Low-rank flat-field correction for artifact reduction in spectral computed tomography
Low-rank flat-field correction for artifact reduction in spectral computed tomography
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DOI：
10.1080/27690911.2023.2176000
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发表时间：
2023-12-31
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影响因子：
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通讯作者：
Jorgensen，Jakob Sauer
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作者：
Bangsgaard，Katrine Ottesen;Burca，Genoveva;Jorgensen，Jakob Sauer
近年来，光谱计算机层析成像受到了极大的关注，因为光谱测量包含了关于感兴趣对象的更丰富的信息。在光谱计算机层析成像中，我们感兴趣的是物体的能量通道重建。然而，这样的重建具有低信噪比的缺点，并与传统的低剂量计算机断层扫描(如环形伪影)一样面临挑战。环形伪影产生于平坦场中的错误，并可能显著降低重建质量。我们提出了一种扩展的平场模型，该模型利用谱平场的高相关性来减少通道重建中的环状伪影。扩展的模型依赖于这样的假设，即谱平坦的场可以用低阶矩阵很好地逼近。我们提出的模型直接在光谱平坦场上工作，并可以与任何现有的重建模型相结合，例如滤波反投影和迭代方法。所提出的模型在中子数据集上得到了验证。实验结果表明，该方法有效地消除了环形伪影，提高了重建质量。此外，结果表明，我们的方法是稳健的；它只需要单一的光谱平场图像，而现有的方法需要多个光谱平场图像才能达到类似的环减缩水平。
Spectral computed tomography has received considerable interest in recent years since spectral measurements contain much richer information about the object of interest. In spectral computed tomography, we are interested in the energy channel-wise reconstructions of the object. However, such reconstructions suffer from a low signal-to-noise ratio and share the challenges of conventional low-dose computed tomography such as ring artifacts. Ring artifacts arise from errors in the flat fields and can significantly degrade the quality of the reconstruction. We propose an extended flat-field model that exploits high correlation in the spectral flat fields to reduce ring artifacts in channel-wise reconstructions. The extended model relies on the assumption that the spectral flat fields can be well-approximated by a low-rank matrix. Our proposed model works directly on the spectral flat fields and can be combined with any existing reconstruction model, e.g. filtered back projection and iterative methods. The proposed model is validated on a neutron data set. The results show that our method successfully diminishes ring artifacts and improves the quality of the reconstructions. Moreover, the results indicate that our method is robust; it only needs a single spectral flat-field image, whereas existing methods need multiple spectral flat-field images to reach a similar level of ring reduction.