IEEE Trans Image Process. 2017 Mar;26(3):1441-1451. doi: 10.1109/TIP.2017.2651370. Epub 2017 Jan 16.
In computed tomography (CT), motion and deformation during the acquisition lead to streak artefacts and blurring in the reconstructed images. To remedy these artefacts, we introduce an efficient algorithm to estimate and correct for global affine deformations directly on the cone beam projections. The proposed technique is data driven and thus removes the need for markers and/or a tracking system. A relationship between affine transformations and the cone beam transform is proved and used to correct the projections. The deformation parameters that describe deformation perpendicular to the projection direction are estimated for each projection by minimizing a plane-based inconsistency criterion. The criterion compares each projection of the main scan with all projections of a fast reference scan, which is acquired prior or posterior to the main scan. Experiments with simulated and experimental data show that the proposed affine deformation estimation method is able to substantially reduce motion artefacts in cone beam CT images.
在计算机断层扫描（CT）中，采集过程中的运动和变形会导致重建图像中的条纹伪影和模糊。为了纠正这些伪影，我们引入了一种有效的算法，直接在锥形束投影上估计和校正全局仿射变形。所提出的技术是数据驱动的，因此不需要标记和/或跟踪系统。证明了仿射变换与锥形束变换之间的关系，并将其用于校正投影。通过最小化基于平面的不一致性准则，为每个投影估计描述垂直于投影方向的变形的变形参数。该准则将主扫描的每个投影与在主扫描之前或之后获取的快速参考扫描的所有投影进行比较。使用模拟和实验数据的实验表明，所提出的仿射变形估计方法能够显著减少锥形束 CT 图像中的运动伪影。
