IDEFIX Identi cation of dental xtures in intraoral X rays

In dental implantology more than one hundred enossal implant systems are in use. Once embedded, the dental X{ray examination is the most important tool for determing implants' producer, name, and type. In this paper, we present a system for automatical detection and identiication of dental xtures in intraoral X rays (IDEFIX) combining common direct digital image acquisition techniques with specially designed image analysis. IDEFIX can process any digital radiograph (e.g. RVG, Sens-A-Ray, Schick, Sidexis, Digora) as well as digitized dental lms. A reference database has been generated by precise measurement on the implant systems used so far (eight implants) including parameters like length, diameter, and cross section area. After binarization of the current digital X{ray image, a parameter set is extracted from each detected object applying mathematical morphology. All objects are classiied using a simpliied nearest neighbor method and the Euclidean distance metric. If the distance of the objects' parameter set to one of the reference sets is below a given threshhold, name and type of the identiied dental xture are displayed on the screen. Otherwise, the actual object will be rejected as a non{implant. IDEFIX has been evaluated by processing various in{vitro acquired radiographs. Diierent implants were classiied captured with identical conditions as well as acquired varying the angulation of the X{ray tube. It is shown that misangulations up to twenty degree are tolerable preserving correct identiication. Other image structures like teeth or llings result in large distances to all reference parameter sets and therefore, they are reliably recognized as non{implants.