Computer-assisted Diagnosis and Monitoring of Periodontal Diseases

In the diagnosis of periodontal diseases, Digital Subtraction Radiography ( DSR) is often used. A pair of dental radiographs is tak en a few months apart. The difference between the two radiographs can be used as a basis for diagnosis. Ev en though the radiographs are in digital form, the alignment process to ensure an exact match between the two radiographs is done manually . Furthermore, there would be mismatch in exposure that affects the substraction and hence diagnosis results. The mismatch is simply ignored in the manual process. We propose a DSR sy stem with computer-assisted alignment; and exposure compensation. In this paper, we focus on the exposure compensation technique that is based on the modified Generaliz ed Fuz z y Operator and least squares method.