工业计算机断层成像的分辨率一直是人们关注的焦点。针对空间分辨率由焦点大小主宰的CT系统, 提出了一种虚拟焦点的超分辨图像重建方法。该方法是将实际焦点的强度分布近似看作两个虚拟焦点的强度分布, 再将虚拟焦点近似成理想的点, 利用插值代数重建算法的思想, 在两个虚拟焦点下做正投影计算估计值和残差, 根据像素对每个探测器单元的贡献对像素进行修正。试验证明, 改进的插值代数重建算法可以有效地减少由焦点造成的模糊。

The spatial resolution is one of the key performance parameters of an industry computed tomography(ICT) device. A virtual-focal-spot-based method for high-resolution image reconstruction was proposed. The actual focal spot of X-ray tube into two virtual focal spots was decomposed so that the accumulation of the weighted distributions of the virtual focal spots was approximate to the distribution of the actual focal spot of X-ray tube. Thus, a datum detected by a detector cell could be thought of as the combined contribution from two virtual focal spots. Then high-resolution image by using the improved interpolative algebraic reconstruction technique(IIART) was reconstructed. The validity of the proposed method is verified by numerical experiments.