Resolution-invariant measurements of small objects in polychromatic CT data
Resolution-invariant measurements of small objects in polychromatic CT data
复制标题
多色 CT 数据中小物体的分辨率不变测量
DOI：
10.1117/12.2532082
复制
发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Ketcham, Richard A.
中科院分区：
文献类型：
--
作者：
Ketcham, Richard A.
当颗粒、孔隙或裂纹等特征相对于数据分辨率较小时，在CT数据中准确测量这些特征具有挑战性，其特征为点扩散函数（PSF）。当与分割配对时，这些挑战尤其严重，因为PSF将来自体素的一些信号分布在相邻体素中;有效地将来自给定对象的一些信号分散到其外部的区域。任何具有PSF量级的一维或多维的感兴趣特征都将受到这种效应的影响，并且基于全局阈值的测量必然失败。相同特征的测量在不同仪器和数据分辨率下应保持一致。PVB（部分体积和模糊）方法通过基于衰减异常量化所有三维中的小特征来成功地进行补偿。通过校准感兴趣相位（在这种情况下，金）的CT数，可以在相隔14年的两台仪器上采集的数据中准确测量<6体素的粒子，尽管存在严重的伪影。总的来说，PVB方法是准确的，可重复的，分辨率不变的，和客观的，它也是值得注意的，其有利的误差结构。主要的挑战是需要有代表性的有效CT数，这不仅反映了感兴趣的特征本身，而且还反映了X射线光谱，尺寸，形状和封闭样品的组成，以及处理细节，如射束硬化校正。经验校准是最有效的方法。
Features such as particles, pores, or cracks are challenging to measure accurately in CT data when they are small relative to the data resolution, characterized as a point-spread function (PSF). These challenges are particularly acute when paired with segmentation, as the PSF distributes some of the signal from a voxel among neighboring ones; effectively dispersing some of the signal from a given object to a region outside of it. Any feature of interest with one or more dimensions on the order of the PSF will be impacted by this effect, and measurements based on global thresholds necessarily fail. Measurements of the same features should be consistent across different instruments and data resolutions. The PVB (partial volume and blurring) method successfully compensates by quantifying features that are small in all three dimensions based on their attenuation anomaly. By calibrating the CT number of the phase of interest (in this case, gold) it is possible to accurately measure particles down to <6 voxels in data acquired on two instruments, 14 years apart, despite severe artifacts. Altogether, the PVB method is accurate, reproducible, resolution-invariant, and objective; it is also notable for its favorable error structure. The principal challenge is the need for representative effective CT numbers, which reflect not only the features of interest themselves, but also the X-ray spectrum, the size, shape and composition of the enclosing sample, and processing details such as beam-hardening correction. Empirical calibration is the most effective approach.
DOI：
10.1029/2018jb017083
发表时间：
2019-04
期刊：
Journal of Geophysical Research: Solid Earth
影响因子：
--
作者：
R. Ketcham;A. Mote
通讯作者：
R. Ketcham;A. Mote
DOI：
10.1016/j.nimb.2013.08.064
发表时间：
2014-04-01
影响因子：
1.3
作者：
Ketcham, Richard A.;Hildebrandt, Jordan
通讯作者：
Hildebrandt, Jordan