X-ray system for the iterative determination of an optimal coordinate transformation between overlapping volumes that have been reconstructed from volume data sets of discretely scanned object areas.

摘要

The invention relates to an X-ray system for obtaining referencing information in the form of a coordinate transformation between a first volume and a second volume, the volumes partially overlapping. Two partially overlapping partial areas of an extended object with a continuous distribution of a physical quantity are discretely scanned with a measuring apparatus, the volumes are reconstructed and the overlapping volumes are iteratively changed, a bandpass being applied to the overlapping volumes, which changes the Fourier space representations of the overlapping volumes. The filtered overlap volumes, in which the artifacts caused by the discrete scanning are matched to one another in the overlapping partial areas, are compared by means of a similarity measure, which is iteratively maximized by means of mathematical optimization. The coordinate transformation with the maximum result for the degree of similarity is used as the optimal coordinate transformation for joining the two volumes in the correct position. One application is the joining of 3D X-ray volumes that have been reconstructed using a cone-beam computer tomograph, preferably a 3D C-arm.