A method for measuring an X-ray image of an area undergoing medicalexamination thathas at least one object. A 3D model is provided of the area undergoingexamination thatincludes a virtual 3D object to be assigned to the object to be measured, adigitallyreconstructed X-ray picture is computed based on the 3D model and under theassumption of a virtual projection direction, the X-ray image is compared withthe digitallyreconstructed X-ray picture, the virtual projection direction is changedrelative to thevirtual 3D object. The steps of comparing and changing are repeated until avirtualprojection direction with maximum correlation between the X-ray image and thedigitallyreconstructed X-ray picture is found. An object plane is determined that is tobe assignedto the virtual 3D object. A corrected projection direction is defined and theX-ray image ismeasured.
