configured to polarize in a second direction light received by the mirror or the camera; a mechanism configured to vary an angular offset between the first and second directions; and an angular-offset identifier system configured to identify at least three different angular offsets.