arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2203.01045math.NAcs.NAstat.AP
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不确定几何条件下CT重建的贝叶斯方法

A Bayesian Approach to CT Reconstruction with Uncertain Geometry

Frederik H. Pedersen, Jakob S. Jørgensen, Martin S. Andersen

摘要:

计算机断层摄影是一种用于从投影集合合成对象的体积或横截面图像的方法。计算机断层扫描的流行重建方法是基于理想化的模型和假设,在实践中可能是无效的。一个这样的假设是精确的投影几何形状是已知的。投影几何描述了每个投影的辐射源、对象和检测器的相对位置。然而,在实践中,用于描述辐射源、对象和检测器的位置和取向的几何参数是具有不确定性的估计量。未能准确估计几何形状可能导致重建时出现严重的未对准伪影,从而显著降低其科学或诊断价值。我们提出了一种新的重建方法,联合估计重建和投影几何。重建方法是基于贝叶斯方法,产生重建和几何参数的点估计,此外,还提供了有关其不确定性的有价值的信息。这是通过使用分层吉布斯采样器从重建和投影几何的联合后验分布中近似采样来实现的。使用真实的断层数据,我们证明了所提出的重建方法显着减少错位文物。与两种常用的对齐方法相比,我们提出的方法在具有挑战性的条件下取得了相当或更好的结果。

英文摘要:

Computed tomography is a method for synthesizing volumetric or cross-sectional images of an object from a collection of projections. Popular reconstruction methods for computed tomography are based on idealized models and assumptions that may not be valid in practice. One such assumption is that the exact projection geometry is known. The projection geometry describes the relative location of the radiation source, object, and detector for each projection. However, in practice, the geometric parameters used to describe the position and orientation of the radiation source, object, and detector are estimated quantities with uncertainty. A failure to accurately estimate the geometry may lead to reconstructions with severe misalignment artifacts that significantly decrease their scientific or diagnostic value. We propose a novel reconstruction method that jointly estimates the reconstruction and the projection geometry. The reconstruction method is based on a Bayesian approach that yields a point estimate for the reconstruction and geometric parameters and, in addition, provides valuable information regarding their uncertainty. This is achieved by approximately sampling from the joint posterior distribution of the reconstruction and projection geometry using a hierarchical Gibbs sampler. Using real tomographic data, we demonstrate that the proposed reconstruction method significantly reduces misalignment artifacts. Compared with two commonly used alignment methods, our proposed method achieves comparable or better results under challenging conditions.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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