牙颌CT图像序列中牙的半自动分割方法

牙颌CT图像序列相邻切片之间,相应牙的大小、位置以及牙区域和轮廓的灰度分布等特征比较接近,并呈一定的变化规律,根据这一特点提出了牙颌CT图像序列中牙的半自动分割方法。首先选取参考切片,加入少量用户操作进行参考切片中牙轮廓的提取,接着以参考切片为起始切片,由已完成轮廓提取的牙包围盒作为待处理切片(相邻切片)相应牙的操作区间,然后在此区间内用区域生长法提取牙轮廓,由此逐张切片处理可以自动地得到所有切片全牙列每颗牙的轮廓。实验结果表明,本方法仅需少量用户交互就能快速、基本准确地从牙颌CT图像序列中分割出牙轮廓,具有一定的实用价值。

A Semi-automatic Method for Tooth Segmentation in Dental CT Images

To reconstruct a tooth model from CT slices,we need to define the accurate contour of each tooth from CT slices.In this paper,we propose a semi-automatic method for drawing the contours of teeth in dental CT images.First of all,we select the reference slice from CT slices and carry out tooth segmentation interactively based on shape characteristic of each tooth.The dental CT images have the following distinct characteristic: in two neighboring CT slices,the size,location and intensity of corresponding tooth is very similar,so we can project the bounding box of the tooth whose contour has been drawn onto the next slice as the operation region of corresponding tooth.And then we perform segmentation operation tooth by tooth in the operation region based on the region growing algorithm using the information passed from the previous slice.With the reference slice as the starting slice,we carry out tooth segmentation slice by slice like this way automatically.The test result shows that the proposed method can detect the contours of teeth quickly and reliably with only little user intervention and it has practical value.