Image registration

Process for defining a common reference system in a set of volume data that represents an area of a patient's jaw and that is recorded with an x-ray imaging process, and a set of surface data, at least some of which represents the same area of the patient's jaw and which is recorded with a process for measuring visible surfaces,

• wherein
• the volume data and surface data are integrated on a screen,
• in a prepositioning, an object, especially a tooth, which can be detected both in the volume data and in the surface data, is superimposed as precisely as possible,
• a volume structure that characterizes the object, in particular in the form of an edge image, is extracted from the volume data, and said edge image is superimposed as much as possible by means of a transformation function with a corresponding surface structure of the surface data, and
• the overlap of the volume structure under optimization of a specified quality criterion is matched in iterative steps to the surface structure, and
• wherein for the prepositioning, at least a first reference point is defined on the surface of the object that is depicted in the 3D volume data, in particular on a tooth, and at least a second reference point is defined on at least almost the same place on the surface of the object that is also visible in the 3D surface data, whereby in the prepositioning, the corresponding reference points of the volume data and the surface data are placed on top of one another as much as possible by means of an automatically calculated transformation.

Process for defining a common reference system in a set of volume data that represents an area of a patient's jaw and that is recorded with an x-ray imaging process, and a set of surface data, at least some of which represents the same area of the patient's jaw and which is recorded with a process for measuring visible surfaces, wherein

• the volume data and surface data are integrated on a screen,
• in a prepositioning, an object, especially a tooth, which can be detected both in the volume data and in the surface data, is superimposed as precisely as possible,
• a volume structure that characterizes the object, in particular in the form of an edge image, is extracted from the volume data, and said edge image is superimposed as much as possible by means of a transformation function with a corresponding surface structure of the surface data, and
• the overlap of the volume structure under optimization of a specified quality criterion is matched in iterative steps to the surface structure, and
• wherein after the prepositioning, relative to at least one reference point of the surface data, test points are extracted, whose removal at the respective reference point is smaller than a specified threshold value, whereby the test points form the surface structure.