Multisensor Support of Computer-aided Dentistry
The possible benefits from the use of machine-processed work pieces in dentistry are numerous. Among them are the reproducible properties of bulk industrial material and feasibility of on-line quality control. For the production of an inlay, for example, the main problems are the acquisition of 3D-data from the cavity and the processing of this data set into an accurate description of a suitable work piece, which is to be sent to a CAM device. In this paper, we describe a possible realization of these concepts. 3D data can be obtained from one or more laser light-sectioning sensors, and be complemented with an ordinary video image from a CCD-camera. With a matching algorithm, several semi-3D views of the cavity from the LSS can be combined into a single truly three-dimensional data set, which has no defects due to shading any more. Using methods from classical image processing, relevant features of the data, in particular edges, are extracted and completed. Once the remaining parts of the chewing surface are so identified, its missing regions can be reconstructed with techniques from interpolation and finite element theory. A model of the inlay then results as the difference image between the completed and the originally measured surfaces. Examples of (intermediate) results of this design process are presented.
KeywordsDifference Image Light Line Dental Technician Light Section Finite Element Theory
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