Vorrichtung und Verfahren zur Bestimmung der Lage der Projektion der Rotationsachse eines Computer-Tomographie-Systems auf dessen Detektoreinheit

The description relates to a device for determining and controlling the relative position and diameter of a focal point of an X-ray tube and a device for determining the position of the projection of the rotary axis of a rotary table on a detector system. The invention is characterized by the fact that at least one object is projected onto at least one detector by at least one bundle of rays, that the intensity distribution of the projection is digitized and is corrected by a shading function, and as a result the relative position and the diameter of the focal point is determined by a least-square fit. The position of the projection of the rotary axis on the detector system is determined from two projection of an object rotated through 180 degrees and the geometric magnification. This device permits high-speed, highly precise and reproducible measurements, in particular for applicatioin in X-ray computer tomography.