Dimensional Quantification of Embedded Voids or Objects in Three Dimensions Using X-Ray Tomography

Abstract

Scientific digital imaging in three dimensions such as when using X-ray computed tomography offers a variety of ways to obtain, filter, and quantify data that can produce vastly different results. These opportunities, performed during image acquisition or during the data processing, can include filtering, cropping, and setting thresholds. Quantifying features in these images can be greatly affected by how the above operations are performed. For example, during binarization, setting the threshold too low or too high can change the number of objects as well as their measured diameter. Here, two facets of three-dimensional quantification are explored. The first will focus on investigating the question of how many voxels are needed within an object to have accurate geometric statistics that are due to the properties of the object and not an artifact of too few voxels. These statistics include but are not limited to percent of total volume, volume of the individual object, Feret shape, and surface area. Using simple cylinders as a starting point, various techniques for smoothing, filtering, and other processing steps can be investigated to aid in determining if they are appropriate for a specific desired statistic for a real dataset. The second area of investigation is the influence of post-processing, particularly segmentation, on measuring the damage statistics in high purity Cu. The most important parts of the pathways of processing are highlighted.

Pore Characteristics and Their Effects on the Material Properties of Foamed Concrete Evaluated Using Micro-CT Images and Numerical Approaches

“…Here, the pore distributions within foamed concrete samples are described using X-ray micro-computed tomography (micro-CT), which is a nondestructive method. From the micro-CT, a set of 2D images of a sample with pixel sizes in the micrometer range can be produced by X-rays without damaging the specimen [18,19]. To classify the pores and the specimen, the image processing of converting the original CT images into binary images is utilized.…”

X-ray CT imaging and finite element computations of the elastic properties of a rigid organic foam compared to experimental measurements: insights into foam variability

“…The number of cells in the 2.72 lm/pixel image was still adequate for proper representation of the foam while giving thicker and more intact cell walls. This 3D structure was analyzed using a dedicated software developed in-house [43,44] based on a watershed algorithm to patch the broken cell walls, identify closed cells, and construct a histogram of cell size distribution, similar to that reported in Schlimper et al [45]. The ''size'' parameter used was the volume-equivalent spherical diameter (VESD), which is defined as the diameter of a sphere with volume equal to that of the particle being studied, in this case a single closed cell.…”

Three dimensional subsurface elemental identification of minerals using confocal micro-X-ray fluorescence and micro-X-ray computed tomography

“…These images are then mathematically reconstructed to yield a stack of 2D images, which can be rendered in 3D using visualization software. Such 3D images obtained disciplines, such as geoscience [17], for the imaging of embedded features; material science, for the imaging of void structures within polymer foams [18,19]; in paleontology, for the imaging of fossilized embryos [20]; and in mineral processing, for mineral exposure [21] and liberation [22,23] analysis. A disadvantage of micro-CT is that it does not yield specific elemental information (which can be obtained from confocal MXRF); however, high absorption particles embedded in a low absorption matrix can easily be detected based on regions of concentrated high grayscale values.…”