The present invention relates to an X-ray radiograph apparatus (10). It is described to placing (110) an X-ray source (20) relative to an X-ray detector (30) to form an examination region for the accommodation of an object, wherein, a reference spatial coordinate system is defined on the basis of geometry parameters of the X-ray radiography apparatus. A camera (40) is located (120) at a position and orientation to view the examination region. A depth image of the object is acquired (130) with the camera within a camera spatial coordinate system, wherein within the depth image pixel values represent distances for corresponding pixels. A processing unit (50) transforms (140), using a mapping function, the depth image of the object within the camera spatial coordinate system to the reference spatial coordinate system, wherein, the camera position and orientation have been calibrated with respect to the reference spatial coordinate system to yield the mapping function that maps a spatial point within the camera spatial coordinate system to a corresponding spatial point in the reference spatial coordinate system. A synthetic image is generated (150) within the reference spatial coordinate system. The synthetic image is output (160) with an output unit (60).
