Comparison of methods for suppressing edge and aliasing artefacts in iterative x-ray CT reconstruction
Comparison of methods for suppressing edge and aliasing artefacts in iterative x-ray CT reconstruction
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DOI：
10.1088/0031-9155/51/7/017
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发表时间：
2006-04-07
影响因子：
3.5
通讯作者：
Beekman, FJ
中科院分区：
文献类型：
--
作者：
Zbijewski, W;Beekman, FJ
利用迭代重建（IR）获得的X射线CT图像可能受到所谓的边缘和混叠伪影的阻碍，这些伪影表现为干涉图案和急剧强度过渡区域中的严重过冲。以前，我们已经证明，这些文物是由离散化误差在IR的投影模拟步骤。虽然这些错误是固有的IR，他们可以充分抑制重建的图像网格，比通常用于分析方法，如过滤反投影更精细。可以防止边缘伪影的两种其他方法是：（i）在重建之前平滑投影或（ii）使用不同于体素的图像表示;球对称Kaiser-Bessel函数是这种表示的经常采用的示例。在本文中，我们比较了重建与上述两种替代战略的边缘伪影减少一个细网格。我们表明，使用细网格的结果在一个更充分的抑制文物比平滑的投影或使用凯撒-贝塞尔图像表示。
X-ray CT images obtained with iterative reconstruction (IR) can be hampered by the so-called edge and aliasing artefacts, which appear as interference patterns and severe overshoots in the areas of sharp intensity transitions. Previously, we have demonstrated that these artefacts are caused by discretization errors during the projection simulation step in IR. Although these errors are inherent to IR, they can be adequately suppressed by reconstruction on an image grid that is finer than that typically used for analytical methods such as filtered back-projection. Two other methods that may prevent edge artefacts are: (i) smoothing the projections prior to reconstruction or (ii) using an image representation different from voxels; spherically symmetric Kaiser-Bessel functions are a frequently employed example of such a representation. In this paper, we compare reconstruction on a fine grid with the two above-mentioned alternative strategies for edge artefact reduction. We show that the use of a fine grid results in a more adequate suppression of artefacts than the smoothing of projections or using the Kaiser-Bessel image representation.