锥束X-射线CT投影数据的仿真

Simulation of Projection Data for Cone X-ray CT

研究CT图像优化问题,针对提高精确性和有效性,传统的解析方法很难应用于几何形状比较复杂的物体。为了提高CT图像重建精度,提出从离散化图像的Radon变换,推导出一种模拟X-射线投影数据的模型,并提出采用模型的快速计算方法。模型不受物体内部几何形状和扫描轨迹限制,用于数字化灰度图像。利用上述方法对三维SHEPP-LOGAN模型的投影数据进行仿真,并对得到的数据采用OS-EM算法进行重建。结果表明,提高了图像精度,进一步验证了方法的有效性。

Accurate and efficient simulation of projection data for x-ray CT plays an important role for the evaluation and improvement of CT image reconstruction algorithms.However,the traditional analytical method is difficult to apply more complex geometric shapes of objects.In this paper,we derive a model for the simulation of projection data form Radon transform of discrete image.And in the implementation of this model,we propose a fast computed method.This model is not restricted by the internal geometry of the object and scanning trajectory and it is adapted to any digital gray image.The projection data of 3-D Shepp-Logan are simulated using the proposed method.Based on the data,images are reconstructed by using OS-EM algorithm.Comparing the reconstructed images with the original ones,we can conclude that the reconstructed results are accurate and the simulation method of projection data is feasible.