Marker projection device

In the disclosure, a marker projection device (100) for use in an augmented-reality system is described. The marker projection device (100) comprises a control unit that receives depth information data indicative of distances to surfaces (202A-C, 204, 206) in the environment of the marker projection device (100) and a marker image indicative of a visual appearance of a fiducial marker. Furthermore, the control unit is configured: to identify one or more potential projection surfaces (202A-C, 204, 206) in the environment using the depth information data; to select one (202B) of the one or more potential projection surfaces; to determine a projection angle (220A, 220B) for the selected projection surface; and to generate, using the depth information data and the projection angle for the selected projection surface, a projection image comprising an adapted marker image, wherein the control unit is configured to generate the adapted marker image by transforming the marker image such that geometrical proportions of the visual appearance of the fiducial marker are preserved when projected on the selected projection surface (202B). In addition, the marker projection device (100) comprises an optical projection unit that receives the projection image and is configured to generate a light projection according to the projection image.