针对CT金属伪影去除算法中, 如何在图像空间准确定位金属区域问题, 提出一种基于切线反投影重建一幅二值图像的方法对CT图像中金属的位置和形状进行标定。方法首先采用检测器等距扇形束扫描结构采集原始投影数据; 然后配合区域生长的图像分割算法对原始投影数据中金属区域的投影进行分割, 再利用原始投影数据分割的结果, 采用基于切线反投影二值图像重建方法对CT图像中金属的位置和形状进行标定; 最后采用计算机仿真实验对上述方法进行评估。实验结果表明, 上述方法能够准确定位模型中金属的位置和形状。

A new method for accurate determination of the location and shape of metallic object in X-ray computed tomography by a binary image reconstruction technique is proposed. The binary image reconstruction technique used here is based on tangent back-projection(TBP). The proposed method firstly uses geometry of Fan-Beam CT scan to obtain simulated raw sinogram. Next, based on region growing image segmentation, the metal region sinogram is segmented from simulated raw sinogram. The final binary image is reconstructed by TBP. A computer simulation experiment demonstrated the proposed method can accurately determinate the location and shape of metallic object in digital phantom.