1. Scanning device for scanning an object, comprising: a projection unit for projecting an alignment image onto the object, said alignment image comprising a main pattern; an image capturing unit for capturing a live camera image of the object, said live camera image comprising a derivative pattern of the main pattern, the derivative pattern being derived from said main pattern and representing said projected alignment image as seen from the image capturing unit viewpoint; a process for processing the captured live camera image, the processor having an alignment unit for providing an indication of a correct position and/or orientation of the scanning device with respect to the scanned object on the basis of the captured live camera image, wherein the projection unit is configured to project a static main pattern, and wherein the alignment unit is a superposition unit configured to update the alignment image by superimposing the captured live camera image and the static main pattern, said updated alignment image indicating the correct position and/or orientation of the scanning device with respect to the scanned object, if the static main pattern and the derivative pattern substantially coincide in the updated alignment image.