Automatic Tooth Segmentation and Classification in Dental Panoramic X-ray Images
Abstract Background: The information of tooth shape, type and tooth position plays an important role in the understanding of pathological features in dental X-ray films. It is of great significance to realize the accurate tooth segmentation and tooth classification of dental panoramic X-ray images for the construction of an intelligent dental diagnosis system.At present, the segmentation results of teeth are relatively rough, and most methods realize tooth recognition and segmentation as independent tasks, ignoring the parameter sharing between the two tasks. Therefore, an instance segmentation method which can realize tooth recognition and tooth segmentation at the same time is proposed. Methods: In model designing, the Mask R-CNN, an instance segmentation model , is adopted, which includes classification branches and segmentation branches. The classification branch can be used to complete the tooth recognition task and the segmentation branch to complete the tooth segmentation task. On this basis, the U-Net architecture is integrated to modify the segmentation branch to improve the segmentation effect. In data engineering, two classification schemes are designed, one according to the function of teeth, the other according to the position of teeth. Results: Based on the data of 400 panoramic X-ray films of teeth, we combined migration learning to conduct experiments on the TensorFlow deep learning framework. The experimental results show that compared with other methods, the classification and segmentation of teeth can be realized simultaneously in this paper, with an accuracy of more than 90%. Compared with the original model, the improved Mask R-CNN proposed in this paper improves the segmentation recall rate by 10%. In the proposed classification scheme, the accuracy of classification based on tooth function is 3% higher than that based on tooth position.Conclusions: The model proposed in this paper combines the two tasks of classification and segmentation, avoids the repetitive training of the model, and improves the segmentation precision with the improved segmentation branch. Compared with the recall rate traditional methods of tooth function classification, the proposed method based on tooth function has better classification effect.