Watershed algorithm based on morphology for dental X-ray images segmentation

A new watershed algorithm based on mathematical morphology, which can be applied to dental X-ray images segmentation, is proposed in the paper. In order to separate each tooth and improve the serious problem of over-segmentation of traditional watershed algorithm, we apply the processing based on morphology to get the images enhanced before watershed algorithm. First, using the top-hat-bottom-hat transformation to amplify the contrast of foreground and background and remove noises. And then erosion procedure is used to weaken the degree of adhesion between teeth. Hole-filling can help to eliminate some unnecessary split-line which can cause the phenomenon of wrong segmentation. Finally we apply the watershed algorithm using distance transformation of the binary image to get the segmentation result. From the experiment results, we can see that this algorithm can separate teeth accurately and overcome the over-segmentation efficiently compared with traditional method.