A method for measuring an X-ray image of an area undergoing medical examination that has at least one object. A 3D model is provided of the area undergoing examination that includes a virtual 3D object to be assigned to the object to be measured, a digitally reconstructed X-ray picture is computed based on the 3D model and under the assumption of a virtual projection direction, the X-ray image is compared with the digitally reconstructed X-ray picture, the virtual projection direction is changed relative to the virtual 3D object. The steps of comparing and changing are repeated until a virtual projection direction with maximum correlation between the X-ray image and the digitally reconstructed X-ray picture is found. An object plane is determined that is to be assigned to the virtual 3D object. A corrected projection direction is defined and the X-ray image is measured.
