CT 滤波伪影。

CT filtration aliasing artifacts.

机构信息

GE Med. Syst., Milwaukee, WI.

出版信息

IEEE Trans Med Imaging. 1991;10(1):99-102. doi: 10.1109/42.75616.

Abstract

Two methods for filtering computerized tomography (CT) projections for the filtered backprojection reconstruction algorithm are evaluated. The methods are based on derivations made in the spatial and Fourier domains. The Fourier method of filtration produces images with DC shifts and low-frequency shading. The spatial method does not generate similar artifacts. It is shown that the artifacts result because of aliasing artifacts that arise when a spatial waveform with infinite extent is sampled in the Fourier domain. It is also shown that it is possible to connect the artifacts generated with the Fourier method by replacing the DC and the first two frequency components with the corresponding terms from the discrete Fourier transforms of the filter used in the spatial method.

摘要

评估了两种用于滤波后向投影重建算法的计算机断层扫描 (CT) 投影滤波方法。这些方法基于在空间域和傅里叶域中的推导。傅里叶滤波方法产生具有直流偏移和低频阴影的图像。空间滤波方法不会产生类似的伪影。结果表明，伪影是由于在傅里叶域中对具有无限幅度的空间波形进行采样时出现的混叠伪影引起的。还表明，可以通过用空间方法中使用的滤波器的离散傅里叶变换的相应项替换傅里叶方法生成的伪影中的直流和前两个频率分量，来连接傅里叶方法生成的伪影。