Characterizing, measuring, and utilizing the resolution of CT imagery for improved quantification of fine-scale features
Characterizing, measuring, and utilizing the resolution of CT imagery for improved quantification of fine-scale features
复制标题
DOI：
10.1016/j.nimb.2013.08.064
复制
发表时间：
2014-04-01
影响因子：
1.3
通讯作者：
Hildebrandt, Jordan
中科院分区：
文献类型：
--
作者：
Ketcham, Richard A.;Hildebrandt, Jordan
从计算机断层扫描（CT）数据集提取的定量结果应在不同分辨率之间以及不同仪器和实验室组之间相同。尽管扫描仪和数据处理方法和工具以及利用它们的科学研究激增，但相对较少强调确保这些结果具有可比性或可重复性。当被成像和测量的特征具有与数据体素相同的数量级大小时，这个问题特别相关，通常是裂缝孔径、孔喉和细胞壁的情况。我们已经创建了一个工具，通过其点扩散函数（PSF），便于量化的CT数据的空间分辨率，其中用户绘制一个穿越两种材料之间的尖锐界面和高斯PSF拟合到该界面的模糊。几何校正考虑了体素形状和到界面的横向角度，其不需要正交。我们使用该工具来调查一系列的网格幻影扫描在不同的条件下，并观察如何PSF内和切片之间的变化。PSF随着切片内径向距离的增加而增加，并且可以在利用相对较少的投影采集的CT数据集中随着径向距离的增加而切向地增加。当使用2-D探测器时，CT切片之间的PSF类似于切片内的PSF，但是当使用准直线性探测器阵列一次一个切片地采集数据时，PSF要尖锐得多。这里描述的功能不仅可以用于校准使用反卷积操作的处理算法，而且还可以帮助在CT研究组内部和之间以及关于正在测量的图像内的特征的常规基础上评估扫描。(C)© 2014 Elsevier B. V.保留所有权利。
Quantitative results extracted from computed tomographic (CT) data sets should be the same across resolutions and between different instruments and laboratory groups. Despite the proliferation of scanners and data processing methods and tools, and scientific studies utilizing them, relatively little emphasis has been given to ensuring that these results are comparable or reproducible. This issue is particularly pertinent when the features being imaged and measured are of the same order size as data voxels, as is often the case with fracture apertures, pore throats, and cell walls. We have created a tool that facilitates quantification of the spatial resolution of CT data via its point-spread function (PSF), in which the user draws a traverse across a sharp interface between two materials and a Gaussian PSF is fitted to the blurring across that interface. Geometric corrections account for voxel shape and the angle of the traverse to the interface, which does not need to be orthogonal. We use the tool to investigate a series of grid phantoms scanned at varying conditions and observe how the PSF varies within and between slices. The PSF increases with increasing radial distance within slices, and can increase tangentially with increasing radial distance in CT data sets acquired with relatively few projections. The PSF between CT slices is similar to that within slices when a 2-D detector is used, but is much sharper when the data are acquired one slice at a time with a collimated linear detector array. The capability described here can be used not only to calibrate processing algorithms that use deconvolution operations, but it can also help evaluate scans on a routine basis within and between CT research groups, and with respect to the features within the imagery that are being measured. (C) 2014 Elsevier B.V. All rights reserved.